|Figure 1: Increase in 5-RM Strength by leucine supplementation in the course of a 12 weeks strength training program (adopted from Ispoglou. 2011).|
the leucine group demonstrated significantly higher gains in total 5-RM strength (sum of 5-RM in eight exercises) and 5-RM strength in five out of the eight exercises (P < .05). The percentage total 5-RM strength gains were 40.8% (± 7.8) and 31.0% (± 4.6) for the leucine and placebo groups respectively. Significant differences did not exist between groups in either total percentage LTM gains or total percentage FM losses (LTM: 2.9% ± 2.5 vs 2.0% ± 2.1, FM: 1.6% ± 15.6 vs 1.1% ± 7.6).You may now argue that the leucine group did gain more muscle mass and lose more fat - yeah that is right, but this difference is way lower than the standard-deviation (i.e. the statistical measure of the mean intra-group difference between the subjects), which renders these results scientifically "insignificant". It is, nevertheless interesting to see some quantifiable data on what I consider the optimal benefits, i.e. the benefit someone with an initially low leucine intake, can derive from a daily dose of 4g supplemental leucine.