Different reversibility of skeletal muscle mass and strength in elderly Japanese women after the first wave of COVID‐19

Abstract Background Restrictions on outdoor movements due to the coronavirus disease (COVID‐19) pandemic have led to a decreased physical activity; this can lead to sarcopenia and frailty in older adults. Our recent study has demonstrated a significant decrease in the trunk muscle mass immediately after the pandemic's first wave (April–May 2020) among Japanese community‐dwelling older women. In the present study, we further examined whether muscle mass recovery or deterioration occurs after 1 year of the pandemic's first wave by comparing physical measurements among the following assessment periods: before the first wave, immediately after the first wave, and at 1‐year follow‐up thereafter. Methods This study included 77 women (78.0 ± 5.7 years) who underwent physical measurements for muscle mass, grip strength, one‐leg stand‐up ability (3 s), and oral motor skills and answered questionnaires on sociality (social network, participation, and support) in the three assessment periods. Results The frequency of going out and the subjective vitality were significantly decreased immediately after the first wave; these recovered at the 1‐year follow‐up ( P < 0.001). When comparing muscular measures, the trunk muscle mass index preferentially decreased immediately after the first wave but recovered significantly at the 1‐year follow‐up ( P < 0.001). Conversely, the appendicular skeletal muscle mass index (ASMI) and grip strength continued to decrease until the 1‐year follow‐up ( P < 0.001 and P = 0.03, respectively). The ability to perform a one‐leg stand‐up for 3 s and the oral motor skills did not change significantly across the assessment periods. The prevalence of pre‐sarcopenia and sarcopenia tended to increase during these periods ( P = 0.068). The reduction and subsequent recovery patterns for sociality were similar to those observed for the trunk muscle mass. Conclusions Our findings demonstrated differences in the reversibility of skeletal muscle mass and strength at 1 year after the first wave of the COVID‐19 pandemic: the trunk muscle mass declined acutely and recovered rapidly, whereas the ASMI and grip strength declined continuously. These differences in the skeletal muscle recovery and deterioration might help formulate short‐term or long‐term strategies for COVID‐19‐related sarcopenia prevention in community‐dwelling older adults.