Effect of Carrying Various Backpack Loads on Serum Creatine Phosphokinase (CPK).

摘要

This study was designed to examine serum creatine phosphokinase (CPK) response of walking with various backpack loads. Twelve, healthy, male volunteers attempted eight, 12-hour treadmill walks at three mph at a 0% grade (20-minute walk/40-minute rest per hour). Subjects carried either 0, 25, 50, or 75% of their respective body weights (BW) as a backpack load during the walks. Each subject performed half of the eight walks wearing a light weight cotton uniform (CAMMIE) and the other half wearing a chemical defense uniform including mask (MOPP). Blood samples were obtained before and after each walk. Results demonstrated that 0% and 25% loads did not significantly (p < 0.05) elevate serum CPK levels. The 50% and 75% loads, however, resulted in significantly increases in CPK following both MOPP and CAMMIE trials. Lastly, there was a linear increase in both post-exercise CPK, and delta CPK when compared across 0, 25, and 50% work loads. No difference was found, however, between MOPP and CAMMIE trials. These results suggest that significant skeletal muscle damage occurs when carrying backpack loads of greater than or equal to 50% of body weight. Furthermore, the magnitude of increase in CPK is linearly related to intensity of work. Keywords: Chemical defense; Creatine; Phosphokinase; CPK; Sustained operations; Pack loads; Lactate dehydrogenase; Cammie; MOPP. (jg)