Abstract
BACKGROUND: Serum creatine kinase (CK) enzyme activity and lactate dehydrogenase (LDH) concentrations are used as indicators of muscle cell membrane state and muscular damage after exercise. The present study examined the effect of concentric strength exercises done at different angular velocities and different stopover durations between sets on the LDH concentrations and CK enzyme activity of participants.
METHOD: The study included 32 sedentary male volunteers (21.35 ± 3.10 years, 71.80 ± 6.20 kg and 178.40 ± 11.90 cm). Subjects were randomly separated into four different groups according to stopover: a) a group performing concentric muscle strength exercises at 60°/s with 1-min stopover (CEG1-60°), b) a group with 3-min stopover (CEG3-60°), c) a group performing concentric muscle strength exercises at 120°/s with 1-min stopover(CEG1-120°), and d) a group with 3-min stopover (CEG3-120°). The LDH and CK concentrations of the four groups were measured pre- and post-exercise and at 24, 48 and 72 hours.
RESULTS: Within both CEG1-120° and CEG3-120°, there were significant differences in LDH concentrations between pretest-24-h times (p< 0.05). The LDH concentrations were the highest at 24-h for all groups. When the LDH concentrations were compared between both CEG1-60° vs. CEG1-120° and CEG3-60° vs. CEG3-120° significant differences were found between pretest-posttest and pretest-24-h times. LDH concentrations were higher for both CEG1-60° and CEG3-60°.
CONCLUSION: Concentric muscle exercises performed at different angular velocities result in differences in both LDH and CK values. These differences are particularly evident following higher intensity exercises. Thus, high-intensity concentric muscle exercises may increase the risk of muscle damage among beginners and amateur sportsmen.