Evaluating The Effects of Two-Minutes Active Recovery On A “Booster” VO2max Test Using Ultramarathon Runners

Abstract

Maximal oxygen consumption (VO2max) tests typically end at the point of volitional exhaustion. However, prior research with averagely fit females and males as well as highly fit female collegiate athletes suggest that concluding a maximal treadmill test with 2min active recovery and allowing subjects to exercise a second time (ie. a booster test) at the workload eliciting the initial volitional exhaustion results in significantly greater VO2max values (1.4% and 4.2% mean increase, respectively). The potential effects of this testing sequence (ie. 2min active recovery) on VO2max treadmill graded exercise tests (GXT) has not been evaluated utilizing ultramarathon runners, yet accurate assessment of these unique athletes’ VO2max is crucial for training program design, implementation, and evaluation of training adaptations. PURPOSE: To examine changes in VO2max values, in fit ultramarathon runners, following 2min of active recovery at the conclusion of a treadmill GXT to volitional exhaustion. METHODS: Twenty-nine (19 males and 10 females) ultramarathon runners completed a max treadmill GXT by reaching volitional exhaustion (MX1). Following 2min active recovery (at 0% grade & 2.5 mph) after reaching MX1, subjects had an immediate return to the ending MX1 speed and grade and exercised (ie. a booster test) to volitional exhaustion a second time (MX2). MX1 and MX2 values were compared using a Paired-Samples t-Test with significant differences occurring at p < 0.05. RESULTS: MX1 (53.9 + 6.0 ml/kg/min) was significantly different (p = 0.03) than MX2 (52.7 + 7.0 ml/kg/min). The mean change from MX1 to MX2 was -2.2%, yet 37.9% of the subjects benefited (+2.9% mean increase) from the booster test with individual increases of +0.2% up to +8.0%. CONCLUSION: Mean results suggest that 2min active recovery may not allow significantly greater VO2max values to be achieved by fit ultramarathon runners during a max treadmill GXT, yet 37.9% of the subjects increased their VO2max during the “booster VO2max test” treadmill protocol. Future research may examine if fitness level, training experience, age, ultramarathon distance specialty, or other variables might affect this exercise testing protocol.