Aims: 

The purpose of the study was to compare the acute physiological effects of two exercise regimens. Specifically, we tested the hypotheses that a single bout of stair jump exercise induces less damage to muscle and more metabolic changes than jump exercise performed at level.

Methods: 

Four trained males executed ten sets of ten repetitions of high intensity single-leg consecutive jumps in two conditions: on stairs (S) with one leg, and at level (L) with the other leg. Exercise conditions were separated by two weeks of rest period. Maximal isometric torque (MVC) of the knee extensors, and unilateral vertical jump height (VJ) was determined at baseline (BL), immediately (IP), 24h and 48h post-exercise. Serum creatine kinase (CK) level, and delayed onset of muscle soreness in knee extensors were evaluated at BL, 24h and 48h. Blood lactate (LA) concentration at BL and IP, and average heart rate (HRav) during exercise were measured.

Results: 

At BL, none of the measured values differed between conditions. LA elevated in both conditions, but at IP it was significantly greater in S. HRav was not different between conditions. From BL to 24h MVC and VJ reduced only in L, and remained depressed at 24h. CK was doubled and peaked at 24h and was still elevated at 48h in both conditions. Muscle soreness developed only in L and it peaked at 24h.

Conclusion: 

Despite similar changes in CK, impaired muscular function and greater soreness may indicate that jump exercise performed at level induces more injuries to contractile muscle elements, compared with stair jumps. Greater lactate response in stair jump training can be attributed to higher energy demand possibly due to the dominance of concentric muscular contractions, compared with level jumps comprising rather high force eccentric actions, initiatives of muscle damage.