Supplementation Strategies for Strength and Power Athletes: Carbohydrate, Protein, and Amino Acid Ingestion

Abstract

It is a common belief amongst strength and power athletes that nutritional supplementation strategies aid recovery by shifting the anabolic/catabolic profile toward anabolism. Factors such as nutrient quantity, nutrient quality, and nutrient timing significantly impact upon the effectiveness of nutritional strategies in optimizing the acute responses to resistance exercise and the adaptive response to resistance training (i.e., muscle growth and strength expression). Specifically, the aim of this review is to address carbohydrates (CHOs), protein (PRO), and/or amino acids (AAs) supplementation strategies, as there is growing evidence suggesting a link between nutrient signaling and the initiation of protein synthesis, muscle glycogen resynthesis, and the attenuation of myofibrillar protein degradation following resistance exercise. Collectively, the current scientific literature indicates that nutritional supplementation strategies utilizing CHO, PRO, and/or AA represents an important approach aimed at enhancing muscular responses for strength and power athletes, primarily increased muscular hypertrophy and enhanced strength expression. There appears to be a critical interaction between resistance exercise and nutrient-cell signaling associated with the principle of nutrient timing (i.e., pre-exercise, during, and post-exercise). Recommendations for nutritional supplementation strategies to promote muscular responses for strength and athletes are provided.

Keywords: amino acids; athlete; carbohydrate; nutrition; protein; strength; supplements.

Figure 1

The pathway of adaptation model represents a theoretical chain of events demonstrating the influence of nutritional supplementation on acute resistance exercise and training. This results in chronic musculoskeletal adaptations that lead to skeletal muscle hypertrophy and increased strength expression. , increase. Adapted from Volek [23].

Figure 2

CHO delivery and stress response to resistance exercise. CHO ingestion during the exercise bout is proposed to sustain blood glucose levels and attenuate the stimulus for the adrenal cortex to secrete cortisol to catabolize cellular protein for gluconeogenic purposes. CHO, carbohydrate; BGL, blood glucose levels; HPA, hypothalamic–pituitary–adrenal axis; 3-MHIS, 3-methylhistidine. Adapted from Tarpenning and colleagues [15,53].

Figure 3

Resistance exercise and amino acid ingestion has an additive effect on protein synthesis. (1) Following an acute bout of resistance exercise, protein synthesis increased by ~100%, whereas protein breakdown increased by ~50% (net protein balance: negative); (2) at rest with increased amino acid availability, protein synthesis increases by ~150% (net protein balance: positive); and (3) after resistance exercise with increased amino acid availability, protein synthesis increases by >200% (net protein balance: positive). RE, resistance exercise; AA, amino acid; NB, net balance. Adapted from Biolo et al. [48,84].

Figure 4

Molecular pathways that lead to protein synthesis and breakdown. (4E-BP1: eukaryotic translation initiation factor 4E binding protein 1; Akt, protein kinase B; AMPK, adenosine monophosphate-activated protein kinase; eEF2, eukaryotic elongation factor-2; eIF-4F, eukaryotic translation initiation factor-4F; FOXO, forkhead box O; mTOR, mammalian target of rapamycin; MURF1, muscle RING-finger protein-1; PGC1α, peroxisome proliferator-activated receptor gamma coactivator 1-alpha; REDD1, regulated in development and DNA damage response 1; Rheb, Ras homolog enriched in brain; rpS6, ribosomal protein S6; S6K1, p70 ribosomal protein S6 kinase; TSC1-2, tuberous sclerosis 1–2).