This is a prospective, open, controlled randomized study (2 x 60 individuals) performed in 5 centers. Participants will perform 24 exercise sessions on cycloergometer (3 sessions/week, 8 weeks). The experimental group (eccentric) will perform 5 habituation sessions: the initial power of the exercise will be set to 10 Watts and then increased by 10% each session, depending on the muscle tolerance. The training power must correspond to 3 times that of the control group to obtain a similar metabolic stimulation. The control group (concentric) will perform exercise training at an intensity of 60% of the reserve heart rate determined during an initial cardiorespiratory test. The primary outcome will be the change in distance covered during the 6-min walk test between the initial assessment and month 2. Secondary outcomes will include study of sarcopenia, muscle strength, general and muscular fatigue, quality of life, blood metabolomic data, ex vitro data for mitochondrial and histo-biochemical functionality from muscle biopsies of the Vastus Lateralis.
With the COVID-19 pandemic, the number of patients to be treated in rehabilitation increased .~Hospitalization for severe infection can induce muscular atrophy and muscular dysfunction that persists for several months and rehabilitation capacities may be exceeded.~Exercises in eccentric mode could be performed, inducing greater muscular hypertrophy, muscle strength, power and speed than concentric exercises.~The goal of this study was to compare functional recovery at 2 months after a training program in eccentric and concentric mode after severe COVID-19.~An effective rehabilitation could help reduce costs and duration of care.