Short-Time β-Alanine Supplementation on the Acute Strength Performance after High-Intensity Intermittent Exercise in Recreationally Trained Men.

Marcelo Conrado Freitas,Giovanni Quizzini,Erico Caperuto,Fabio Lira,Nelo Eidy Zanchi,Fabrício Eduardo Rossi,Jason Cholewa,Caique Figueiredo,Valéria Panissa,João Vitor De Oliveira,Luis Alberto Gobbo

doi:10.3390/sports7050108

Abstract

(1) Background: We investigated the effects of 28 days of beta-alanine (β-alanine) supplementation on the acute interference effect of high-intensity intermittent exercise (HIIE) on lower-body resistance exercise performance, body composition, and strength when combined with a resistance training program. (2) Methods: Twenty-two males were randomized into: β-alanine supplementation (6.4 g/day) or placebo (6.4 g/day maltodextrin) during 28 days. Total body water, intracellular and extracellular water, fat-free mass (FFM), and fat mass were assessed using bioelectrical impedance. Participants performed 5000-m HIIE (1:1 effort and rest ratio) followed by resistance exercise (four sets of 80% at 45° leg press until muscular failure) at baseline and after 28 days. The resistance training program consisted of three sets of 10 to 12 RM with 90 s of rest, four days per week. (3) Results: For the post-HIIE leg press volume, higher values were observed post-training than pre-training, but no group x time interaction was observed. There was a non-significant trend for an interaction in the FFM change (β-alanine = 2.8% versus placebo = 1.0%, p = 0.072). (4) Conclusion: Twenty-eight days of β-alanine supplementation did not prevent acute strength loss during resistance exercise after high-intensity interval exercise, nor increase strength or hypertrophic adaptations associated with resistance training.

Highlights

Concurrent exercise describes performing both resistance and aerobic or high-intensity intermittent exercise (HIIE) during the same training session, and a growing body of literature suggests that acuteHIIE impairs subsequent resistance exercise performance [1,2,3,4]
The comparison between groups in the dietary intake are displayed in Table S2 in the Supplementary Material
There was a main effect of time for body mass (F = 4.78; p = 0.040), extracellular water (ECW) (F = 6.86; p = 0.019), intracellular water (ICW) (F = 8.59; p = 0.010), and total body water (TBW) (F = 6.02; p = 0.027), with higher values post- than pre-training for all

Summary

Introduction

Concurrent exercise describes performing both resistance and aerobic or high-intensity intermittent exercise (HIIE) during the same training session, and a growing body of literature suggests that acuteHIIE impairs subsequent resistance exercise performance [1,2,3,4]. Abernethy [8] reported a reduction in force output 4 h following an intense aerobic bout of exercise. Muscle pH likely returned to baseline values 4 h after exercise, suggesting that mechanisms other than muscle acid–base balance, such as central fatigue or the acute immunological response, may contribute to impaired acute strength performance [2,8]. In this sense, sport supplement interventions that attenuate peripheral fatigue may be an effective strategy to reduce the negative effects of acute

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