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.
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.