Muscle Recovery and Myofibrillar Protein Synthesis after Damaging Exercise with Recombinant Bovine β-Lactoglobulin, Dairy-Derived Whey or Carbohydrate Supplementation in Young Healthy Adults.

BACKGROUND

Supplementation with recombinant bovine β-lactoglobulin (rBLG), a precision-engineered mimetic of dairy-derived whey, supports similar resistance exercise (RE) training-induced muscle remodeling to whey protein (WHEY). However, the influence of rBLG on recovery indices and muscle protein synthesis rates after damaging exercise is unknown.

OBJECTIVES

To determine the influence of rBLG supplementation on indices of muscle recovery and integrated myofibrillar protein synthesis (iMyoPS) over 72 h following damaging RE, compared with WHEY and a carbohydrate placebo.

METHODS

In a randomized double-blind, placebo-controlled, parallel-group design, 27 healthy adults consuming a controlled diet (∼0.9 g/kg body mass/d of protein) were supplemented thrice daily with 0.3 g/kg body mass of rBLG, WHEY, or isocaloric carbohydrate placebo for 3 d following an acute bout of damaging lower-body RE (8 × 10 maximal, unilateral, eccentric knee extensions). Consumption of deuterated water combined with serial vastus lateralis muscle biopsies permitted the measurement of iMyoPS 72 h before (habitual) and after RE. Knee extensor maximum voluntary contraction (MVC), muscle soreness, and plasma concentrations of creatine kinase and lactate dehydrogenase (LDH) were also assessed post-RE to characterize muscle recovery.

RESULTS

iMyoPS fractional synthetic rate (%/d) increased following damaging RE (P < 0.001), with no significant differences between groups. Knee extensor MVC decreased, and subjective muscle soreness and plasma LDH concentrations increased following strenuous exercise (P < 0.05 for all) with no significant differences between groups.

CONCLUSIONS

At habitual dietary protein intakes ∼0.9 g/kg body mass/d, further rBLG or WHEY supplementation did not influence muscle recovery or iMyoPS rates, suggesting that protein supplementation, at the intakes studied, may have limited efficacy as a tool to enhance muscle recovery and remodeling from damaging exercise.