A Pilot Study of Combined Cycle Ergometry and Amino Acids in the ICU

Inclusion Criteria: 1. \>=18 years old 2. Requiring mechanical ventilation or high flow nasal cannula (HFNC) with actual or expected total duration of mechanical ventilation or HFNC \>48 hours 3. Expected ICU stay \>4 days after enrollment (to permit adequate exposure to the proposed intervention) Exclusion Criteria: 1. \>120 continuous hours of mechanical ventilation or HFNC before enrollment 2. Expected death or withdrawal of life-sustaining treatments within 7 days from enrollment 3. No expectation for any nutritional intake within the subsequent 72 hours 4. Severe chronic liver disease (MELD score \>20) or acute fulminant hepatitis. 5. Documented allergy to the amino acid intervention 6. Not ambulating independently prior to ICU admission (use of gait aid permitted) 7. Pre-existing primary systemic neuromuscular disease (e.g. Guillain Barre) 8. Neuromuscular blocker infusion (eligible once infusion discontinued if other inclusion criteria met) 9. Pre-existing intracranial or spinal process affecting motor function 10. Pre-existing cognitive impairment or language barrier that prohibits outcomes assessment 11. Lower extremity impairments that prevent cycling (e.g. amputation, knee/hip injury) 12. Weight \>150kg 13. Pregnant 14. Incarcerated