Active And Passive Re-warm-up At Half-time

Abstract

The initial period (15 min) of the second half in professional soccer is characterised by a high incidence of goals conceded and injuries sustained. This could be due to the reduced body temperature during the 15 min passive half-time (HT) rest interval, resulting in a greater risk of injury and a decreased high-intensity running performance. PURPOSE To investigate the effects of active and passive re-warm-up strategies during the soccer HT interval upon, heart rate (HR), core temperature (Tc), and secondhalf soccer-specific endurance performance (SSEP). METHODS Seven professional soccer players performed two intermittent endurance field tests of 16.5 min duration, interceded by a 15 min HT interval. On separate occasions, in a randomized order, four trials were completed during which different HT strategies were undertaken. Two passive trials were completed where players either rested (CON), or were immersed to the gluteal fold in a hot (∼40°C) water bath (PH). In the active re-warm-up trials the players performed either steady-state non-specific active heating (NSAH) or intermittent soccer-specific active heating (SSAH). The experimental conditions were applied between 7–14 min of the HT period and the active trials were undertaken at 70% maximum HR, with players either cycling (NSAH) or performing repeated sprints (SSAH). The HR and Tc were measured every 5 min. A two-way mixed factorial (TRIAL × TIME) ANOVA was used to identify changes in HR and Tc' and SSEP was compared between trials using a repeated measures ANOVA, and paired-samples t-tests for post hoc analysis, with significance accepted at P≤0.05 unless adjusted via Bonferroni correction. RESULTS Active re-warm-up strategies NSAH and SSAH maintained SSEP in the second period with respect to CON (−0.5 ± 1.3, −0.4 ± 1.4 %, respectively; p<0.01), whereas PH did not reduce the decrement in performance (1.2 ± 1.9 %; p>0.05). Active heating strategies significantly increased HR (NSAH: 128 ± 5; SSAH: 128 ± 8 beats ± min−1; p<0.01) during HT in comparison to CON (110 ± 4 beats·min−1), whereas PH did not (113 ± 6 beats·min−1; p>0.05). During the HT period in the CON trial, Tc decreased by 0.97 ± 0.29°C, undertaking PH (0.7 ± 0.4°C) and SSAH (0.77 ± 0.16 °C) trials did not attenuate this decrease (p>0.01), whereas NSAH (0.52 ± 0.18 °C) increased Tc in respect to CON (p<0.01). However, these differences in HR and Tc between re-warm-up strategies during HT were not apparent at the end of the trials. CONCLUSIONS Active re-warm-up strategies during HT attenuated the SSEP decrement in the second half observed during passive trials.