Effect of Remote Tai Chi Training vs. Strength Training on Muscle Mass and Grip Strength in Older Mexican Adults in the Context of the COVID-19 Pandemic.

Tele-exercise (TEF) is an option for maintaining the vitality of people who have difficulty exercising outside the home and in confinement situations. The aim of the present study was to determine the effect of TEF in Tai Chi (TC) compared to Strength Training (ST) on muscle mass and strength in older Mexican adults. The effect was measured in the following groups: (i) TC Group (TCG) n = 22; (ii) ST Group (STG) n = 22; and (iii) Control Group (CG) n = 21. Skeletal muscle mass (SMM), Skeletal Muscle Mass Index (SMMI), FM (%) (percentage of fat mass), handgrip strength (HS), and sit-stand test (SST) were assessed before and after the intervention. The data presented comes from a per-protocol design and only include the results of people who completed the study. An ANCOVA was performed and the mean difference (MD) was estimated with a 95% confidence interval (CI). The effect size was also calculated using the partial squared eta (η2p). A high percentage of study dropout was observed in all three groups (TCG, 20/42 = 48%; STG, 19/41 = 46%; CG, 19/40 = 47%). Both TCG and STG showed an increase respect CG in SMM (TCG: MD = 1.79, CI 0.71, 2.88; STG: MD = 1.10, CI 0.18, 2.02, p < 0.01) and SMMI (TCG: MD = 0.73, CI 0.28, 1.19; STG: MD = 0.40, CI 0.05, 0.77, p < 0.01). Likewise, they showed a significant decrease in FM (%) (TCG: MD -4.81, CI -8.17, -1.44; STG: MD = -3.99, CI -6.84, -1.13, p < 0.01). Regarding the effect size, it was observed large statistically significant effects in SSM (η2p = 0.19, F = 5.38, p < 0.01); SMMI (η2p = 0.19, F = 5.23, p < 0.01); FM% (η2p = 0.18, F = 5.06, p < 0.01); FM/FFM (η2p = 0.19, F = 5.47, p < 0.01); and STST (η2p = 0.16, F = 4.42, p < 0.01). Our findings suggest that Tai Chi or Strength Training tele-exercise has a similar positive effect on skeletal muscle mass coupled with a decrease in the percentage of fat mass, so one of these exercises could be an option to continue with physical exercise training at home for older adults in confinement situations. However, the results cannot be generalized due to limitations in the quasi-experimental study design, the non-representative sample size, the high dropout rate, and selection bias. For this reason, more randomized intention-to-treat clinical trials with representative samples are necessary.