The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease 2019 (COVID-19) affect at late march 2021 more than 127 millions of persons worldwide (including more than 4.5 millions in France, according to John Hopkins University https://coronavirus.jhu.edu/map.html, consulted 2021/3/25). Among these persons, 17% of the confirmed cases the COVID-19 develop an acute respiratory distress syndrome (ARDS) (Chen et al., 2020), requiring an hospitalization in intensive care unit with mechanical ventilation for prolonged periods (in median up to 21 days whereas 3.3 is the usual mean length of stay). This prolonged period of inactivity causes dramatical muscles and cardio-respiratory losses. These patients experience a dramatical decrease in the physical ability which is reinforce by the protective isolation measures and containment to prevent the further spread of the virus.

Rehabilitation of patients with a severe form of the COVID-19 faced new challenges due to the novelty of the disease and protective isolation measures to prevent the further spread of the virus. Rehabilitation target a recovery of the cardio-respiratory, muscle deficits and improvement in activity. Functional electrical stimulation (FES) is one innovative technique, among other. FES have been shown as effective to improve the respiratory function in patients with a severe chronic obstructive pulmonary disease (Acheche et al., 2020; Maddocks et al., 2016), reduce the muscle loss due to zero gravity in space for astronauts (Maffiuletti et al., 2019), or increase strength in persons with incomplete spinal cord injury (de Freitas et al., 2018). FES has been recently delivered during cycling to restore pedaling movements with an adequate rhythm of muscle contraction. To date, FES cycling has been successfully administered in patients with spinal cord injury, and has been shown to be more effective in patient with severe COPD for improving the exercising intensity; reducing fatigue and improving quality of life in persons with multiple sclerosis (Backus et al., 2020).

In a pilot study, we shown that 4 week of physical therapy incluing FES cycling resulted in a fasten recovery of active postures as compared to physical therapy including cycling alone. (Mateo et al., under revision). Therefore, we hypothesize that a 4-week period of rehabilitation based on physical therapy with FES cycling would result in a significantly increase of activity profile (decrease in inactive posture duration) in patient with a severe form of COVID-19 (i.e., with an ARDS requiring mechanical ventilation).

Inclusion Criteria:

• Age ≥ 18 years
• Being hospitalized for rehabilitation because of a severe form of the COVID-19 that required an admission in intensive care unit for acute distress respiratory syndrome treated by mechanical ventilation.
• Being beneficiary of the French social security.

Exclusion Criteria:

• Person requiring supplementation in oxygen > 4 L/min because above this threshold, the oxygen flow is considered to be associated with an increased risk of aerosolization and further virus spread in patient being contagious;
• Oxygen desaturation during exercise (i.e., SpO2 < 90%) and requiring supplementation in oxygen > 4 L/min.
• Person showing a lower motor neuron disease as defined by the medical research council score < 48/60 including hyporeflexia (quadricipital and triceps tendons) and decrease in lower limb sensation.
• Persons showing denervated muscle (including quadriceps, hamstring, gluteus and triceps) confirmed by electromyography because the electrical stimulations delivered by the stimulator (i.e., symmetric and rectangular biphasic currents) are not appropriate to restore a pedaling movement;
• Person with osteo-articular disease at lower limbs including reduction in range of motion at the hip, knee and ankle preventing cycling pedaling in a sitting position;
• Persons with associated neurologic or psychiatric disease;
• Person with a medical contraindication to intensive rehabilitation;
• Person suffering from suspected or diagnosed epilepsy;
• Person with an implanted device;
• Person included in another ongoing research or during an exclusion period of another research;
• Adults protected by law (guardianship or curatorship);
• Pregnant women