Background: The aim of the study was to determine the effect of simultaneous supplementation of β-hydroxy-β-methylbutyrate and L-arginine α-ketoglutarate on lower limb power and muscle damage in medium distance runners aged 15.3 (± 0.9) years old.
Methods: The study group consisted of 40 volunteers (men and women) aged 14-17 (juniors and younger juniors) who have been practicing medium distance running for at least two years. The study followed a randomised, double-blind, placebo-controlled design. All subjects attended a familiarisation session on day 0 before the test commenced. The subjects were randomly divided into two groups: supplements group and placebo group. A similar training cycle protocol was used in both groups. Daily sRPE values, countermovement jump measurement as well as blood creatine kinase and lactate dehydrogenase were measured during 12-day training period.
Results: After the end of the training cycle, a significant (p = 0.002) decrease in the countermovement jump (CMJ) height was found in the placebo group when compared to the baseline measurement. In the supplements group, there was no decrease in the countermovement jump value, which was close to the baseline level after the end of the training cycle (p>0.05). During the 12-day training period, statistically significant changes in creatine kinase and lactate dehydrogenase levels were recorded between the supplements and placebo groups; its concentration increased during the training weeks similarly, and decreased on rest. All the changes were at a comparable level in both groups. The research results indicate that the supplement combination used in the supplements group prevented a reduction in the CMJ values. In contrast to supplements group, in the placebo group, the CMJ changes were statistically significant: a noticeable (p = 0.002) decrease in CMJ was noted between the baseline measurement and the 6th measurement. The well-being of the subjects from both groups changed significantly during the training period, and the intergroup differences in the mood level were similar and not statistically significant.
Conclusions: The results of this study indicate that the daily co-supplementation with β-hydroxy-β-methylbutyrate (6 g) and L-arginine α-ketoglutarate (8 g) during the 12-day intensive training camp may prevent deterioration of lower limb muscle power measured by the CMJ test in the well-trained youth track and field athletes. Keywords: training camp supplementation, medium distance runners, β-hydroxy-β-methylbutyrate, HMB, L-arginine α-ketoglutarate, AAKG, countermovement jump, CK- creatine kinase, LDH – lactate dehydrogenase.