The Effect of Phase Change Material on Recovery of Neuromuscular Function Following Competitive Soccer Match-Play.

Callum G Brownstein,Jakob Škarabot,Paul Ansdell,Stuart Goodall,Kevin Thomas,Malachy P Mchugh,Glyn Howatson

doi:10.3389/fphys.2019.00647

Abstract

Aim: Cryotherapy is commonly implemented following soccer match-play in an attempt to accelerate the natural time-course of recovery, but the effect of this intervention on neuromuscular function is unknown. The aim of the present study was to examine the effect of donning lower-body garments fitted with cooled phase change material (PCM) on recovery of neuromuscular function following competitive soccer match-play.Methods: Using a randomized, crossover design, 11 male semi-professional soccer players wore PCM cooled to 15°C (PCMcold) or left at ambient temperature (PCMamb; sham control) for 3 h following soccer match-play. Pre-, and 24, 48, and 72 h post-match, participants completed a battery of neuromuscular, physical, and perceptual tests. Maximal voluntary contraction force (MVC) and twitch responses to electrical (femoral nerve) and magnetic (motor cortex) stimulation (TMS) during isometric knee-extension and at rest were measured to assess central nervous system (CNS) (voluntary activation, VA) and muscle contractile (quadriceps potentiated twitch force, Qtw,pot) function. Fatigue and perceptions of muscle soreness were assessed via visual analog scales, and physical function was assessed through measures of jump [countermovement jump (CMJ) height and reactive strength index (RSI)] performance. A belief questionnaire was completed pre- and post-intervention to determine the perceived effectiveness of each garment.Results: Competitive soccer match-play elicited persistent decrements in MVC, VA measured with femoral nerve stimulation, Qtw,pot, as well as reactive strength, fatigue and muscle soreness (P < 0.05). Both MVC and VA were higher at 48 h post-match after wearing PCMcold compared with PCMamb (P < 0.05). However, there was no effect of PCM on the magnitude or time-course of recovery for any other neuromuscular, physical function, or perceptual indices studied (P > 0.05). The belief questionnaire revealed that players perceived that both PCMcold and PCMamb were moderately effective in improving recovery, with no difference between the two interventions (P = 0.56).Conclusion: Although wearing cooled PCM garments improved MVC and VA 48 h following match-play, the lack of effect on measures of physical function or perceptual responses to match-play suggest that PCM offers a limited benefit to the recovery process. The lack of effect could have been due to the relatively small magnitude of change in most of the outcome measures studied.

Highlights

Association football is an intermittent-sprint sport which imposes high physiological, neuromuscular and cognitive demands (Mohr et al, 2005)
It was hypothesized that wearing cold PCM garments would expedite recovery of impaired neuromuscular function and attenuate muscle soreness, possibly by reducing the negative effects associated with the acute inflammatory response on contractile and central nervous system (CNS) function
There was no difference in the change in any of the neuromuscular, physical function or perceptual indices over time, as indicated by the lack of a treatment × time interaction, maximal voluntary contraction (MVC) and voluntary activation (VA) were higher 48 h post-match after wearing PCMcold compared with PCMamb, with the between-treatment differences at these time-points greater than the measurement error

Summary

Introduction

Association football (soccer) is an intermittent-sprint sport which imposes high physiological, neuromuscular and cognitive demands (Mohr et al, 2005). An inexorable consequence of these demands is fatigue, defined as a sensation of tiredness and weakness underpinned and/or modulated by a multitude of physiological and psychological processes (Thomas et al, 2018). The fatigue which occurs as a result of soccer match-play persists post-exercise, and can take days to resolve (Rampinini et al, 2011). Due to the demanding nature of soccer match-play and the congested fixture schedules in the modern-day game, understanding the etiology of fatigue, the time-course of recovery, and strategies to alleviate fatigue and expedite recovery are pertinent issues (Nedelec et al, 2012, 2013)

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