Dynamic Proteomic Responses to Timing-Specific Amino Acid Intake During High-Intensity Endurance Training

Abstract

This study is about whether the timing-specific amino acid intake affects muscle protein synthesis (MPS) and protein abundance during high-intensity endurance training (HIET). The timing of nutrient consumption is essential to maximize recovery and muscle adaptations, but the proteomic effects of amino acid intake during various times (pre, post, or both) have not been thoroughly studied. HIET was applied to a total of 16 respondents (9 females, 7 males, 21 ± 2 years old) under different amino acid supplementation regimens. Baseline, Week 1, and Week 10 muscle biopsies were obtained to measure protein synthesis and abundance, and protein turnover was measured by labeling with deuterium oxide (D2O). The rate of fractional synthesis rate (FSR) was computed, and the proteomic analysis was carried out through mass spectrometry. The statistical analyses (paired t-tests and ANOVA) found significant protein synthesis increase in both pre- and post-exercise amino acid groups, with the latter showing the most significant increase in myofibrillar protein synthesis (FSR of 1.3% at Week 1 and 2.0% at Week 10). The levels of ribosomal and contractile proteins in the post-exercise group rose by 46% and 50% compared to the pre-exercise group (38% and 52%). Correlation analysis revealed that there was a strong positive correlation between protein synthesis and abundance in the post-exercise group (R = 0.65, p < 0.01). This paper establishes that the intake of amino acids after exercise boosts muscle adaptation and protein synthesis. It is recommended that future research be focused on evaluating the long-term effects of nutrition timing on physical performance and muscle recovery for different populations.