Alterations in Muscle Contractile Properties, Structure, and Function During 10-Day Bed Rest, Post-Recovery, and Following COVID-19 LockdownŠimunič, Boštjan (Avtor) Franchi, Martino V. (Avtor) Sarto, Fabio (Avtor) Monti, Elena (Avtor) AtrophyBed restPhysical inactivitySkeletal muscleTensiomyographyWe aimed to identify early tensiomyography alterations in six muscles during a 10-day bed rest (BR10), followed by a 30-day recovery period (R+30), and to compare these changes with those observed after the 54-day COVID-19 lockdown in ten healthy males (22.9 ± 5.0 years). Tensiomyography and muscle thickness (sonography) were assessed at baseline, during bed rest, at BR10, R+30, and after the COVID-19 lockdown. Additional assessments included vertical jump performance (force plate), body composition (bioimpedance), physical activity (GPAQ), and lower back pain (VAS). By BR10, participants experienced a 1.9% body mass loss, a 3.8% increase in fat mass, and a 2.4% reduction in muscle mass. While anthropometric parameters returned to baseline by R+30, fat mass increased again by 3.9% post-lockdown. Jump height declined by 10.1% at BR10, returned to baseline at R+30, and remained stable thereafter. Muscle thickness decreased by 7.0% in the vastus lateralis at BR10 and by 10.1% post-lockdown. Tensiomyographic amplitude increased in all five leg muscles prior to BR10, recovered at R+30 and increased again after the COVID-19 lockdown, while a reduction was observed in the erector spinae within the first 48 hours, coinciding with reported lower back pain. In the erector spinae, both delay and contraction time decreased during BR10 and post-lockdown. In contrast, contraction time of the biceps femoris increased before BR10 and remained elevated post-lockdown. Overall, tensiomyographic parameters after the COVID-19 lockdown changed in the same direction as during bed rest, though to a lesser degree, make it a sensitive tool for detecting changes in muscle structural and functional quality after bed rest and reduced activity paradigms.02025-06-24 23:43:51Delo ni kategorizirano22783sl