Effects of multicomponent training on functional outcomes, persistent symptoms, body composition and muscle function in patients severely impaired by COVID-19: a secondary analysis of CORE-randomized clinical trial

Purpose To investigate the medium-term effects of the CORE (COVID-19 and Rehabilitation) Study—a randomized-controlled clinical trial—on functional outcomes, persistent symptoms, body composition, phase angle, and muscle function in adults and older adults after severe and critical COVID-19. Methods Participants were randomly assigned (1:1) to an intervention group (IG), which received 11 weeks of multicomponent training (balance/aerobic/resistance) twice weekly, or a control group (CG), which received structured physical activity recommendations. Six-minute walk test was the primary outcome. Analyses followed intention-to-treat principle ( α = 0.05). Results Forty participants were evaluated (19 women; 52.0 ± 12.9 years). In the main analysis, both groups improved performance in the 6-min walk test (IG: 42 m, 95% CI: 14.7 to 69.3; CG: 29 m, 95% CI: −24.9 to 82.6; p = 0.021), sit-to-stand (IG: 2 reps, 95% CI: 0.9 to 2.7; CG: 1 rep, 95% CI: −1.2 to 3.2; p = 0.023), and timed up and go at usual speed (IG:−1.3 s, 95% CI: −2.3 to 0.1; CG:−0.5 s, 95% CI: −1.2 to 0.1; p = 0.008). Reductions in frailty were observed only in IG in the physical (−1.4 points, 95% CI: −2.3 to 0.6; p < 0.001) and general (−1.7 points, 95% CI: −2.7 to 0.6; p = 0.001) domains. Fat percentage increased in CG (2.27%, 95% CI: 0.0 to 4.5; p = 0.050). Conclusion An 11-week multicomponent training program showed promising effects in reducing frailty and preventing increases in fat percentage in patients severely affected by COVID-19. Trial registry Brazilian Registry of Clinical Trials (RBR-10y6jhrs), 22 February 2022, retrospectively registered.