***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE To investigate the effect of ice slurry ingestion on thermoregulatory responses and submaximal running time in the heat . METHODS On two separate occasions , in a counterbalanced order , 10 males ingested 7.5 g·kg(-1 ) of either ice slurry ( -1 ° C ) or cold water ( 4 ° C ) before running to exhaustion at their first ventilatory threshold in a hot environment ( 34.0 ° C ± 0.2 ° C , 54.9 % ± 5.9 % relative humidity ) . Rectal and skin temperatures , HR , sweating rate , and ratings of thermal sensation and perceived exertion were measured . RESULTS Running time was longer ( P = 0.001 ) after ice slurry ( 50.2 ± 8.5 min ) versus cold water ( 40.7 ± 7.2 min ) ingestion . Before running , rectal temperature dropped 0.66 ° C ± 0.14 ° C after ice slurry ingestion compared with 0.25 ° C ± 0.09 ° C ( P = 0.001 ) with cold water and remained lower for the first 30 min of exercise . At exhaustion , however , rectal temperature was higher ( P = 0.001 ) with ice slurry ( 39.36 ° C ± 0.41 ° C ) versus cold water ingestion ( 39.05 ° C ± 0.37 ° C ) . During exercise , mean skin temperature was similar between conditions ( P = 0.992 ) , as was HR ( P = 0.122 ) and sweat rate ( P = 0.242 ) . After ice slurry ingestion , subjects stored more heat during exercise ( 100.10 ± 25.00 vs 78.93 ± 20.52 W·m(-2 ) , P = 0.005 ) , and mean ratings of thermal sensation ( P = 0.001 ) and perceived exertion ( P = 0.022 ) were lower . CONCLUSIONS Compared with cold water , ice slurry ingestion  lowered preexercise rectal temperature , increased submaximal endurance running time in the heat ( + 19 % ± 6 % ) , and allowed rectal temperature to become higher at exhaustion . As such , ice slurry ingestion may be an effective and practical precooling maneuver for athletes competing in hot environments The present study tested the hypothesis that perceived exertion during prolonged exercise in hot environments is associated with changes in cerebral electrical activity rather than changes in the electromyogram ( EMG ) of the exercising muscles . Therefore ,  electroencephalogram ( EEG )  in three positions ( frontal , central , and occipital cortex ) ,  EMG , rating of perceived exertion ( RPE ) , and core temperature were measured in 14 subjects during  submaximal exercise in normal ( 18 degrees C , control ) and hot ( 40 degrees C , hyperthermia ) environments .  RPE increased from 11 + /- 1 units at 5 min to 20 + /- 0 units at exhaustion ( 50 + /- 3 min ) in the trial with progressive hyperthermia , whereas exercise in the control trial was maintained with a stable core temperature for 1 h without exhausting the subjects . Altered EEG activity was observed in all electrode positions , and stepwise forward-regression analysis identified core temperature and a frequency index of the EEG over the frontal cortex as the best predictors of RPE . In contrast , there were no significant correlations between RPE and any of the measured EMG parameters ( median spectral frequency , root mean square , or amplitude ) , and the EMG parameters were not different in hyperthermia compared with control . Thus hyperthermia does not seem to affect the activation pattern of the muscles . Rather , the linear correlation among core temperature , EEG frequency index , and RPE indicates that alterations in cerebral activity may be associated with the hyperthermia-induced development of fatigue during prolonged exercise in hot environments PURPOSE To develop and investigate the efficacy of a new precooling strategy combining external and internal techniques on the performance of a cycling time trial ( TT ) in a hot and humid environment . METHODS Eleven well-trained male cyclists undertook three trials of a laboratory-based cycling TT simulating the course characteristics of the Beijing Olympic Games event in a controlled hot and humid environment ( 32 ° C-35 ° C at 50%-60 % relative humidity ) . The trials , separated by 3 - 7 d , were undertaken in a r and omized crossover design and consisted of the following : 1 ) CON-no treatment apart from the ad libitum consumption of cold water ( 4 ° C ) , 2 ) STD COOL-whole-body immersion in cold ( 10 ° C ) water for 10 min followed by wearing a cooling jacket , or 3 ) NEW COOL-combination of consumption of 14 g of ice slurry ( " slushie " ) per kilogram body mass made from a commercial sports drink while applying iced towels . RESULTS There was an observable effect on rectal temperature ( T(rec ) ) before the commencement of the TT after both precooling techniques ( STD COOL < NEW COOL < CON , P < 0.05 ) , but pacing of the TT result ed in similar T(rec ) , HR , and RPE throughout the cycling protocol in all trials . NEW COOL was associated with a 3.0 % increase in power ( approximately 8 W ) and a 1.3 % improvement in performance time ( approximately 1:06 min ) compared with the CON trial , with the true likely effects ranging from a trivial to a large benefit . The effect of the STD COOL trial compared with the CON trial was " unclear . " CONCLUSIONS This new precooling strategy represents a practical and effective technique that could be used by athletes in preparation for endurance events undertaken in hot and humid conditions This study examined the independent and combined importance of aerobic fitness and body fatness on physiological tolerance and exercise time during weight-bearing exercise while wearing a semipermeable protective ensemble .  Twenty-four men and women were matched for aerobic fitness and body fatness in one of four groups ( 4 men and 2 women in each group ) . Aerobic fitness was expressed per kilogram of lean body mass ( LBM ) to eliminate the influence of body fatness on the expression of fitness . Subjects were defined as trained ( T ; regularly active with a peak aerobic power of 65 ml x kg LBM(-1 ) x min(-1 ) ) or untrained ( UT ; sedentary with a peak aerobic power of 53 ml x kg LBM(-1 ) x min(-1 ) ) with high ( High ; 20 % ) or low ( Low ; 11 % ) body fatness . Subjects exercised until exhaustion or until rectal temperature reached 39.5 degrees C or heart rate reached 95 % of maximum . Exercise times were significantly greater in T(Low ) ( 116 + /- 6.5 min ) compared with their matched sedentary ( UT(Low ) ; 70 + /- 3.6 min ) or fatness ( T(High ) ; 82 + /- 3.9 min ) counterparts , indicating an advantage for both a high aerobic fitness and low body fatness . However , similar effects were not evident between T(High ) and UT(High ) ( 74 + /- 4.1 min ) or between the UT groups ( UT(Low ) and UT(High ) ) . The major advantage attributed to a higher aerobic fitness was the ability to tolerate a higher core temperature at exhaustion ( the difference being as great as 0.9 degrees C ) , whereas both body fatness and rate of heat storage affected the exercise time as independent factors We investigated whether fatigue during prolonged exercise in uncompensable hot environments occurred at the same critical level of hyperthermia when the initial value and the rate of increase in body temperature are altered . To examine the effect of initial body temperature [ esophageal temperature ( Tes ) = 35.9 + /- 0.2 , 37.4 + /- 0 . 1 , or 38.2 + /- 0.1 ( SE ) degrees C induced by 30 min of water immersion ] , seven cyclists ( maximal O2 uptake = 5.1 + /- 0.1 l/min ) performed three r and omly assigned bouts of cycle ergometer exercise ( 60 % maximal O2 uptake ) in the heat ( 40 degrees C ) until volitional exhaustion . To determine the influence of rate of heat storage ( 0.10 vs. 0.05 degrees C/min induced by a water-perfused jacket ) , four cyclists performed two additional exercise bouts , starting with Tes of 37.0 degrees C. Despite different initial temperatures , all subjects fatigued at an identical level of hyperthermia ( Tes = 40 . 1 - 40.2 degrees C , muscle temperature = 40.7 - 40.9 degrees C , skin temperature = 37.0 - 37.2 degrees C ) and cardiovascular strain ( heart rate = 196 - 198 beats/min , cardiac output = 19.9 - 20.8 l/min ) . Time to exhaustion was inversely related to the initial body temperature : 63 + /- 3 , 46 + /- 3 , and 28 + /- 2 min with initial Tes of approximately 36 , 37 , and 38 degrees C , respectively ( all P < 0.05 ) . Similarly , with different rates of heat storage , all subjects reached exhaustion at similar Tes and muscle temperature ( 40.1 - 40.3 and 40 . 7 - 40.9 degrees C , respectively ) , but with significantly different skin temperature ( 38.4 + /- 0.4 vs. 35.6 + /- 0.2 degrees C during high vs. low rate of heat storage , respectively , P < 0.05 ) . Time to exhaustion was significantly shorter at the high than at the lower rate of heat storage ( 31 + /- 4 vs. 56 + /- 11 min , respectively , P < 0.05 ) . Increases in heart rate and reductions in stroke volume paralleled the rise in core temperature ( 36 - 40 degrees C ) , with skin blood flow plateauing at Tes of approximately 38 degrees C. These results demonstrate that high internal body temperature per se causes fatigue in trained subjects during prolonged exercise in uncompensable hot environments . Furthermore , time to exhaustion in hot environments is inversely related to the initial temperature and directly related to the rate of heat storage The purpose of this study was to examine the effect of environmental temperature on variability in power output , self-selected pacing strategies , and performance during a prolonged cycling time trial . Nine trained male cyclists r and omly completed four 40 km cycling time trials in an environmental chamber at 17 ° C , 22 ° C , 27 ° C , and 32 ° C ( 40 % RH ) . During the time trials , heart rate , core body temperature , and power output were recorded . The variability in power output was assessed with the use of exposure variation analysis . Mean 40 km power output was significantly lower during 32 ° C ( 309 ± 35 W ) compared with 17 ° C ( 329 ± 31 W ) , 22 ° C ( 324 ± 34 W ) , and 27 ° C ( 322 ± 32 W ) . In addition , greater variability in power production was observed at 32 ° C compared with 17 ° C , as evidence d by a lower ( P = .03 ) st and ard deviation of the exposure variation matrix ( 2.9 ± 0.5 vs 3.5 ± 0.4 units , respectively ) . Core temperature was greater ( P < .05 ) at 32 ° C compared with 17 ° C and 22 ° C from 30 to 40 km , and the rate of rise in core temperature throughout the 40 km time trial was greater ( P < .05 ) at 32 ° C ( 0.06 ± 0.04 ° C·km-1 ) compared with 17 ° C ( 0.05 ± 0.05 ° C·km-1 ) . This study showed that time-trial performance is reduced under hot environmental conditions , and is associated with a shift in the composition of power output . These finding provide insight into the control of pacing strategies during exercise in the heat QUESTIONS Does the PEDro scale measure only one construct ie , the method ological quality of clinical trials ? What is the hierarchy of items of the PEDro scale from least to most adhered to ? Is there any effect of year of publication of trials on item adherence ? Are PEDro scale ordinal scores equivalent to interval data ? DESIGN Rasch analysis of two independent sample s of 100 clinical trials from the PEDro data base scored using the PEDro scale . RESULTS Both sample s of PEDro data showed fit to the Rasch model with no item misfit . The  PEDro scale item hierarchy was the same in both sample s , ranging from the most adhered to item r and om allocation , to the least adhered to item therapist blinding . There was no differential item functioning by year of publication . Original PEDro ordinal scores were highly correlated with transformed PEDro interval scores ( r = 0.99 ) . CONCLUSION The PEDro scale is a valid measure of the method ological quality of clinical trials . It is valid to sum PEDro scale item scores to obtain a total score that can be treated as interval level measurement and subjected to parametric statistical analysis Abstract In this study we examined the influence of menstrual cycle phase and oral contraceptive use on thermoregulation and tolerance during uncompensable heat stress . Eighteen women ( 18–35 years ) , who differed only with respect to oral contraceptive use ( n = 9 ) or non-use ( n = 9 ) , performed light intermittent exercise at 40 ° C and 30 % relative humidity while wearing nuclear , biological and chemical protective clothing . Their responses were compared during the early fol 
    Output:
    
Effect size calculations indicated moderate evidence that cold water immersion effectively improved endurance performance , and limited evidence that ice slurry ingestion improved performance .
Cooling garments were ineffective .
Conclusions Current evidence indicates cold water immersion may be the most effective method of pre-cooling to improve endurance performance in hot conditions , although practicality must be considered .
Ice slurry ingestion appears to be the most promising practical alternative .
Interestingly , cooling garments appear of limited efficacy , despite their frequent use .