The effect of stretching application on muscle damage in young men

The aim of this study was to investigate the effect of post-exercise stretching on muscle damage. 23 young male volunteers participated in the study and randomly assigned into two groups (Experimental group n = 12, Control group n = 11). The study was designed according to the pre-test post-test control group experimental design. Muscle damage was assessed before, immediately after the exercise, and at 24, 48, 72 and 96th hours after exercise; Perceived pain levels, creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), hamstring flexibility, quadriceps flexibility and mid-thigh circumference measurements were determined. For muscle damaging exercise protocol 6x20 repetitive depth jump and for stretching protocol 3x30 second static stretching.was applied to lower body extremity muscle groups. Variance analysis for repeated measures was used for statistical analysis. According to the analysis of variance for repeated measurements; significant main effect for time was indicated in pain [F (5-105) = 60,528; p = 0.001], CK [F (5-105) = 10,454; p = 0,000], LDH [F (5-105) = 13,214; p = 0,000], AST [F (5-105) = 6,722; p = 0,000], hamstring flexibility [F (5-105) = 4,675; p = 0.001] and thigh circumference value [F (5-105) = 9.919; p = 0,000]. Moreover Time x Group interaction for pain [F (5-105) = 2,902; p = 0.017] and thigh circumference value [F (5-105) = 2,475; p = 0.037] was statisticaly significant. According to the results of CK, LDH, AST, hamstring flexibility, pain and thigh circumference measurements it is concluded that exercise protocol caused significant muscle damage. Stretching exercise protocol applied following muscle damaging exercise has no protective effect on muscle damage. On the contrary due to inreased pain and thigh circumferce values it is concluded that repeated static stretching after muscle damaging exercise has negative effect on damage responses. Key words: AST, CK, flexibility, LDH, pain.