The energy expenditure and substrate oxidation of treadmill running and cycle ergometer exercise in normal-weight vs. overweight and obese men

The energy expenditure and substrate oxidation of treadmill running and cycle ergometer exercise in normal-weight vs. overweight and obese men | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The energy expenditure and substrate oxidation of treadmill running and cycle ergometer exercise in normal-weight vs. overweight and obese men Jingjing Xue, Shuo Li, Tingting Sun, Kongjun Zhang, Ping Hong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9503097/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Backgrounds The purpose of the study was to assess energy expenditure and substrate oxidation to treadmill running (TR) and cycle ergometer (CE) exercise in normal-weight (NW) vs. overweight and obese (OB) men. Methods 27 NW (BMI: 21.2 ± 1.2 kg/m 2 ) and 25 OB (BMI: 27.2 ± 1.3 kg/m 2 ) men were recruited in this study. Each participant completed resting metabolic rate and energy expenditure tests during TR at 7 and 8 km/h and CE at 50 and 100 W by indirect calorimetry. Results Gross VO 2 (L/min) was higher for OB during CE at 100 W ( p < 0.05), and TR at 7 and 8 km/h (both p < 0.01), but lower gross and net VO 2 (all p < 0.01) when the values were adjusted for body mass. While net energy expenditure (kcal/min) was greater for OB group during TR at 7 and 8 km/h (both p < 0.01), but similar in both groups during CE at 50 and 100 W. Gross efficiency was significantly lower in OB during CE at 50 and 100 W (both p < 0.01), but no difference was found in net efficiency. A higher fat oxidation rate was found during CE at 50 and 100 W (both p < 0.05) for OB than the NW. For both NW and OB subjects, fat contribution (%) was greater during CE exercise at 50 W than CE exercise at 100 W. Conclusions These findings showed that OB was less economical and efficient than NW individuals during CE and TR, especially during TR. The obesity, exercise intensity and type all influence substrate oxidation during exercise. energy expenditure net metabolic rate fat oxidation mechanical efficiency cycle ergometer exercise treadmill running Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction The increasing trend in obesity have become a public health issue in China and throughout the world [ 1 , 2 ]. Obesity is associated with cardiovascular diseases, type 2 diabetes mellitus, metabolic diseases, and cancer, leading to an increased risk of death [ 3 – 5 ]. The critical for obesity is greater energy intake than energy expenditure of physical activity (PA). Physical activity and exercise play an important role in managing and losing weight [ 6 – 8 ]. However, many studies revealed that one of the most important contributors to the maintenance of obesity is that obese individuals tend to have more sedentary behavior or insufficient PA [ 9 , 10 ]. Effective weight management requires an accurate exercise prescription of exercise type and intensity, energy expenditure, and substrate metabolism during exercise, and mechanical efficiency characteristics for obese populations. While treadmills and cycle ergometer exercises are popular, convenient, and relatively safe types of exercise, these two modes are commonly used in exercise testing and clinical settings. There is a fundamental difference between these two modes of exercise, cycling is a weight-independent exercise and not influenced by balance and gait issues, which can easily be performed by most people; while treadmill running is weight-dependent and influenced by balance and gait. Several differences in physiological responses to treadmill exercise and cycle ergometer exercise are investigated in normal weight subjects [ 11 , 12 ], and few in overweight and obese individuals [ 13 ], and rarely including comparison between treadmill running and cycle ergometer exercise. In addition, the gross energy cost and net energy cost have been found to be higher in obese individuals during different movements by several researchers [ 13 – 15 ], due to the effect of the greater body mass involved in the physical activity [ 13 , 16 ] or a lower mechanical efficiency [ 17 , 18 ]. Nevertheless, the difference between obese and normal-weight subjects is greatly reduced when the metabolic rate is adjusted for total body weight [ 19 ], which suggests that total body weight may play a role in the energy cost of physical activity. The greater body mass may lead to the reduction of the exercise effectiveness in weight loss programs, further contributing to the maintenance of obesity. It is well known that the dominant fuels oxidized during exercise are carbohydrates (CHO) and free fatty acids, and that the CHO contribution and fat contribution are influenced by exercise type, intensity, as well as duration [ 20 , 21 ]. Maunder et al. showed that obese subjects were found to perform lower maximal rates of fat oxidation during exercise than that of lean counterparts [ 22 ]. Previous studies have shown that [ 23 , 24 ] fat utilization rate is maximal during low intensity exercise (lower than 50%VO 2MAX ) in untrained subjects. Therefore, how to achieve the maximal fat oxidation is also important in the process of body weight management in obesity. Consequently, it’s necessary to understand the differences and the degree of differences of physiological response and energy expenditure in different exercises in obese subjects and normal-weight subjects, which is important for appropriate exercise prescriptions or PA programs for obese subjects. The primary purpose of this study was to compare the energy metabolism (energy cost and substrate oxidation) between normal-weight vs. overweight and obese men. A secondary purpose of this study was to determine the characteristics of energy metabolism during treadmill running and cycle ergometer to provide guidance in the exercise programs or PA prescriptions in clinical for obesity. Materials and Methods Experimental Approach to the Problem To analyze the effects of obesity, exercise type, and intensity on energy expenditure and substrate oxidation, two groups (normal-weight vs. overweight and obese subjects) were recruited. All participants underwent anthropometric data collection, RMR at rest, and energy expenditure testing during CE (50 and 100 W) and TR (7 and 8 km/h). The gross and net metabolic rate, substrate oxidation, and gross and net efficiency data during the same exercise type and intensity were compared between NW and OB groups to identify the effect of obesity on energy expenditure. The gross and net metabolic rate, substrate oxidation, and gross and net efficiency during the different exercise types and intensities were compared in NW and OB to identify the effect of exercise type and intensity on energy expenditure. Subjects 27 Normal-weight (age: 28.3 ± 2.3 years, BMI: 21.2 ± 1.2 kg/m 2 ) and 25 obese men (age: 28.9 ± 2.1 years, BMI: 27.2 ± 1.3 kg/m 2 ) participated in this study. The total sample size needed using power analysis was 73, taking into account the effect size (0.5) seen in similar studies. We recruited 64 male subjects in total, however, 5 normal and 7 obese did not complete all tests. We calculated post-hoc power using power analysis and the sample size in this study provided a strong power (0.8395) to detect the effect we're investigating. All participants were healthy, free of cardiovascular, respiratory, and metabolic diseases and did not have regular physical activity in daily life that could affect their energy metabolism. Inclusion criteria for overweight and obese subjects were BMI ≥ 23 kg/m 2 and 18.5-23 kg/m 2 for the NW subjects, which were in accordance with the WHO classification for Asians [25]. The physical characteristics of all subjects (Mean ± SD) are shown in Table 1. Table1 Physical characteristics of normal-weight vs. overweight and obese subjects NW (n = 27) OB (n = 25) Age (years) 28.3 ± 2.3 28.9 ± 2.1 Height (cm) 174.2 ± 5.0 174.3 ± 6.5 Weight (kg) 64.3 ± 4.8 ** 82.8 ± 7.4 BMI (kg/m 2 ) 21.2 ± 1.2 ** 27.2 ± 1.3 Body Fat Percentage (%) 16.8 ± 2.5 ** 26.8 ± 4.4 RMR (kcal/day） 1877.1 ± 258.1 ** 2185.0 ± 226.9 BMI = Body Mass Index, RMR = Resting Metabolic Rate. ∗∗ p <0.01. Procedures All subjects were asked to arrive at the laboratory in a fasted state before 8:00 am on the test day. Before the exercise energy expenditure measurements, every participant underwent anthropometric measurements and Resting Metabolic Rate (RMR) measurements. All testers in this study were professionally trained and each test project is tested by the same tester. All participants were asked to wear the same comfortable clothes and shoes during each testing session and were motivated to finish their exercise testing. Anthropometric Measures Standing height (m) and body mass (kg) were assessed according to international standards for anthropometric assessment. To evaluate height and body mass, the Su Heng Health Scale (RGZ-120, Jiangsu, China) with precisions of 0.1 cm and 0.1 kg were used, respectively. The BMI was calculated (kg/m 2 ). A bioelectrical impedance analysis composition analyzer (Inbody 770, Biospace Corp., Korea) was used to determine body composition. RMR Measurement After the anthropometric measurements, participants rested supine for 10 min prior to RMR data collection. Steady-state RMR was measured by using indirect calorimetry (Cortex Metamax 3B-R2 metabolic system, Germany) in the supine position for 30 min in a semi-darkened, quiet and controlled environment temperature (22–25 ℃) and humidity (40–50%) room. The RMR was calculated by using the VO 2 and VCO 2 of the steady periods for about 20 min according to the Weir [26] formula. Exercise Energy-Expenditure Tests Measures of exercise energy metabolic rate were performed during TR (7 and 8 km/h) (Rodby RL3500E, Sweden) and CE exercise (50 and 100 W) (Wattbike, England), maintained for 6 min each exercise, by indirect calorimetry (Cortex Metamax 3B-R2 metabolic system, Germany). The system (Cortex Metamax 3B-R2, Germany) was calibrated before each test with standard gases of known oxygen and carbon dioxide concentration. An initial steady state at 5 km/h and 20 W for 3 min was allowed for warming. The treadmill and ergometer were set to operate at a constant speed of 7 and 8 km/h and power of 50 and 100 Watts, respectively. The participants were instructed to perform these exercises according to the workloads of treadmill and ergometer. The saddle and hand bar positions during the ergometer exercise were individually adjusted. Heart rate (HR) was continuously monitored by a wireless heart rate (HR) monitor (Polar H7, Finland). Each exercise test was performed in a randomized order and separated by rest between trials until their HR recovered to a level ± 5% of their resting HRs (at least 5 minutes). Gross VO 2 and VCO 2 output were measured breath-by-breath and averaged over the last 3 steady-state minutes of each test. The net metabolic rate was obtained by subtracting the resting metabolic rate from the gross metabolic rate. Fat and CHO oxidation were calculated from VO 2 and VCO 2 according to equations assuming a nonprotein respiratory quotient. CHO and fat oxidation contributions were estimated by using the following formulas [27]: Fat oxidation (g/min) = 1.695× VO 2 (l/min) - 1.701 × VCO 2 (l/min) Carbohydrate oxidation (g/min) = 4.585 ×VCO 2 (l/min) - 3.226 ×VO 2 (l/min) Mechanical efficiency during CE at different workloads was calculated as gross efficiency and net efficiency as defined by Gaesser and Brooks [28]. Statistical Analyses Statistical analysis was performed by using SPSS software version 26.0 (IBM Corp., Armonk, NY, USA). All data are presented as mean ± SD. Data were checked for normality using the Kolmogorov-Smirnov test. Differences between NW and OB subjects (group differences) in physical characteristics and energy expenditure data were investigated using independent Student’s t tests. A two-way repeated measure ANOVA was used to examine how different exercise type and obesity affected gross VO 2 , net VO 2 , CHO and fat oxidation rate. For all tests, the significance level was set at p < 0.05. Results Table 2 shows the cardiorespiratory and energy expenditure data of NW and OB groups during cycle ergometer exercise and treadmill running. Gross VO 2 (L/min) and gross energy expenditure (kcal/min) of OB during cycle ergometer at 100 W and treadmill running at 7 and 8 km/h, respectively, were greater than those of the NW group (both p < 0.05, both p < 0.01, both p < 0.01), whereas no statistically significant difference in HR and RER was detected between the two groups during any exercise. What’s more, normalization of VO 2 to body weight (ml/kg/min) resulted in obese subjects having a lower gross and net metabolic rates compared to normal-weight subjects during all exercises. The net VO 2 (L/min) and energy expenditure (kcal/min) were greater for the OB group in treadmill running at 7 and 8 km/h compared with their normal-weight counterparts (both p < 0.01) (Table 2, Figure 1B). However, there were no significant differences in net VO 2 (L/min) and net energy expenditure (kcal/min) in the cycle ergometer at 50 and 100 W between the NW and OB groups (Table 2, Figure 1B), indicating that the body-weight involved in running movements may be responsible for the higher energy cost for OB subjects. The HR, gross VO 2 (L/min), net VO 2 (L/min), gross and net VO 2 (ml/kg/min), gross and net VO 2 (ml/kg FFM/min), and gross and net energy expenditure (kcal/min) increased with increasing power output from 50 to 100 W and running speed from 7 to 8 km/h in both NW and OB groups (Table 2, Figure1). Intensity and type of exercise both have a significant effect on the HR, gross and net VO 2 (L/min), gross and net VO 2 (ml/kg/min), gross and net VO 2 (ml/kg FFM/min), and gross and net energy expenditure (kcal/min) in the NW and OB groups. Table 2 Cardiorespiratory and energy expenditure (EE) data of normal-weight vs. overweight and obese subjects. NW (n = 27) OB (n = 25) Cycle ergometer at 50 W HR (b/min) 120.1 ± 15.8 aa 120.3 ± 17.5 bb Intensity (%HR max ) 62.7 ± 8.1 aa 62.9 ± 9.0 bb Gross VO 2 (L/min) 1.07 ± 0.15 aa 1.15 ± 0.16 bb Net VO 2 (L/min) 0.79 ± 0.15 aa 0.84 ± 0.15 bb RER 0.832 ± 0.064 aa 0.805 ± 0.05 bb Gross VO 2 (ml/kg/min) 16.6 ± 2.0 **aa 14.0 ± 2.4 bb Gross VO 2 (ml/kg FFM/min) 20.0 ± 2.7 aa 19.2 ± 3.7 bb Net VO 2 (ml/kg/min) 12.4 ± 2.1 **aa 10.2 ± 2.2 bb Net VO 2 (ml/kg FFM/min) 15.0 ± 2.8 aa 14.0 ± 3.3 bb Cycle ergometer at 100 W HR (b/min) 141.5 ± 20.3 137.0 ± 17.5 Intensity (%HR max ) 73.8 ± 10.5 71.7 ± 9.2 Gross VO 2 (L/min) 1.59 ± 0.18 * 1.71 ± 0.18 Net VO 2 (L/min) 1.32 ± 0.18 1.39 ± 0.18 RER 0.897 ± 0.065 0.864 ± 0.064 Gross VO 2 (ml/kg/min) 24.9 ± 3.17 ** 20.8 ± 2.87 Gross VO 2 (ml/kg FFM/min) 29.9 ± 4.0 28.5 ± 4.6 Net VO 2 (ml/kg/min) 20.65 ± 3.22 ** 16.92 ± 2.70 Net VO 2 (ml/kg FFM/min) 24.9 ± 4.1 23.2 ± 4.2 Treadmill running at 7 km/h HR (b/min) 147.5 ± 21.3 cc 151.4 ± 16.0 dd Intensity (%HR max ) 76.9 ± 11.0 cc 79.2 ± 8.4 dd Gross VO 2 (L/min) 1.84 ± 0.17 **cc 2.19 ± 0.22 dd Net VO 2 (L/min) 1.57 ± 0.17 **cc 1.87 ± 0.21 dd RER 0.843 ± 0.069 0.846 ± 0.051 Gross VO 2 (ml/kg/min) 28.7 ± 2.85 **cc 26.5 ± 2.22 dd Gross VO 2 (ml/kg FFM/min) 34.6 ± 3.7 cc 36.3 ± 3.8 dd Net VO 2 (ml/kg/min) 24.5 ± 2.96 *cc 22.7 ± 2.08 dd Net VO 2 (ml/kg FFM/min) 29.6 ± 3.8 cc 31.1 ± 3.4 dd Treadmill running at 8 km/h HR (b/min) 155.5 ± 20.2 159.4 ± 17.1 Intensity (%HR max ) 81.1 ± 10.5 83.4± 9.0 Gross VO 2 (L/min) 2.02 ± 0.24 ** 2.40 ± 0.20 Net VO 2 (L/min) 1.76 ± 0.25 ** 2.09 ± 0.19 RER 0.847 ± 0.057 0.852 ± 0.057 Gross VO 2 (ml/kg/min) 31.6 ± 3.81 ** 29.1 ± 2.34 Gross VO 2 (ml/kg FFM/min) 38.0 ± 5.0 39.9 ± 4.3 Net VO 2 (ml/kg/min) 27.4 ± 4.01 * 25.3 ± 2.20 Net VO 2 (ml/kg FFM/min) 33.3 ± 5.2 34.7 ± 3.9 * p < 0.05 compared with the same data between NW and OB; ** p < 0.01 compared with the same data between NW and OB; aa p < 0.01 CE at 50 vs. 100 W in NW group; bb p < 0.01 CE at 50 vs. 100 W in OB group; cc p < 0.01 TR at 7 vs. 8 km/h in NW group; dd p < 0.01 TR at 7 vs. 8 km/h in OB group. **Table 2 about here** The results of the two-way ANOVA are shown in Table 3 for the energy expenditure data. While different types of exercise appear to have a significant effect on gross and net VO 2 (ml/kg/min) and fat and CHO oxidation rate (without interactions with obesity). Obesity has significant effects on gross and net VO 2 (ml/kg/min) and fat oxidation rate (without interactions with exercise). Table 3 Effect of obesity and different types of exercise on energy expenditure df F-ratio p Gross VO 2 (ml/kg/min) Between subjects Obesity 1 55.069 <0.001 Within subjects Exercise 3 292.144 <0.001 Obesity*Exercise 3 1.186 0.316 Net VO 2 (ml/kg/min) Between subjects Obesity 1 42.163 <0.001 Within subjects Exercise 3 291.774 <0.001 Obesity*Exercise 3 1.184 0.317 Fat oxidation rate (g/min) Between subjects Obesity 1 12.026 0.001 Within subjects Exercise 3 20.628 <0.001 Obesity*Exercise 3 0.136 0.938 CHO oxidation rate (g/min) Between subjects Obesity 1 0.882 0.349 Within subjects Exercise 3 31.568 <0.001 Obesity*Exercise 3 2.715 0.046 Figure 2 shows the substrate oxidation during cycle ergometer exercise and treadmill running. The OB participants showed a significantly greater fat utilization rate during cycle ergometer exercise at 50 and 100 W (both p < 0.05) than the NW participants. CHO oxidation rate increased significantly with increasing power output in both NW and OB participants (both p < 0.01), but CHO oxidation rate increased significantly with increasing running speed only in OB participants ( p < 0.01). Figure 3 shows the fat and carbohydrate (CHO) contribution during cycle ergometer exercise and treadmill running. For both NW and OB subjects, fat contribution (%) was greater during CE exercise at 50 W than CE exercise at 100 W. There was no significant difference in fat contribution (%) between TR at 7 and 8 km/h for both NW and OB subjects. There was no significant difference in CHO contribution (%) between NW and OB subjects for any exercise. Figure 4 shows the gross efficiency and net efficiency during cycle ergometer exercise for NW and OB subjects. Gross efficiency for CE at 50 and 100 W was significantly higher in the NW group compared to the OB group (both p 0.05) (Figure 4B). Discussion The main findings from the present study demonstrated that obese subjects exhibited a higher gross metabolic rate (L/min) during CE and TR exercises than normal-weight individuals, which is in agreement with most findings in different types of exercise [ 13 , 29 ]. Previous studies have indicated that total body weight is the primary determinant of the energy cost of physical activity and that exercise could be more expensive for obese due to the more body fat carried during exercise [ 19 , 30 ]. The results of this study also showed that when gross and net metabolic rates were expressed per unit of body weight, OB subjects presented lower values than NW subjects in all CE and TR exercises. DeLany et al. [ 31 ] indicated a lower activity energy expenditure per body weight in obese individuals and Elbelt et al. [ 32 ] showed a lower body weight-adjusted activity energy expenditure in higher degrees of obesity, which is consistent with our findings. However, there are several studies suggesting that obese have a higher relative net metabolic rate (ml/kg/min) for treadmill walking than normal-weight adults [ 19 , 33 ]. Primavesi et al. [ 34 ] suggested that the energy cost and mechanics of walking appear to be affected by the class of obesity. The OB subjects in this study were in a BMI range of greater than 24.9, and were obese class I (with a mean BMI of 27.2) according to the WHO Asian classification [ 25 ]. Therefore, it is possible that the differences in activity energy expenditure were reduced due to the obesity levels, the similar results (no differences between the NW and OB participants) in values of activity energy expenditure expressed per unit of body weight (kg) were reported by LeCheminant et al. [ 35 ]. Lafortuna et al. [ 13 ] have found that the net metabolic rate was higher in OB than NW during both treadmill walking and cycle ergometer exercise, which differed from our results showing that the net energy expenditure (kcal/min) was higher for the OB group during TR rather than CE exercise. Several studies have suggested that subjects perform more complex movement work involving many body segments during treadmill exercise than during cycling, which mainly uses the legs, leading to differences in workload and movement patterns between the two exercise modes [ 36 , 37 ]. This would explain that when subtracting the RMR, the net energy expenditure of TR exercise appeared significantly different between OB and NW subjects, since CE exercise is a non-weight-bearing activity. what’s more, the present study supports existing studies that the mode and intensity of exercise significantly influence the cardiovascular response [ 13 , 38 ], gross energy expenditure, and net energy expenditure [ 13 , 39 ] for obese and normal-weight individuals. Fat oxidation is important in the prevention and treatment of obesity and is influenced by exercise intensity [ 21 , 40 ]. Different from the finding of lower fat oxidation rate in OB [ 22 ], the present study found that exercise at a lower intensity (50W) resulted in a higher fat oxidation rate in OB than NW subjects and an increased fat oxidation contribution in OB and NW subjects. One possible explanation was that short duration low-intensity exercise triggered more plasma free fatty acids oxidation of OB than NW [ 40 ]. Bogdanis et al. [ 23 ] also found that peak fat oxidation was observed in overweight men and women at the intensity of lower than 40% VO 2max . Van Aggel-Leijssen et al. [ 41 ] have shown that a high-intensity training with about 70% VO 2max did not affect fat oxidation during exercise. For 8 weeks (1 hour of cycling per session, 4 times per week) low-intensity cycling improved fat oxidation by ~ 30% in overweight and obese adults [ 42 ]. These findings were consistent with this study. The key point we could get from previous studies and the present study is that when we make an exercise prescription for obesity, we could select a relative low exercise intensity with a longer time rather than a high exercise intensity with a shorter time to the same energy expenditure goal. Normal-weight subjects appeared to have a higher gross cycling efficiency than obese subjects. Several studies have shown that obese subjects appear to have a lower mechanical efficiency [ 17 , 18 ], which is generally consistent with our findings. When exercising at lower intensities, the proportion of energy required for basal metabolism is relatively higher than at higher intensities, resulting in lower gross efficiency [ 43 ], and oxygen consumption was greater in obese than in lean counterparts, resulting in lower efficiency in obese subjects [ 44 ]. Chen et al. found that there was a negative correlation between the efficiency of walking and body fatness [ 45 ], meaning that the more body fat, the lower the efficiency. Rosenbaum et al. reported that work efficiency during cycle ergometry could be predicted by weight change [ 46 ]. Thus, we can speculate that treadmill running would be more expensive for obese subjects due to their more body fat, which suggests that total body weight is one of the main reasons leading to the higher energy consumption during running. Considering that exercise and PA are one of key means to treat obesity and to make exercise prescription more scientific, effective, and targeted for obese individuals, more research should be done on the effects of age, sex, and obesity class on the energy cost and mechanics of more different exercise modes with different exercise intensities and characteristics. Practical Applications This study shows that body fat mass appears to have a significant effect on energy cost and substrate oxidation. The results suggest that cycling at a low power output may be an appropriate exercise recommendation to start a weight management prescription in obese adults to increase the fat oxidation. Therefore, due to the different cardiovascular responses to TR and CE in OB, CE exercise may be preferable compared to TR because it is an easier-performing exercise mode for OB to achieve target energy expenditure without body mass burden, however, it also needs a longer time to achieve the target energy expenditure. These findings are important when designing exercise programs for weight management in obese individuals. Innovation of the study Treadmill running and cycle ergometer are two common exercise modalities used for exercise and leisure. Though several researches have reported physiological responses to these two exercise modalities, few focused on obese group and energy expenditure comparison between the TR and CE. To our knowledge, this is the first study to assess efficiency of CE in group of NW and OB adults, and make energy cost and substrate oxidation comparison between TR and CE for NW and OB, which is important in exploring the relationship between energy expenditure and substrate oxidation of physical activity and body weight regulation. The results could help in prescribing for in obese population and further studies in assessing different physiological responses in different level obese populations during different exercise modalities, effects of different physical activities. Limitations of the study In the present study, there were several limitations. First, there may be biomechanical differences between NW and OB individuals that affect EE during treadmill running and economy of running. As our study did not assess these biomechanical variables, we cannot determine the effect of biomechanical factors on EE and economy of movement. Second, the subjects in this study were overweight and class I obese. It is possible that more severely obese subjects would result in decreasing economy of movement compared to NW and obese I participants, which may result in different results in EE and efficiency of TR and CE; however, this result is speculative and needs to be investigated in the future. Conclusion We conclude that, overweight and obese men consumed more energy during cycle ergometer exercise and treadmill running at different intensities than normal weight men. Due to the greater body mass, obese men appeared to be less economical than normal-weight subjects during treadmill running than cycle ergometer exercise. Our results suggest that CE at a lower intensity resulting in a higher fat oxidation contribution without weight burden may be a better exercise choice for starting a fat loss prescription in obese adults and needs to be applied in clinical study to investigate the efficacy of the prescription. Abbreviations BMI Body mass index CE Cycle ergometer CHO Carbohydrates EE Energy expenditure HR Heart rate NW Normal-weight OB Obese PA Physical activity RMR Resting metabolic rate RER Respiratory exchange ratio TR Treadmill running VO 2 Oxygen consumption VCO 2 Carbon dioxide production Declarations Ethics approval and consent to participate All procedures were followed in accordance with the Helsinki Declaration and were approved by the ethics committee for human research of the China Institute of Sport Science (Ethical code: CISSIRD-201604); informed consent was obtained from all participants prior to participation. Consent for publication Not applicable. Availability of data and materials The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request. Competing Interests The authors declare that they have no competing interests. Funding This work was supported by Key Research and Development Project of Hainan Province (Grant No. ZDYF2025(LALH)004). Author contributions JJ. X and SL performed the experiment, JJ. X completed statistical analysis and wrote the manuscript; TT. S participated to analysis and interpretation of the data.SL and KJ. ZH reviewed the manuscript; PH designed the study and reviewed the manuscript. All the authors read and approved the manuscript. Acknowledgements The authors thank all the subjects involved in the study for their participations in all testing. References NCD Risk Factor Collaboration (NCD-RisC). Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants. Lancet. 2016;387(10026):1377-96. https://doi.org/10.1016/S0140-6736(16)30054-X. 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The role of free-living daily walking in human weight gain and obesity. Diabetes. 2008;57(3):548-54. https://doi.org/10.2337/db07-0815. Berry MJ, Storsteen JA, Woodard CM. Effects of body mass on exercise efficiency and VO2 during steady-state cycling. Med Sci Sports Exerc. 1993;25(9):1031-7 Fernández Menéndez A, Uva B, Favre L, Hans D, Borrani F, Malatesta D. Mass-normalized internal mechanical work in walking is not impaired in adults with class III obesity. J Appl Physiol (1985). 2020;129(1):194-203. https://doi.org/10.1152/japplphysiol.00837.2019. Salvadori A, Fanari P, Fontana M, Buontempi L, Saezza A, Baudo S, Miserocchi G, Longhini E. Oxygen uptake and cardiac performance in obese and normal subjects during exercise. Respiration. 1999;66(1):25-33. https://doi.org/10.1159/000029333. Browning RC, Kram R. Energetic cost and preferred speed of walking in obese vs. normal weight women. Obes Res. 2005;13(5):891-9. https://doi.org/10.1038/oby.2005.103. Clamp LD, Mendham AE, Kroff J, Goedecke JH. Higher baseline fat oxidation promotes gynoid fat mobilization in response to a 12-week exercise intervention in sedentary, obese black South African women. Appl Physiol Nutr Metab. 2020;45(3):327-35. https://doi.org/10.1139/apnm-2019-0460. Venables MC, Achten J, Jeukendrup AE. Determinants of fat oxidation during exercise in healthy men and women: a cross-sectional study. J Appl Physiol (1985). 2005;98(1):160-7. https://doi.org/10.1152/japplphysiol.00662.2003. Maunder E, Plews DJ, Kilding AE. Contextualising Maximal Fat Oxidation During Exercise: Determinants and Normative Values. Front Physiol. 2018;9:599. https://doi.org/10.3389/fphys.2018.00599. Bogdanis GC, Vangelakoudi A, Maridaki M. Peak fat oxidation rate during walking in sedentary overweight men and women. J Sports Sci Med. 2008;7(4):525-31 Makino A, Yamaguchi K, Sumi D, Ichikawa M, Ohno M, Goto K. Comparison of energy expenditure and substrate oxidation between walking and running in men and women. Phys Act Nutr. 2022;26(1):8-13. https://doi.org/10.20463/pan.2022.0002. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004;363(9403):157-63. https://doi.org/10.1016/S0140-6736(03)15268-3. WEIR JB. New methods for calculating metabolic rate with special reference to protein metabolism. J Physiol. 1949;109(1-2):1-9. https://doi.org/10.1113/jphysiol.1949.sp004363. Dumortier M, Thöni G, Brun JF, Mercier J. Substrate oxidation during exercise: impact of time interval from the last meal in obese women. Int J Obes (Lond). 2005;29(8):966-74. https://doi.org/10.1038/sj.ijo.0802991. Gaesser GA, Brooks GA. Muscular efficiency during steady-rate exercise: effects of speed and work rate. J Appl Physiol. 1975;38(6):1132-9. https://doi.org/10.1152/jappl.1975.38.6.1132. Lafortuna CL, Proietti M, Agosti F, Sartorio A. The energy cost of cycling in young obese women. Eur J Appl Physiol. 2006;97(1):16-25. https://doi.org/10.1007/s00421-006-0137-5. Volpe Ayub B, Bar-Or O. Energy cost of walking in boys who differ in adiposity but are matched for body mass. Med Sci Sports Exerc. 2003;35(4):669-74. https://doi.org/10.1249/01.MSS.0000058355.45172.DE. DeLany JP, Kelley DE, Hames KC, Jakicic JM, Goodpaster BH. High energy expenditure masks low physical activity in obesity. Int J Obes (Lond). 2013;37(7):1006-11. https://doi.org/10.1038/ijo.2012.172. Elbelt U, Schuetz T, Hoffmann I, Pirlich M, Strasburger CJ, Lochs H. Differences of energy expenditure and physical activity patterns in subjects with various degrees of obesity. Clin Nutr. 2010;29(6):766-72. https://doi.org/10.1016/j.clnu.2010.05.003. Ohrström M, Hedenbro J, Ekelund M. Energy expenditure during treadmill walking before and after vertical banded gastroplasty: a one-year follow-up study in 11 obese women. Eur J Surg. 2001;167(11):845-50. https://doi.org/10.1080/11024150152717689. Primavesi J, Fernández Menéndez A, Hans D, Favre L, Crettaz von Roten F, Malatesta D. The Effect of Obesity Class on the Energetics and Mechanics of Walking. Nutrients. 2021;13(12):390-8. https://doi.org/10.3390/nu13124546. LeCheminant JD, Heden T, Smith J, Covington NK. Comparison of energy expenditure, economy, and pedometer counts between normal weight and overweight or obese women during a walking and jogging activity. Eur J Appl Physiol. 2009;106(5):675-82. https://doi.org/10.1007/s00421-009-1059-9. Abiodun OO, Balogun MO, Akintomide AO, Adebayo RA, Ajayi OE, Ogunyemi SA, Amadi VN, Adeyeye VO. Comparison between treadmill and bicycle ergometer exercise tests in mild-to-moderate hypertensive Nigerians. Integr Blood Press Control. 2015;8:51-5. https://doi.org/10.2147/IBPC.S75888. Ren C, Zhu J, Shen T, Song Y, Tao L, Xu S, Zhao W, Gao W. Comparison Between Treadmill and Bicycle Ergometer Exercises in Terms of Safety of Cardiopulmonary Exercise Testing in Patients With Coronary Heart Disease. Front Cardiovasc Med. 2022;9:864637. https://doi.org/10.3389/fcvm.2022.864637. Lafortuna CL, Chiavaroli S, Rastelli F, De Angelis M, Agosti F, Patrizi A, Sartorio A. Energy cost and cardiovascular response to upper and lower limb rhythmic exercise with different equipments in normal-weight and severely obese individuals. J Endocrinol Invest. 2011;34(2):131-9. https://doi.org/10.1007/BF03347043. Greiwe JS, Kohrt WM. Energy expenditure during walking and jogging. J Sports Med Phys Fitness. 2000;40(4):297-302 Romijn JA, Coyle EF, Sidossis LS, Gastaldelli A, Horowitz JF, Endert E, Wolfe RR. Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. Am J Physiol. 1993;265(3 Pt 1):E380-91. https://doi.org/10.1152/ajpendo.1993.265.3.E380. van Aggel-Leijssen DP, Saris WH, Wagenmakers AJ, Senden JM, van Baak MA. Effect of exercise training at different intensities on fat metabolism of obese men. J Appl Physiol (1985). 2002;92(3):1300-9. https://doi.org/10.1152/japplphysiol.00030.2001. Lefai E, Blanc S, Momken I, Antoun E, Chery I, Zahariev A, Gabert L, Bergouignan A, Simon C. Exercise training improves fat metabolism independent of total energy expenditure in sedentary overweight men, but does not restore lean metabolic phenotype. INTERNATIONAL JOURNAL OF OBESITY. 2017;41(12):1728-36. https://doi.org/10.1038/ijo.2017.151. Moseley L, Jeukendrup AE. The reliability of cycling efficiency. Med Sci Sports Exerc. 2001;33(4):621-7. https://doi.org/10.1097/00005768-200104000-00017. Dempsey JA, Reddan W, Balke B, Rankin J. Work capacity determinants and physiologic cost of weight-supported work in obesity. J Appl Physiol. 1966;21(6):1815-20. https://doi.org/10.1152/jappl.1966.21.6.1815. Chen KY, Acra SA, Donahue CL, Sun M, Buchowski MS. Efficiency of walking and stepping: relationship to body fatness. Obes Res. 2004;12(6):982-9. https://doi.org/10.1038/oby.2004.120. Rosenbaum M, Vandenborne K, Goldsmith R, Simoneau JA, Heymsfield S, Joanisse DR, Hirsch J, Murphy E, Matthews D, Segal KR, Leibel RL. Effects of experimental weight perturbation on skeletal muscle work efficiency in human subjects. Am J Physiol Regul Integr Comp Physiol. 2003;285(1):R183-92. https://doi.org/10.1152/ajpregu.00474.2002. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9503097","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":635500252,"identity":"15bb4ea4-3c83-4c7c-b6f4-987d6aa51f5e","order_by":0,"name":"Jingjing Xue","email":"","orcid":"","institution":"University of Science and Technology Beijing","correspondingAuthor":false,"prefix":"","firstName":"Jingjing","middleName":"","lastName":"Xue","suffix":""},{"id":635500253,"identity":"f894b25b-1633-4fda-adea-f7cc7d03af65","order_by":1,"name":"Shuo Li","email":"","orcid":"","institution":"Beijing Institute of Fashion Technology","correspondingAuthor":false,"prefix":"","firstName":"Shuo","middleName":"","lastName":"Li","suffix":""},{"id":635500254,"identity":"c4e3f2ea-3b11-4537-9e94-fd4ab9080b21","order_by":2,"name":"Tingting Sun","email":"","orcid":"","institution":"Beijing Sport University","correspondingAuthor":false,"prefix":"","firstName":"Tingting","middleName":"","lastName":"Sun","suffix":""},{"id":635500255,"identity":"c2d36e7b-c094-4fa3-b186-fbed49e3bfe1","order_by":3,"name":"Kongjun Zhang","email":"","orcid":"","institution":"University of Science and Technology Beijing","correspondingAuthor":false,"prefix":"","firstName":"Kongjun","middleName":"","lastName":"Zhang","suffix":""},{"id":635500256,"identity":"052af855-a6fe-49e0-96a5-e76607b9c541","order_by":4,"name":"Ping Hong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYBACAxhpf775GEToALFaGG4cSyNFC1hljhlxWszZew+/Lii4Y9fYcObbw59tDHJ8NxIYPxfg0WLZcy7NeobBs+Rm5t7txrxtDMaSNxKYpWfgc9iNHDNjHoPDyWwMZ7dJM7YxJG64kcDGzEOMFh6GnGeSQIfVE6PF+DFQi50EQw6bBNBhCQYEtZw5Y8Y8w+BwgoHEMXNjnnMShjPPPGyWxqvleI/x54I/h+0N+JufPfxRZiPPdzz54Gd8WoCATRpIJDZAOBJAzNiAXwMDA/NnIGFPSNUoGAWjYBSMYAAAk19OVUarlB0AAAAASUVORK5CYII=","orcid":"","institution":"Beijing Sport University","correspondingAuthor":true,"prefix":"","firstName":"Ping","middleName":"","lastName":"Hong","suffix":""}],"badges":[],"createdAt":"2026-04-23 06:53:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9503097/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9503097/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108957224,"identity":"85be3e1c-4b94-4a25-837a-6c16e5f0ca0a","added_by":"auto","created_at":"2026-05-11 08:17:18","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":217623,"visible":true,"origin":"","legend":"\u003cp\u003eGross and net energy expenditure during cycle ergometer exercise and treadmill running in NW and OB subjects.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e*\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05 compared with the same data between NW and OB;\u003csup\u003e **\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 compared with the same data between NW and OB;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eaa \u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 CE at 50 vs. 100 W in NW group;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ebb \u003c/sup\u003e\u003cem\u003ep \u003c/em\u003e\u0026lt; 0.01 CE at 50 vs. 100 W in OB group;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ecc \u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 TR at 7 vs. 8 km/h in NW group;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003edd \u003c/sup\u003e\u003cem\u003ep \u003c/em\u003e\u0026lt; 0.01 TR at 7 vs. 8 km/h in OB group.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-9503097/v1/71e0e5d8fd4c03ecc3e0fae9.png"},{"id":108957194,"identity":"e5f8e69c-c311-4c3d-ab7d-8a404c62cfd4","added_by":"auto","created_at":"2026-05-11 08:17:12","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":246072,"visible":true,"origin":"","legend":"\u003cp\u003eFat oxidation and carbohydrate (CHO) oxidation during cycle ergometer exercise and treadmill running in NW and OB subjects.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e*\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05 compared with the same data between NW and OB;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eaa \u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 CE at 50 vs. 100 W in NW group;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ebb \u003c/sup\u003e\u003cem\u003ep \u003c/em\u003e\u0026lt; 0.01 CE at 50 vs. 100 W in OB group;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ecc \u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 TR at 7 vs. 8 km/h in OB group.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9503097/v1/456ea9fabc18177b018c63ef.png"},{"id":108957141,"identity":"52f92653-4a2d-45e0-9700-40168d964b5c","added_by":"auto","created_at":"2026-05-11 08:16:56","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":183959,"visible":true,"origin":"","legend":"\u003cp\u003eFat and carbohydrate (CHO) contribution during cycle ergometer exercise and treadmill running in NW and OB subjects.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eaa \u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 CE at 50 vs. 100 W in NW group;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ebb \u003c/sup\u003e\u003cem\u003ep \u003c/em\u003e\u0026lt; 0.01 CE at 50 vs. 100 W in OB group.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-9503097/v1/cfd0aad9b1eab1f9acdbbf34.png"},{"id":108957140,"identity":"09229261-9e4a-4665-91c0-f58d2c22d626","added_by":"auto","created_at":"2026-05-11 08:16:56","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":118118,"visible":true,"origin":"","legend":"\u003cp\u003eGross efficiency and net efficiency during cycle ergometer exercise in NW and OB subjects.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e*\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05 compared with the same data between NW and OB.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-9503097/v1/306b0df2131d6cd79259e686.png"},{"id":108978221,"identity":"5bd005f1-5607-4757-9cf3-465f2d06fd07","added_by":"auto","created_at":"2026-05-11 11:35:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1230979,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9503097/v1/ce1b69c5-a90d-4766-9830-6ffc9fce6443.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The energy expenditure and substrate oxidation of treadmill running and cycle ergometer exercise in normal-weight vs. overweight and obese men","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe increasing trend in obesity have become a public health issue in China and throughout the world [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Obesity is associated with cardiovascular diseases, type 2 diabetes mellitus, metabolic diseases, and cancer, leading to an increased risk of death [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The critical for obesity is greater energy intake than energy expenditure of physical activity (PA). Physical activity and exercise play an important role in managing and losing weight [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, many studies revealed that one of the most important contributors to the maintenance of obesity is that obese individuals tend to have more sedentary behavior or insufficient PA [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Effective weight management requires an accurate exercise prescription of exercise type and intensity, energy expenditure, and substrate metabolism during exercise, and mechanical efficiency characteristics for obese populations.\u003c/p\u003e \u003cp\u003eWhile treadmills and cycle ergometer exercises are popular, convenient, and relatively safe types of exercise, these two modes are commonly used in exercise testing and clinical settings. There is a fundamental difference between these two modes of exercise, cycling is a weight-independent exercise and not influenced by balance and gait issues, which can easily be performed by most people; while treadmill running is weight-dependent and influenced by balance and gait. Several differences in physiological responses to treadmill exercise and cycle ergometer exercise are investigated in normal weight subjects [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and few in overweight and obese individuals [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], and rarely including comparison between treadmill running and cycle ergometer exercise.\u003c/p\u003e \u003cp\u003eIn addition, the gross energy cost and net energy cost have been found to be higher in obese individuals during different movements by several researchers [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], due to the effect of the greater body mass involved in the physical activity [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] or a lower mechanical efficiency [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Nevertheless, the difference between obese and normal-weight subjects is greatly reduced when the metabolic rate is adjusted for total body weight [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], which suggests that total body weight may play a role in the energy cost of physical activity. The greater body mass may lead to the reduction of the exercise effectiveness in weight loss programs, further contributing to the maintenance of obesity.\u003c/p\u003e \u003cp\u003eIt is well known that the dominant fuels oxidized during exercise are carbohydrates (CHO) and free fatty acids, and that the CHO contribution and fat contribution are influenced by exercise type, intensity, as well as duration [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Maunder et al. showed that obese subjects were found to perform lower maximal rates of fat oxidation during exercise than that of lean counterparts [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Previous studies have shown that [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] fat utilization rate is maximal during low intensity exercise (lower than 50%VO\u003csub\u003e2MAX\u003c/sub\u003e) in untrained subjects. Therefore, how to achieve the maximal fat oxidation is also important in the process of body weight management in obesity.\u003c/p\u003e \u003cp\u003eConsequently, it\u0026rsquo;s necessary to understand the differences and the degree of differences of physiological response and energy expenditure in different exercises in obese subjects and normal-weight subjects, which is important for appropriate exercise prescriptions or PA programs for obese subjects. The primary purpose of this study was to compare the energy metabolism (energy cost and substrate oxidation) between normal-weight vs. overweight and obese men. A secondary purpose of this study was to determine the characteristics of energy metabolism during treadmill running and cycle ergometer to provide guidance in the exercise programs or PA prescriptions in clinical for obesity.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eExperimental Approach to the Problem\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo analyze the effects of obesity, exercise type, and intensity on energy expenditure and substrate oxidation, two groups (normal-weight vs. overweight and obese subjects) were recruited. All participants underwent anthropometric data collection, RMR at rest, and energy expenditure testing during CE (50 and 100 W) and TR (7 and 8 km/h). The gross and net metabolic rate, substrate oxidation, and gross and net efficiency data during the same exercise type and intensity were compared between NW and OB groups to identify the effect of obesity on energy expenditure. The gross and net metabolic rate, substrate oxidation, and gross and net efficiency during the different exercise types and intensities were compared in NW and OB to identify the effect of exercise type and intensity on energy expenditure.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSubjects\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e27 Normal-weight (age: 28.3 \u0026plusmn; 2.3 years, BMI: 21.2 \u0026plusmn; 1.2 kg/m\u003csup\u003e2\u003c/sup\u003e) and 25 obese men (age: 28.9 \u0026plusmn; 2.1 years, BMI: 27.2 \u0026plusmn; 1.3 kg/m\u003csup\u003e2\u003c/sup\u003e) participated in this study. The total sample size needed using power analysis was 73, taking into account the effect size (0.5) seen in similar studies. We recruited 64 male subjects in total, however, 5 normal and 7 obese did not complete all tests. We calculated post-hoc power using power analysis and the sample size in this study provided a strong power (0.8395) to detect the effect we\u0026apos;re investigating. All participants were healthy, free of cardiovascular, respiratory, and metabolic diseases and did not have regular physical activity in daily life that could affect their energy metabolism. Inclusion criteria for overweight and obese subjects were BMI \u0026ge; 23 kg/m\u003csup\u003e2\u003c/sup\u003e and 18.5-23 kg/m\u003csup\u003e2\u003c/sup\u003e for the NW subjects, which were in accordance with the WHO classification for Asians\u0026nbsp;[25]. The physical characteristics of all subjects (Mean \u0026plusmn; SD) are shown in Table 1.\u003c/p\u003e\n\u003cp\u003eTable1 Physical characteristics of normal-weight vs. overweight and obese subjects\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003eNW (n = 27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003eOB (n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003e28.3 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003e28.9 \u0026plusmn; 2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\n \u003cp\u003eHeight (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003e174.2 \u0026plusmn; 5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003e174.3 \u0026plusmn; 6.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\n \u003cp\u003eWeight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003e64.3 \u0026plusmn; 4.8\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003e82.8 \u0026plusmn; 7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003e21.2 \u0026plusmn; 1.2\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003e27.2 \u0026plusmn; 1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\n \u003cp\u003eBody Fat Percentage (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003e16.8 \u0026plusmn; 2.5\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003e26.8 \u0026plusmn; 4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 208px;\"\u003e\n \u003cp\u003eRMR (kcal/day）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 147px;\"\u003e\n \u003cp\u003e1877.1 \u0026plusmn; 258.1\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\" style=\"width: 112px;\"\u003e\n \u003cp\u003e2185.0 \u0026plusmn; 226.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eBMI = Body Mass Index, RMR = Resting Metabolic Rate.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e\u0026lowast;\u0026lowast;\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e\u0026lt;0.01.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eProcedures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll subjects were asked to arrive at the laboratory in a fasted state before 8:00 am on the test day. Before the exercise energy expenditure measurements, every participant underwent anthropometric measurements and Resting Metabolic Rate (RMR) measurements. All testers in this study were professionally trained and each test project is tested by the same tester. All participants were asked to wear the same comfortable clothes and shoes during each testing session and were motivated to finish their exercise testing.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnthropometric Measures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStanding height (m) and body mass (kg) were assessed according to international standards for anthropometric assessment. To evaluate height and body mass, the Su Heng Health Scale (RGZ-120, Jiangsu, China) with precisions of 0.1 cm and 0.1 kg were used, respectively. The BMI was calculated (kg/m\u003csup\u003e2\u003c/sup\u003e). A bioelectrical impedance analysis composition analyzer (Inbody 770, Biospace Corp., Korea) was used to determine body composition.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRMR Measurement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter the anthropometric measurements, participants rested supine for 10 min prior to RMR data collection.\u0026nbsp;Steady-state RMR was measured by using indirect calorimetry (Cortex Metamax 3B-R2 metabolic system, Germany) in the supine position for 30 min in a semi-darkened, quiet and\u0026nbsp;controlled environment temperature (22\u0026ndash;25 ℃) and humidity (40\u0026ndash;50%)\u0026nbsp;room.\u0026nbsp;The\u0026nbsp;RMR was calculated by using the VO\u003csub\u003e2\u003c/sub\u003e and VCO\u003csub\u003e2\u003c/sub\u003e of the steady periods for about 20 min according to the Weir [26] formula.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExercise Energy-Expenditure Tests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMeasures of exercise energy metabolic rate were performed during TR (7 and 8 km/h) (Rodby RL3500E, Sweden) and CE exercise (50 and 100 W) (Wattbike, England), maintained for 6 min each exercise, by indirect calorimetry (Cortex Metamax 3B-R2 metabolic system, Germany). The system (Cortex Metamax 3B-R2, Germany) was calibrated before each test with standard gases of known oxygen and carbon dioxide concentration. An initial steady state at 5 km/h and 20 W for 3 min was allowed for warming. The treadmill and ergometer were set to operate at a constant speed of 7 and 8 km/h and power of 50 and 100 Watts, respectively. The participants were instructed to perform these exercises according to the workloads of treadmill and ergometer. The saddle and hand bar positions during the ergometer exercise were individually adjusted. Heart rate (HR) was continuously monitored by a wireless heart rate (HR) monitor (Polar H7, Finland). Each exercise test was performed in a randomized order and separated by rest between trials until their HR recovered to a level \u0026plusmn; 5% of their resting HRs (at least 5 minutes). Gross VO\u003csub\u003e2\u003c/sub\u003e and VCO\u003csub\u003e2\u003c/sub\u003e output were measured breath-by-breath and averaged over the last 3 steady-state minutes of each test. The net metabolic rate was obtained by subtracting the resting metabolic rate from the gross metabolic rate. Fat and CHO oxidation were calculated from VO\u003csub\u003e2\u003c/sub\u003e and VCO\u003csub\u003e2\u003c/sub\u003e according to equations assuming a nonprotein respiratory quotient. CHO and fat oxidation contributions were estimated by using the following formulas [27]:\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFat oxidation (g/min) = 1.695\u0026times; VO\u003csub\u003e2\u003c/sub\u003e (l/min) - 1.701 \u0026times; VCO\u003csub\u003e2\u003c/sub\u003e (l/min)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCarbohydrate oxidation (g/min) = 4.585 \u0026times;VCO\u003csub\u003e2\u003c/sub\u003e (l/min) - 3.226 \u0026times;VO\u003csub\u003e2\u003c/sub\u003e (l/min)\u0026nbsp;\u003c/em\u003eMechanical efficiency during CE at different workloads was calculated as gross efficiency and net efficiency as defined by Gaesser and Brooks [28].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStatistical Analyses\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistical analysis was performed by using SPSS software version 26.0 (IBM Corp., Armonk, NY, USA). All data are presented as mean \u0026plusmn; SD. Data were checked for normality using the Kolmogorov-Smirnov test. Differences between NW and OB subjects (group differences) in physical characteristics and energy expenditure data were investigated using\u0026nbsp;independent Student\u0026rsquo;s t tests. A two-way repeated measure ANOVA was used to examine how different exercise type and obesity affected gross VO\u003csub\u003e2\u003c/sub\u003e, net VO\u003csub\u003e2\u003c/sub\u003e, CHO and fat oxidation rate. For all tests, the significance level was set at \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eTable 2 shows the cardiorespiratory and energy expenditure data of NW and OB groups during cycle ergometer exercise and treadmill running.\u0026nbsp;Gross VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min) and gross energy expenditure (kcal/min) of OB during cycle ergometer at 100 W and treadmill running at 7 and 8 km/h, respectively, were greater than those of the NW group (both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05, both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01, both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01), whereas no statistically significant difference in HR and RER was detected between the two groups during any exercise. What\u0026rsquo;s more, normalization of VO\u003csub\u003e2\u003c/sub\u003e to body weight (ml/kg/min) resulted in obese subjects having a lower gross and net metabolic rates compared to normal-weight subjects during all exercises. The net VO\u003csub\u003e2\u003c/sub\u003e (L/min) and energy expenditure (kcal/min) were greater for the OB group in treadmill running at 7 and 8 km/h compared with their normal-weight counterparts (both \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01) (Table 2, Figure 1B). However, there were no significant differences in net VO\u003csub\u003e2\u003c/sub\u003e (L/min) and net energy expenditure (kcal/min) in the cycle ergometer at 50 and 100 W between the NW and OB groups (Table 2, Figure 1B), indicating that the body-weight involved in running movements may be responsible for the higher energy cost for OB subjects. The HR, gross VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min), net VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min), gross and net\u0026nbsp;VO\u003csub\u003e2\u003c/sub\u003e\u003csub\u003e\u0026nbsp;\u003c/sub\u003e(ml/kg/min), gross and net VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min), and gross and net energy expenditure (kcal/min) increased with increasing power output from 50 to 100 W and running speed from 7 to 8 km/h in both NW and OB groups (Table 2, Figure1). Intensity and type of exercise both have a significant effect on the HR, gross and net VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min), gross and net\u0026nbsp;VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(ml/kg/min),\u0026nbsp;gross and net VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min), and gross and net energy expenditure (kcal/min) in the NW and OB groups.\u003c/p\u003e\n\u003cp\u003eTable 2 Cardiorespiratory and energy expenditure (EE) data of normal-weight vs. overweight and obese subjects.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"586\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\" style=\"width: 132px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eNW (n = 27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eOB (n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"8\" style=\"width: 132px;\"\u003e\n \u003cp\u003eCycle ergometer\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eat 50 W\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eHR (b/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e120.1 \u0026plusmn; 15.8\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e120.3 \u0026plusmn; 17.5\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eIntensity (%HR\u003csub\u003emax\u003c/sub\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e62.7 \u0026plusmn; 8.1\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e62.9 \u0026plusmn; 9.0\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.07 \u0026plusmn; 0.15\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.15 \u0026plusmn; 0.16\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.79 \u0026plusmn; 0.15\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.84 \u0026plusmn; 0.15\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eRER\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.832 \u0026plusmn; 0.064\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.805 \u0026plusmn; 0.05\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e16.6 \u0026plusmn; 2.0\u003csup\u003e**aa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e14.0 \u0026plusmn; 2.4\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e20.0 \u0026plusmn; 2.7\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e19.2 \u0026plusmn; 3.7\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e12.4 \u0026plusmn; 2.1\u003csup\u003e**aa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e10.2 \u0026plusmn; 2.2\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e15.0 \u0026plusmn; 2.8\u003csup\u003eaa\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e14.0 \u0026plusmn; 3.3\u003csup\u003ebb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"8\" style=\"width: 132px;\"\u003e\n \u003cp\u003eCycle ergometer\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eat 100 W\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eHR (b/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e141.5 \u0026plusmn; 20.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e137.0 \u0026plusmn; 17.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eIntensity (%HR\u003csub\u003emax\u003c/sub\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e73.8 \u0026plusmn; 10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e71.7 \u0026plusmn; 9.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1.59 \u0026plusmn; 0.18\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1.71 \u0026plusmn; 0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.32 \u0026plusmn; 0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.39 \u0026plusmn; 0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eRER\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.897 \u0026plusmn; 0.065\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.864 \u0026plusmn; 0.064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e24.9 \u0026plusmn; 3.17\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e20.8 \u0026plusmn; 2.87\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e29.9 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e28.5 \u0026plusmn; 4.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e20.65 \u0026plusmn; 3.22\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e16.92 \u0026plusmn; 2.70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e24.9 \u0026plusmn; 4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e23.2 \u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"8\" style=\"width: 132px;\"\u003e\n \u003cp\u003eTreadmill running\u0026nbsp;at 7 km/h\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eHR (b/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e147.5 \u0026plusmn; 21.3\u003csup\u003ecc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e151.4 \u0026plusmn; 16.0\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eIntensity (%HR\u003csub\u003emax\u003c/sub\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e76.9 \u0026plusmn; 11.0\u003csup\u003ecc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e79.2 \u0026plusmn; 8.4\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1.84 \u0026plusmn; 0.17\u003csup\u003e**cc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e2.19 \u0026plusmn; 0.22\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.57 \u0026plusmn; 0.17\u003csup\u003e**cc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.87 \u0026plusmn; 0.21\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eRER\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.843 \u0026plusmn; 0.069\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.846 \u0026plusmn; 0.051\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e28.7 \u0026plusmn; 2.85\u003csup\u003e**cc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e26.5 \u0026plusmn; 2.22\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e34.6 \u0026plusmn; 3.7\u003csup\u003ecc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e36.3 \u0026plusmn; 3.8\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e24.5 \u0026plusmn; 2.96\u003csup\u003e*cc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e22.7 \u0026plusmn; 2.08\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e29.6 \u0026plusmn; 3.8\u003csup\u003ecc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e31.1 \u0026plusmn; 3.4\u003csup\u003edd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"8\" style=\"width: 132px;\"\u003e\n \u003cp\u003eTreadmill running at 8 km/h\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eHR (b/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e155.5 \u0026plusmn; 20.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e159.4 \u0026plusmn; 17.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eIntensity (%HR\u003csub\u003emax\u003c/sub\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e81.1 \u0026plusmn; 10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e83.4\u0026plusmn; 9.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e2.02 \u0026plusmn; 0.24\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e2.40 \u0026plusmn; 0.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(L/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.76 \u0026plusmn; 0.25\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e2.09 \u0026plusmn; 0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eRER\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.847 \u0026plusmn; 0.057\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0.852 \u0026plusmn; 0.057\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(ml/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e31.6 \u0026plusmn; 3.81\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e29.1 \u0026plusmn; 2.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e38.0 \u0026plusmn; 5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e39.9 \u0026plusmn; 4.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003e(ml/kg/min)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e27.4 \u0026plusmn; 4.01\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e25.3 \u0026plusmn; 2.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 208px;\"\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg FFM/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e33.3 \u0026plusmn; 5.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 123px;\"\u003e\n \u003cp\u003e34.7 \u0026plusmn; 3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003e*\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05 compared with the same data between NW and OB; \u003csup\u003e**\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 compared with the same data between NW and OB;\u0026nbsp;\u003csup\u003eaa\u0026nbsp;\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 CE at 50 vs. 100 W in NW group; \u003csup\u003ebb\u0026nbsp;\u003c/sup\u003e\u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01 CE at 50 vs. 100 W in OB group; \u003csup\u003ecc\u0026nbsp;\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01 TR at 7 vs. 8 km/h in NW group; \u003csup\u003edd\u0026nbsp;\u003c/sup\u003e\u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01 TR at 7 vs. 8 km/h in OB group.\u003c/p\u003e\n\u003cp\u003e**Table 2 about here**\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe results of the two-way ANOVA are shown in Table 3 for the energy expenditure data. While different types of exercise appear to have a significant effect on gross and net VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min) and fat and CHO oxidation rate (without interactions with obesity). Obesity has significant effects on gross and net VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min) and fat oxidation rate (without interactions with exercise).\u003c/p\u003e\n\u003cp\u003eTable 3 Effect of obesity and different types of exercise on energy expenditure\u0026nbsp;\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003edf\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eF-ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBetween subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e55.069\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eWithin subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eExercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e292.144\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity*Exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.186\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.316\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eNet VO\u003csub\u003e2\u003c/sub\u003e (ml/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBetween subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e42.163\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eWithin subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eExercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e291.774\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity*Exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.184\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.317\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eFat oxidation rate (g/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBetween subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e12.026\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eWithin subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eExercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e20.628\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity*Exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.136\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.938\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eCHO oxidation rate (g/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBetween subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.882\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.349\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eWithin subjects\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eExercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e31.568\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eObesity*Exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e2.715\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.046\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eFigure 2 shows the substrate oxidation during cycle ergometer exercise and treadmill running. The OB participants showed a significantly greater fat utilization rate during cycle ergometer exercise at 50 and 100 W (both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05) than the NW participants. CHO oxidation rate increased significantly with increasing power output in both NW and OB participants (both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01), but CHO oxidation rate increased significantly with increasing running speed only in OB participants (\u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.01).\u003c/p\u003e\n\u003cp\u003eFigure 3 shows the fat and carbohydrate (CHO) contribution during cycle ergometer exercise and treadmill running. For both NW and OB subjects, fat contribution (%) was greater during CE exercise at 50 W than CE exercise at 100 W. There was no significant difference in fat contribution (%) between TR at 7 and 8 km/h for both NW and OB subjects. There was no significant difference in CHO contribution (%) between NW and OB subjects for any exercise.\u003c/p\u003e\n\u003cp\u003eFigure 4 shows the gross efficiency and net efficiency during cycle ergometer exercise for NW and OB subjects. Gross efficiency for CE at 50 and 100 W was significantly higher in the NW group compared to the OB group (both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05) (Figure 4A). Net efficiency for CE at 50 and 100 W did not differ between groups (both \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026gt; 0.05) (Figure 4B).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe main findings from the present study demonstrated that obese subjects exhibited a higher gross metabolic rate (L/min) during CE and TR exercises than normal-weight individuals, which is in agreement with most findings in different types of exercise [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Previous studies have indicated that total body weight is the primary determinant of the energy cost of physical activity and that exercise could be more expensive for obese due to the more body fat carried during exercise [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The results of this study also showed that when gross and net metabolic rates were expressed per unit of body weight, OB subjects presented lower values than NW subjects in all CE and TR exercises. DeLany et al. [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] indicated a lower activity energy expenditure per body weight in obese individuals and Elbelt et al. [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] showed a lower body weight-adjusted activity energy expenditure in higher degrees of obesity, which is consistent with our findings. However, there are several studies suggesting that obese have a higher relative net metabolic rate (ml/kg/min) for treadmill walking than normal-weight adults [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Primavesi et al. [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] suggested that the energy cost and mechanics of walking appear to be affected by the class of obesity. The OB subjects in this study were in a BMI range of greater than 24.9, and were obese class I (with a mean BMI of 27.2) according to the WHO Asian classification [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Therefore, it is possible that the differences in activity energy expenditure were reduced due to the obesity levels, the similar results (no differences between the NW and OB participants) in values of activity energy expenditure expressed per unit of body weight (kg) were reported by LeCheminant et al. [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eLafortuna et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] have found that the net metabolic rate was higher in OB than NW during both treadmill walking and cycle ergometer exercise, which differed from our results showing that the net energy expenditure (kcal/min) was higher for the OB group during TR rather than CE exercise. Several studies have suggested that subjects perform more complex movement work involving many body segments during treadmill exercise than during cycling, which mainly uses the legs, leading to differences in workload and movement patterns between the two exercise modes [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. This would explain that when subtracting the RMR, the net energy expenditure of TR exercise appeared significantly different between OB and NW subjects, since CE exercise is a non-weight-bearing activity. what\u0026rsquo;s more, the present study supports existing studies that the mode and intensity of exercise significantly influence the cardiovascular response [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], gross energy expenditure, and net energy expenditure [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] for obese and normal-weight individuals.\u003c/p\u003e \u003cp\u003eFat oxidation is important in the prevention and treatment of obesity and is influenced by exercise intensity [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Different from the finding of lower fat oxidation rate in OB [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], the present study found that exercise at a lower intensity (50W) resulted in a higher fat oxidation rate in OB than NW subjects and an increased fat oxidation contribution in OB and NW subjects. One possible explanation was that short duration low-intensity exercise triggered more plasma free fatty acids oxidation of OB than NW [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Bogdanis et al. [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] also found that peak fat oxidation was observed in overweight men and women at the intensity of lower than 40% VO\u003csub\u003e2max\u003c/sub\u003e. Van Aggel-Leijssen et al. [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] have shown that a high-intensity training with about 70% VO\u003csub\u003e2max\u003c/sub\u003e did not affect fat oxidation during exercise. For 8 weeks (1 hour of cycling per session, 4 times per week) low-intensity cycling improved fat oxidation by ~\u0026thinsp;30% in overweight and obese adults [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. These findings were consistent with this study. The key point we could get from previous studies and the present study is that when we make an exercise prescription for obesity, we could select a relative low exercise intensity with a longer time rather than a high exercise intensity with a shorter time to the same energy expenditure goal.\u003c/p\u003e \u003cp\u003eNormal-weight subjects appeared to have a higher gross cycling efficiency than obese subjects. Several studies have shown that obese subjects appear to have a lower mechanical efficiency [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], which is generally consistent with our findings. When exercising at lower intensities, the proportion of energy required for basal metabolism is relatively higher than at higher intensities, resulting in lower gross efficiency [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e], and oxygen consumption was greater in obese than in lean counterparts, resulting in lower efficiency in obese subjects [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Chen et al. found that there was a negative correlation between the efficiency of walking and body fatness [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e], meaning that the more body fat, the lower the efficiency. Rosenbaum et al. reported that work efficiency during cycle ergometry could be predicted by weight change [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]. Thus, we can speculate that treadmill running would be more expensive for obese subjects due to their more body fat, which suggests that total body weight is one of the main reasons leading to the higher energy consumption during running.\u003c/p\u003e \u003cp\u003eConsidering that exercise and PA are one of key means to treat obesity and to make exercise prescription more scientific, effective, and targeted for obese individuals, more research should be done on the effects of age, sex, and obesity class on the energy cost and mechanics of more different exercise modes with different exercise intensities and characteristics.\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003ePractical Applications\u003c/h2\u003e \u003cp\u003eThis study shows that body fat mass appears to have a significant effect on energy cost and substrate oxidation. The results suggest that cycling at a low power output may be an appropriate exercise recommendation to start a weight management prescription in obese adults to increase the fat oxidation. Therefore, due to the different cardiovascular responses to TR and CE in OB, CE exercise may be preferable compared to TR because it is an easier-performing exercise mode for OB to achieve target energy expenditure without body mass burden, however, it also needs a longer time to achieve the target energy expenditure. These findings are important when designing exercise programs for weight management in obese individuals.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eInnovation of the study\u003c/h2\u003e \u003cp\u003eTreadmill running and cycle ergometer are two common exercise modalities used for exercise and leisure. Though several researches have reported physiological responses to these two exercise modalities, few focused on obese group and energy expenditure comparison between the TR and CE. To our knowledge, this is the first study to assess\u003c/p\u003e \u003cp\u003eefficiency of CE in group of NW and OB adults, and make energy cost and substrate oxidation comparison between TR and CE for NW and OB, which is important in exploring the relationship between energy expenditure and substrate oxidation of physical activity and body weight regulation. The results could help in prescribing for in obese population and further studies in assessing different physiological responses in different level obese populations during different exercise modalities, effects of different physical activities.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eLimitations of the study\u003c/h2\u003e \u003cp\u003eIn the present study, there were several limitations. First, there may be biomechanical differences between NW and OB individuals that affect EE during treadmill running and economy of running. As our study did not assess these biomechanical variables, we cannot determine the effect of biomechanical factors on EE and economy of movement. Second, the subjects in this study were overweight and class I obese. It is possible that more severely obese subjects would result in decreasing economy of movement compared to NW and obese I participants, which may result in different results in EE and efficiency of TR and CE; however, this result is speculative and needs to be investigated in the future.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe conclude that, overweight and obese men consumed more energy during cycle ergometer exercise and treadmill running at different intensities than normal weight men. Due to the greater body mass, obese men appeared to be less economical than normal-weight subjects during treadmill running than cycle ergometer exercise. Our results suggest that CE at a lower intensity resulting in a higher fat oxidation contribution without weight burden may be a better exercise choice for starting a fat loss prescription in obese adults and needs to be applied in clinical study to investigate the efficacy of the prescription.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eBMI \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eBody mass index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eCE \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eCycle ergometer\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eCHO \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eCarbohydrates\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eEE \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eEnergy expenditure\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eHR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eHeart rate\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eNW \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eNormal-weight\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eOB \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eObese\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePA \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003ePhysical activity\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eRMR \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eResting metabolic rate\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eRER \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eRespiratory exchange ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eTR\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eTreadmill running\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eVO\u003csub\u003e2\u003c/sub\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eOxygen consumption\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eVCO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003eCarbon dioxide production\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures were followed in accordance with the Helsinki Declaration and were approved by the ethics committee for human research of the China Institute of Sport Science (Ethical code: CISSIRD-201604); informed consent was obtained from all participants prior to participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Key Research and Development Project of Hainan Province (Grant No. ZDYF2025(LALH)004).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJJ. X and SL performed the experiment, JJ. X completed statistical analysis and wrote the manuscript; TT. S participated to analysis and interpretation of the data.SL and KJ. ZH reviewed the manuscript; PH designed the study and reviewed the manuscript. All the authors read and approved the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank all the subjects involved in the study for their participations in all testing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eNCD Risk Factor Collaboration (NCD-RisC). Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19\u0026middot;2 million participants. 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Clin Nutr. 2010;29(6):766-72. https://doi.org/10.1016/j.clnu.2010.05.003.\u003c/li\u003e\n\u003cli\u003eOhrstr\u0026ouml;m M, Hedenbro J, Ekelund M. Energy expenditure during treadmill walking before and after vertical banded gastroplasty: a one-year follow-up study in 11 obese women. Eur J Surg. 2001;167(11):845-50. https://doi.org/10.1080/11024150152717689.\u003c/li\u003e\n\u003cli\u003ePrimavesi J, Fern\u0026aacute;ndez Men\u0026eacute;ndez A, Hans D, Favre L, Crettaz von Roten F, Malatesta D. The Effect of Obesity Class on the Energetics and Mechanics of Walking. Nutrients. 2021;13(12):390-8. https://doi.org/10.3390/nu13124546.\u003c/li\u003e\n\u003cli\u003eLeCheminant JD, Heden T, Smith J, Covington NK. Comparison of energy expenditure, economy, and pedometer counts between normal weight and overweight or obese women during a walking and jogging activity. 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Exercise training improves fat metabolism independent of total energy expenditure in sedentary overweight men, but does not restore lean metabolic phenotype. INTERNATIONAL JOURNAL OF OBESITY. 2017;41(12):1728-36. https://doi.org/10.1038/ijo.2017.151.\u003c/li\u003e\n\u003cli\u003eMoseley L, Jeukendrup AE. The reliability of cycling efficiency. Med Sci Sports Exerc. 2001;33(4):621-7. https://doi.org/10.1097/00005768-200104000-00017.\u003c/li\u003e\n\u003cli\u003eDempsey JA, Reddan W, Balke B, Rankin J. Work capacity determinants and physiologic cost of weight-supported work in obesity. J Appl Physiol. 1966;21(6):1815-20. https://doi.org/10.1152/jappl.1966.21.6.1815.\u003c/li\u003e\n\u003cli\u003eChen KY, Acra SA, Donahue CL, Sun M, Buchowski MS. Efficiency of walking and stepping: relationship to body fatness. Obes Res. 2004;12(6):982-9. https://doi.org/10.1038/oby.2004.120.\u003c/li\u003e\n\u003cli\u003eRosenbaum M, Vandenborne K, Goldsmith R, Simoneau JA, Heymsfield S, Joanisse DR, Hirsch J, Murphy E, Matthews D, Segal KR, Leibel RL. Effects of experimental weight perturbation on skeletal muscle work efficiency in human subjects. Am J Physiol Regul Integr Comp Physiol. 2003;285(1):R183-92. https://doi.org/10.1152/ajpregu.00474.2002.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"energy expenditure, net metabolic rate, fat oxidation, mechanical efficiency, cycle ergometer exercise, treadmill running","lastPublishedDoi":"10.21203/rs.3.rs-9503097/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9503097/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackgrounds\u003c/h2\u003e \u003cp\u003eThe purpose of the study was to assess energy expenditure and substrate oxidation to treadmill running (TR) and cycle ergometer (CE) exercise in normal-weight (NW) vs. overweight and obese (OB) men.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003e27 NW (BMI: 21.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 kg/m\u003csup\u003e2\u003c/sup\u003e) and 25 OB (BMI: 27.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 kg/m\u003csup\u003e2\u003c/sup\u003e) men were recruited in this study. Each participant completed resting metabolic rate and energy expenditure tests during TR at 7 and 8 km/h and CE at 50 and 100 W by indirect calorimetry.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eGross VO\u003csub\u003e2\u003c/sub\u003e (L/min) was higher for OB during CE at 100 W (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and TR at 7 and 8 km/h (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), but lower gross and net VO\u003csub\u003e2\u003c/sub\u003e (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01) when the values were adjusted for body mass. While net energy expenditure (kcal/min) was greater for OB group during TR at 7 and 8 km/h (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), but similar in both groups during CE at 50 and 100 W. Gross efficiency was significantly lower in OB during CE at 50 and 100 W (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), but no difference was found in net efficiency. A higher fat oxidation rate was found during CE at 50 and 100 W (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) for OB than the NW. For both NW and OB subjects, fat contribution (%) was greater during CE exercise at 50 W than CE exercise at 100 W.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThese findings showed that OB was less economical and efficient than NW individuals during CE and TR, especially during TR. The obesity, exercise intensity and type all influence substrate oxidation during exercise.\u003c/p\u003e","manuscriptTitle":"The energy expenditure and substrate oxidation of treadmill running and cycle ergometer exercise in normal-weight vs. overweight and obese men","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-11 08:16:49","doi":"10.21203/rs.3.rs-9503097/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-18T07:35:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"153468918220710053387914632463005621444","date":"2026-05-11T13:14:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"202027698714530290305864874302008726626","date":"2026-05-09T13:07:35+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T09:16:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"111337819485777573561449999008294354662","date":"2026-04-30T09:00:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-29T12:59:27+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-29T11:56:02+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-04-28T10:45:31+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-25T11:02:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Sports Science, Medicine and Rehabilitation","date":"2026-04-25T10:58:23+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e999d3b7-33ad-49eb-972a-02453c62f4bc","owner":[],"postedDate":"May 11th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-18T07:35:08+00:00","index":51,"fulltext":""},{"type":"reviewerAgreed","content":"153468918220710053387914632463005621444","date":"2026-05-11T13:14:39+00:00","index":50,"fulltext":""},{"type":"reviewerAgreed","content":"202027698714530290305864874302008726626","date":"2026-05-09T13:07:35+00:00","index":45,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T09:16:55+00:00","index":33,"fulltext":""},{"type":"reviewerAgreed","content":"111337819485777573561449999008294354662","date":"2026-04-30T09:00:04+00:00","index":28,"fulltext":""},{"type":"reviewersInvited","content":"21","date":"2026-04-29T12:59:27+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-29T11:56:02+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T08:16:50+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-11 08:16:49","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9503097","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9503097","identity":"rs-9503097","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}