Background and Objective: High-intensity interval training is highly effective for improving athletic performance. However, the substantial mechanical and metabolic stress associated with this training may cause considerable post-exercise inflammation and transient biochemical disturbances. This study aimed to compare the effects of six weeks of high-intensity interval training combined with L-arginine supplementation on interleukin-6, interleukin-10, and liver enzyme levels in soccer players.
Methods: This clinical trial included 20 volunteer semiprofessional soccer players in Mashhad during 2025. Participants were allocated by simple randomization to either an exercise-plus-supplement group or an exercise-plus-placebo group. The six-week intervention consisted of three high-intensity interval-training sessions per week. Blood samples were collected at two time points (pretest and posttest), both at 8:00 a.m. after a 12-hour fast. Cytokine concentrations were measured by enzyme-linked immunosorbent assay, and the liver enzymes ALT and AST were measured using standard photometric methods and an autoanalyzer.
Results: At posttest, the exercise-plus-supplement group showed a statistically significant increase in interleukin-10 and a statistically significant decrease in alanine aminotransferase compared with the placebo group (P<0.05). Within-group comparisons showed a statistically significant reduction in interleukin-6 in the exercise-plus-supplement group (P<0.05), whereas no significant change occurred in the exercise-plus-placebo group. Interleukin-10 increased significantly by the end of the intervention in the exercise-plus-supplement group (P<0.05), but did not change significantly in the exercise-plus-placebo group. Aspartate aminotransferase and alanine aminotransferase decreased significantly in the exercise-plus-supplement group (P<0.05), whereas neither enzyme changed significantly in the exercise-plus-placebo group.
Conclusion: Exercise combined with L-arginine supplementation significantly increases interleukin-10 and reduces interleukin-6 and liver enzyme levels.