Daily protein-polyphenol ingestion increases daily myofibrillar protein synthesis rates and promotes early muscle functional gains during resistance training.

George F Pavis,Benjamin T Wall,Nima Alamdari,Tom S O Jameson,Francis B Stephens,Jonathan Fulford,Andrew J Murton,Doaa R Abdelrahman,Jamie R Blackwell,Catherine R Mikus

doi:10.1152/ajpendo.00328.2021

Abstract

Factors underpinning the time-course of resistance-type exercise training (RET) adaptations are not fully understood. This study hypothesized that consuming a twice-daily protein-polyphenol beverage (PPB; n = 15; age, 24 ± 1 yr; BMI, 22.3 ± 0.7 kg·m-2) previously shown to accelerate recovery from muscle damage and increase daily myofibrillar protein synthesis (MyoPS) rates would accelerate early (10 sessions) improvements in muscle function and potentiate quadriceps volume and muscle fiber cross-sectional area (fCSA) following 30 unilateral RET sessions in healthy, recreationally active, adults. Versus isocaloric placebo (PLA; n = 14; age, 25 ± 2 yr; BMI, 23.9 ± 1.0 kg·m-2), PPB increased 48 h MyoPS rates after the first RET session measured using deuterated water (2.01 ± 0.15 vs. 1.51 ± 0.16%·day-1, respectively; P < 0.05). In addition, PPB increased isokinetic muscle function over 10 sessions of training relative to the untrained control leg (%U) from 99.9 ± 1.8 pretraining to 107.2 ± 2.4%U at session 10 (vs. 102.6 ± 3.9 to 100.8 ± 2.4%U at session 10 in PLA; interaction P < 0.05). Pre to posttraining, PPB increased type II fCSA (PLA: 120.8 ± 8.2 to 109.5 ± 8.6%U; PPB: 92.8 ± 6.2 to 108.4 ± 9.7%U; interaction P < 0.05), but the gain in quadriceps muscle volume was similar between groups. Similarly, PPB did not further increase peak isometric torque, muscle function, or MyoPS measured posttraining. This suggests that although PPB increases MyoPS and early adaptation, it may not influence longer term adaptations to unilateral RET.NEW & NOTEWORTHY Using a unilateral model of resistance training, we show for the first time that a protein-polyphenol beverage increases initial rates of myofibrillar protein synthesis and promotes early functional improvements. Following a prolonged period of training, this strategy also increases type II fiber hypertrophy and causes large individual variation in gains in quadricep muscle cross-sectional area.

Highlights

A period of isokinetic or isotonic resistance-type exercise training (RET) comprising concentric and eccentric loading phases induces skeletal muscle hypertrophy and increases strength [1–5]
Given the tight coupling of myofibrillar protein synthesis (MyoPS) with hypertrophy at 10 wk of RET, we hypothesized that this early improvement would be associated with greater posttraining MyoPS rates, and a greater increase in quadriceps muscle volume and fiber CSA
This study hypothesized that a daily postexercise and prebed polyphenol beverage (PPB) nutritional intervention known to accelerate recovery from muscle damage and increase MyoPS would accelerate improvements in muscle function over an early period of RET ($3 wk; 10 sessions)

Summary

Introduction

A period of isokinetic or isotonic resistance-type exercise training (RET) comprising concentric and eccentric loading phases induces skeletal muscle hypertrophy and increases strength [1–5]. Given that Damas et al [9] observed marked myofibrillar disruption (z-band streaming in 60% of fibers), muscle pain (60/100 AU), and a loss of muscle strength (À22%) 48 h after the first RET session, it was suggested that early rates of MyoPS instead reflect a demand for myofibrillar repair following damage rather than net protein accrual. Supporting this suggestion is that the gains in muscle thickness over the first 3 wk of RET

Objectives

Methods

Results

Conclusion