Potential therapeutic effects of branched-chain amino acids supplementation on resistance exercise-based muscle damage in humans

Branched-chain amino acids (BCAA) supplementation has been considered an interesting nutritional strategy to improve skeletal muscle protein turnover in several conditions. In this context, there is evidence that resistance exercise (RE)-derived biochemical markers of muscle soreness (creatine kinase (CK), aldolase, myoglobin), soreness, and functional strength may be modulated by BCAA supplementation in order to favor of muscle adaptation. However, few studies have investigated such effects in well-controlled conditions in humans. Therefore, the aim of this short report is to describe the potential therapeutic effects of BCAA supplementation on RE-based muscle damage in humans. The main point is that BCAA supplementation may decrease some biochemical markers related with muscle soreness but this does not necessarily reflect on muscle functionality

Effect of tibia rotation on the electromyographical activity of the vastus medialis oblique and vastus lateralis longus muscles during isometric leg press

Objectives: To evaluate the electrical activity of the vastus medialis obliquus (VMO) and vastus lateralis longus (VLL) with the tibia in neutral, medial and lateral rotation on the horizontal leg press. Design: Repeated measures analysis of the effects of tibia rotation on VMO and VLL activity. Setting: Evaluation and intervention in orthopaedics and traumatology laboratory. Participants: Fifteen healthy participants, no previous musculoskeletal damage of the lower limb. Main outcome measures: Electrical activity (Root Mean Square) of the VMO and VLL was measured during submaximal isometric contractions (SIC) with the knee at 90 degrees of flexion. The effect of tibia rotation in electrical activity of the VMO and VLL was measured. Results: VLL activity was significantly higher than VMO activity with the tibia in medial rotation (p = 0.03). Tibia rotation did not influence the activity of the VMO muscle (p = 0.26). VLL activity was significantly higher with medial than neutral tibia rotation (p = 0.005). Conclusions: The results suggest that tibia rotation does not strengthen selectively the VMO muscle during isometric leg press at 90 degrees knee flexion. (c) 2004 Elsevier Ltd. All rights reserved.61152