Muscle wasting occurred early and rapidly in critically ill patients. Early therapeutic strategies to either maintain muscle structure and function should be encouraged. Neuromuscular electrical stimulation (NMES) is an attractive intervention to maintain muscle mass and strength in critically ill patients during the first week of ICU stay. This study will test the hypothesis that the number of contraction per day evoked by NMES in the first two weeks of illness may influence in muscle wasting, with beneficial effects on the physical and functional status in mechanically ventilated patients.

Patients with prolonged mechanical ventilation require deep sedation and mechanical ventilation, factors predisposing to the development of skeletal muscle wasting and acute muscle atrophy. Strategies to attenuate this process must be used. The neuromuscular electrostimulation (NMES) leads to the application of electrical currents in the skin aiming at muscle contraction, has beneficial effects for the population of critical patients. However, the number of contractions induced by NMES to attenuate the loss of muscle mass in this population is not yet established. This randomized controlled trial with 120 patients that will be randomized to one of the 3 study groups: 100 continuous daily contractions (100Cd), 50 continuous daily contractions (50Cd) and control group. Muscle thickness, NMES-induced strength, and clinical and functional parameters at the time of discharge from the ICU and hospital discharge will be assessed daily. The results of this project will provide an important contribution to the understanding of the mechanisms associated with NMES treatment as a tool to minimize the effects of muscle disuse, as well as providing scientific support for the clinical use of this resource in the treatment in the light of the policies' health system.

Inclusion Criteria:

• Aged 18 years or older
• Intubated and expected to remain invasively mechanically ventilated the day after tomorrow
• laboratory confirmed COVID-19 (diagnosis of SARS-CoV-2 via reverse transcriptase polymerase chain reaction as per the World Health Organization protocol or by nucleic acid based isothermal amplification)

Exclusion Criteria:

• Dependent for activities of daily living in the month prior to current ICU admission (gait aids are acceptable).
• Documented cognitive impairment.
• Proven or suspected spinal cord injury or other neuromuscular disease that will result in permanent or prolonged weakness (not including ICU acquired weakness)
• Death is deemed inevitable as a result of the current illness and either the patient or treating clinical or substitute decision maker are not committed to full active treatment
• pregnancy
• patients with unstable fractures in the vertebral column and lower limbs.

The assessors will be blinded to randomization