Exercise-induced pain, stiffness, and tubular aggregation in skeletal muscle.

Abstract
The case is described of a 36 yr old man with exercise-induced pain, stiffness, and tubular aggregation in skeletal muscle. Persistent creatine phosphokinase elevation and a normal forearm ischemic exercise test were demonstrated. Electromyography was normal. Muscle biopsy showed aggregates of tubular structures in most fibers by histochemical and ultrastructural analysis. A relationship of this syndrome to known defects in muscle energy metabolism is postulated.