The effect of singular and combined ice vest and neck collar cooling used pre-match and at half-time, during a soccer specific simulation in the heat

Abstract

The globalisation of soccer has seen matches during international tournaments being played at hot environments, where key physical performance variables including high-speed running and sprinting are decreased, due to an elevation in both actual and perceived body temperatures. The singular use of cooling modalities including ice vests and neck cooling collars have been shown to favourably alter these body temperatures when used throughout a simulated soccer match. However, to not interfere with the laws of soccer, these cooling modalities can only be used within a warm-up pre-match and down-time during half-time. Therefore, the current study explored the singular and combined utilisation of these practical cooling modalities, throughout a soccer specific warm-up, downtime before kick-off and at half-time on simulated soccer performance using an environmental chamber at 28°C Wet Bulb Globe temperature (WGBT). Ten male University level soccer players volunteered for this study, completing the Level 1 Yo-Yo Intermittent recovery test, two non-motorised treadmill-based familiarisations, one peak speed assessment and four randomised, counterbalanced, experimental trials of intermittent soccer performance test (iSPT) using (1) Ice vest (VEST); (2) Neck collar (NECK); (3) combination of ice vest and neck collar cooling (MM) and (4) No-cooling (CON). Physical performance (total, high-speed and sprint distance covered), physiological (rectal, skin (Tsk) and neck (NECKtsk) temperature and heart rate (HR) and perceptual (thermal sensation (TS), thermal comfort (TC), rate of perceived exertion (RPE) and neck thermal sensation (NECKTS) responses were all measured during the first (0-45 min) and second (60-105 min) half of each experimental trial. From 0-15 min, both SD (P < 0.05) and HSD (P < 0.05) covered were significantly increased in NECK and MM compared to CON. These occurred in association with a significant dampening (P = 0.01) of thermal sensation and skin temperature following the warm-up until the first 15-min in MM (3.30 ± 1.11) compared to CON. During the second half, both SD (60-105 min) and HSD (75-105 min) covered in MM were significantly increased (P < 0.05) by a large effect size (d =1.03) compared with CON. Furthermore, there was a significant increase (P < 0.05) to HSD (90-105 min) and SD covered (75-105 min) by a small effect size (d = 0.3) during the second half in NECK compared with CON. Half-time cooling significantly decreased (P < 0.05) Tsk, TNECK TS, NECKTS, however, these were not maintained throughout the second half. The VEST showed no significant improvement (P > 0.05) to physical performance throughout the iSPT. Overall, mixed-methods pre-match applied throughout a soccer specific warm-up and downtime before kick-off and at half-time cooling enhanced physical performance and reduced physiological and perceptual strain in the heat (WBGT: 28°C).