CHANGES IN AEROBIC FITNESS PARAMETERS OF COMPETITIVE RUNNERS DURING A YEAR

T.M. Lehr,L. Young The University of Montana Western, Dillon, MT Competitive runners train to increase their aerobic fitness and economy. PURPOSE: The purpose of this study is to compare aerobic fitness parameters in competitive runners from southwest Montana over the time span of one calendar year. METHODS: Fourteen competitive runners volunteered for this study (N=14, 8M, 18.75 ± 0.5 yr., 20.66 ± 0.99 kg/m2BMI and 6F, 19.75 ± 0.5 yr., 20.45 ± 1.86 kg/m2BMI). Subjects completed a graded exercise test on a treadmill connected to an open-circuit computerized gas analysis system at 4 assessment periods throughout a year (W17, S18, F18, W18) for the determination of VO2peak, total time to exhaustion (TTE), maximal respiratory exchange ratio (max RER), and Time at RER\u3e1.0. The graded exercise test consisted of a 3-minute warm-up at 3.5 miles per hour (mph). Males completed a ramp protocol initiated at 7 mph and increased in speed 1 mph every 90 seconds until 12 mph. At 12 mph, a 0.5% grade increase occurred every 90 seconds until volitional exhaustion. Female subjects completed a protocol initiated at 6 mph and increasing 1 mph every 90 seconds until 10mph; followed by 0.5% grade increase every 90 seconds until volitional exhaustion. Verbal encouragement was provided in all tests. A Kruskal-Wallis ANOVA with post-hoc tests were calculated (alpha p = \u3c0.05) to compare BMI, VO2peak, TTE, max RER, and Time at RER\u3e1.0between each assessment period for all subjects. A repeated measures ANOVA with planned comparisons was used to evaluate outcomes within genders. RESULTS: There were no differences in BMI, VO2peak, TTE or Time at RER\u3e1.0 within males or females at any assessment time point. Combined male and female data (N=14), revealed an increase in VO2peak in W17 vs. W18 (52.61 ± 7.66; 65.5 ± 9.85 ml/kg/min-1, p=0.04). Max RER decreased in W17 vs. F18 (1.13 ± 0.03; 1.05 ± 0.01, p\u3e0.00) and S17 vs. W18 (1.11 ± 0.04; 1.05 ± 0.01, p=0.03), in addition Time at RER\u3e1.0 was decreased in W17 vs. W18 (2:46 ± 1:03; 1:33 ± 0:12 min, p=0.02). CONCLUSION: An increase in VO2peak was only observed in the initial (W17) assessment period, while max RER and Time at RER\u3e1.0 continued to decline throughout the year. This occurred without a concurrent change in VO2peak. A decrease in Time at RER\u3e1.0 could suggest an increase in fat utilization with training, although further testing is needed to evaluate these conclusions