Thermoregulatory responses to warm-up and cooling strategies: Considerations for para-athletes

Prolonged intermittent exercise or passive rest/daily ambulation in hot environmental conditions have been shown to place the Paralympic athlete under far greater thermal and perceptual strain when compared to the Olympic athlete. Consequently, in wheelchair sports (e.g., wheelchair basketball, rugby and tennis) decrements in performance are evident due to potential dysfunctional thermoregulatory systems because of the impairment type (e.g., spinal cord injury [SCI], amputation etc.). Four main focuses; warm-up, cooling interventions available in SCI, recovery following induced increases in body temperature, and pre-cooling have been investigated in an attempt to provide further insights to the physical preparations of wheelchair rugby players, who have a large proportion of players with an SCI.

The current thesis examined the thermoregulatory responses to warming-up and the subsequent effects on simulated performance (chapter 3) in wheelchair rugby players. Those players with an SCI experienced a greater peak core temperature (Tcore) at the end of the simulated game. Notably, a high intensity warm-up improved performance (e.g., increased power output) during the first quarter in some players. In chapter 4, the cooling strategies available to athletes with an SCI were characterised using a meta-analysis. Pre- and per-cooling were found to attenuate the increase in thermal strain in this cohort of athletes. The specific focus on the timing of cooling interventions (pre- and per-cooling), indicated that pre-cooling had a greater effect on Tcore than per-cooling, with the beneficial effects of cooling being greater in athletes with a high SCI lesion level.

To further these recommendations, chapter 5 investigated the use of ice slurry ingestion on thermal strain in response to hyperthermia, and as a pre-cooling method in wheelchair rugby players (chapter 6). Reductions in thermal strain (notably heat storage and rectal temperature) from ice slurry ingestion during a 60-minute passive recovery period following hyperthermia were noted. Specifically, when heat loss via evaporation and convection was compromised, a delay in reducing markers of thermal strain was apparent. To investigate the effects of internal cooling on thermal strain in wheelchair rugby players during “real-world” sporting scenarios, the final study employed a passive heating phase replicating typical environmental conditions of the then upcoming Tokyo 2020 Paralympic Games, followed by an intermittent sprint protocol. Prior to the start of the intermittent sprint protocol, ice slurry ingestion reduced thermal strain in the SCI group. No performance benefits were apparent.

These novel studies were designed to be used in real-life competitive sporting environments. It may be obvious that wheelchair rugby players with an SCI should consider cooling interventions to offset the rise in thermal strain as a result of daily ambulation in hot/humid environments such as when getting to the sporting venue and/or increased intensity of their preconditioning routines. To date not many coaches have individualised these strategies and this thesis provides practical recommendations and supports the use of ‘internal cooling’, since ice slurry ingestion does not neglect the rules of game play.