Effort-related chronic compartment syndrome (ERCCS) of the lower extremity is often misdiagnosed, requiring repeated visits to the physician and subsequent delay in definitive treatment. The most significant causes of chronic leg pain in physically active individuals are stress fractures, shin splints, and "exercise-induced" or effort-related chronic compartment syndrome. In patients susceptible to ERCCS, the fascial compartments are too small to accommodate the associated 20% increase in muscle mass that typically occurs with heavy exercise. The increased pressure within a small unyielding compartment limits circulation and subsequent muscle function. The only appropriate conservative treatment is cessation of the offending activity. Early suspicion of the condition is paramount, because the definitive treatment is fasciotomy. ERCCS has only recently been recognized, and therefore it may be underdiagnosed. Family physicians and general medical officers caring for otherwise healthy soldiers and athletes should be aware of ERCCS so that prompt orthopedic referral for evaluation and definitive treatment will not be delayed.