Wearing lacrosse uniform during exercise-simulated match in heat increases physiological strain index

Abstract

Japanese collegiate and club lacrosse games are often held under environmental conditions of extreme heat in the summer. Lacrosse players are also required to wear protective equipment, which is a risk factor for heat-related illness. Nevertheless, the thermoregulatory responses of lacrosse players under such conditions are poorly understood. The present study compared the thermoregulatory responses in subjects wearing the mens' lacrosse uniform or general athletic clothes during an exercise-simulated lacrosse match played in the heat (high temperatures). Eight men performed two experimental trials of 4 × 15-min intermittent cycling exercise in the heat (35°C, 50% relative humidity). All participants performed two trials wearing a lacrosse uniform (WEAR) or general athletic clothes (CON). The physiological strain index was significantly higher (p < 0.05) in the WEAR condition than in CON, and exceeded the high risk level for heat-related illness in WEAR during the 3 rd quarter. Additionally, rectal temperature, skin temperature, heart rate, and ratings for perceived exertion, thermal sensation, and thermal comfort were significantly higher (p < 0.05) in the WEAR condition than in CON. Rectal temperature continued to increase during half-time in the WEAR condition, but not in CON (p < 0.05). These findings indicate that lacrosse players are at a higher risk of heat-related illness compared to other team sport athletes during a match because of the protective equipment worn, especially after half-time. Although further studies are required to confirm the thermoregulatory responses during an actual lacrosse match, our data will be useful in developing strategies to minimize the risk of heat-related illness.

Addition of in‐Play Cooling Breaks During Intermittent Exercise while Wearing Lacrosse Uniforms in the Heat Attenuates Increases in Rectal Temperature

“…Physiological strain is described on a universal scale of 0-10, where 0 represents "no strain" and 10 "very strenuous" (Moran et al, 1998), while >7.5 is categorized as "at risk" for heat-related illness (Buller et al, 2008). A recent study by Osakabe et al (2022) reported that mean PSI values exceeded 7.5 from the latter stages of the 3rd quarter during the cycling intermittent exercise protocol designed to mimic the activity pattern of a men's lacrosse match in a hot-humid environment. In the current study, the PSI value at the end of the 4th quarter in the REG condition (7.2±1.4) was very close to the critical marker of 7.5, whereas the PSI value was considerably below the critical marker of 7.5 in the WBTO condition (6.5±0.9).…”

“…Each 90-s period started with 30s of unloaded cycling with a cadence of 80 rpm followed by 10s of high-intensity cycling (i.e., 130% of VO 2max , 80 rpm), and ended with 50s of moderate-intensity cycling (i.e., 60% of VO 2max , 80rpm). The 15-min intermittent exercise protocol was the same as that used in a previous study examining thermoregulation during cycling exercise designed to mimic the activity patterns of a lacrosse match ( Osakabe et al, 2022 ), which was based on an earlier study designed to reflect a soccer match using a cycle ergometer ( Yanaoka et al, 2018 ). The protocol was adjusted to match the activity profile of an actual lacrosse match reported in a previous study (Akiyama et al, 2018).…”

“…In addition, because lacrosse is classified as a full-contact sport, players are required to wear protective equipment (shoulder pads, arm pads, gloves and helmet) during the match. However, wearing protective equipment is an important risk factor for the development of EHS ( Casa et al, 2015 ), because it can inhibit evaporative, convective, and radiant heat loss ( Casa et al, 2015 ), resulting in a faster rate of increases in core body temperature ( Armstrong et al, 2010 ; Kulka et al, 2002 ; Osakabe et al, 2022 ). Although soccer players are not required to wear protective equipment, a previous study reported that peak core body temperatures exceeded 39.5°C during a soccer match in hot and humid conditions (36°C, 61% relative humidity [RH]) ( Ozgünen et al, 2010 ).…”

“…Although soccer players are not required to wear protective equipment, a previous study reported that peak core body temperatures exceeded 39.5°C during a soccer match in hot and humid conditions (36°C, 61% relative humidity [RH]) ( Ozgünen et al, 2010 ). A recent study by Osakabe et al (2022) reported that when wearing lacrosse uniforms during cycling exercise designed to mimic the activity patterns of a lacrosse match in hot conditions (35°C, 50% RH), the core body temperature at the end of the 4 th quarter was 0.7°C higher than that when wearing general athletic clothes. Thus, lacrosse players are at a high risk of heat-related illness during the match due to the wear of protective equipment.…”