Physical inactivity and muscle weakness in the critically ill

This article puts forward some of the causes for muscle weakness in intensive care. The aquired muscle weakness reflects loss of mechanical loading due to physical inactivity, bed rest, or immobilization. They go on to describe the complex adaptive response that is stimualted with mechanical unloading and results in muscle atrophy and loss of specific force. Countermeasures that lessen the effects of unloading include physical activity, nutritional supplements, hormone therapy, and antioxidant administration. 

Chambers, A., Moylan, JS., Reid, MB. CRITICAL CARE MEDICINE 2009; 37 (10): S337 – S346

Physical activity programme

A series of five online courses that comprehensively explore physical activity and the related role of physiotherapy / physical therapy