Muscle dysfunction can be lead to poor outcomes moreover ICU muscle weakness recovery are not correctly described.

The investigators aimed to assess the ability for quadriceps or respiratory muscles to repeat an effort at a maximal loading.

Inclusion Criteria:

• Mechanically ventilated at least at 24 Hours
• Maximal inspiratory pressure < 30 centimeter of water
• MRC score < 48/60

Exclusion Criteria:

• Age < 18 years
• Patients with neurological pathology or pre existing neuromuscular dysfunction
• Patient unable to walk 50 meters before ICU admission
• Patient with a thoracic or abdominal surgery
• Inability to carry out maximal voluntary contraction

Patients weaned from mechanical ventilation and developping ICU muscle weakness diagnosed by a maximal inspiratory pressure and a MRC score