Dear Editor, Resistance training is a well-established strategy for preventing sarcopenia and frailty. However, many older adults face barriers to starting and maintaining a regular routine, such as a lack of nearby facilities and limited transport options.1 The coronavirus disease 2019 pandemic further impacted these barriers to exercise participation, as face-to-face group exercise classes were widely suspended, even for those older adults who were willing and able to participate. In connection with these circumstances, home-based exercise interventions using information and communication technology (ICT) have received a great deal of attention.2 In previous studies, we developed a 12-week, twice-weekly, slow-movement bodyweight-based resistance training (SBRT) program consisting of nine exercises. This protocol has been shown to increase muscle mass, strength and physical function in older adults with no adverse events reported.3,4 Building on this foundation, this study designed a remotely supervised online exercise class (OEC) that delivered SBRT via a bidirectional ICT tool, Zoom (San Jose, USA). To increase its suitability for home-based settings, the OEC was structured as a 7-week course involving four core exercises that target lower limb strength: The squat, split squat, shoulder press, and chair-seated crunch. A total of eight community-dwelling older adults (five women and three men, with a mean age of 70.0 ± 7.7 years) participated in the study. The OEC was conducted twice per week for 7 weeks, followed by a 7-week self-directed exercise (SDE). Physical function was assessed using the 30-s chair stand test (CS-30), a validated measure of lower limb muscle strength, and the assessments were performed remotely at three time points: Before the OEC, after the OEC and after SDE. Participants were instructed in advance to prepare a chair approximately 40 cm in height and practice the test during an orientation session prior to measurement. To evaluate the exercise continuation and its potential impact during the SDE period, all participants recorded the volume of lower-limb training (i.e., repetitions of squat and split squat) separately for the OEC and SDE periods using self-reported logs. Each participant completed the OEC course and assessments at home with remote guidance via Zoom. This study aimed to examine whether changes in lower-limb training volume from the OEC to the SDE period were associated with changes in CS-30 performance during the SDE period, thus revealing the impact of continued training after structured OEC education. Our study yielded several key findings. First, participants demonstrated a significant improvement in lower-limb strength during the SDE period, as indicated by an increase in CS-30 scores (24.0 ± 3.2–27.8 ± 3.8, P = 0.002), comparable to results from our previous face-to-face classes.3 Most importantly, the change in lower-limb training volume between the OEC and SDE periods was significantly and positively correlated with the change in CS-30 performance r = 0.802, P < 0.05; Figure 1, suggesting that maintaining a higher volume of lower-limb exercises was associated with improvements in physical function. Therefore, this study shows that a 7-week SBRT-based OEC may encourage older adults to continue exercising and improve their physical function. However, this study has several limitations. First, as a pilot study, the sample size was small, and no control group was included. Second, only the CS-30 test was used because assessments were conducted remotely for reasons of safety and feasibility. Third, exercise adherence was monitored solely through self-reported logs. Therefore, the findings should be interpreted as preliminary. Future research should increase the sample size, incorporate a control group, and use wearable devices as well as a broader range of outcome measures to more comprehensively evaluate the effectiveness of online SBRT in promoting physical activity among older adults.Figure 1: Correlation between the rate of change in training volume of lower limbs repetitions from the online exercise class to self-directed exercise (SDE) periods and the rate of change in 30-s chair stand test performance during the SDE period. CS-30: 30-s chair stand test, SDE: Self-directed exercise, OEC: Online exercise class, Lower limb training: Squats and split squats. *P < 0.05Ethics statememt The study was conducted in accordance with the Declaration of Helsinki and was approved by The Ethics Committee of the Juntendo University Graduate School of Health and Sports Science Institutional Review Board with approval Number: 2021-50. Written informed consent was obtained from all eight participants prior to the intervention. Data availability statement The data that support the findings of this study are available from the corresponding author upon reasonable request. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
LIU et al. (Tue,) studied this question.