Exertional Demands In US Rugby-7 s Increases Concerns In Hyperthermia And Exercise Induced Asthma Incidence

PURPOSE: In US rugby-7 s, exertional demand illnesses (EDI) are concerns, whether exercise-induced asthma (EIA) or hyperthermia variants. An analysis of diagnoses incidents and field surface-types was conducted. BACKGROUND: US rugby-7 s exertional demands including, running, collisions and seasonal play warrant an understanding of EDI influences. Bronchoconstriction (aka EIA), and exacerbation and hyperthermia and its variants, due to physiological demands and inspired factors, are injurious. EDI incidence may vary amongst regional playing surfaces. METHODOLOGY: The cross-sectional study analyzed exertional demand illnesses in rugby-7 s players (2010 to 2023) in the hospital-based North American Rugby Injury Registry. Medical personnel collected athlete injury data (demographics/injury data/cause/treatment/field type/location) at US rugby 7 s tournaments. Climate details were expanded retrospectively. EDI incidence was calculated per 1000-player hours. RESULTS: Exposure was 54,887.44 player-match-hours (ph) for 97,507 players (69,628 male; 27,879 female). Exposure on grass surfaces was 52,637.24 ph, compared to 2,250.20 ph on artificial turf in the same cohort. Of the 5287 registry injuries, 28 EDI cases were identified (EIA n = 4; hyperthermia n = 24), 2 cases occurred on artificial turf (n = 1 EIA, n = 1 hyperthermia). Overall EDI incidence was 0.51/1000 ph (n = 28; 95% CI:0.32-0.70). Artificial turf EDI incidence = 0.89/1000 ph (95% CI:-0.34-2.12), higher than the grass incidence = 0.49/1000 ph (95% CI:0.30-0.68). Athletes competing on artificial turf were 1.70 times (IRR = 1.70, 95% CI:0.43-7.58) more likely to experience EDI than those on grass surfaces. CONCLUSION: Education on athlete preparation, for internal body heat system regulation, as well as, possible bronchoconstriction techniques and modifiers/influencers must be conveyed to US Rugby players playing in various regions. Complicating this, is the dearth of literature, mainly due to the lack of data appropriately captured. These findings may influence categorization of EDIs, in consensus statements, as a sports time-loss injury, due to match occurrence and player removal. There suggests an association between the field type and EDI. This warrants further study of the regional air quality indexes with EDIs among US rugby.