Effect of Treadmill Protocol on Attainment of VO2max Criteria in Collegiate Women Athletes

Abstract

When performing the same test protocol, athletes from sports of differing metabolic demands may vary in the achievement of physiological criteria that are indicative of attaining maximal oxygen consumption (VO2max). PURPOSE: To examine whether the attainment of VO2max criteria differs in two sports with differing metabolic demands as a result of the graded exercise treadmill test (GXT) protocol used. METHODS: Twenty-nine National Collegiate Athletic Association Division 1 women athletes (basketball (WBB): n=11; lacrosse (WLAX): n=18) completed a continuous GXT to volitional fatigue. Speed increased following each 1-minute stage with a 1% constant grade. VO2peak indicated the highest VO2 value reached during a single test, while VO2max indicated the subject’s functional limit was reached. The criteria to attain VO2max were: VO2 plateau of <0.15 L/min with an increase in the last two workloads; maximum heart rate (HRmax) within 10 bpm of age-predicted heart rate max; respiratory exchange ratio (RER)>1.10; rating of perceived exertion (RPE, 1-10 scale)>8; blood lactate (LAC) collected 5-min post-test >8mmol/L. The attainment > 3 of 5 criteria was required for VO2max. Independent t-tests were used for comparison of values between teams, and chi-squared test was used for comparison of criteria attainment. Alpha level was set at p<0.05. RESULTS: Relative VO2peak values did not differ between teams (WBB: 55.3 ± 8.1; WLAX: 53.8 ± 5.4 mL∙kg-1∙min-1). The percent of athletes that met each of the five criteria were: plateau (WBB: 55%, WLAX: 56%), HRmax (WBB: 27%, WLAX: 39%), RER (WBB: 0%, WLAX: 17%), RPE (WBB: 55%, WLAX: 44%), LAC (WBB: 100%, WLAX: 83%). More WLAX attained VO2peak than VO2max (55% vs. 45%). WBB was evenly distributed between VO2peak (50%) and VO2max (50%). There was no statistical difference between WBB and WLAX in VO2max or the number of athletes from each team who met each individual criterion. Significant differences between teams were observed for LAC (WBB 13.3 ± 1.7, WLAX 10.3 ± 2.3 mmol/L; p=0.001) and RER (WBB 0.96 ± 0.05, WLAX 1.04 ± 0.09; p=0.002). CONCLUSION: These findings suggest physiological responses to a fixed VO2max protocol may vary between sport teams of different metabolic demands. Consideration should be given to such variations when selecting test protocols and interpreting results.