Leucine + Whey = Upper Body Strength and Mass Gains

In a very recent study, Walker et. al. (Walker. 2010) investigated the effect of 8 weeks whey-Protein and leucine Supplementation on physical and cognitive performance. The provided 30 moderately fit individuals with 19.7g whey and 6.2 g leucine (WPL) or a calorie-equivalent placebo (P) and put them on a standardized exercise regimen. The results suggests that the availability of high quality protein adds to the protein anabolic effect of leucine to produce strength and lean mass gains:

Bench-press performance increased significantly from Week 1 to Week 8 in the WPL group, whereas the increase in the P group was not significant. Push-up performance increased significantly for WPL, and P showed a nonsignificant increase. Total mass, fat-free mass, and lean body mass all increased significantly in the WPL group but showed no change in the P group.

Are you missing something? Yes? To be honest, I cannot tell you about the effect on cognitive performance, because, obviously, the authors forgot to include the results in the abstract (full-text of the study is not yet available). I assume there won't have been any effects, because otherwise this would have been the more exciting result of a study which otherwise only confirms what we already knew: leucine is protein anabolic, but it needs sufficient levels of all other amino acids to work its magic.