A high-intensity warm-up increases thermal strain but does not affect repeated sprint performance in athletes with a cervical spinal cord injury

Purpose: To compare the effects of typical competition versus high-intensity intermittent warm-up (WU) on thermoregulatory responses and repeated sprint performance during wheelchair rugby (WR) gameplay. Methods: An intermittent sprint protocol (ISP) simulating the demands of WR was performed by male WR players (7 with cervical spinal cord injury (SCI) and 8 without SCI (NON-SCI)) following two WU protocols. These included a typical competition WU (CON) and a WU consisting of high-intensity efforts (INT). Core temperature (T_core), thermal sensation and thermal comfort were recorded. Wheelchair performance variables associated to power, speed, and fatigue were also calculated. Results: During the WU, T_core was similar between conditions for both groups. During the ISP, a higher T_core was found for SCI compared with NON-SCI (38.1±0.3 vs 37.7±0.3℃: p=0.036, d=0.75), and the SCI group experienced a higher peak T_core for INT compared with CON (39.0±0.4 vs 38.6±0.6; p=0.004). Peak T_core occurred later in the ISP for players with SCI (96±5.8 vs 48±2.7 min; p<0.001). All players reported a higher thermal sensation and thermal comfort following INT (p<0.001), with no differences between conditions throughout the ISP. No significant differences were found in wheelchair performance variables during the ISP between conditions (p≥0.143). Conclusions: The high-intensity WU increased thermal strain in the SCI group during the ISP, potentially due to increased metabolic heat production and impaired thermoregulation, whilst not impacting on repeated sprint performance. It may be advisable to limit high-intensity bouts during a WU in players with SCI to mitigate issues related to hyperthermia in subsequent performance.