The acute and delayed impact of the 5-m shuttle run test on oxidative stress, muscle damage, and immune response, and their relationship with performance in rugby union players

Abstract Background High-intensity physical exercise induces oxidative stress, muscle damage, and changes in immune markers. However, these parameters' acute and delayed responses to the 5-m shuttle run test (5-m SRT) and their relationship with performance have yet to be assessed. This study evaluated the effects of the 5-m SRT on acute and delayed responses related to antioxidants, oxidative stress markers, muscle damage, and immunity, and their relationship with performance in rugby players. Methods Sixteen amateur rugby players completed the 5-m SRT with performance measured by distance covered and the rating of perceived exertion (RPE) was recorded 30-min post-test. Blood samples were collected before, immediately after, and at 24-, 48-, and 72-h post-exercise. Delayed onset of muscle soreness (DOMS) was assessed before the test, at 24, 48, and 72 h. Results The 5-m SRT significantly increased white blood cells (WBC) and neutrophils (NEU) 5-min post-exercise, with levels decreasing over 72 h. Lactate dehydrogenase (LDH) and creatine kinase (CK) peaked at 5min and subsequently declined at 24 and 48 h. Antioxidants and oxidative stress markers peaked 5-min post-exercise, while DOMS was highest at 72 h. Significant correlations were found between performance and NEU response ( p = 0.001, r = 0.74) and changes in lymphocytes (LYM) from 5 min to 48 h ( p = 0.005, r = – 0.66) and 72 h ( p = 0.004, r = – 0.67). Conclusion The 5-m SRT affects post-exercise immune function, oxidative stress, and muscle damage responses, needing 72 h for recovery to baseline levels. Despite correlations between performance and changes in NEU and LYM, these markers stayed within normal ranges, indicating that their fluctuations may not directly influence performance.