Whey protein hydrolysate augments tendon and muscle hypertrophy independent of resistance exercise contraction mode

In a comparative study, we investigated the effects of maximal eccentric or concentric resistance training combined with whey protein or placebo on muscle and tendon hypertrophy. 22 subjects were allocated into either a high-leucine whey protein hydrolysate+carbohydrate group (WHD) or a carbohydrate group (PLA). Subjects completed 12weeks maximal knee extensor training with one leg using eccentric contractions and the other using concentric contractions. Before and after training cross-sectional area (CSA) of m. quadriceps and patellar tendon CSA was quantified with magnetic resonance imaging and a isometric strength test was used to assess maximal voluntary contraction (MVC) and rate of force development (RFD). Quadriceps CSA increased by 7.3 +/- 1.0% (P<0.001) in WHD and 3.4 +/- 0.8% (P<0.01) in PLA, with a greater increase in WHD compared to PLA (P<0.01). Proximal patellar tendon CSA increased by 14.9 +/- 3.1% (P<0.001) and 8.1 +/- 3.2% (P=0.054) for WHD and PLA, respectively, with a greater increase in WHD compared to PLA (P<0.05), with no effect of contraction mode. MVC and RFD increased by 15.6 +/- 3.5% (P<0.001) and 12-63% (P<0.05), respectively, with no group or contraction mode effects. In conclusion, high-leucine whey protein hydrolysate augments muscle and tendon hypertrophy following 12weeks of resistance training - irrespective of contraction mode.