Effect of New Zealand Blackcurrant Extract on Isometric Contraction-Induced Fatigue and Recovery: Potential Muscle-Fiber Specific Effects.

Mark E. T. Willems,Ian C. Perkins,Sam D. Blacker,Megan Bradley

doi:10.3390/sports8100135

Mark E. T. Willems, Ian C. Perkins + Show 2 more

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https://doi.org/10.3390/sports8100135

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Abstract

New Zealand blackcurrant (NZBC) extract has shown performance-enhancing effects during cycling, running and sport climbing. We examined effects of NZBC extract on (1) voluntary and twitch force of the quadriceps femoris muscles during repeated isometric contraction-induced fatigue, (2) twitch force during recovery and (3) muscle fiber-specific effects. Familiarized recreationally active males (n = 12, age: 24 ± 5 yrs; height: 180 ± 5 cm; body mass: 89 ± 11 kg) performed sixteen, 5-s voluntary maximal isometric contractions (iMVC) separated by 3-s rest. Twitch force was recorded before, during the 3-s rests and 5-min recovery. Supplementation consisted of 7-days intake of NZBC extract (600 mg∙day−1 containing 210 mg anthocyanin) in a double-blind, randomized, placebo-controlled crossover design with a 14-days washout. NZBC extract allowed for greater force in the first quartile of the iMVCs. Twitch force at baseline was 12% higher with NZBC extract (p = 0.05). However, there was no effect of NZBC for twitch force during the 16-iMVCs and recovery. Based on the maximum post-activation potentiation during the placebo 16-iMVCs, four subjects were classified of having a predominant type I or II muscle fiber typology. In type II, NZBC extract provided a trend for increased MVC force (~14%) in the first quartile and for type I in the fourth quartile (~10%). In type I, NZBC extract seemed to have higher twitch forces during the fatiguing exercise protocol and recovery, indicating increased fatigue resistance. New Zealand blackcurrant extract affects force during repeated maximal isometric contractions. Future work on mechanisms by NZBC extract for muscle fiber-specific fatigue-induced force responses is warranted.

Highlights

In recent years, studies have examined the ergogenic potential of fruit and vegetable derived components
Blackcurrant is a berry with a high content of primarily four anthocyanins
The main goal of the experiments was to determine whether there was an effect of New Zealand blackcurrant extract on the force of the quadriceps femoris muscles during maximal voluntary contractions and surface electrical stimulation-induced twitch force by performing a fatiguing exercise protocol

Summary

Introduction

Studies have examined the ergogenic potential of fruit and vegetable derived components. 6 days of nitrate-rich beetroot juice provided performance-enhancing effects for severe-intensity cycling exercise to exhaustion [1]. For fruit-derived supplements (e.g., blackcurrant, blueberry, Montmorency cherry, pomegranate), the efficacy for performance-enhancement is associated with the polyphenol composition [2]. Blackcurrant is a berry with a high content of primarily four anthocyanins. An anthocyanin is a flavonoid with potential anti-oxidant and anti-inflammatory properties providing health benefits [3].

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