Reduced Muscle Strength in Patients with Long-COVID-19 Syndrome Is Mediated by Limb Muscle Mass.

Understanding the impact of COVID-19 on muscle strength may help to elucidate the organ systems that contribute to acute and chronic COVID-19 sequelae. We questioned whether patients with postdischarge symptoms after COVID-19 had compromised muscle strength compared with a control group, and if this potential relationship was mediated by the lower appendicular lean mass index (ALMI). A total of 99 patients with long-COVID-19 and 97 control participants were screened. Maximal grip strength was assessed with a TKK 5101 digital dynamometer, and leg extension 1RM was measured using EGYM Smart Strength machines. Body composition (fat mass percentage, lean mass, visceral fat and appendicular lean mass index) was determined using a whole-body dual-energy X-ray densitometer. Results showed that grip strength and leg extension strength were significantly higher in controls than in COVID-19 survivors (mean [SD], 32.82 [10.01] vs. 26.94 [10.33] kg; difference, 5.87 kg; P < 0.001) and (mean [SD], 93.98 [33.73] vs. 71.59 [33.70] kg; difference, 22.38 kg; P < 0.001), respectively). The relationship between long-COVID syndrome and grip/leg strength levels was partly mediated by ALMI, which explained 52% of the association for grip strength and 39% for leg extension. Our findings provide novel insights into the mechanisms underlying the relationship between long-COVID syndrome and grip/leg strength levels, supporting the negative effects of long-COVID syndrome on muscle function.

Resistance training and clinical status in patients with postdischarge symptoms after COVID-19: protocol for a randomized controlled crossover trial "The EXER-COVID Crossover Study".

BACKGROUND: Physical exercise induces a coordinated response of multiple organ systems, including the immune system. In fact, it has been proposed that physical exercise may modulate the immune system. However, the potential effect of an exercise program on COVID-19 survivors has not been investigated. Thus, the aim of this study is to evaluate the modifications in immunological parameters, physical condition, inflammatory profile, and perceived persistent symptoms after 6 weeks of supervised resistance training (RT), in addition to the standard care on the clinical status of patients with persistent COVID-19 symptoms. The objective of this protocol is to describe the scientific rationale in detail and to provide information about the study procedures. METHODS/DESIGN: A total of 100 patients with postdischarge symptoms after COVID-19 will be randomly allocated into either a group receiving standard care (control group) or a group performing a multicomponent exercise program two times a week over a period of 6 weeks. The main hypothesis is that a 6-week multicomponent exercise program (EXER-COVID Crossover Study) will improve the immunological and inflammatory profile, physical condition, and persistent perceived symptoms (fatigue/tiredness, musculoskeletal pain, and shortness of breath) in patients with postdischarge symptoms after COVID-19. DISCUSSION: Our results will provide insights into the effects of a multicomponent exercise program on immunological parameters, physical condition, inflammatory profile, and persistent perceived symptoms in patients with postdischarge symptoms after COVID-19. Information obtained by this study will inform future guidelines on the exercise training rehabilitation of patients with postdischarge symptoms after COVID-19. TRIAL REGISTRATION: NCT04797871 , Version 2. Registered on March 15, 2021.

Relationship between parents' and children's objectively assessed movement behaviours prior to and during the COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic could have provoked undesirable harmful effects on movement behaviours among children. OBJECTIVE: To compare levels of physical activity (PA), sedentary behaviour (SB), and sleep time in children prior to and during the COVID-19 pandemic (after the lockdown) and to determine the association between changes in moderate-to-vigorous PA (MVPA), total PA (TPA), SB, and sleep time between mothers and fathers with their children. METHODS: A total of 110 children (aged 4-7 years) and their parents (63 mothers and 52 fathers) wore GENEActiv accelerometers for 6 days (4 weekdays and 2 weekend days) prior to the pandemic and 1 year into the pandemic to assess SB, MVPA, TPA, and sleep time. RESULTS: Children performed more MVPA on weekdays (p = 0.002), had higher SB (p = 0.001), and slept fewer hours during the pandemic than before (p < 0.001). Likewise, children performed more weekend day MVPA and TPA (p < 0.001) during the pandemic, and slept less than prior to the pandemic (p = 0.002). On weekdays, an increase in mother's MVPA and TPA (categorized as tertiles) was associated with higher increased on MVPA (p = 0.030) and TPA in their children (p = 0.023), respectively. On weekends, an increase in mother's MVPA was also associated with higher increases in MVPA (p = 0.011) in their children. CONCLUSION: During the pandemic, children got more MVPA, more SB, and slept fewer hours than before. Changes in PA seem to be associated with mother's behaviours, especially during weekdays.