Objective:To determine which intrinsic and extrinsic exertional heat illness(EHI)risk factors exist in youth American football players and observe perceptual and physiological responses of players during events(games ...Objective:To determine which intrinsic and extrinsic exertional heat illness(EHI)risk factors exist in youth American football players and observe perceptual and physiological responses of players during events(games and practices).Methods:Cross-sectional cohort study observing 63 youth football players,varying in position.Independent variables were league(weightrestricted(WR,n=27)and age-restricted(AR,n=36))and event type.Dependent variables were anthropometrics,work-to-rest ratio,and wet bulb globe temperature.Descriptive variables included preparticipation examination and uniform configuration.A subset of 16 players participated in physiological variables(heart rate and gastrointestinal temperature).Data collection occurred on 7 AR and 8 WR nonconsecutive practices and the first 3 games of the season.Results:Mean values for anthropometric variables were higher(p<0.05)in the AR league than the WR league.Work time(χ^2(1,111)=4.232;p=0.039)and rest time(χ^2(1,111)=43.41;p<0.001)were significantly greater for games,but ratios were significantly higher for practices(χ^2(1,111)=40.62;p<0.001).The majority of events(77%)observed were in black and red flag wet bulb globe temperature risk categories.A total of 57%of the players had a preparticipation examination,and up to 82%of events observed were in full uniforms.Individual gastrointestinal temperature and heart rate responses ranged widely and no players reached critical thresholds.Conclusion:Extrinsic(disproportionate work ratios,environmental conditions)and intrinsic(higher body mass index)EHI risk factors exist in youth football.Certain risk factors may be influenced by event and league type.National youth football organizations need to create thorough guidelines that address EHI risk factors for local leagues to adopt.展开更多
Non-steroidal anti-inflammatory drugs’anti-pyretic and anti-inflammatory effects has led some individuals to theorize these medications may blunt core body temperature(Tc)increases during exercise.We utilized a doubl...Non-steroidal anti-inflammatory drugs’anti-pyretic and anti-inflammatory effects has led some individuals to theorize these medications may blunt core body temperature(Tc)increases during exercise.We utilized a double-blind,randomized,and counterbalanced cross-over design to examine the effects of a 24-h naproxen dose(3–220 mg naproxen pills)and placebo(0 mg naproxen)on Tc and plasma interleukin-6(IL-6)concentrations during cycling in a hot or ambient environment.Participants(n=11;6 male,5 female;age=27.8±6.5 years,weight=79.1±17.9 kg,height=177±9.5 cm)completed 4 conditions:1)placebo and ambient(Control);2)placebo and heat(Heat);3)naproxen and ambient(Npx);and 4)naproxen and heat(NpxHeat).Dependent measures were taken before,during,and immediately after 90 min of cycling and then 3 h after cycling.Overall,Tc significantly increased pre-(37.1±0.4℃)to post-cycling(38.2±0.3℃,F_(1.7,67.3)=150.5,p<0.001)and decreased during rest(37.0±0.3℃,F_(2.0,81.5)=201.6,p<0.001).Rate of change or maximum Tc were not significantly different between conditions.IL-6 increased pre-(0.54±0.06 pg/ml)to post-exercise(2.46±0.28 pg/ml,p<0.001)and remained significantly higher than pre-at 3 h post-(1.17±0.14 pg/ml,95%CI=-1.01 to-0.23,p=0.001).No significant IL-6 differences occurred between conditions.A 24-h,over-the-counter naproxen dose did not significantly affect Tc or IL-6 among males and females cycling in hot or ambient environments.展开更多
Using a double-blind,randomized and counterbalanced,cross-over design,we assessed naproxen's effects on gastrointestinal(GI)distress and performance in eleven volunteers(6 male,5 female).Participants completed 4 t...Using a double-blind,randomized and counterbalanced,cross-over design,we assessed naproxen's effects on gastrointestinal(GI)distress and performance in eleven volunteers(6 male,5 female).Participants completed 4 trials:1)placebo and ambient);2)placebo and heat;3)naproxen and ambient;and 4)naproxen and heat.Independent variables were one placebo or 220 mg naproxen pill every 8 h(h)for 24 h and ambient(22.7±1.8℃)or thermal environment(35.7±1.3℃).Participants cycled 80 min at a steady heart rate then 10 min for maximum distance.Perceived exertion was measured throughout cycling.Gastrointestinal distress was assessed pre-,during,post-,3 h post-,and 24 h post-cycling using a GI index for upper,lower,and systemic symptoms.No statistically significant differences occurred between conditions at any time for GI symptoms or perceived exertion,distance,or heart rate during maximum effort.A 24 h naproxen dose did not significantly affect performance or cause more frequent or serious GI distress when participants were euhydrated and cycling at moderate intensity in a thermal environment.展开更多
文摘Objective:To determine which intrinsic and extrinsic exertional heat illness(EHI)risk factors exist in youth American football players and observe perceptual and physiological responses of players during events(games and practices).Methods:Cross-sectional cohort study observing 63 youth football players,varying in position.Independent variables were league(weightrestricted(WR,n=27)and age-restricted(AR,n=36))and event type.Dependent variables were anthropometrics,work-to-rest ratio,and wet bulb globe temperature.Descriptive variables included preparticipation examination and uniform configuration.A subset of 16 players participated in physiological variables(heart rate and gastrointestinal temperature).Data collection occurred on 7 AR and 8 WR nonconsecutive practices and the first 3 games of the season.Results:Mean values for anthropometric variables were higher(p<0.05)in the AR league than the WR league.Work time(χ^2(1,111)=4.232;p=0.039)and rest time(χ^2(1,111)=43.41;p<0.001)were significantly greater for games,but ratios were significantly higher for practices(χ^2(1,111)=40.62;p<0.001).The majority of events(77%)observed were in black and red flag wet bulb globe temperature risk categories.A total of 57%of the players had a preparticipation examination,and up to 82%of events observed were in full uniforms.Individual gastrointestinal temperature and heart rate responses ranged widely and no players reached critical thresholds.Conclusion:Extrinsic(disproportionate work ratios,environmental conditions)and intrinsic(higher body mass index)EHI risk factors exist in youth football.Certain risk factors may be influenced by event and league type.National youth football organizations need to create thorough guidelines that address EHI risk factors for local leagues to adopt.
文摘Non-steroidal anti-inflammatory drugs’anti-pyretic and anti-inflammatory effects has led some individuals to theorize these medications may blunt core body temperature(Tc)increases during exercise.We utilized a double-blind,randomized,and counterbalanced cross-over design to examine the effects of a 24-h naproxen dose(3–220 mg naproxen pills)and placebo(0 mg naproxen)on Tc and plasma interleukin-6(IL-6)concentrations during cycling in a hot or ambient environment.Participants(n=11;6 male,5 female;age=27.8±6.5 years,weight=79.1±17.9 kg,height=177±9.5 cm)completed 4 conditions:1)placebo and ambient(Control);2)placebo and heat(Heat);3)naproxen and ambient(Npx);and 4)naproxen and heat(NpxHeat).Dependent measures were taken before,during,and immediately after 90 min of cycling and then 3 h after cycling.Overall,Tc significantly increased pre-(37.1±0.4℃)to post-cycling(38.2±0.3℃,F_(1.7,67.3)=150.5,p<0.001)and decreased during rest(37.0±0.3℃,F_(2.0,81.5)=201.6,p<0.001).Rate of change or maximum Tc were not significantly different between conditions.IL-6 increased pre-(0.54±0.06 pg/ml)to post-exercise(2.46±0.28 pg/ml,p<0.001)and remained significantly higher than pre-at 3 h post-(1.17±0.14 pg/ml,95%CI=-1.01 to-0.23,p=0.001).No significant IL-6 differences occurred between conditions.A 24-h,over-the-counter naproxen dose did not significantly affect Tc or IL-6 among males and females cycling in hot or ambient environments.
文摘Using a double-blind,randomized and counterbalanced,cross-over design,we assessed naproxen's effects on gastrointestinal(GI)distress and performance in eleven volunteers(6 male,5 female).Participants completed 4 trials:1)placebo and ambient);2)placebo and heat;3)naproxen and ambient;and 4)naproxen and heat.Independent variables were one placebo or 220 mg naproxen pill every 8 h(h)for 24 h and ambient(22.7±1.8℃)or thermal environment(35.7±1.3℃).Participants cycled 80 min at a steady heart rate then 10 min for maximum distance.Perceived exertion was measured throughout cycling.Gastrointestinal distress was assessed pre-,during,post-,3 h post-,and 24 h post-cycling using a GI index for upper,lower,and systemic symptoms.No statistically significant differences occurred between conditions at any time for GI symptoms or perceived exertion,distance,or heart rate during maximum effort.A 24 h naproxen dose did not significantly affect performance or cause more frequent or serious GI distress when participants were euhydrated and cycling at moderate intensity in a thermal environment.
