Acute Effect of the Timing of Resistance Exercise and Nutrient Intake on Muscle Protein Breakdown.

Wataru Kume,Takeshi Hashimoto,Jun Yasuda

doi:10.3390/nu12041177

Abstract

Background: Combining resistance exercise (RE) with nutrient intake stimulates muscle protein net balance. However, it is still unclear whether the optimal timing of nutrient intake is before or after RE, especially on muscle protein breakdown (MPB) for an augmented muscle anabolic response. The aim of this study was to investigate the effect of a substantial mixed meal (i.e., nutrient- and protein-dense whole foods) before or after RE, compared with RE without a meal on the acute response of MPB in a crossover-design study. Methods: Eight healthy young men performed three trials: (1) meal intake before RE (Pre), (2) meal intake after RE (Post), and (3) RE without meal intake (No). Plasma insulin and 3-methylhistidine (3-MH), an MPB marker, were measured. Results: Time course change in plasma insulin level after RE was significantly higher in the Post condition than in the Pre and No conditions. The area under the curve of 3-MH concentration was significantly lower in the Post condition than in the Pre and No conditions. Conclusions: These results suggest that a substantial mixed meal immediately after RE may effectively suppress MPB in the morning.

Highlights

Resistance exercise (RE) maintains and increases muscle mass by inducing an anabolic response in which muscle protein synthesis (MPS) surpasses muscle protein breakdown (MPB) [1]
The suppression of MPB following resistance exercise (RE) may contribute to upregulated muscle protein net balance and increased muscle mass [2,3,6,7]
Rasmussen et al (2000) reported that ingestion of amino acid (AA) and carbohydrate (CHO) at 1 h post-exercise tends to suppress MPB compared with the effect of ingestion at 3 h post-exercise [8]

Summary

Introduction

Resistance exercise (RE) maintains and increases muscle mass by inducing an anabolic response in which muscle protein synthesis (MPS) surpasses muscle protein breakdown (MPB) [1]. Performing RE in a fasted state promotes MPS and MPB after RE by increased proteasome activity [2], resulting in an attenuated muscle anabolic response In this regard (i.e., the promotion of MPB in a fasted state), it is important to provide nutrient intake to upregulate muscle protein net balance (MPS minus MPB) [2,3,4,5]. Combining resistance exercise (RE) with nutrient intake stimulates muscle protein net balance It is still unclear whether the optimal timing of nutrient intake is before or after RE, especially on muscle protein breakdown (MPB) for an augmented muscle anabolic response. Results: Time course change in plasma insulin level after RE was significantly higher in the Post condition than in the Pre and No conditions. Conclusions: These results suggest that a substantial mixed meal immediately after RE may effectively suppress MPB in the morning

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