Topic overview

Start with the big picture

The lesson surveys a range of muscle conditions, from Duchenne muscular dystrophy and neuromuscular-junction disorders to inflammatory myopathies and fibromyalgia. It also covers urgent or painful problems such as compartment syndrome, rhabdomyolysis, tetanus, cramps, and delayed-onset muscle soreness. Exercise physiology provides a second focus: resistance training is associated with larger muscle fibers and strength-related adaptations, while endurance training supports oxidative capacity. The topic distinguishes hypertrophy, an increase in fiber size, from hyperplasia, and introduces satellite cells and sarcopenia. Together, these concepts show how clinical features, mechanisms, and muscle adaptation can be considered across injury, training, and aging.