Adequate conditioning should be ensured before starting strenuous exercise. Saddles should be checked for proper fit. In these cases tenectomy may be needed to restore limb function. During exercise, horses develop a short stiff stride, sweat profusely, and have an elevated respiratory rate. Upon stopping horses are reluctant to move, males frequently posture to urinate and in severe cases myoglobinuria may be apparent.
Physical examination reveals painful muscle cramps especially in the gluteal area.
Scintigraphic evaluation of horses with rhabdomyolysis following exercise show symmetrical damage to the gluteal, semitendinosus and semimembranosus muscles. Some horses may be extremely painful which could be confused with colic. Muscle pain usually persist for several hours. Endurance horses often show other signs of exhaustion including a rapid heart rate, dehydration, hyperthermia, synchronous diaphragmatic flutter and collapse. These serum proteins are listed in the order of their rate of increase in the blood and in reverse of their rate of clearance from serum.