ABSTRACT ACKNOWLEDGEMENTS PRACTICAL APPLICATION INTRODUCTION PURPOSE: The purpose of this pilot study was to determine the influence of lower-body compression garments (LBCG) on selected physiological measures while traversing extreme terrain at altitude. METHODS: Nine (n=9) recreationally active males (Age: 26.9 ± 4.9; Ht: cm ± 5.89; Wt: 85 kg ± 13.3). Participants performed two 7 kilometer (3.5 k ascent; 3.5k descent) time trials at altitude, the first in self-selected normal active wear and the second, 7 days later, wearing graduated LBCG’s made of a circular knit 50 Denier Lycra fabric (2XU, Melbourne, Australia). Physiological data was captured with a Zephyr Bioharness 3™ chest strap (Zephyr Technology Corporation; Annapolis, Maryland) and muscle soreness ratings at 24, 48 and 72 hours were collected with a questionnaire. Statistical Analysis: Descriptive statistical analysis, SPSS 21.0, was conducted to determine the mean scores and standard deviations for the total sample. Mean scores differences were determined via a series of Wilcoxon signed rank tests. RESULTS: Significant differences were discovered between trials in physiological load (p=.04); training load (p=.01); average physiological intensity (p=.05) and estimated caloric expenditure (p=.02) for the 7k route. Significant differences were also discovered between trials for the 3.5 k ascent portion of the route in estimated caloric expenditure (p =.04). During the 3.5 k descent portion of the route significant differences were discovered between trials in physiological load (p=.01); mechanical load (p =.01); and average physiological intensity (p=.01); average mechanical intensity (p =.02); and estimated caloric expenditure (p=.01). Furthermore, significant differences were discovered between pain scale ratings at 48 hours (p=.01) and 72hours (p=.04) post event with significantly less pain reported after activity in which the LBCG’s were worn. CONCLUSION: LBCG’s may help improve physiological performance and perception of pain within 72 hours after intense activity. Lower-body compression garments (LBCG’s) have been used extensively in therapeutic medicine, however in recent years the use of LBCG’s as an ergogenic aid has dramatically increased. CG’s may be beneficial for conserving high- energy phosphates for subsequent short, bursts of energy and improved repeated performances at high speeds. This finding may also be applicable to the military soldier that often needs to cover short distances as quickly as possible to advance on a designated target or maintain personal safety. Thus, the purpose of this pilot study was to determine the influence of lower-body compression garments (LBCG) on selected physiological measures while traversing extreme terrain at altitude Nine (n=9) recreationally active males (Age: 26.9 ±4.9; Ht: cm ±5.89; Wt: 85kg ±13.3). performed two 7 kilometer (3.5k ascent; 3.5k descent) time trials up the Barr Trail located in Manitou Springs, Colorado. The first trial was in self-selected normal active wear and the second, 7 days later, wearing graduated LBCG’s made of a circular knit 50 Denier Lycra fabric (2XU, Melbourne, Australia). The route had a beginning elevation of 1990 meters and a peak of 2606 meters. Participants were then outfitted with a Zephyr Bioharness 3™ chest strap (Zephyr Technology Corporation; Annapolis, Maryland) to collect the following physiological data: heart rate, heart rate variability, estimated core temperature, breathing rate, peak acceleration, physiological and mechanical load, physiological and mechanical intensity, training load, activity level, and estimated caloric expenditure. Additionally, subjective muscle soreness ratings at 24, 48 and 72 hours were collected utilizing a questionnaire. The second trial followed the same pre and post- test procedures with only the garment changing to LBCGs. Statistical Analysis: Using SPSS 21.0, a descriptive statistical analysis was conducted to determine the mean scores and standard deviations for the total sample. Differences in mean scores were determined via a series of Wilcoxon signed rank tests. METHODS RESULTS Significant differences were discovered between trials in physiological load (p=.04); training load (p=.01); average physiological intensity (p=.05) and estimated caloric expenditure (p=.02) for the 7k route. Significant differences were also discovered between trials for the 3.5k ascent portion of the route in estimated caloric expenditure (p =.04). During the 3.5k descent portion of the route significant differences were discovered between trials in physiological load (p=.01); mechanical load (p=.01); and average physiological intensity (p=.01); average mechanical intensity (p=.02); and estimated caloric expenditure (p=.01). Furthermore, significant differences were discovered between pain scale ratings at 48 hours (p=.01) and 72 hours (p=.04) post event with significantly less pain reported after activity in which the LBCG’s were worn. Table 1: Barr Trail Time Trial: Descent Only (3.5 k ) Variable Measured Trial 1 (Control) (Mean ± SD) Trial 2 (2XU) (Mean ± SD) Significance Estimated core temperature ± ± 0.98p =.04 Physiological load ± ± 71.44p=.01 Mechanical load 175 ± ± 32.66p=.01 Average physiological intensity ± ± 20.68p=.01 Average mechanical intensity 7.7 ± ± 1.44p=.02 Estimated caloric expenditure ± ± 71.44p=.01 LBCG’s may help improve physiological performance and perception of pain within 72 hours after intense activity. Wearing LBCG’s during intense physical activity may help reduce the physiological burden experienced during physical activity and lead to reduced perceptions of pain in the days following strenuous physical activity. Funding for this pilot study was provided by 2XU, Melbourne, Australia. DISCUSSION