Wheelchair marathon racing causes striated muscle distress in individuals with spinal cord injury.

OBJECTIVE: To assess the effects of wheelchair marathon racing in individuals with spinal cord injury (SCI) on circulating muscle enzymes and myoglobin.

SUBJECTS: Thirty-one men with SCI, including 25 wheelchair marathon athletes and 6 sedentary men.

DESIGN: Serum myoglobin (Mb), creatine kinase (CK) activity, and lactate dehydrogenase (LDH) were measured in participants of the 1995 Oita International Wheelchair Marathon Race (42.195 km). Blood samples were obtained 24 hours before, immediately after, 24 hours after, and 7 days after the race.

RESULTS: Marathon racing resulted in significant increases in serum Mb, total CK activity, and LDH (p<.01) after the race. The peak Mb and LDH levels occurred immediately after the race; total CK activity peaked 24 hours after the race. Evaluation of cardiac muscle enzymes showed no significant changes in two CK isoenzymes (CK-MM and CK-MB).

CONCLUSIONS: Propulsion of the wheelchair in a marathon race induced muscle stress in athletes with SCI. Completion of the marathon race did not cause cardiac muscle damage, however. Elevated muscle enzyme levels likely resulted from muscle distress rather than from dehydration.