Author(s): DAAB, W., NASSIS, G.P., ABAIDIA, A., BOUZID, M.A., Institution: COLLEGE OF SPORT SCIENCE, UNIVERSITY OF KALBA, UNITED ARAB EMIRATES, Country: UNITED ARAB EMIRATES, Abstract-ID: 876

INTRODUCTION:
Soccer is often played in hot and humid environments, where heat stress accelerates fatigue and may impair performance and increase injury risk (1). Half-time provides a key window for cooling interventions such as neck cooling (2).However, their effects on neuromuscular fatigue during football-specific exercise in the heat remain unclear. Therefore, this study examined the effects of half-time neck cooling on neuromuscular function, sprint performance, and thermal and perceptual responses during a simulated football match in hot and humid conditions.
METHODS:
14 non-heat-acclimatized amateur male football players (age: 26.8 ± 4.3 years) completed two familiarization trials before undertaking two randomized, counterbalanced crossover experimental trials. In each experimental trial, participants performed the Loughborough Intermittent Shuttle Test (LIST; 90 min, six 15-min blocks) in hot and humid conditions (36 °C, 55% RH), separated by a standardized 15-min half-time break. During half-time (HT), players received either neck cooling using a cold wet towel (4-5 °C; PC) or a thermoneutral wet towel (25–30 °C; CON). Towels were wrapped to cover the anterior and lateral neck regions and were replaced every 3 min in both conditions. Neuromuscular assessments were conducted at baseline, HT, and full-time (FT) and included maximal voluntary contraction (MVC), potentiated twitch force (Ptw), and voluntary activation (VA). Sprint performance (SP) was assessed during each exercise block. Skin temperature (ST), thermal sensation (TS), and thermal comfort (TC) were monitored throughout exercise.
RESULTS:
Neuromuscular function declined over time in both conditions. MVC and Ptw decreased from baseline to FT (both p < 0.001), with no significant difference between CON and PC. VA also declined over time (p < 0.001), with VA better maintained under PC at FT (p < 0.001).
Sprint performance declined across LIST (p < 0.001), with faster sprint times observed under PC compared with CON during the latter stages of exercise (p = 0.041). ST increased over time (p < 0.001) and differed between conditions (p < 0.001), with higher values in CON than PC during the second half. TS increased over time (p < 0.001), with lower TS under PC (p = 0.03). Better TC reported under PC at FT (p = 0.016).
CONCLUSION:
The results of the present study indicate that cooling at half-time of a simulated football match performed in hot and humid conditions did not alter maximal force capacity or muscle contractile function. However, cooling was associated with lower skin temperature and improved thermal sensation and comfort during the second half of the LIST. Taken together, these findings suggest that the improved thermal and perceptual state following half-time cooling may contribute to the maintenance of VA which may maintain sprint performance during the latter stages of the exercise.
(1) Nassis G.P. et al. Br J Sports Med 2015 ;49:609–13.
(2) Tyler et al. Br J Sports Med 2015 ;49:7–13.