As is well know, predniosne/glucocorticoids causes muscle atrophy. Prednisone inhibits glucose uptake in muscle which eventually contributes to breakdown of muscle proteins, and directly affect muscle protein content, both by stimulating protein degradation and inhibiting protein synthesis. Prednisone is also selective in causing more damage to type II muscle fibers. This means patients experience a significant loss in their capacity to generate maximum muscle force and less change in muscle endurance. However, prednisone therapy does result in loss of both endurance and strength.
Of course this means patients need to exercise in order to minimize the muscle atrophy, and that a program of aerobic exercise and weight training is warrented. It also means that patients will be at risk for injury if they exercise. So patients need to know their own medical history and their own limitations.
To determine the extent of myopathy, levels of creatine in the urine provide an overall indicator of the degree of protein degradation. Serum creatine kinase and aspartate aminotransferase also should be monitored to assess tolerance to exercise training. Both creatine kinase and aspartate aminotransferase are good indicators of exercise-induced muscle injury and rise in proportion to the degree of muscle injury.
Full weight bearing exercise may be inappropriate for patients with osteoporosis or avascular necrosis (AVN); therefore, pool or cycling exercises are often the best aerobic exercise mode. It should also be noted that inadequate hydration levels may impair exercise tolerance and lead to hypotension in patients with electrolyte imbalances and/or hyperglycemia.
Resistance training with low weight and high repetitions is generally recommended to prevent ligament, tendon, and muscle ruptures and pathologic fractures. Exercise should be stopped if systolic blood pressure exceeds 250 mm Hg or diastolic blood pressure exceeds 120 mm Hg.
[Kinney-LaPier, MS,PT, Glucocorticoid-Induced Muscle Atrophy The Role of Exercise in Treatment and Prevention, 1997, J Cardiopulmonary Rehabil, 17:76-84]