Impact of BRACTS exercises on muscular strength in eumenorrheic women.

A two-armed parallel design, single-blinded (assessor-blinded), single-centered pilot trial designed by a randomized controlled trial, devised following the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 guidelines 28 and reported following Consolidated Standards of Reporting Trials (CONSORT) guidelines 29 . Patient enrollment, intervention allocation, follow-up, and data analysis are visually described in the CONSORT diagram (Fig.  2 ). The parallel arm research design is widely used study design where subjects are randomized to one or more study arms and each study arms is allocated to a different intervention. Post randomization each of the participants stays in their respective treatment arms for the duration of study 30 . In this study a two arm parallel design as applied, setting two arms for the study one treatment and other control group. The primary objective was to evaluate the effects of BRACTS exercise on muscular strength of women so exercise was considered the independent variable and as the muscular strength was directly affected by the exercise it was considered dependent variable. Fig. 2 CONSORT study flow diagram 31 . CONSORT study flow diagram 31 . A sample size of 40 eumenorrheic women was calculated by G* power, with an effect size of 0.54, alpha level of 0.05, and power (1-β) of 0.95. Eumenorrheic menstrual cycles were defined as consistent cycles spanning 24 to 35 days 32 . The participants were recruited for the study of the following inclusion criteria: Eumenorrheic menstrual cycles were defined as consistent cycles spanning 24 to 35 days 32 . Females with an age range of 20 to 40 years. Body mass index between 18.5 and 24.9 (normal) 33 . Women should be able to maintain a sitting balance without requiring upper limb support or had a minimum score of 25 on the trunk control test 34 . These participants had refrained from any exercise regimen over the preceding six months. Eumenorrheic menstrual cycles were defined as consistent cycles spanning 24 to 35 days 32 . Females with an age range of 20 to 40 years. Body mass index between 18.5 and 24.9 (normal) 33 . Women should be able to maintain a sitting balance without requiring upper limb support or had a minimum score of 25 on the trunk control test 34 . These participants had refrained from any exercise regimen over the preceding six months. Exclusions from the study were made for. women who were currently taking oral contraceptives, women who were pregnant, lactating. women who had undergone a cesarean section within the past six months. Furthermore, individuals with menstrual irregularities such as endometriosis, ovarian cysts, or other comorbidities, including a history of cardiac events or seizures, were not included 35 . women who were currently taking oral contraceptives, women who were pregnant, lactating. women who had undergone a cesarean section within the past six months. Furthermore, individuals with menstrual irregularities such as endometriosis, ovarian cysts, or other comorbidities, including a history of cardiac events or seizures, were not included 35 . This study was conducted in Lahore, which is the capital of province Punjab, Pakistan. A finite list of respondents fulfilling the criteria was not available. Therefore, researchers decided first to conduct a benchmark survey to develop the sampling frame. For this purpose, a six-month survey was organized to identify the targeted populations. Benchmark surveys assess the coverage of the sampling frame by comparing the frame to external data sources 36 . Snowball sampling was used to reach the potential study participants, as researchers had contact with a few females who fulfilled the criteria. Based on their recommendations, researchers reached out to universities, hospitals, schools, and some females who were educated but were living in their homes. After they consented to participate, their names were included, and the total population reached 120 potential participants. From the identified population, 40 were chosen as study participants using a sample size calculating formula G* Power. The 120 females served as the sampling frame, and 40 respondents were chosen using simple random sampling. Selecting a sample frame for a survey is important, as it determines the extent to which the target population is covered, the accuracy of contact information, and the cost 37 . Moreover, probability sampling, such as simple random sampling, improves convergence speed and reduces bias by shifting the focus from bias potentials to probability distribution reconstruction. Random sampling was employed to select the respondents to minimize bias. Of the total 120 potential participants, each was given an equal chance of being chosen as study participants using random table generators. Table  1 present the participants’ characteristics. The study received approval from the Research Ethics Committee of Riphah International University (Protocol ID: REC/Lhr/22/1101), and all participants provided written informed consent. This study is registered on clinicaltrials.gov (ID: NCT05460741 ). In addition, all experiments were performed in accordance with relevant guidelines and regulations. Table 1 Characteristics of participants in percentage and frequency ( n  = 40). Experimental Group ( n  = 20) Control Group ( n  = 20) Total ( n  = 40) Education  Matric 3(15%) 4 (20%) 7 (17.5%)  Bachelors 10 (50%) 9 (45%) 19 (47.5%)  Masters 3 (15%) 4 (20%) 7 (17.5%)  PhD 4 (20%) 3 (15%) 7 (17.5%) Occupation  Student 8 (40%) 6 (30%) 14 (35%)  House wives 5 (25%) 8 (40%) 13 (32.5%)  Working 7 (35%) 6 (30%) 13 (32.5%) Marital status  Married 8 (40%) 7 (35%) 15 (37.5%)  Single 9 (45%) 9 (45%) 18 (45%)  Divorced 3 (15%) 4 (20%) 7 (17.5%)  Age (Mean ± SD) 30.10 ± 6.20 29.60 ± 6.05 29.85 ± 6.11  Weight (kg) (Mean ± SD) 58.10 ± 4.65 57.80 ± 4.80 57.95 ± 4.70  Height (cm) (Mean ± SD) 160.10 ± 2.75 159.80 ± 2.85 159.95 ± 2.80 *SD = Standard deviation. Characteristics of participants in percentage and frequency ( n  = 40). *SD = Standard deviation. The menstrual cycle phase of the participants was calculated by the gynecologist using the calendar method during the past three months to monitor any abnormality. The baseline blood serum profile of estrogen (estradiol), progesterone, and total testosterone were taken on the 4th, 14th, and 24th day of the menstrual cycle (which formulate follicular, mid-cycle, and luteal phases of MC) to see the normal ranges of hormones in those participants and monitor any abnormality in the hormonal level at the baseline 38 . Randomization was done using random allocation by a computerized random table generator method in which each participant was assigned a number. Later, the numbers were drawn randomly by computer, and a random sample was achieved. During the trial, a 1:1 ratio of the participants was maintained for both groups. Verifying the integrity of the treatment allocation process is important before and during a trial 39 . Therefore, randomization was ensured using a widely accepted approach. Randomization eliminates accidental bias and provides a basis for using probability theory in clinical studies 40 . This trial was single-blinded, with the assessor-blinded, because the patients and the principal investigator could not be blinded due to the nature of the intervention. The statistician was blinded by coding the data into A and B or any other name to ensure unbiased analysis. A Randomized Controlled Trial was conducted at Aadil Hospital Defence, Lahore, involving participants who underwent initial screening and blood profiling. Following this assessment, the participants were randomly assigned to two groups. Both groups received an awareness program focusing on menstrual cycle hygiene and maintaining an active lifestyle (Appendix 1). The awareness program was designed to educate participants on menstrual cycle hygiene and the importance of maintaining an active lifestyle. During awareness an interactive question and answer session, along with discussion, was organized. Additionally, a demonstration of simple exercises and stretches beneficial during menstrual cycles was performed. The awareness program included the following key areas: Explanation of the menstrual cycle and common variations. Importance of personal hygiene during menstruation. Use of sanitary products (pads, tampons, menstrual cups) and proper disposal methods. Addressing myths and misconceptions related to menstruation. Importance of balanced nutrition during menstruation to support overall health and well-being. Discussion on foods that can help alleviate menstrual discomfort. Benefits of regular physical activity in managing menstrual discomfort (e.g., reducing cramps, bloating, and fatigue). Safe exercises and activities to promote an active lifestyle during the menstrual cycle. Importance of personal hygiene during menstruation. Use of sanitary products (pads, tampons, menstrual cups) and proper disposal methods. Addressing myths and misconceptions related to menstruation. Importance of balanced nutrition during menstruation to support overall health and well-being. Discussion on foods that can help alleviate menstrual discomfort. Benefits of regular physical activity in managing menstrual discomfort (e.g., reducing cramps, bloating, and fatigue). Safe exercises and activities to promote an active lifestyle during the menstrual cycle. Stress management techniques to support mental and emotional well-being. BRACTS is generally a new concept in the literature and literature is not available to directly endorse this BRACTS intervention. However, literature is evident that exercise-based interventions had a significant influence on the quality of human life 41 – 46 . The control group was instructed to engage in 30 min of brisk walking thrice a week on alternate days for 16 weeks and adhere to a standard dietary plan (provided by dietician, Appendix 2). On the other hand, the experimental group attended the hospital’s Physiotherapy department, where a physiotherapist guided them through 50-minute BRACTS exercises on alternative days, totaling three sessions per week over 16 weeks. This protocol incorporated various exercises, including resistance, endurance, and balance, along with proper warm-ups, cool-downs, and rest intervals, as described in Table  2 . The exercises required minimal setup, primarily involving handheld dumbbells. The primary goal was for participants to remain engaged in core-strengthening exercises for the full 5-minute duration, even if they took brief pauses or performed modified movements. The total number of repetitions or continuous time spent was recorded for each participant, with modifications duly noted. If any participant was unable to perform crunches for the full 5 min, Participants were encouraged to take short breaks as needed if they experienced fatigue or discomfort. These rest periods were limited to 10–15 s, allowing them to resume the exercise without losing momentum. Table 2 Exercise protocol along with duration. Exercise Allocated time Exercise posture Exercise schedule Warm-ups High marching 5 min 3 times a week on alternate days for 16 weeks B Bending 5 min Rest interval 2.5 min R Roll ups 5 min Rest interval 2.5 min A Arm swings with resistance (using load) 5 min Rest interval 2.5 min C Crunches 5 min Rest interval 2.5 min T Tandem walk 5 min Rest interval 2.5 min S Squats 5 min Cool downs High marching 5 min Total duration: 50 min The figures used in the Table to portray the exercise posture are sourced from Yandex.com. Exercise protocol along with duration. The figures used in the Table to portray the exercise posture are sourced from Yandex.com. All these exercises, as described in Table  2 , were performed under the supervision of the Principal Investigator Physiotherapist, for which illustrations were provided by the therapist herself before performing the prescribed exercises. Before each session, participants were advised to abstain from alcohol, caffeine, or strenuous physical activities for a full day. The exercise sessions commenced between 10 a.m. and 12 p.m., following a breakfast consumed at least two hours before the session. A nutritionist provided dietary guidance to ensure participants followed these recommendations 48 h before each session, minimizing potential nutritional influences on the study’s primary outcomes (to ensure the compliance participants were interviewed before each session). Additionally, participants had a standardized breakfast before each session, irrespective of their menstrual cycle phase. The strength of the hand grip muscles (both right and left hand) were calculated using hand-held dynamometer (Camry 200 Lbs/90 kg digital dynamometer, Lahore, Pakistan) with the participant seated comfortably with their back straight and shoulders relaxed. The arm being tested was positioned at the side of the body, without touching the trunk, and the shoulder remained neutral. The elbow was flexed at a 90-degree angle, which was crucial to isolate the muscles of the hand and forearm. The forearm was in a neutral position with the thumb facing upwards, and the wrist slightly extended (15–30 degrees) to ensure optimal grip. The participant was instructed to squeeze the dynamometer with maximum effort for 3–5 s, ensuring the grip is steady and not jerky. Whereas, quadriceps (right and left) and gastro-soleus (right and left) strength were calculated using pressure biofeedback unit (Chattanooga stabilizer pressure bioresponse, Lahore, Pakistan) respectively. The highest reading from the trials was recorded, providing an assessment of the strength of each muscle. For quadriceps the women were asked to lie in a supine position, with the leg being tested straight and relaxed, while the other leg remained flat. The knee of the tested leg was slightly bent, around 30 degrees of flexion, to facilitate optimal quadriceps contraction. The pressure biofeedback unit (PBU) was placed under the popliteal region (behind the knee). During the test, the participant was instructed to extend their knee against resistance, either pressing the back of the knee toward the bed. To assess the strength of the gastrocnemius-soleus muscles using a pressure biofeedback unit, the women were seated on a firm chair with their feet flat on the floor and knees bent at approximately 90 degrees. The tested leg remained in this position with the foot firmly on the ground, and the body remained upright with a straight, relaxed posture. The PBU was placed under the ball of the foot (metatarsal heads) to accurately measure the force generated during plantarflexion. The participant was then instructed to press the ball of their foot down into the PBU, mimicking the motion of pressing a gas pedal, allowing the PBU to record the pressure increase as the gastro-soleus complex contracts. These tests were performed 3 times, with a rest period of 1–2 min between each attempt to prevent fatigue. The highest reading from the trials was recorded, providing an assessment of the strength of each muscle. The readings were taken for all these muscles at the start of the intervention on the 4th day, 14th day, and 24th day of the menstrual cycle for all the participants. The second reading was taken during the intervention’s 6th to 8th week (mid-intervention) and again on the 4th, 14th and 24th day of the menstrual cycle. In contrast, the last and final reading was taken during the intervention plan’s 14th to 16th week (post-intervention), making the three menstrual cycles in total for which the readings were taken. The data were represented as tables’ mean ± standard deviation (SD). Bonferroni correction was used for multiple comparisons. A Shapiro-Wilk test was performed to assess the normality of the variables. ANOVA was used to examine the main effects of menstrual cycle days (4th, 14th, and 24th), the interaction between phases, and the timing of the readings taken for the variable, as mentioned earlier. Additionally, in cases where Mauchly’s test indicated a violation of the assumption of sphericity, the Greenhouse–Geisser correction was applied. Partial eta squared was used to calculate the effect sizes, allowing assessment of the magnitude of the observed changes, with threshold values categorized as values around 0.01, 0.06, and 0.14 considered small, medium, and large effect sizes 47 . Furthermore, 95% confidence intervals (CI) were computed, and statistical significance was established at p  < 0.05. An effect size was also deemed meaningful if its CI did not encompass zero 48 . In addition, Cohen’s d was applied to examine the effect size on muscular strength between groups and across the different phases of the menstrual cycle (follicular, mid-cycle, luteal). This indicates the effect size will be reported as 0.2 = small effect, 0.5 = moderate effect, and 0.8 = large effect 49 . All statistical procedures were executed using SPSS software, version 25 (IBM Corp., Armonk, NY, USA).

The study’s primary outcome was to see the effects of BRACTS exercises on strength during different phases of the menstrual cycle and to evaluate how various stages of the menstrual cycle integrate these parameters. Table 3 Mean values of strength of left and right-hand grip during different phases of the menstrual cycle. Phases of menstrual cycle Intervention levels The treatment group of females Mean ± SD of left-hand grip strength Effect size Cohen’s d Mean ± SD of right hand grip strength Effect size Cohen’s d Follicular phase Pre-intervention Experimental 16.52 ± 1.64 1.72 16.91 ± 1.21 1.06 Control 13.54 ± 1.82 15.38 ± 1.65 Mid intervention Experimental 18.23 ± 2.00 2.48 18.41 ± 1.33 1.88 Control 13.36 ± 1.92 15.51 ± 1.73 Post-intervention Experimental 20.15 ± 2.00 3.36 20.53 ± 1.57 3.06 Control 13.59 ± 1.90 15.53 ± 1.70 Mid-cycle phase Pre-intervention Experimental 16.55 ± 2.18 1.29 15.69 ± 1.80 1.33 Control 14.25 ± 1.28 13.63 ± 1.25 Mid intervention Experimental 17.36 ± 2.93 1.44 18.05 ± 2.63 2.14 Control 14.15 ± 1.19 13.69 ± 1.18 Post-intervention Experimental 17.20 ± 2.68 1.48 19.09 ± 2.46 2.82 Control 14.31 ± 1.24 13.68 ± 1.15 Luteal phase Pre-intervention Experimental 16.25 ± 2.68 0.06 16.89 ± 2.60 0.53 Control 16.12 ± 1.42 15.73 ± 1.65 Mid intervention Experimental 18.54 ± 3.09 0.94 18.70 ± 3.07 1.19 Control 16.27 ± 1.44 15.79 ± 1.58 Post-intervention Experimental 19.43 ± 3.26 1.33 19.54 ± 3.18 1.48 Control 16.14 ± 1.27 15.77 ± 1.68 *SD = Standard Deviation. Mean values of strength of left and right-hand grip during different phases of the menstrual cycle. *SD = Standard Deviation. Table  3 shows the mean differences of the control and experimental group whereas within-group analysis for both groups is presented in Table  4 . The Cohen’s d value in Table  3 was maximum during the follicular phase of menstrual cycle. The Table  4 shows the statistically significant difference between the treatment groups during different phases of the menstrual cycle. There was a significant difference between the groups. The grip strength of women in the experimental group improved. This improvement is reflected in the value of eta square. Table 4 Mixed model ANOVA for within-group and between group analyses. Left hand grip strength Right hand grip strength df Mean square F Sig. Partial eta squared Observed power df Mean square F Sig. Partial eta squared Observed Power Phases * Group 2 64.59 7.11 0.00 0.15 0.92 2 15.49 3.03 0.05 0.07 0.57 Phases * Time * Group 4 2.17 4.92 0.00 0.11 0.95 4 0.77 1.74 0.14 0.04 0.52 Left-hand grip strength Right-hand grip strength df Mean Square F Sig. Partial Eta Squared Observed Power df Mean Square F Sig. Partial Eta Squared Observed Power Group 1 1138.34 61.25 0.00 0.61 1.00 1 1074.12 53.85 0.00 0.58 1.00 Mixed model ANOVA for within-group and between group analyses. Table  5 shows the mean values of the left and right quadriceps at 3 intervention and 3 menstrual cycle phases for both the control and experimental groups. It shows the mean values of the experimental groups to be more than the control group, showing the significant improvement in the strength of both the left and right quadriceps in the experimental group with Cohen’s d value to be maximum during the mid-cycle phase for quadriceps (both left and right). Table 5 Mean values of left and right quadriceps during different phases of menstrual cycle. Phases of the menstrual cycle Levels of interventions The treatment group of females Mean ± SD of left quadriceps Effect size Cohen’s d Mean ± SD of right quadriceps Effect size Cohen’s d Follicular phase Pre-intervention Experimental 65.60 ± 13.17 0.02 65.10 ± 11.87 0.23 Control 65.90 ± 9.70 68.00 ± 12.74 Mid intervention Experimental 72.10 ± 14.04 0.49 70.70 ± 13.83 0.10 Control 66.39 ± 7.99 69.34 ± 11.17 Post-intervention Experimental 78.10 ± 12.98 1.11 74.00 ± 12.81 0.47 Control 66.36 ± 7.83 68.31 ± 11.07 Mid-cycle phase Pre-intervention Experimental 59.40 ± 9.84 0.51 56.60 ± 11.22 0.00 Control 54.40 ± 9.70 56.70 ± 13.40 Mid intervention Experimental 68.80 ± 13.30 1.20 64.30 ± 16.24 1.56 Control 54.81 ± 9.65 56.18 ± 12.51 Post-intervention Experimental 76.70 ± 14.29 1.79 72.50 ± 15.86 1.58 Control 54.83 ± 9.61 55.13 ± 12.39 Luteal phase Pre-intervention Experimental 70.00 ± 12.75 0.00 64.80 ± 15.04 0.42 Control 69.90 ± 10.29 70.80 ± 13.14 Mid intervention Experimental 77.50 ± 14.03 0.57 76.90 ± 14.45 0.48 Control 70.41 ± 10.23 70.19 ± 12.96 Post-intervention Experimental 89.00 ± 16.88 1.35 88.80 ± 17.54 1.20 Control 70.31 ± 10.23 70.11 ± 13.13 *SD = Standard Deviation. Mean values of left and right quadriceps during different phases of menstrual cycle. *SD = Standard Deviation. Table  6 shows the within-group analysis for the control and experimental groups, which shows significant changes across the group and phases. It further indicates the between-group analyses for the control and experimental groups. Table 6 Mixed model ANOVA for within-group and between-group analyses. Left quadriceps Right quadriceps df Mean Square F Sig. Partial Eta Squared Observed Power df Mean Square F Sig. Partial Eta Squared Observed Power Phases * Group 2 363.48 3.67 0.03 0.08 0.65 2 376.20 3.38 0.03 0.08 0.62 Phases * Time * Group 4 54.12 6.77 0.00 0.15 0.99 4 162.72 12.26 0.00 0.24 1.00 Left quadriceps Right quadriceps df Mean Square F Sig. Partial Eta Squared Observed Power df Mean Square F Sig. Partial Eta Squared Observed Power Group 1 5900.36 5.95 0.01 0.13 0.66 1 1951.143 1.455 0.235 0.037 0.217 Mixed model ANOVA for within-group and between-group analyses. Table  7 shows the mean values for left and right gastro-soleus during 3 phases of the menstrual cycle, showing the improvement in the mean values of muscle strength in the experimental group in all phases with Cohen’s d value to be maximum during mid-cycle phase. Table  8 shows the within-group and between-group analysis for both the control and experimental groups, showing significant changes across the groups and phases. Table 7 Mean values of left and right gastro-soleus during different phases of menstrual cycle. Phases of menstrual cycle Strength of left gastro-soleus The treatment group of females Mean ± SD of left gastro-soleus Effect size Cohen’s d Mean ± SD of right gastro-soleus Effect size Cohen’s d Follicular phase Pre-intervention Experimental 87.22 ± 22.38 0.06 79.40 ± 15.06 0.52 Control 86.10 ± 12.57 87.50 ± 15.66 Mid intervention Experimental 94.22 ± 22.35 0.42 88.40 ± 15.43 0.08 Control 86.49 ± 12.55 87.00 ± 15.83 Post-intervention Experimental 105.77 ± 17.39 1.29 99.30 ± 10.86 0.92 Control 86.57 ± 11.66 86.88 ± 15.64 Mid-cycle phase Pre-intervention Experimental 71.88 ± 16.33 0.00 70.20 ± 18.06 0.13 Control 71.80 ± 9.60 72.40 ± 13.37 Mid intervention Experimental 86.77 ± 16.01 1.09 81.90 ± 23.81 1.42 Control 72.22 ± 9.71 73.75 ± 13.29 Post-intervention Experimental 93.11 ± 13.63 1.74 88.60 ± 20.40 1.93 Control 72.39 ± 9.58 72.43 ± 13.59 Luteal phase Pre-intervention Experimental 86.22 ± 22.07 0.10 73.60 ± 11.57 1.65 Control 88.10 ± 12.79 95.10 ± 14.21 Mid intervention Experimental 96.88 ± 18.90 0.56 87.00 ± 16.35 0.24 Control 88.23 ± 14.05 90.57 ± 13.19 Post-intervention Experimental 108.33 ± 15.00 1.28 105.20 ± 13.28 1.10 Control 80.72 ± 26.43 90.75 ± 12.99 *SD = Standard Deviation. Mean values of left and right gastro-soleus during different phases of menstrual cycle. *SD = Standard Deviation. Table 8 Mixed model ANOVA for within group analyses and between group analyses. df Mean square F Sig. Partial eta squared Observed power df Mean square F Sig. Partial eta squared Observed power Phases * Group 2 73.99 0.39 0.67 0.01 0.11 2 961.93 5.74 0.00 0.13 0.85 Phases * Time * 4 212.00 3.31 0.01 0.084 0.83 4 90.27 5.49 0.00 0.12 0.97 Left gastro-soleus Right gastro-soleus df Mean Square F Sig. Partial Eta Squared Observed Power df Mean Square F Sig. Partial Eta Squared Observed Power Group 1 8486.65 5.38 0.02 0.13 0.61 1 42.50 0.02 0.87 0.00 0.05 Mixed model ANOVA for within group analyses and between group analyses. Overall, the results suggest that exercise has a significant and varying impact on muscle strength across different phases of the menstrual cycle. Both left- and right-hand grip strength and quadriceps strength are notably affected by exercise, with right-hand grip strength showing the most significant effect. Gastrocnemius soleus strength is also influenced by exercise, albeit to a somewhat lesser extent. These findings emphasize the importance of considering the menstrual cycle phase when assessing changes in muscle strength.

Our study aimed to investigate the effects of BRACTS exercises on muscle strength while considering the different phases of the menstrual cycle. Previous research predominantly examined the effects of resistance exercises on hormonal levels and their effect on athletes’ physical performance 50 . However, in the modern era, there is a growing emphasis on the ‘Integrated Exercise Approach,’ which combines various exercise types into a single plan to maximize benefits 51 – 54 . This study examined the impact of a recently developed integrated exercise approach called BRACTS, which requires minimal equipment and is cost-effective and practical for implementation across a broad spectrum of women. Moreover, this study aims to increase the validity and reliability of the study by introducing the dietary plan (given in Appendix) that was followed by all participating women and readings were taken at the morning time to avoid any circadian rhythm of the hormones that may impact the strengths of the muscles 55 . Our findings suggest that the specific exercise plan we implemented positively impacted muscle strength compared to maintaining a general active lifestyle. However, what is particularly interesting is that our study detected significant differences in the adaptation to the exercise plan across the various phases of the menstrual cycle. In other words, specific phase appeared to offer a clear advantage in terms of muscle strength improvement during the exercise regime, with the effect that hand grip muscles (both left and right) showed the maximum improvement in the follicular phase of the menstrual cycle. For the left and right quadriceps, left and right gastro-soleus, the maximum gain in strength was observed during the mid-cycle phase of the menstrual cycle while maximum change of strength was observed in the left grip hand strength. These results align with several previous studies examining the influence of the menstrual cycle on exercise performance. For instance, an observational study was done by Ayesha Juhi et al. in 2019 56 , which stated that muscle performance is highest during the F2 phase of the menstrual cycle, which corresponds with estrogen peak during ovulation, and declines during the L2 phase when estrogen levels decline while other study done by Anupi Das et al. in 2023 57 suggested that muscle strength and endurance increase during the follicular phase of the menstrual cycle in women. Moreover, a systematic review and meta-analysis conducted in 2021 stated that hormone fluctuations during the menstrual cycle impact exercise-induced muscle damage (EIMD) and, in turn, strength loss. It suggests that during phases with higher hormone concentrations, training loads for strength conditioning could be increased 21 . However, some studies are in contrast to our findings Colenso-Semple et al. 58 reported that menstrual cycle phases did not have any noticeable effect on acute strength performance or adaptations to resistance exercise training that may be due to resistance training was the exercise included, whereas, in present exercise regime there were a combination of exercises like resistance, aerobic and balance. Moreover, it is documented that they noted a pattern of poor and inconsistent methodological practices in the literature, which may have affected this hypothesis. Similarly, Romero-Moraleda et al. 59 documented that eumenorrheic women exhibited similar muscle strength and power performance in specific exercises across different menstrual cycle phases, reinforcing the idea that no phase was superior for exercise outcomes which may also be due to the absence of any control group and no dietary monitoring was done and only squatting was used as exercise plan without any warm up and cool down exercises. Furthermore, our findings align with the conclusions drawn from the systematic review and meta-analysis conducted by Niering et al. 60 , which indicated that exercise performance is affected during the menstrual cycle phase. They state that the late follicular phase is likely the best period for attaining peak dynamic maximal strength, potentially due to the elevated estrogen levels during this time. In contrast, the mid-luteal phase is seen as the least favorable for optimal muscle function, owing to lower estrogen levels (which reduce neuromuscular facilitation) and higher progesterone levels. Given the small effect size, the substantial variation between studies, and the inclusion of low-quality studies in their analysis, they suggested that general guidelines on exercise performance across the menstrual cycle should not be universally applied. Instead, they recommended adopting a personalized approach that considers individual responses to exercise performance during different menstrual phases. While the literature has explored the influence of menstrual cycle phases on various aspects of exercise performance, including muscle strength, it is becoming increasingly evident that the effects are nuanced and depend on individual factors. As noted by Kissow and colleagues 50 , further research is needed better to understand the implications of menstrual cycle-based resistance training and to identify the optimal approaches for enhancing resistance training outcomes. In conclusion, our study contributes to the growing body of evidence suggesting that while hormonal fluctuations during the menstrual cycle may have some impact on exercise performance, these effects are generally trivial and highly individualized. As such, there is no clear-cut advantage to be gained from planning exercise regimes around specific menstrual phases. Instead, a personalized approach that considers each individual’s response to exercise performance across the menstrual cycle may be more appropriate. To the best of our knowledge, this study represents a pioneering effort in formulating a comprehensive exercise protocol designed for women to perform at home, devoid of the need for specialized exercise equipment. This protocol also incorporates essential components such as proper warm-up and cool-down sessions. Furthermore, the study stands out for its investigation of the potential influence of the menstrual cycle on exercise performance. This was achieved by conducting repeated measurements on the same female subjects throughout various menstrual phases, thereby minimizing potential variations and enhancing the overall validity of the findings. In addition to these methodological advancements, strict adherence to randomization criteria was maintained, and the assessors were kept blind to the experimental conditions. These measures collectively contribute to the augmentation of internal and external validity, addressing deficiencies observed in prior research within this domain, which have suffered from suboptimal research designs. Nonetheless, it is imperative to acknowledge that further research endeavors are warranted to refine our comprehension of the intricate relationship between the menstrual cycle and exercise performance. By delving deeper into this study area, it will be possible to provide more tailored and evidence-based recommendations for women and optimizing their training regimens. In conclusion, this study underscores the importance of exercise as a significant contributor to muscle strength improvement, with significant impact observed across different menstrual cycle phases in women. This study has far-reaching applicability on women’s health and at the same time is a good addition to the existing literature on women athletes. This study challenge the existing belief that the menstrual cycle’s phases do not influence an athlete’s performance. As a result, these results can be valuable in developing exercise regimens for women athletes as well, providing them with the confidence that their performance can be optimized according to their menstrual cycle, allowing them to focus on their training and goals. Practical application. This study was the first to formulate an exercise plan with a minimal setup that can be widely applied to women. It included proper warm-ups, cool-downs, and rest intervals to ensure its applicability and international standards. We conducted a thorough review of recent articles, including systematic reviews, and this study remains one of the earliest to investigate the specific integrated approach used in this study. Furthermore, the study investigated the effects of exercise on strength across all menstrual cycle phases, providing insights into how exercise interacts with different stages of the menstrual cycle that may help in policy-making for the primary prevention of women’s diseases like breast cancer, arthritis, and others mediated by hormonal variations in women. This study may contribute to developing training programs for a broad population of women aimed at enhancing muscular strength. The intervention’s ease of application and cost-effectiveness, requiring no specialized gym facilities or equipment, increase its potential for widespread adoption and accessibility. This study was the first to formulate an exercise plan with a minimal setup that can be widely applied to women. It included proper warm-ups, cool-downs, and rest intervals to ensure its applicability and international standards. We conducted a thorough review of recent articles, including systematic reviews, and this study remains one of the earliest to investigate the specific integrated approach used in this study. Furthermore, the study investigated the effects of exercise on strength across all menstrual cycle phases, providing insights into how exercise interacts with different stages of the menstrual cycle that may help in policy-making for the primary prevention of women’s diseases like breast cancer, arthritis, and others mediated by hormonal variations in women. This study may contribute to developing training programs for a broad population of women aimed at enhancing muscular strength. The intervention’s ease of application and cost-effectiveness, requiring no specialized gym facilities or equipment, increase its potential for widespread adoption and accessibility.

The focus of this study was to enhance the study’s validity and potential confounding factors like diet, ethnicity, psychological status, and natural hormonal fluctuations throughout the day. The study team made every effort to address these previously documented limitations effectively. Still, it was too difficult to maintain the standard environment regarding food and psychological factors to ensure the validity of the results. Moreover, the work routine of different individuals from different occupations may affect the hormonal levels and strength of the individuals, as well as their quality of sleep and pattern. The blood serum profiles were only taken at baseline but were not taken to ensure the phases of the menstrual cycle. Moreover, 2.5 to 3 L of water was recommended to the participants, which does not account for the widely accepted daily guideline of 35 ml of water per kilogram of body weight, so this limitation may be addressed in future studies to ensure that water intake is adequately tailored to each participant’s daily needs based on their body weight.

Women possess several distinct physiological characteristics that set them apart from men, one of the most significant being the variation in the levels of sex steroid hormones. These hormones include androgens such as testosterone and androstenedione, as well as estrogen, estradiol, estrone, and progesterone. Notably, these hormones fluctuate periodically throughout the menstrual cycle, leading to distinct hormonal profiles during each phase of the cycle 1 . Typically, the menstrual cycle is divided into three phases: 1 the early follicular phase, characterized by low levels of estrogen and progesterone; 2 the ovulatory phase, marked by a peak in estrogen and low progesterone levels; and 3 the mid-luteal phase, characterized by elevated levels of both estrogen and progesterone 2 as shown in Fig.  1 . While these hormones are primarily associated with reproductive functions, research has unveiled their intricate effects on various physiological systems, including cardiovascular, respiratory, metabolic, and neuromuscular parameters such as muscle mass, strength, and elasticity 3 – 5 . These effects can influence exercise performance 6 . Numerous mechanisms have been proposed to explain how the cyclical fluctuations in estrogen and progesterone across the MC might impact performance. Estrogen, for instance, is believed to have neuroexcitatory properties and an anabolic influence on skeletal muscle 7 , 8 . It also alters substrate metabolism by increasing muscle glycogen storage and promoting greater fat utilization 9 . On the contrary, progesterone is thought to exert anti-estrogenic effects 10 . It is important to note that many factors can modulate these hormones, leading to positive or negative impacts on the overall physiology of females. Diet, for instance, plays a significant role in influencing metabolism and reproductive functions related to sex hormones 11 . Certain foods can affect the levels of women hormones, including estrogen and progesterone 12 . Additionally, heightened stress levels can lead to decreased hormone production in the ovaries, potentially causing an imbalance in estrogen and progesterone or an excess of estrogen. Moreover, short-term psychosocial stress can temporarily elevate the levels of sex steroids, such as testosterone, estradiol, and androstenedione, in both men and women 13 . It’s important to note that physical activity can influence levels of free testosterone, androstenedione, and dehydroepiandrosterone sulfate and reduce markers of adiposity. Nonetheless, these effects may vary depending on the type and intensity of exercise and individual characteristics 14 . Cross-sectional research has indicated that women with low levels of physical activity tend to have higher serum concentrations of estradiol after menopause 14 . Observational studies have also suggested that exercise can lower the levels of bioavailable sex hormones, potentially reducing the risk of developing breast cancer 15 . Still, as these findings are based on associations observed in observational studies, and further research is needed to establish causality. As a result, changes in exercise performance may be linked to the varying hormonal profiles across the MC 16 . However, existing research on the effects of MC fluctuations on exercise performance has produced conflicting results. Some studies have reported improved performance during the early follicular 17 , 18 , ovulatory 19 , and mid-luteal phases 20 , 21 , while others have found no significant differences in exercise performance between MC phases 7 , 22 , 23 . Consequently, a consensus regarding the impact of the MC on exercise performance remains elusive, and evidence-based guidelines for managing exercise performance across the MC are currently lacking for both women athletes and practitioners working with elite sportswomen. Given the increasing participation of women in exercise and the complex interplay between exercise and sex steroid hormones, it is essential to explore how exercise influences strength across different phases of the menstrual cycle. This study aims to test the effects of the BRACTS exercise protocol, with appropriate warm-up, cool-down, and rest intervals that women can universally adopt. These exercises are acronyms for Bending, roll-ups, Arm swings with loads, Crunches, Tandem walks, and Squats, which are a mixture of aerobic, resistance exercises, balance, and coordination exercises. This protocol serves as the integrated exercise plan that does not need any gym setup or expensive devices but provides the maximum benefit of being simple, accessible, and effective like some extensive exercise regime (hence the name BRACTS, the small leaf-like structure that is very small in appearance but gives the same aroma of flower). Regarding the selection of specific exercises in the BRACTS protocol—Bending, Roll-ups, Arm swings with loads, Crunches, Tandem walks, and Squats—these were chosen based on their ability to target multiple muscle groups while requiring minimal equipment, making them accessible and cost-effective. Each exercise addresses key components of functional fitness, such as strength, flexibility, balance, and coordination, which are essential for improving overall muscular strength, particularly in women. For example, squats and tandem walking enhance lower body strength and balance 24 , while arm swings with loads and crunches contribute to upper body and core stability 25 . Additionally, bending and roll-ups promote flexibility and spinal mobility 26 . This combination was designed to provide comprehensive benefits with minimal resource requirements, aligning with our goal of practical implementation across diverse populations. This study seeks to evaluate the overall muscle strength of women across various phases of the menstrual cycle and ascertain whether these physical changes influence strength during exercise. Moreover, this study addresses the potential sources of bias, such as variations in protocols in previous studies and shortcomings in study design and randomization techniques. By implementing a standardized exercise regimen for all participants and ensuring transparent randomization and assessor blinding, this study aims to minimize these biases and improve the reliability of the findings. Fig. 1 Variation of sex steroid hormones in MC 27 . Variation of sex steroid hormones in MC 27 .