This study examined the efficacy of short-term alpha-ketoisocaproic acid (KIC) monotherapy supplementation immediately prior to moderate- and high-intensity single bout exercise performance.

Thirteen resistance trained men (22.8 ± 2.5 years; 81.6 ± 12.6 kg) participated in a prospective, randomized, double blind, placebo controlled crossover experiment. Each subject completed one familiarization and four experimental trials with either 1.5 g or 9.0 g of either KIC or isocaloric placebo control (CONT), following an overnight fast. During the experimental trials, subjects consumed the supplement regimen and then completed leg and chest press repetitions to failure and 30 s of repeated maximal vertical jumping (VJ) on a force plate.

In this treatment regimen, no significant differences (p > 0.05) were observed between dosages or conditions for leg press (low CONT = 19.8 ± 0.4 SEM, low KIC = 21.0 ± 0.5, high CONT = 20.1 ± 0.3, high KIC = 22.4 ± 0.6) or chest press (low CONT = 18.1 ± 0.2, low KIC = 18.5 ± 0.3, high CONT = 17.8 ± 0.3, high KIC = 18.0 ± 0.3) repetitions to failure. Additionally, no significant differences were observed for peak or mean VJ performance (low CONT = 34.6 ± 2.2 cm and 28.6 ± 1.8 cm; low KIC = 35.6 ± 2.0 cm and 29.4 ± 1.6 cm; high CONT = 35.7 ± 2.1 cm and 29.4 ± 1.7 cm; high KIC = 34.8 ± 2.3 cm and 28.3 ± 1.7 cm), respectively.

Based on our results, we conclude that acute KIC ingestion by itself with no other ergogenic supplement, immediately prior to exercise, did not alter moderate- nor high-intensity single-bout exercise performance in young resistance-trained males. This study addressed single-dose single-bout performance events; the efficacy of KIC monotherapy supplementation on repeated high-intensity exercise bouts and long-term exercise training remains unknown.