Impact of long-term electrical stimulation of the lower leg muscles at home on gait speed in community-dwelling older adults

Impact of long-term electrical stimulation of the lower leg muscles at home on gait speed in community-dwelling older adults | 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 Article Impact of long-term electrical stimulation of the lower leg muscles at home on gait speed in community-dwelling older adults Naho Misawa, Mototsugu Nishii, Saki Morita, Yuri Yaguchi, Kazuya Sakai, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6586131/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract We explored the unknown effects of electrical muscle stimulation (EMS) at home on gait speed. Eighty-one community-dwelling independent older adults were enrolled in a prospective observational study. EMS to the lower leg muscles for 23 minutes per day was added to the daily routine during the 12-week observational period. Comfortable gait speed (CGS), stride length (SL), and plantar centre of gravity (COG) were assessed at enrollment and 12 weeks in a 10-m walking test using plantar sensor shoes. In 43 participants with a CGS of < 1.0 m/sec at enrollment, age, gender, and physical and nutritional features did not differ between the EMS (n = 23) and non-EMS (n = 20) groups. However, absolute changes in CGS and SL after 12 weeks were significantly higher in the EMS group than in the non-EMS group (0.25 vs. 0.02 m/sec, P = 0.0037; 0.21 vs. 0.03 m, P = 0.0038; respectively). Moreover, greater distribution of COG to the small toe ball during gait was associated with slower CGS and decreased after EMS. Long-term home EMS targeting the lower leg muscles thus improves reduced gait speed in community-dwelling independent older adults, which may involve changes in the plantar centre of gravity during gait. Health sciences/Health care Health sciences/Risk factors Electrical muscle stimulation home-based lower leg muscle older adults gait speed plantar center of gravity Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction The intervention for physical frailty, which can lead to falls and debilitation in older adults, is critical for maintaining emergency medical services in an ageing society. 1 This was highlighted by the COVID-19 pandemic. 2 Maintaining gait speed is an important strategy for preventing frailty and mitigating its progression in older adults. Indeed, gait speed has been closely associated with health and physical status, survival, well-being, and risk of care and falls in the older adults. 3 – 12 However, there is as yet no widely disseminated intervention for reduced gait speed. For optimal gait speed, the lower leg muscles need to function well, 13 – 14 but their strength and function decline with aging, causing a reduction in gait speed. 15 – 16 We focused on the lower leg muscles as a target of intervention to ameliorate the reduced gait speed in older adults. So far, active exercises for strengthening lower leg musculature have been proposed for older people and their effects on balance, functional mobility, and falls have been reported. 17 – 19 However, in general, there are many challenges to active exercise, including exercise habits, time, access to special facilities, third-party oversight, professional guidance, fatigue, pain, accident, injury, and the presence of illness. These challenges prevent people, especially older adults, from continuing to be motivated to exercise. Meanwhile, electrical muscle stimulation (EMS) devices available for use at home, which deliver electrical impulses to electrodes on target muscles through various forms of current, have recently been developed as a simple, safe, comfortable, and time-saving passive exercise complement to active training methods. 20 – 21 Home EMS is increasingly valued as an easy exercise method for older adults with low physical ability and low motivation to exercise 22 , and as its benefit, an improvement in the functional performance of aging muscles has been shown. 23 – 25 EMS has the potential to be a widespread exercise modality for older adults. However, its actual effect on gait speed remains uncertain. Therefore, we hypothesized that a home EMS would be beneficial for older adults. To test this hypothesis, the present study investigated if and how long-term use of a home EMS device targeting the lower leg muscles affects gait speed in older adults. Results Study population Study flow in our single-centre prospective observational study is shown in Fig. 1 . Eighty-one community-dwelling independent older adults were enrolled. This population consisted of 40 participants in the EMS group and 41 in the non-EMS group. During the 12-week observation period after enrollment, in the EMS group, 2 participants discontinued EMS due to discomfort or hassle, and 4 failed to achieve EMS enforcement of > 15 days per month. Additionally, another two participants were unable to walk on their own. In the non-EMS group, 16 participants were unable to participate in the assessment at 12 weeks and another 3 required physical care. That is, the primary outcome, gait speed, was evaluated in 32 participants in the EMS group and 22 in the non-EMS group. Furthermore, since gait speed of < 1.0 or ≥ 1.0 m/s is strongly associated with subsequent changes in physical activity, 12 they were subgrouped according to comfortable gait speed (CGS) at enrolment. As a result, there were 23 EMS and 20 non-EMS participants in the < 1.0 m/sec group, but only 9 EMS and 2 non-EMS participants in the ≥ 1.0 m/sec group. Therefore, we finally analyzed the data from 43 participants with a CGS of < 1.0 m/sec at enrolment. Baseline characteristics Table 1 shows the baseline characteristics of the 43 participants with a CGS of < 1.0 m/sec at enrolment (0.71 [0.57–0.86] m/sec). Their median age was 80.0 [74.0–85.0] years and most of them (77%) were female. Their grip strength (GS) was nearly comparable to data from a meta-analysis in Japanese community-dwelling older adults (18.5 [14.3–21.8] kg). 26 Moreover, their nutritional status and physical activity were relatively well maintained, as indicated by the mini nutritional assessment short-form (MNA-SF) (13.0 [11.8–14.0]), body mass index (BMI) (23.2 [20.0–24.7]), and a simple questionnaire to rapidly diagnose sarcopenia (SARC-F) (1.0 [0.0–2.0]). 27 – 28 Table 1 Baseline profiles. Variables Non-EMS EMS P value n 43 20 23 Age (Year) 80.0 [74.0–85.0] 77.0 [71.5–85.0] 80.0 [74.0–85.0] 0.3525 Gender (Female) 33 (77%) 16 (80%) 17 (74%) 0.9129 Falls within the past 1 year 15 (35%) 7 (35%) 8 (35%) 0.7597 SARC-F 1.0 [0.0–2.0] 1.0 [0.0–2.0] 1.0 [0.0–2.0] 0.8588 MNA-SF 13.0 [11.8–14.0] 13.0 [12.3–13.8] 13.0 [11.0–14.0] 0.8685 BMI 23.2 [20.0–24.7] 22.7 [21.2–23.8] 23.2 [19.3–24.9] 0.7862 MV (kg) 36.8 [33.0–41.4] 36.4 [33.2–40.8] 36.8 [33.3–49.7] 0.9068 CGS (m/sec) 0.71 [0.57–0.86] 0.71 [0.58–0.84] 0.74 [0.57–0.89] 0.4939 SL (m) 0.83 [0.65–1.00] 0.86 [0.61–0.94] 0.82 [0.65–1.0] 0.9545 GS (kg) 18.5 [14.3–21.8] 18.0 [12.0–20.5] 19.0 [15.0–22.0] 0.3300 LLC (cm) 33.0 [31.5–34.2] 33.3 [30.8–34.1] 33.0 [32.0–34.3] 0.9595 EMS enforcement days (Day) 26.5 [26.0–27.8] All categorical variables were presented as n (%). Continuous variables are shown as median values and [interquartile ranges]. EMS: electrical muscle stimulation; SARC-F: a simple questionnaire to rapidly diagnose sarcopenia; MNA-SF: mini nutritional assessment-short form; BMI: body mass index; MV: muscle volume; CGS: comfortable gait speed; SL: stride length; GS: grip strength; LLC: lower leg circumference. Effects of EMS for lower leg muscles on gait speed Baseline profiles such as age, gender, history of falls in the past year, physical measurements (BMI, CGS, GS, stride length [SL], whole-body muscle volume [MV], lower leg circumference [LLC]), SARC-F, and MNA-SF at enrollment did not differ between the EMS (n = 23) and non-EMS (n = 20) groups, as shown in Table 1 . However, the absolute changes in CGS and SL during the 12-week observation period, namely delta CGS and delta SL, were significantly higher in the EMS group than in the non-EMS group (delta CGS: 0.25 [0.11–0.43] vs. 0.02 [-0.04–0.24] m/sec, P = 0.0037; delta SL: 0.21 [0.11–0.47] vs. 0.03 [-0.08–0.17] m, P = 0.0038; respectively) (Figs. 2 A and 2 B, respectively). Therefore, long-term home EMS for the lower leg muscles was implicated in a significant increase in gait speed in older adults whose CGS had decreased to < 1.0 m/sec. Effects of EMS for lower leg muscles on the plantar center of gravity during gait To explore the mechanism by which EMS positively affects gait speed, the center of gravity (COG) of the plantar foot during gait was assessed simultaneously with gait speed. CGS at enrollment was significantly and negatively correlated with the distribution of COG on small toe ball (STB) during gait (r = -0.4355, 95% confidence interval [CI]: -0.7469 – -0.1241, P = 0.0035), but not with the distribution of COG on big toe ball or heel (r = 0.2789, 95% CI: -0.0712–0.5679, P = 0.1926; r = 0.0281, 95% CI: -0.3238–0.3732, P = 0.8786; respectively) (Fig. 3 A). Thus, the impact of EMS on COG of STB was examined. The absolute change in the COG distribution on STB during the 12-week observation period, namely delta STB COG, was significantly lower in the EMS group than in the non-EMS group (-2.0 [-3.9–0] vs. 0.4 [-0.7–2.4] %, P = 0.0077, respectively) (Fig. 3 B). Therefore, the greater distribution of COG on the STB during gait, which was associated with slower gait speeds, was significantly reduced by long-term home EMS for the lower leg muscles. Effects of EMS for lower leg muscles on other parameters Delta MV during the 12-week observation period did not differ between the EMS and non-EMS groups (-0.1 [-0.8–0.5] vs. -0.5 [-1.2–0.25] kg, P = 0.3681, respectively) (Fig. 4 A). Meanwhile, delta LLC is rather lower in the EMS group than in the non-EMS group (-1.0 [-1.5–0.0] vs. 0.0 [-0.5–0.1] cm, P = 0.0190, respectively) (Fig. 4 B). Alternatively, delta GS was significantly higher in the EMS group than in the non-EMS group (2.0 [1.0–5.0] vs. 0.5 [0.0–2.1] kg, P = 0.0143, respectively) (Fig. 4 C). Delta GS was positively correlated with delta CGS (r = 0.4834, 95% CI: 0.2064–0.6886, P = 0.0005) (Fig. 4 D). Discussion Gait speed is associated with health status, physical activity, survival, well-being, and risk of care and falls in the older adults. 3 – 12 The present study demonstrates for the first time that long-term EMS targeting only the lower leg muscles at home increases gait speed, along with stride length and grip strength, in community-dwelling independent older adults whose comfortable gait speed has decreased to < 1.0 m/sec. Moreover, our data suggest that the mechanism may involve a change in the plantar centre of gravity during gait. The data presented here confer new potential as an effective strategy to improve reduced gait speed to home EMS. Our data suggest the practical benefit of a home-use 20 Hz EMS device on older adults. Low-frequency EMS (20 Hz) is more favorable for fatigue and muscle torque production than high-frequency EMS (50, 60, and 80 Hz). 29 – 30 So far, EMS intervention at 20Hz has been demonstrated to enhance muscle strength and muscle thickness in older adults (Age: 75.6 ± 3.7 years). 31 The present study added a new effect of an improvement in gait speed in the same age population (Age: 78.9 ± 1.2 years). Alternatively, a meaningful change in comfortable gait speed for physical activity in older adults is > 0.1 m/s. 32–33 In the present study, the median change in comfortable gait speed after EMS was 0.25 (95% CI: 0.16–0.34 ) m/sec versus 0.02 (95% CI: -0.02–0.15) m/sec in the control group. Community-dwelling older adults in our study preserved their nutritional status and physical activity, even when their gait speed was < 1.0 m/sec, reflecting the risk of need for care. In such older adults, home-use 20 Hz EMS targeting only the lower leg muscles can generate clinically meaningful increases in gait speed and may help prevent care. Another new finding was the impact of EMS for the lower leg muscles on the plantar centre of gravity during gait. Loss of lateral stability during gait has been shown to be a major risk factor for gait dysfunction in older adults, leading to short-length and wide-based gait. 34 Moreover, balance-impaired older adults demonstrate greater lateral center of gravity during obstacle crossing than young adults. 35 Thus, the lateral center of gravity during gait is likely to adversely affect gait speed in older adults. Consistently, the present study showed that a greater distribution of the centre of gravity to the small toe ball during gait is associated with reduced gait speed. Moreover, our data also showed that in the EMS group, its centre of gravity distribution was significantly diminished. So far, the benefit of EMS on physical balance has also been demonstrated with the berg balance scale. 36 Given these observations, long-term EMS for the lower leg muscles positively influences the plantar centre of gravity during gait, which may be involved in its benefit on gait speed in older adults. We also found that EMS targeting the lower leg muscles seems to increase grip strength. A positive correlation between grip strength and gait speed (r = 0.47, P < 0.001) has been shown in community-dwelling older adults (Age: 73.9 ± 6.8 years; female: 55.1%). 37 Consistently, in the present study population (Age: 78.9 ± 1.2 years; female: 77.0%), a positive correlation was also detected between changes in these measurements during the observation period (r = 0.48, P = 0.0005). Although the underlying mechanism is unclear, the increase in gait speed with EMS may contribute to potentiating grip strength via improved physical performance. Study limitations Our study has several limitations. First, the study was a single-center observational study. Thus, our observation needs to be further examined and validated by a randomized clinical trial (RCT). Second, we assessed total body muscle mass and lower leg circumference, but not muscle strength and muscle mass specific to the lower leg. Therefore, the mechanism of effect of EMS targeting the lower leg muscles on gait speed could not be explained from these perspectives. Third, it was difficult to detect the impact of EMS on frailty in this study. In the present study population, where most participants maintained physical activity at baseline, as indicated by a SARC-F of < 4.0, the 12-week study period may be too short to show changes in physical activity. Ultimately, based on the findings and issues from this study, we have designed and are now conducting an RCT on the effectiveness of EMS in community-dwelling older adults (jRCT1032240312). Methods Study design The study is a prospective observational study conducted with independent older adults living in Kamakura City, Japan, and aims to identify the benefit of long-term EMS targeting the lower leg muscles at home on older adults. The primary outcome was gait speed after 12 weeks of observation. This study was approved by the Institutional Ethics Board of Yokohama City University Hospital (No. F220700053) and was conducted in accordance with the principles of the Declaration of Helsinki. Participants The eligibility criteria included: age ≥ 65 years; no need for physical care in daily life; no need for walking aids; able to ambulate independently; and no participation in any resistance exercise program other than or including EMS in the past 6 months. Patients with cognitive impairment, myalgia, arthralgia, sensory problems, or neurological disorders were excluded from enrolment. Prior to enrollment, written informed consent was obtained from all participants who were provided with sufficient information on the purpose and contribution of the study and the use of the data. In this study, no rewards were offered to participants. EMS protocol EMS for bilateral lower leg muscles was performed for 23 minutes once a day in a sitting position at home using a portable EMS device (SIXPAD Foot Fit 2, MTG Co., Ltd., Nagoya, Japan). The stimulation was delivered at an intensity of 4.85 mA with a frequency of 20 Hz, using square wave pulses with a pulse duration of 100 µs and a pulse cycle of 50 ms. 31 , 36 EMS enforcement was checked monthly through daily records. If the enforcement was ≤ 15 days per month, participants were excluded from the study. Participants in the non-EMS group, who had not undergone a resistance exercise program including EMS, continued with their daily routine only. All participants were to undertake no additional exercise during the 12-week observation period following enrollment. Evaluation of outcome To evaluate the effects of EMS on gait speed, CGS and SL were assessed in the 10-m walking test by blinded examiners at enrollment and within a few days after the end of observation. The test course consisted of a 10-meter flat walkway with additional 2-meter acceleration and deceleration zones at both ends. The time measurement was conducted over the middle 10 meters. SL was calculated by dividing the walking distance by the number of steps. 38 Moreover, during the walking test, the COG of the plantar foot during gait was simultaneously evaluated by wearing shoes with force sensors embedded in the insole located on the big toe ball, small toe ball, and heel (Shokaku Shoes, Touchence Inc., Tokyo. Japan). The sensors can measure vertical ground reaction force at 0.02-second intervals. 39 The COG was calculated from the force values of these three sensors and plotted as coordinates. The distribution of the plantar COG during gait was expressed as the ratio of the number of COG plots on each sensor site to the total number of COG plots on the left foot (Figure S1 ). Other assessments Other parameters were also assessed by blinded examiners at the same time as the CGS. GS was measured using a Smedley-type hand dynamometer with participants in a standing position, arms straight at their sides. Measurements were taken alternately between the right and left hands, with two attempts for each hand. The final GS was calculated as the mean of the better scores from each hand. 40 – 41 MV in whole body as well as BMI was evaluated using a bioelectrical impedance analysis device (InnerScan Voice BC-202, TANITA Corporation, Tokyo, Japan). The lower leg muscle mass parameter, LLC, was also measured at the point of maximum calf circumference on the left leg with the participant seated in a chair with the feet on the horizontal floor. 42 Physical activity was assessed using SARC-F, consisting of five questions on muscle strength, assistance walking, rising from a chair, climbing stairs, and falls. 28 Nutritional status was also assessed using MNA-SF. 27 Sample size The required sample size for between-group analyses of the primary outcome measure of this study was calculated using G*Power 3 analysis set for F-test analysis of covariance. 43 We anticipated that Cohen’s f effect size would be 0.40 (large) for the primary outcome based on previous studies. 44 – 45 The calculations showed that 26 participants are needed per group (total of 52 participants) for a power of 80% and an α value of 5%. Finally, assuming a 30% patient loss during the observation period, we planned to enroll a total of 80 participants in this study. Statistical analysis Statistical analyses were performed using JMP ver. Pro 17.0 software. All categorical variables were presented as n (%). Continuous variables are shown as median values and interquartile ranges. Differences between subgroups were analyzed with Fisher’s exact test (for categorical data) or the Mann-Whitney U test (for continuous data). Correlations between variables were analyzed by a two-tailed Spearman’s rank test. A gait speed of < 1.0 or ≥ 1.0 m/s is strongly associated with future physical activity. 12 Therefore, a final analysis of EMS effects was conducted in subgroups according to CGS (< 1.0 or ≥ 1.0 m/s) at enrolment. Statistical significance was set at P < 0.05. Declarations Authors’ contributions M.N. and N.M. generated hypothesis and experimental design. M.N. and N.M. prepared the manuscript. N.M., S.M., Y.Y., and K.S. collected and analyzed the data. M.T., T.S., and I.T. advised on this study. T.N. supervised this study. All the authors reviewed and edited the manuscript. Acknowledgments The authors thank all the study participants. This work was supported by a support project for teachers' community contribution activities in Yokohama City University. Competing interests The authors declare no competing interests. Disclosure Statement EMS device for the lower leg muscles (Foot fit Ⅱ) was provided by MTG Co., Ltd. Data availability statement The data underlying this article will be shared upon reasonable request to the corresponding author. References Dent, E. et al. Marc Sim. Frailty increases the long-term risk for fall and fracture-related hospitalizations and all-cause mortality in community-dwelling older women. J. Bone Min. Res. 39 , 222–230 (2024). Thomas, S. et al. Impact of the COVID-19 pandemic on hospital episodes for falls and fractures associated with new-onset disability and frailty in England: a national cohort study. Age Ageing . 53 , afae071. 10.1093/ageing/afae071 (2024). Cesari, M. et al. Prognostic value of usual gait speed in well-functioning older people. J. Am. Geriatr. Soc. 53 , 1675–1680 (2005). Rosano, C., Newman, A. B., Katz, R., Hirsch, C. H. & Kuller, L. H. Association between lower digit symbol substitution test score and slower gait and greater risk of mortality and of developing incident disability in well-functioning older adults. J. Am. Geriatr. Soc. 56 , 1618–1625 (2008). Cesari, M. et al. Added value of physical performance measures in predicting adverse health-related events: results from the Health, Aging And Body Composition Study. J. Am. Geriatr. Soc. 57 , 251–259 (2009). Studenski, S. et al. Gait speed and survival in older adults. JAMA 305 , 50–58 (2011). van Abellan, G. et al. Gait speed at usual pace as a predictor of adverse outcomes in community-dwelling older people. J. Nutr. Health Aging . 13 , 881–889 (2009). Kim, M., Yabushita, N. & Tanaka, K. Exploring effective items of physical function in slow walking speed and self-reported mobility limitation in community-dwelling older adults. Geriatr. Gerontol. Int. 12 , 50–58 (2012). Peel, N. M., Navanathan, S. & Hubbard, R. E. Gait speed as a predictor of outcomes in post-acute transitional care for older people. Geriatr. Gerontol. Int. 14 , 906–910 (2014). Quach, L. et al. The nonlinear relationship between gait speed and falls: the Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly of Boston Study. J. Am. Geriatr. Soc. 59 , 1069–1073 (2011). Adam, C. E. et al. Change in gait speed and fall risk among community-dwelling older adults with and without mild cognitive impairment: a retrospective cohort analysis. BMC Geriatr. 23 , 328. 10.1186/s12877-023-03890-6 (2023). Shimada, H. et al. Performance-based assessments and demand for personal care in older Japanese people: a cross-sectional study. BMJ Open . 10 , e002424. 10.1136/bmjopen-2012-002424 (2013). Neptune, R. R., Sasaki, K. & Kautz, S. A. The effect of walking speed on muscle function and mechanical energetics. Gait Posture . 28 , 135–143 (2008). Hirano, Y., Yamada, Y., Matsui, Y., Ota, S. & Arai, H. Lower limb muscle quality and phase angle contribute to the reduced walking speed among older adults. Geriatr. Gerontol. Int. 22 , 603–609 (2022). Mitchell, W. K. et al. Sarcopenia, dynapenia and the impact of advancing age on human skeletal muscle size and strength; a quantitative review. Front. Physiol. 3 , 260. 10.3389/fphys.2012.00260 (2012). Marcell, T. J., Hawkins, S. A. & Wiswell, R. A. Leg strength declines with advancing age despite habitual endurance exercise in active older adults. J. Strength. Cond Res. 28 , 504–513 (2014). Hortobágyi, T. et al. Effects of three types of exercise interventions on healthy old adults’ gait speed: A systematic review and meta-analysis. Sports Med. 45 , 1627–1643 (2015). Sadeghi, H. et al. Effects of 8 Weeks of Balance Training, Virtual Reality Training, and Combined Exercise on Lower Limb Muscle Strength, Balance, and Functional Mobility Among Older Men: A Randomized Controlled Trial. Sports Health . 13 , 606–612 (2021). Feng, Y., Liu, J. & Si, J. Effects of Chinese fitness dancing on lower limb strength and fall risk in middle-aged and older women: A cross-sectional study. Nurs. Health Sci. 25 , 80–88 (2023). Kemmler, W. et al. Efficacy and Safety of Low Frequency Whole-Body Electromyostimulation (WB-EMS) to Improve Health-Related Outcomes in Non-athletic Adults. A Systematic Review. Front. Physiol. 9 , 573. 10.3389/fphys.2018.00573 (2018). Moritani, T. Electrical muscle stimulation: Application and potential role in aging society. J. Electromyogr. Kinesiol. 61 , 102598. 10.1016/j.jelekin.2021.102598 (2021). O'Connor, D., Brennan, L. & Caulfield, B. The use of neuromuscular electrical stimulation (NMES) for managing the complications of ageing related to reduced exercise participation. Maturitas 113 , 13–20 (2018). Mayr, W. Neuromuscular Electrical Stimulation for Mobility Support of Elderly. Eur. J. Transl Myol . 25 , 263–268 (2015). Zampieri, S. et al. Physical Exercise in Aging: Nine Weeks of Leg Press or Electrical Stimulation Training in 70 Years Old Sedentary Elderly People. Eur. J. Transl Myol . 25 , 237–242 (2015). Kern, H. et al. Electrical stimulation counteracts muscle decline in seniors. Front. Aging Neurosci. 6 , 189. 10.3389/fnagi.2014.00189 (2014). Kamide, N., Kamiya, R., Nakazono, T. & Ando, M. Reference values for hand grip strength in Japanese community-dwelling elderly: a meta-analysis. Environ. Health Prev. Med. 20 , 441–446 (2015). Rubenstein, L. Z., Harker, J. O., Salvà, A., Guigoz, Y. & Vellas, B. Screening for undernutrition in geriatric practice: developing the short-form mini-nutritional assessment (MNA-SF). J. Gerontol. Biol. Sci. Med. Sci. 56 , 366–372 (2001). Malmstrom, T. K. & Morley, J. E. SARC-F: a simple questionnaire to rapidly diagnose sarcopenia. J. Am. Med. Dir. Assoc. 14 , 531–532 (2013). Moritani, T., Muro, M. & Kijima, A. Electromechanical changes during electrically induced and maximal voluntary contractions: electrophysiologic responses of different muscle fiber types during stimulated contractions. Exp. Neurol. 88 , 471–483 (1985). Moritani, T., Muro, M., Kijima, A., Gaffney, F. A. & Parsons, D. Electromechanical changes during electrically induced and maximal voluntary contractions: surface and intramuscular EMG responses during sustained maximal voluntary contraction. Exp. Neurol. 88 , 484–499 (1985). Nishikawa, Y. et al. The effect of a portable electrical muscle stimulation device at home on muscle strength and activation patterns in locomotive syndrome patients: A randomized control trial. J. Electromyogr. Kinesiol. 45 , 46–52 (2019). Perera, S., Mody, S. H., Woodman, R. C. & Studenski, S. A. Meaningful change and responsiveness in common physical performance measures in older adults. J. Am. Geriatr. Soc. 54 , 743–749 (2006). Bohannon, R. W. & Glenney, S. S. Minimal clinically important difference for change in comfortable gait speed of adults with pathology: a systematic review. J. Eval Clin. Pract. 20 , 295–300 (2014). Maki, B. E. Gait changes in older adults: predictors of falls or indicators of fear. J. Am. Geriatr. Soc. 45 , 313–320 (1997). Chou, L. S., Kaufman, K. R., Hahn, M. E. & Brey, R. H. Medio-lateral motion of the center of mass during obstacle crossing distinguishes elderly individuals with imbalance. Gait Posture . 18 , 125–133 (2003). Nishikawa, Y. et al. The Effect of Electrical Muscle Stimulation on Muscle Mass and Balance in Older Adults with Dementia. Brain Sci. 11 , 339. 10.3390/brainsci11030339 (2021). Lin, Y. H., Chen, H. C., Hsu, N. W. & Chou, P. Using hand grip strength to detect slow walking speed in older adults: the Yilan study. BMC Geriatr. 21 , 428. 10.1186/s12877-021-02361-0 (2021). Makino, K. et al. Fear of falling and gait parameters in older adults with and without fall history. Geriatr. Gerontol. Int. 17 , 2455–2459 (2017). Takahashi, H. & Shimazaki, K. Measurement of plantar reaction force during running using insoles with six-axis tactile sensors. Descente Sports Sci. 45 , 12–21 (2024). Oxford, K. L. Elbow positioning for maximum grip performance. J. Hand Ther. 13 , 33–36 (2000). Kishimoto, H. et al. Midlife and late-life handgrip strength and risk of cause- specific death in a general Japanese population: the Hisayama Study. J. Epidemiol. Commun. Health . 68 , 663–668 (2014). Ishii, S. et al. Development of a simple screening test for sarcopenia in older adults. Geriatr. Gerontol. Int. 14 , 93–101 (2014). Faul, F., Erdfelder, E., Lang, A. G. & Buchner, A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav. Res. Methods . 39 , 175–191 (2007). Maddocks, M., Gao, W., Higginson, I. J. & Wilcock, A. Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease. Cochrane Database Syst. Rev. 1 10.1002/14651858.CD009419 (2013). Jones, S. et al. Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease. Cochrane Database Syst. Rev. 10 10.1002/14651858.CD009419 (2016). Additional Declarations No competing interests reported. Supplementary Files ScientificreportTable1.docx ScientificreportFigureS1.tif ScientificreportSupplementalfigurelegends.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 09 Jul, 2025 Reviews received at journal 22 Jun, 2025 Reviewers agreed at journal 07 Jun, 2025 Reviewers invited by journal 28 May, 2025 Editor assigned by journal 23 May, 2025 Editor invited by journal 19 May, 2025 Submission checks completed at journal 16 May, 2025 First submitted to journal 03 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6586131","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":463161086,"identity":"bdfe67e5-f94d-4822-82fe-1ab0abd34090","order_by":0,"name":"Naho Misawa","email":"","orcid":"","institution":"Yokohama City University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Naho","middleName":"","lastName":"Misawa","suffix":""},{"id":463161088,"identity":"e31a32f5-f25b-4107-b5aa-95764f5a2ecb","order_by":1,"name":"Mototsugu Nishii","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFUlEQVRIie3QP0vDQBjH8SccNMul80HFCL6BJ2RQwT9vJSHQLgoZHYLclEmc6+RbqIurTzm4Lqdz4Cbp2qEgSIcqth2kFK7FTfC+Uzj4kN8dgM/3J1NEUxT7AC1g6+fMBSDQ+bBfHqe/IMwcKj69zuUmcRbXBoij6A1GdT4uq6cYQoMwqyA8chA0L0QCxdXAaJX2tU0kv8TgVgM7kQ4iXjPCJWl6dYe3bPDccIRIAkNyDHuYIGWLYbgiX/ZCCo7B5xYCZJAIRYZNV3ei2uZLwrb9BUlnQ4kiuTe6SKM7W0jeLdWeFs67xFKp9/n8Jm6P6mTMP+yZDNXj26Q6LVwv9tPB+ozFtyhwF4k3Z5zvJD6fz/df+gaa32EHExgohQAAAABJRU5ErkJggg==","orcid":"","institution":"Yokohama City University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Mototsugu","middleName":"","lastName":"Nishii","suffix":""},{"id":463161089,"identity":"94ac7427-bc43-4793-91a1-7902876f9831","order_by":2,"name":"Saki Morita","email":"","orcid":"","institution":"Yokohama City University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Saki","middleName":"","lastName":"Morita","suffix":""},{"id":463161090,"identity":"793c080c-769e-476a-be01-308ded70e411","order_by":3,"name":"Yuri Yaguchi","email":"","orcid":"","institution":"Yokohama City University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yuri","middleName":"","lastName":"Yaguchi","suffix":""},{"id":463161091,"identity":"5b4a1aa0-3131-4210-8db0-f9d6f929e623","order_by":4,"name":"Kazuya Sakai","email":"","orcid":"","institution":"Yokohama City University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kazuya","middleName":"","lastName":"Sakai","suffix":""},{"id":463161092,"identity":"d347b187-5caf-4e7f-82de-a7aa58b88c56","order_by":5,"name":"Megumi Taketani","email":"","orcid":"","institution":"MTG Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Megumi","middleName":"","lastName":"Taketani","suffix":""},{"id":463161094,"identity":"a0a39a84-9057-427c-b515-26f289ac85d6","order_by":6,"name":"Tomoyuki Shirai","email":"","orcid":"","institution":"MTG Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Tomoyuki","middleName":"","lastName":"Shirai","suffix":""},{"id":463161096,"identity":"1c98cdf8-3e19-442f-bfbf-646629443927","order_by":7,"name":"Ichiro Takeuchi","email":"","orcid":"","institution":"Yokohama City University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Ichiro","middleName":"","lastName":"Takeuchi","suffix":""},{"id":463161097,"identity":"aa71c16a-03a2-466d-b43f-3450fecf1416","order_by":8,"name":"Toyoaki Nishii","email":"","orcid":"","institution":"Nishii Clinic, Medical Corporation Hoju-kai","correspondingAuthor":false,"prefix":"","firstName":"Toyoaki","middleName":"","lastName":"Nishii","suffix":""}],"badges":[],"createdAt":"2025-05-04 00:53:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6586131/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6586131/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83811357,"identity":"ca147828-3dc2-493b-b3cb-7074fe474aac","added_by":"auto","created_at":"2025-06-03 07:03:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":268251,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStudy flow and participants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEMS: electrical stimulation for the lower leg muscles, CGS: comfortable gait speed.\u003c/p\u003e","description":"","filename":"ScientificreportFigure1.png","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/48c2268fdf2d7b6ce5424c92.png"},{"id":83812397,"identity":"b874346a-3739-4566-bd78-b62ee06ad959","added_by":"auto","created_at":"2025-06-03 07:11:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":160939,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of long-term electrical stimulation for the lower leg muscles (EMS) on gait speed\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAbsolute changes in comfortable walking speed (CGS) (\u003cstrong\u003eA\u003c/strong\u003e) and stride length (SL) (\u003cstrong\u003eB\u003c/strong\u003e) during the 12-week observation period, namely delta CGS and SL were compared between the EMS and non-EMS groups. All values are shown as the box-and-whisker diagram and dot plot. *\u003cem\u003e P\u003c/em\u003e\u0026lt; 0.01.\u003c/p\u003e","description":"","filename":"ScientificreportFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/570034d0092adca1b9e3d740.png"},{"id":83811360,"identity":"fa1afd2c-a179-464e-80fb-beed29beb7a1","added_by":"auto","created_at":"2025-06-03 07:03:24","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":343121,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of long-term electrical stimulation for the lower leg muscles (EMS) on the plantar center of gravity.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(\u003cstrong\u003eA\u003c/strong\u003e) The correlations between comfortable gait speed (CGS) and the ratios of the center of gravity (COG) plots of the small toe ball (STB), big toe ball (BTB), and heel (HL) to the total plantar COG plots during gait at enrollment were evaluated. Closed circles indicate individual levels. (\u003cstrong\u003eB\u003c/strong\u003e) Absolute changes in the COG plot ratio of STB during the 12-week observation period, namely delta STB COG were compared between the EMS and non-EMS groups. All values are shown as the box-and-whisker diagram and dot plot. * \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01.\u003c/p\u003e","description":"","filename":"ScientificreportFigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/da4a59365623b6519a6dc2fa.png"},{"id":83812400,"identity":"dd79be08-19e6-4e75-a6ff-ecfa3cbda813","added_by":"auto","created_at":"2025-06-03 07:11:24","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":202955,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of long-term electrical stimulation for the lower leg muscles (EMS) on other parameters.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(\u003cstrong\u003eA\u003c/strong\u003e, \u003cstrong\u003eB, \u003c/strong\u003eand\u003cstrong\u003e C\u003c/strong\u003e) Absolute changes in whole-body muscle volume (MV) (\u003cstrong\u003eA\u003c/strong\u003e), lower leg circumference (LLC) (\u003cstrong\u003eB\u003c/strong\u003e), and grip strength (GS) (\u003cstrong\u003eC\u003c/strong\u003e) during the 12-week observation period, namely delta MV, LLC, and GS were compared between the EMS and non-EMS groups. All values are shown as the box-and-whisker diagram and dot plot. #\u003cem\u003e P\u003c/em\u003e \u0026lt; 0.05. (\u003cstrong\u003eD\u003c/strong\u003e) The correlation between absolute changes in comfortable gait speed (CGS) and GS after 12 weeks, namely delta CGS and delta GS was evaluated. Closed circles indicate individual levels.\u003c/p\u003e","description":"","filename":"ScientificreportFigure4.png","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/ac4391e09e35c0d343b53066.png"},{"id":83813197,"identity":"1ecc6fb7-6a64-42a3-b33c-6b8c423c3cfb","added_by":"auto","created_at":"2025-06-03 07:19:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1682926,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/af9901b4-2f7e-4ebd-a4ac-d7f76052f600.pdf"},{"id":83811351,"identity":"2dfe4b82-0834-4837-be45-e39956b93d13","added_by":"auto","created_at":"2025-06-03 07:03:24","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":22336,"visible":true,"origin":"","legend":"","description":"","filename":"ScientificreportTable1.docx","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/da3a6f2d2e5b1d284e43cb1e.docx"},{"id":83811355,"identity":"d93efb32-f0c3-4dfb-8c0a-186c443f97e1","added_by":"auto","created_at":"2025-06-03 07:03:24","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1538170,"visible":true,"origin":"","legend":"","description":"","filename":"ScientificreportFigureS1.tif","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/b54e794e45ef8cc090a5c6b1.tif"},{"id":83811354,"identity":"f0585660-10d4-4488-8433-72985b5175a4","added_by":"auto","created_at":"2025-06-03 07:03:24","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":16237,"visible":true,"origin":"","legend":"","description":"","filename":"ScientificreportSupplementalfigurelegends.docx","url":"https://assets-eu.researchsquare.com/files/rs-6586131/v1/974b3aa492435758d35dc5e1.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of long-term electrical stimulation of the lower leg muscles at home on gait speed in community-dwelling older adults","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe intervention for physical frailty, which can lead to falls and debilitation in older adults, is critical for maintaining emergency medical services in an ageing society.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e This was highlighted by the COVID-19 pandemic.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e Maintaining gait speed is an important strategy for preventing frailty and mitigating its progression in older adults. Indeed, gait speed has been closely associated with health and physical status, survival, well-being, and risk of care and falls in the older adults.\u003csup\u003e\u003cspan additionalcitationids=\"CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e However, there is as yet no widely disseminated intervention for reduced gait speed.\u003c/p\u003e \u003cp\u003eFor optimal gait speed, the lower leg muscles need to function well,\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e but their strength and function decline with aging, causing a reduction in gait speed.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e We focused on the lower leg muscles as a target of intervention to ameliorate the reduced gait speed in older adults. So far, active exercises for strengthening lower leg musculature have been proposed for older people and their effects on balance, functional mobility, and falls have been reported.\u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e However, in general, there are many challenges to active exercise, including exercise habits, time, access to special facilities, third-party oversight, professional guidance, fatigue, pain, accident, injury, and the presence of illness. These challenges prevent people, especially older adults, from continuing to be motivated to exercise.\u003c/p\u003e \u003cp\u003eMeanwhile, electrical muscle stimulation (EMS) devices available for use at home, which deliver electrical impulses to electrodes on target muscles through various forms of current, have recently been developed as a simple, safe, comfortable, and time-saving passive exercise complement to active training methods.\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e Home EMS is increasingly valued as an easy exercise method for older adults with low physical ability and low motivation to exercise \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e, and as its benefit, an improvement in the functional performance of aging muscles has been shown.\u003csup\u003e\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e EMS has the potential to be a widespread exercise modality for older adults. However, its actual effect on gait speed remains uncertain.\u003c/p\u003e \u003cp\u003eTherefore, we hypothesized that a home EMS would be beneficial for older adults. To test this hypothesis, the present study investigated if and how long-term use of a home EMS device targeting the lower leg muscles affects gait speed in older adults.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy population\u003c/h2\u003e \u003cp\u003eStudy flow in our single-centre prospective observational study is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Eighty-one community-dwelling independent older adults were enrolled. This population consisted of 40 participants in the EMS group and 41 in the non-EMS group. During the 12-week observation period after enrollment, in the EMS group, 2 participants discontinued EMS due to discomfort or hassle, and 4 failed to achieve EMS enforcement of \u0026gt;\u0026thinsp;15 days per month. Additionally, another two participants were unable to walk on their own. In the non-EMS group, 16 participants were unable to participate in the assessment at 12 weeks and another 3 required physical care. That is, the primary outcome, gait speed, was evaluated in 32 participants in the EMS group and 22 in the non-EMS group. Furthermore, since gait speed of \u0026lt;\u0026thinsp;1.0 or \u0026ge;\u0026thinsp;1.0 m/s is strongly associated with subsequent changes in physical activity,\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e they were subgrouped according to comfortable gait speed (CGS) at enrolment. As a result, there were 23 EMS and 20 non-EMS participants in the \u0026lt;\u0026thinsp;1.0 m/sec group, but only 9 EMS and 2 non-EMS participants in the \u0026ge;\u0026thinsp;1.0 m/sec group. Therefore, we finally analyzed the data from 43 participants with a CGS of \u0026lt;\u0026thinsp;1.0 m/sec at enrolment.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eBaseline characteristics\u003c/h3\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the baseline characteristics of the 43 participants with a CGS of \u0026lt;\u0026thinsp;1.0 m/sec at enrolment (0.71 [0.57\u0026ndash;0.86] m/sec). Their median age was 80.0 [74.0\u0026ndash;85.0] years and most of them (77%) were female. Their grip strength (GS) was nearly comparable to data from a meta-analysis in Japanese community-dwelling older adults (18.5 [14.3\u0026ndash;21.8] kg).\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e Moreover, their nutritional status and physical activity were relatively well maintained, as indicated by the mini nutritional assessment short-form (MNA-SF) (13.0 [11.8\u0026ndash;14.0]), body mass index (BMI) (23.2 [20.0\u0026ndash;24.7]), and a simple questionnaire to rapidly diagnose sarcopenia (SARC-F) (1.0 [0.0\u0026ndash;2.0]).\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eBaseline profiles.\u003c/b\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNon-EMS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEMS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (Year)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80.0 [74.0\u0026ndash;85.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e77.0 [71.5\u0026ndash;85.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80.0 [74.0\u0026ndash;85.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.3525\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender (Female)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33 (77%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (80%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17 (74%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.9129\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFalls within the past 1 year\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.7597\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSARC-F\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.0 [0.0\u0026ndash;2.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.0 [0.0\u0026ndash;2.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.0 [0.0\u0026ndash;2.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.8588\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMNA-SF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.0 [11.8\u0026ndash;14.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.0 [12.3\u0026ndash;13.8]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.0 [11.0\u0026ndash;14.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.8685\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.2 [20.0\u0026ndash;24.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.7 [21.2\u0026ndash;23.8]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.2 [19.3\u0026ndash;24.9]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.7862\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMV (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.8 [33.0\u0026ndash;41.4]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36.4 [33.2\u0026ndash;40.8]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e36.8 [33.3\u0026ndash;49.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.9068\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCGS (m/sec)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.71 [0.57\u0026ndash;0.86]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.71 [0.58\u0026ndash;0.84]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.74 [0.57\u0026ndash;0.89]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.4939\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSL (m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.83 [0.65\u0026ndash;1.00]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.86 [0.61\u0026ndash;0.94]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.82 [0.65\u0026ndash;1.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.9545\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGS (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.5 [14.3\u0026ndash;21.8]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.0 [12.0\u0026ndash;20.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.0 [15.0\u0026ndash;22.0]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.3300\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLLC (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.0 [31.5\u0026ndash;34.2]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.3 [30.8\u0026ndash;34.1]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33.0 [32.0\u0026ndash;34.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.9595\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEMS enforcement days (Day)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26.5 [26.0\u0026ndash;27.8]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eAll categorical variables were presented as n (%). Continuous variables are shown as median values and [interquartile ranges]. EMS: electrical muscle stimulation; SARC-F: a simple questionnaire to rapidly diagnose sarcopenia; MNA-SF: mini nutritional assessment-short form; BMI: body mass index; MV: muscle volume; CGS: comfortable gait speed; SL: stride length; GS: grip strength; LLC: lower leg circumference.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eEffects of EMS for lower leg muscles on gait speed\u003c/h3\u003e\n\u003cp\u003eBaseline profiles such as age, gender, history of falls in the past year, physical measurements (BMI, CGS, GS, stride length [SL], whole-body muscle volume [MV], lower leg circumference [LLC]), SARC-F, and MNA-SF at enrollment did not differ between the EMS (n\u0026thinsp;=\u0026thinsp;23) and non-EMS (n\u0026thinsp;=\u0026thinsp;20) groups, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. However, the absolute changes in CGS and SL during the 12-week observation period, namely delta CGS and delta SL, were significantly higher in the EMS group than in the non-EMS group (delta CGS: 0.25 [0.11\u0026ndash;0.43] vs. 0.02 [-0.04\u0026ndash;0.24] m/sec, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0037; delta SL: 0.21 [0.11\u0026ndash;0.47] vs. 0.03 [-0.08\u0026ndash;0.17] m, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0038; respectively) (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB, respectively). Therefore, long-term home EMS for the lower leg muscles was implicated in a significant increase in gait speed in older adults whose CGS had decreased to \u0026lt;\u0026thinsp;1.0 m/sec.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003e\u003c/h3\u003e\n\u003cdiv class=\"Heading\"\u003e\u003cb\u003eEffects of EMS for lower leg muscles on the plantar center of gravity during gait\u003c/b\u003e\u003c/div\u003e \u003cp\u003eTo explore the mechanism by which EMS positively affects gait speed, the center of gravity (COG) of the plantar foot during gait was assessed simultaneously with gait speed. CGS at enrollment was significantly and negatively correlated with the distribution of COG on small toe ball (STB) during gait (r = -0.4355, 95% confidence interval [CI]: -0.7469 \u0026ndash; -0.1241, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0035), but not with the distribution of COG on big toe ball or heel (r\u0026thinsp;=\u0026thinsp;0.2789, 95% CI: -0.0712\u0026ndash;0.5679, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.1926; r\u0026thinsp;=\u0026thinsp;0.0281, 95% CI: -0.3238\u0026ndash;0.3732, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.8786; respectively) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). Thus, the impact of EMS on COG of STB was examined. The absolute change in the COG distribution on STB during the 12-week observation period, namely delta STB COG, was significantly lower in the EMS group than in the non-EMS group (-2.0 [-3.9\u0026ndash;0] vs. 0.4 [-0.7\u0026ndash;2.4] %, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0077, respectively) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB). Therefore, the greater distribution of COG on the STB during gait, which was associated with slower gait speeds, was significantly reduced by long-term home EMS for the lower leg muscles.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eEffects of EMS for lower leg muscles on other parameters\u003c/h3\u003e\n\u003cp\u003eDelta MV during the 12-week observation period did not differ between the EMS and non-EMS groups (-0.1 [-0.8\u0026ndash;0.5] vs. -0.5 [-1.2\u0026ndash;0.25] kg, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.3681, respectively) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). Meanwhile, delta LLC is rather lower in the EMS group than in the non-EMS group (-1.0 [-1.5\u0026ndash;0.0] vs. 0.0 [-0.5\u0026ndash;0.1] cm, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0190, respectively) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB). Alternatively, delta GS was significantly higher in the EMS group than in the non-EMS group (2.0 [1.0\u0026ndash;5.0] vs. 0.5 [0.0\u0026ndash;2.1] kg, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0143, respectively) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC). Delta GS was positively correlated with delta CGS (r\u0026thinsp;=\u0026thinsp;0.4834, 95% CI: 0.2064\u0026ndash;0.6886, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0005) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eD).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eGait speed is associated with health status, physical activity, survival, well-being, and risk of care and falls in the older adults.\u003csup\u003e\u003cspan additionalcitationids=\"CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e The present study demonstrates for the first time that long-term EMS targeting only the lower leg muscles at home increases gait speed, along with stride length and grip strength, in community-dwelling independent older adults whose comfortable gait speed has decreased to \u0026lt;\u0026thinsp;1.0 m/sec. Moreover, our data suggest that the mechanism may involve a change in the plantar centre of gravity during gait. The data presented here confer new potential as an effective strategy to improve reduced gait speed to home EMS.\u003c/p\u003e \u003cp\u003eOur data suggest the practical benefit of a home-use 20 Hz EMS device on older adults. Low-frequency EMS (20 Hz) is more favorable for fatigue and muscle torque production than high-frequency EMS (50, 60, and 80 Hz).\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e So far, EMS intervention at 20Hz has been demonstrated to enhance muscle strength and muscle thickness in older adults (Age: 75.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7 years).\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e The present study added a new effect of an improvement in gait speed in the same age population (Age: 78.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 years). Alternatively, a meaningful change in comfortable gait speed for physical activity in older adults is \u0026gt;\u0026thinsp;0.1 m/s.\u003csup\u003e32\u0026ndash;33\u003c/sup\u003e In the present study, the median change in comfortable gait speed after EMS was 0.25 (95% CI: 0.16\u0026ndash;0.34 ) m/sec versus 0.02 (95% CI: -0.02\u0026ndash;0.15) m/sec in the control group. Community-dwelling older adults in our study preserved their nutritional status and physical activity, even when their gait speed was \u0026lt;\u0026thinsp;1.0 m/sec, reflecting the risk of need for care. In such older adults, home-use 20 Hz EMS targeting only the lower leg muscles can generate clinically meaningful increases in gait speed and may help prevent care.\u003c/p\u003e \u003cp\u003eAnother new finding was the impact of EMS for the lower leg muscles on the plantar centre of gravity during gait. Loss of lateral stability during gait has been shown to be a major risk factor for gait dysfunction in older adults, leading to short-length and wide-based gait.\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e Moreover, balance-impaired older adults demonstrate greater lateral center of gravity during obstacle crossing than young adults.\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e Thus, the lateral center of gravity during gait is likely to adversely affect gait speed in older adults. Consistently, the present study showed that a greater distribution of the centre of gravity to the small toe ball during gait is associated with reduced gait speed. Moreover, our data also showed that in the EMS group, its centre of gravity distribution was significantly diminished. So far, the benefit of EMS on physical balance has also been demonstrated with the berg balance scale.\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e Given these observations, long-term EMS for the lower leg muscles positively influences the plantar centre of gravity during gait, which may be involved in its benefit on gait speed in older adults.\u003c/p\u003e \u003cp\u003eWe also found that EMS targeting the lower leg muscles seems to increase grip strength. A positive correlation between grip strength and gait speed (r\u0026thinsp;=\u0026thinsp;0.47, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) has been shown in community-dwelling older adults (Age: 73.9\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8 years; female: 55.1%).\u003csup\u003e37\u003c/sup\u003e Consistently, in the present study population (Age: 78.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 years; female: 77.0%), a positive correlation was also detected between changes in these measurements during the observation period (r\u0026thinsp;=\u0026thinsp;0.48, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0005). Although the underlying mechanism is unclear, the increase in gait speed with EMS may contribute to potentiating grip strength via improved physical performance.\u003c/p\u003e\n\u003ch3\u003eStudy limitations\u003c/h3\u003e\n\u003cp\u003eOur study has several limitations. First, the study was a single-center observational study. Thus, our observation needs to be further examined and validated by a randomized clinical trial (RCT). Second, we assessed total body muscle mass and lower leg circumference, but not muscle strength and muscle mass specific to the lower leg. Therefore, the mechanism of effect of EMS targeting the lower leg muscles on gait speed could not be explained from these perspectives. Third, it was difficult to detect the impact of EMS on frailty in this study. In the present study population, where most participants maintained physical activity at baseline, as indicated by a SARC-F of \u0026lt;\u0026thinsp;4.0, the 12-week study period may be too short to show changes in physical activity. Ultimately, based on the findings and issues from this study, we have designed and are now conducting an RCT on the effectiveness of EMS in community-dwelling older adults (jRCT1032240312).\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eStudy design\u003c/h2\u003e \u003cp\u003eThe study is a prospective observational study conducted with independent older adults living in Kamakura City, Japan, and aims to identify the benefit of long-term EMS targeting the lower leg muscles at home on older adults. The primary outcome was gait speed after 12 weeks of observation. This study was approved by the Institutional Ethics Board of Yokohama City University Hospital (No. F220700053) and was conducted in accordance with the principles of the Declaration of Helsinki.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eParticipants\u003c/h2\u003e \u003cp\u003eThe eligibility criteria included: age\u0026thinsp;\u0026ge;\u0026thinsp;65 years; no need for physical care in daily life; no need for walking aids; able to ambulate independently; and no participation in any resistance exercise program other than or including EMS in the past 6 months. Patients with cognitive impairment, myalgia, arthralgia, sensory problems, or neurological disorders were excluded from enrolment. Prior to enrollment, written informed consent was obtained from all participants who were provided with sufficient information on the purpose and contribution of the study and the use of the data. In this study, no rewards were offered to participants.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eEMS protocol\u003c/h2\u003e \u003cp\u003eEMS for bilateral lower leg muscles was performed for 23 minutes once a day in a sitting position at home using a portable EMS device (SIXPAD Foot Fit 2, MTG Co., Ltd., Nagoya, Japan). The stimulation was delivered at an intensity of 4.85 mA with a frequency of 20 Hz, using square wave pulses with a pulse duration of 100 \u0026micro;s and a pulse cycle of 50 ms.\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e EMS enforcement was checked monthly through daily records. If the enforcement was \u0026le;\u0026thinsp;15 days per month, participants were excluded from the study. Participants in the non-EMS group, who had not undergone a resistance exercise program including EMS, continued with their daily routine only. All participants were to undertake no additional exercise during the 12-week observation period following enrollment.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eEvaluation of outcome\u003c/h2\u003e \u003cp\u003eTo evaluate the effects of EMS on gait speed, CGS and SL were assessed in the 10-m walking test by blinded examiners at enrollment and within a few days after the end of observation. The test course consisted of a 10-meter flat walkway with additional 2-meter acceleration and deceleration zones at both ends. The time measurement was conducted over the middle 10 meters. SL was calculated by dividing the walking distance by the number of steps.\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e Moreover, during the walking test, the COG of the plantar foot during gait was simultaneously evaluated by wearing shoes with force sensors embedded in the insole located on the big toe ball, small toe ball, and heel (Shokaku Shoes, Touchence Inc., Tokyo. Japan). The sensors can measure vertical ground reaction force at 0.02-second intervals.\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e The COG was calculated from the force values of these three sensors and plotted as coordinates. The distribution of the plantar COG during gait was expressed as the ratio of the number of COG plots on each sensor site to the total number of COG plots on the left foot (Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eOther assessments\u003c/h2\u003e \u003cp\u003eOther parameters were also assessed by blinded examiners at the same time as the CGS. GS was measured using a Smedley-type hand dynamometer with participants in a standing position, arms straight at their sides. Measurements were taken alternately between the right and left hands, with two attempts for each hand. The final GS was calculated as the mean of the better scores from each hand.\u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e MV in whole body as well as BMI was evaluated using a bioelectrical impedance analysis device (InnerScan Voice BC-202, TANITA Corporation, Tokyo, Japan). The lower leg muscle mass parameter, LLC, was also measured at the point of maximum calf circumference on the left leg with the participant seated in a chair with the feet on the horizontal floor.\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e Physical activity was assessed using SARC-F, consisting of five questions on muscle strength, assistance walking, rising from a chair, climbing stairs, and falls.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e Nutritional status was also assessed using MNA-SF.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eSample size\u003c/h2\u003e \u003cp\u003eThe required sample size for between-group analyses of the primary outcome measure of this study was calculated using G*Power 3 analysis set for F-test analysis of covariance.\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e We anticipated that Cohen\u0026rsquo;s f effect size would be 0.40 (large) for the primary outcome based on previous studies.\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e The calculations showed that 26 participants are needed per group (total of 52 participants) for a power of 80% and an α value of 5%. Finally, assuming a 30% patient loss during the observation period, we planned to enroll a total of 80 participants in this study.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses were performed using JMP ver. Pro 17.0 software. All categorical variables were presented as n (%). Continuous variables are shown as median values and interquartile ranges. Differences between subgroups were analyzed with Fisher\u0026rsquo;s exact test (for categorical data) or the Mann-Whitney U test (for continuous data). Correlations between variables were analyzed by a two-tailed Spearman\u0026rsquo;s rank test. A gait speed of \u0026lt;\u0026thinsp;1.0 or \u0026ge;\u0026thinsp;1.0 m/s is strongly associated with future physical activity.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e Therefore, a final analysis of EMS effects was conducted in subgroups according to CGS (\u0026lt;\u0026thinsp;1.0 or \u0026ge;\u0026thinsp;1.0 m/s) at enrolment. Statistical significance was set at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eM.N. and N.M. generated hypothesis and experimental design. M.N. and N.M. prepared the manuscript. N.M., S.M., Y.Y., and K.S. collected and analyzed the data. M.T., T.S., and I.T. advised on this study. T.N. supervised this study. All the authors reviewed and edited the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank all the study participants. This work was supported by a support project for teachers\u0026apos; community contribution activities in Yokohama City University.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisclosure Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEMS device for the lower leg muscles (Foot fit Ⅱ) was provided by\u0026nbsp;MTG Co., Ltd.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data underlying this article will be shared upon reasonable request to the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eDent, E. et al. Marc Sim. Frailty increases the long-term risk for fall and fracture-related hospitalizations and all-cause mortality in community-dwelling older women. \u003cem\u003eJ. Bone Min. Res.\u003c/em\u003e \u003cb\u003e39\u003c/b\u003e, 222\u0026ndash;230 (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThomas, S. et al. Impact of the COVID-19 pandemic on hospital episodes for falls and fractures associated with new-onset disability and frailty in England: a national cohort study. \u003cem\u003eAge Ageing\u003c/em\u003e. \u003cb\u003e53\u003c/b\u003e, afae071. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ageing/afae071\u003c/span\u003e\u003cspan address=\"10.1093/ageing/afae071\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCesari, M. et al. Prognostic value of usual gait speed in well-functioning older people. \u003cem\u003eJ. Am. Geriatr. Soc.\u003c/em\u003e \u003cb\u003e53\u003c/b\u003e, 1675\u0026ndash;1680 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRosano, C., Newman, A. B., Katz, R., Hirsch, C. H. \u0026amp; Kuller, L. H. Association between lower digit symbol substitution test score and slower gait and greater risk of mortality and of developing incident disability in well-functioning older adults. \u003cem\u003eJ. Am. Geriatr. Soc.\u003c/em\u003e \u003cb\u003e56\u003c/b\u003e, 1618\u0026ndash;1625 (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCesari, M. et al. Added value of physical performance measures in predicting adverse health-related events: results from the Health, Aging And Body Composition Study. \u003cem\u003eJ. Am. Geriatr. Soc.\u003c/em\u003e \u003cb\u003e57\u003c/b\u003e, 251\u0026ndash;259 (2009).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStudenski, S. et al. Gait speed and survival in older adults. \u003cem\u003eJAMA\u003c/em\u003e \u003cb\u003e305\u003c/b\u003e, 50\u0026ndash;58 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan Abellan, G. et al. Gait speed at usual pace as a predictor of adverse outcomes in community-dwelling older people. \u003cem\u003eJ. Nutr. Health Aging\u003c/em\u003e. \u003cb\u003e13\u003c/b\u003e, 881\u0026ndash;889 (2009).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim, M., Yabushita, N. \u0026amp; Tanaka, K. Exploring effective items of physical function in slow walking speed and self-reported mobility limitation in community-dwelling older adults. \u003cem\u003eGeriatr. Gerontol. Int.\u003c/em\u003e \u003cb\u003e12\u003c/b\u003e, 50\u0026ndash;58 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePeel, N. M., Navanathan, S. \u0026amp; Hubbard, R. E. Gait speed as a predictor of outcomes in post-acute transitional care for older people. \u003cem\u003eGeriatr. Gerontol. Int.\u003c/em\u003e \u003cb\u003e14\u003c/b\u003e, 906\u0026ndash;910 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQuach, L. et al. The nonlinear relationship between gait speed and falls: the Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly of Boston Study. \u003cem\u003eJ. Am. Geriatr. Soc.\u003c/em\u003e \u003cb\u003e59\u003c/b\u003e, 1069\u0026ndash;1073 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdam, C. E. et al. Change in gait speed and fall risk among community-dwelling older adults with and without mild cognitive impairment: a retrospective cohort analysis. \u003cem\u003eBMC Geriatr.\u003c/em\u003e \u003cb\u003e23\u003c/b\u003e, 328. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12877-023-03890-6\u003c/span\u003e\u003cspan address=\"10.1186/s12877-023-03890-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShimada, H. et al. Performance-based assessments and demand for personal care in older Japanese people: a cross-sectional study. \u003cem\u003eBMJ Open\u003c/em\u003e. \u003cb\u003e10\u003c/b\u003e, e002424. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/bmjopen-2012-002424\u003c/span\u003e\u003cspan address=\"10.1136/bmjopen-2012-002424\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNeptune, R. R., Sasaki, K. \u0026amp; Kautz, S. A. The effect of walking speed on muscle function and mechanical energetics. \u003cem\u003eGait Posture\u003c/em\u003e. \u003cb\u003e28\u003c/b\u003e, 135\u0026ndash;143 (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHirano, Y., Yamada, Y., Matsui, Y., Ota, S. \u0026amp; Arai, H. Lower limb muscle quality and phase angle contribute to the reduced walking speed among older adults. \u003cem\u003eGeriatr. Gerontol. Int.\u003c/em\u003e \u003cb\u003e22\u003c/b\u003e, 603\u0026ndash;609 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMitchell, W. K. et al. Sarcopenia, dynapenia and the impact of advancing age on human skeletal muscle size and strength; a quantitative review. \u003cem\u003eFront. Physiol.\u003c/em\u003e \u003cb\u003e3\u003c/b\u003e, 260. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fphys.2012.00260\u003c/span\u003e\u003cspan address=\"10.3389/fphys.2012.00260\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarcell, T. J., Hawkins, S. A. \u0026amp; Wiswell, R. A. Leg strength declines with advancing age despite habitual endurance exercise in active older adults. \u003cem\u003eJ. Strength. Cond Res.\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e, 504\u0026ndash;513 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHortob\u0026aacute;gyi, T. et al. Effects of three types of exercise interventions on healthy old adults\u0026rsquo; gait speed: A systematic review and meta-analysis. \u003cem\u003eSports Med.\u003c/em\u003e \u003cb\u003e45\u003c/b\u003e, 1627\u0026ndash;1643 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSadeghi, H. et al. Effects of 8 Weeks of Balance Training, Virtual Reality Training, and Combined Exercise on Lower Limb Muscle Strength, Balance, and Functional Mobility Among Older Men: A Randomized Controlled Trial. \u003cem\u003eSports Health\u003c/em\u003e. \u003cb\u003e13\u003c/b\u003e, 606\u0026ndash;612 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFeng, Y., Liu, J. \u0026amp; Si, J. Effects of Chinese fitness dancing on lower limb strength and fall risk in middle-aged and older women: A cross-sectional study. \u003cem\u003eNurs. Health Sci.\u003c/em\u003e \u003cb\u003e25\u003c/b\u003e, 80\u0026ndash;88 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKemmler, W. et al. Efficacy and Safety of Low Frequency Whole-Body Electromyostimulation (WB-EMS) to Improve Health-Related Outcomes in Non-athletic Adults. A Systematic Review. \u003cem\u003eFront. Physiol.\u003c/em\u003e \u003cb\u003e9\u003c/b\u003e, 573. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fphys.2018.00573\u003c/span\u003e\u003cspan address=\"10.3389/fphys.2018.00573\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoritani, T. Electrical muscle stimulation: Application and potential role in aging society. \u003cem\u003eJ. Electromyogr. Kinesiol.\u003c/em\u003e \u003cb\u003e61\u003c/b\u003e, 102598. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jelekin.2021.102598\u003c/span\u003e\u003cspan address=\"10.1016/j.jelekin.2021.102598\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO'Connor, D., Brennan, L. \u0026amp; Caulfield, B. The use of neuromuscular electrical stimulation (NMES) for managing the complications of ageing related to reduced exercise participation. \u003cem\u003eMaturitas\u003c/em\u003e \u003cb\u003e113\u003c/b\u003e, 13\u0026ndash;20 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMayr, W. Neuromuscular Electrical Stimulation for Mobility Support of Elderly. \u003cem\u003eEur. J. Transl Myol\u003c/em\u003e. \u003cb\u003e25\u003c/b\u003e, 263\u0026ndash;268 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZampieri, S. et al. Physical Exercise in Aging: Nine Weeks of Leg Press or Electrical Stimulation Training in 70 Years Old Sedentary Elderly People. \u003cem\u003eEur. J. Transl Myol\u003c/em\u003e. \u003cb\u003e25\u003c/b\u003e, 237\u0026ndash;242 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKern, H. et al. Electrical stimulation counteracts muscle decline in seniors. \u003cem\u003eFront. Aging Neurosci.\u003c/em\u003e \u003cb\u003e6\u003c/b\u003e, 189. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fnagi.2014.00189\u003c/span\u003e\u003cspan address=\"10.3389/fnagi.2014.00189\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKamide, N., Kamiya, R., Nakazono, T. \u0026amp; Ando, M. Reference values for hand grip strength in Japanese community-dwelling elderly: a meta-analysis. \u003cem\u003eEnviron. Health Prev. Med.\u003c/em\u003e \u003cb\u003e20\u003c/b\u003e, 441\u0026ndash;446 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRubenstein, L. Z., Harker, J. O., Salv\u0026agrave;, A., Guigoz, Y. \u0026amp; Vellas, B. Screening for undernutrition in geriatric practice: developing the short-form mini-nutritional assessment (MNA-SF). \u003cem\u003eJ. Gerontol. Biol. Sci. Med. Sci.\u003c/em\u003e \u003cb\u003e56\u003c/b\u003e, 366\u0026ndash;372 (2001).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMalmstrom, T. K. \u0026amp; Morley, J. E. SARC-F: a simple questionnaire to rapidly diagnose sarcopenia. \u003cem\u003eJ. Am. Med. Dir. Assoc.\u003c/em\u003e \u003cb\u003e14\u003c/b\u003e, 531\u0026ndash;532 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoritani, T., Muro, M. \u0026amp; Kijima, A. Electromechanical changes during electrically induced and maximal voluntary contractions: electrophysiologic responses of different muscle fiber types during stimulated contractions. \u003cem\u003eExp. Neurol.\u003c/em\u003e \u003cb\u003e88\u003c/b\u003e, 471\u0026ndash;483 (1985).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoritani, T., Muro, M., Kijima, A., Gaffney, F. A. \u0026amp; Parsons, D. Electromechanical changes during electrically induced and maximal voluntary contractions: surface and intramuscular EMG responses during sustained maximal voluntary contraction. \u003cem\u003eExp. Neurol.\u003c/em\u003e \u003cb\u003e88\u003c/b\u003e, 484\u0026ndash;499 (1985).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNishikawa, Y. et al. The effect of a portable electrical muscle stimulation device at home on muscle strength and activation patterns in locomotive syndrome patients: A randomized control trial. \u003cem\u003eJ. Electromyogr. Kinesiol.\u003c/em\u003e \u003cb\u003e45\u003c/b\u003e, 46\u0026ndash;52 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePerera, S., Mody, S. H., Woodman, R. C. \u0026amp; Studenski, S. A. Meaningful change and responsiveness in common physical performance measures in older adults. \u003cem\u003eJ. Am. Geriatr. Soc.\u003c/em\u003e \u003cb\u003e54\u003c/b\u003e, 743\u0026ndash;749 (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBohannon, R. W. \u0026amp; Glenney, S. S. Minimal clinically important difference for change in comfortable gait speed of adults with pathology: a systematic review. \u003cem\u003eJ. Eval Clin. Pract.\u003c/em\u003e \u003cb\u003e20\u003c/b\u003e, 295\u0026ndash;300 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaki, B. E. Gait changes in older adults: predictors of falls or indicators of fear. \u003cem\u003eJ. Am. Geriatr. Soc.\u003c/em\u003e \u003cb\u003e45\u003c/b\u003e, 313\u0026ndash;320 (1997).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChou, L. S., Kaufman, K. R., Hahn, M. E. \u0026amp; Brey, R. H. Medio-lateral motion of the center of mass during obstacle crossing distinguishes elderly individuals with imbalance. \u003cem\u003eGait Posture\u003c/em\u003e. \u003cb\u003e18\u003c/b\u003e, 125\u0026ndash;133 (2003).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNishikawa, Y. et al. The Effect of Electrical Muscle Stimulation on Muscle Mass and Balance in Older Adults with Dementia. \u003cem\u003eBrain Sci.\u003c/em\u003e \u003cb\u003e11\u003c/b\u003e, 339. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/brainsci11030339\u003c/span\u003e\u003cspan address=\"10.3390/brainsci11030339\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLin, Y. H., Chen, H. C., Hsu, N. W. \u0026amp; Chou, P. Using hand grip strength to detect slow walking speed in older adults: the Yilan study. \u003cem\u003eBMC Geriatr.\u003c/em\u003e \u003cb\u003e21\u003c/b\u003e, 428. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12877-021-02361-0\u003c/span\u003e\u003cspan address=\"10.1186/s12877-021-02361-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMakino, K. et al. Fear of falling and gait parameters in older adults with and without fall history. \u003cem\u003eGeriatr. Gerontol. Int.\u003c/em\u003e \u003cb\u003e17\u003c/b\u003e, 2455\u0026ndash;2459 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTakahashi, H. \u0026amp; Shimazaki, K. Measurement of plantar reaction force during running using insoles with six-axis tactile sensors. \u003cem\u003eDescente Sports Sci.\u003c/em\u003e \u003cb\u003e45\u003c/b\u003e, 12\u0026ndash;21 (2024).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOxford, K. L. Elbow positioning for maximum grip performance. \u003cem\u003eJ. Hand Ther.\u003c/em\u003e \u003cb\u003e13\u003c/b\u003e, 33\u0026ndash;36 (2000).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKishimoto, H. et al. Midlife and late-life handgrip strength and risk of cause- specific death in a general Japanese population: the Hisayama Study. \u003cem\u003eJ. Epidemiol. Commun. Health\u003c/em\u003e. \u003cb\u003e68\u003c/b\u003e, 663\u0026ndash;668 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIshii, S. et al. Development of a simple screening test for sarcopenia in older adults. \u003cem\u003eGeriatr. Gerontol. Int.\u003c/em\u003e \u003cb\u003e14\u003c/b\u003e, 93\u0026ndash;101 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFaul, F., Erdfelder, E., Lang, A. G. \u0026amp; Buchner, A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. \u003cem\u003eBehav. Res. Methods\u003c/em\u003e. \u003cb\u003e39\u003c/b\u003e, 175\u0026ndash;191 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaddocks, M., Gao, W., Higginson, I. J. \u0026amp; Wilcock, A. Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease. \u003cem\u003eCochrane Database Syst. Rev.\u003c/em\u003e \u003cb\u003e1\u003c/b\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/14651858.CD009419\u003c/span\u003e\u003cspan address=\"10.1002/14651858.CD009419\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJones, S. et al. Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease. \u003cem\u003eCochrane Database Syst. Rev.\u003c/em\u003e \u003cb\u003e10\u003c/b\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/14651858.CD009419\u003c/span\u003e\u003cspan address=\"10.1002/14651858.CD009419\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2016).\u003c/span\u003e\u003c/li\u003e\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":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Electrical muscle stimulation, home-based, lower leg muscle, older adults, gait speed, plantar center of gravity","lastPublishedDoi":"10.21203/rs.3.rs-6586131/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6586131/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWe explored the unknown effects of electrical muscle stimulation (EMS) at home on gait speed. Eighty-one community-dwelling independent older adults were enrolled in a prospective observational study. EMS to the lower leg muscles for 23 minutes per day was added to the daily routine during the 12-week observational period. Comfortable gait speed (CGS), stride length (SL), and plantar centre of gravity (COG) were assessed at enrollment and 12 weeks in a 10-m walking test using plantar sensor shoes. In 43 participants with a CGS of \u0026lt;\u0026thinsp;1.0 m/sec at enrollment, age, gender, and physical and nutritional features did not differ between the EMS (n\u0026thinsp;=\u0026thinsp;23) and non-EMS (n\u0026thinsp;=\u0026thinsp;20) groups. However, absolute changes in CGS and SL after 12 weeks were significantly higher in the EMS group than in the non-EMS group (0.25 vs. 0.02 m/sec, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0037; 0.21 vs. 0.03 m, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0038; respectively). Moreover, greater distribution of COG to the small toe ball during gait was associated with slower CGS and decreased after EMS. Long-term home EMS targeting the lower leg muscles thus improves reduced gait speed in community-dwelling independent older adults, which may involve changes in the plantar centre of gravity during gait.\u003c/p\u003e","manuscriptTitle":"Impact of long-term electrical stimulation of the lower leg muscles at home on gait speed in community-dwelling older adults","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-03 07:03:19","doi":"10.21203/rs.3.rs-6586131/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"338697758297525828470233801795560287607","date":"2025-07-09T13:31:11+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-22T19:57:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"130039505098404433450476922788013381297","date":"2025-06-07T15:16:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-28T13:34:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-23T13:11:08+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-05-20T01:34:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-16T12:33:07+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-05-04T00:41:08+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"30fdcf69-1440-4b1d-ab08-fe3aa44a4315","owner":[],"postedDate":"June 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":49179846,"name":"Health sciences/Health care"},{"id":49179847,"name":"Health sciences/Risk factors"}],"tags":[],"updatedAt":"2025-06-03T07:03:19+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-03 07:03:19","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6586131","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6586131","identity":"rs-6586131","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}