Response of creatine kinase and lactate dehydrogenase enzymes to rest interval between sets and set-repetition configuration during bouts of eccentric exercise.

Background and aims: Various studies have demonstrated that different rest intervals and set-repetition have a significant effect on hormonal and metabolic responses. These factors can lead to different muscle damage responses.

Methods: Forty untrained subjects (25.4 ± 0.068 years, height: 1.74 ± 0.97 cm, and weight: 30.8 ± 8.48 kg) in three sessions of eccentric resistance exercise with 24-h rest between each session participated in this study. Subjects were divided into four groups of 10 subjects who performed 50 eccentric contractions with different number of 5 and 10 sets, 5 and 10 repetitions, and the interset rest interval 1 and 3 min with 85% of one repetition maximum (1RM). Creatine kinase and lactate dehydrogenase were measured immediately before each session, immediately after each session, and 24 h after the last training session. Variance analysis with repeated measurement and Bonferroni post hoc test were used for statistical analysis of data.

Results: There is no significant difference in creatine kinase and lactate dehydrogenase between four groups at different time points (p < 0.05).

Conclusion: The repetition of eccentric exercise for three consecutive days causes muscle damage that is independent of manipulating the interset rest intervals and the number of set-repetition.