Data_.xlsx

This study aimed to evaluate the effects of an 8-week eccentric training program utilizing the reverse Nordic exercise (RNE) integrated into karate training compared to regular karate training only on measures of physical fitness in youth karate athletes. Twenty-seven youth karatekas were recruited and allocated to either RNE group (n=13; age=15.35±1.66 years) 7 males and 6 females) or an active CG (n=14; 7 males, and 7 females; age=15.30±1.06 years). To track the changes in measures of physical fitness before and after training, tests to assess linear sprint speed (i.e., 10-m), change of direction (CoD) speed (i.e., modified 505 CoD), vertical jumping (i.e., countermovement jump [CMJ] height), and horizontal jumping distance (i.e., standing long jump [SLJ]), and lower-limb asymmetry score were carried out. Results indicated significant group-by-time interactions in all measures of physical fitness (effect size [ES] = 1.03 to 2.89). Post-hoc analyses revealed significant changes in the RNE group across all performance measures (effect size [ES]=0.33 to 1.63). Additionally, the asymmetry score exhibited a moderate decrease (∆46.96%, ES=0.64). In contrast, no significant changes were observed in the CG across all fitness measures. Moreover, the individual response analysis indicated that consistently more karatekas from the RNE group achieved improvements beyond the smallest worthwhile change threshold across all fitness measures. In summary, RNE training is an effective approach to enhance various physical fitness measures besides lower-limb asymmetry scores in youth karatekas and is easy to incorporate into regular karate training. Practitioners are therefore encouraged to integrate RNE training consistently to enhance essential physical fitness components in young karatekas.