Effect of resistive exercise on muscle damage in water and on land.

The purpose of this study was to compare the effects of resistance exercise in water and on land on blood levels of creatine kinase (CK), a known indirect marker of muscle damage. Nine men (age: 23 +/- 1.58 years; weight: 79.37 +/- 11.15 kg; height: 176.33 +/- 4.09 cm), who had not practiced resistance training for at least 6 months before this experiment, performed 3 sets of maximum elbow flexion and extension exercises in water and on land, separated by 2-minute periods of rest. A 10-repetition maximum test was used to load control on land with free weights, and in water the exercise was performed at maximum velocity with aquatic resistance equipment. The duration of the exercise in water was the same as that performed on land, to reproduce the same metabolic route. Plasma CK activity was determined using a commercially available kit (Labtest Enzymatic-UV) before exercise, after exercise, and at 24 and 48 hours after exercise. Significant increases in CK were found at 48 hours postexercise on land (preexercise land: 160.75 +/- 96.05 UxL; 48 hours: 326.87 +/- 240.84 UxL), and significant differences were found between land and water (preexercise water: 147.75 +/- 46.48 UxL; 48 hours: 121.75 +/- 30.86 UxL) for this measure. However, no significant differences were found in water. In conclusion, the water environment influenced the absence of significant muscle damage. This type of exercise protocol may be appropriate for situations in which limited muscle tissue damage is desired.