Physiological Responses To Running On The Boost Anti-gravity Treadmill

Abstract

Lower body positive pressure treadmills have become popular as a training supplement to full weight bearing running. However, the effects of reduced body mass (BM) on an individual’s physiological response to running at high velocity on the Boost Treadmill (BT) has not been investigated. PURPOSE: To determine the physiological responses of running at a range of running velocities and BM support using the BT. METHODS: Twenty trained collegiate distance runners (11 M, 9F, 20 ± 1 yrs) completed maximal running GXTs at three different percentages (100%, 90%, 80%) of BM in a counterbalance manner separated by 7-days. Cardiorespiratory responses were measured at each incremental stage until participants were no longer able to sustain steady-state VO2. Thereafter, the treadmill was increased by 1% grade per minute until volitional exhaustion. An independent t-test was used to compare differences in the dependent variables between genders at 9 and 10 mph and maximal velocity. ANOVA with repeated measures were used to assess differences in these variables at 100, 90 and 80% BM with significance set at p < 0.05. RESULTS: VO2max was different between genders at all three BM percentages (64 ± 4 to 52 ± 3, 66 ± 4 to 55 ± 3, and 71 ± 5 to 60 ± 4 ml*kg-1*min-1 for M vs F at 100%, 90% 80%, respectively, p < 0.05). Gender combined VO2 values were lower at 80% BM at 9 and 10mph than at 90% and 100% BM (44 ± 5 vs 45 ± 5 and 45 ± 4 and 49 ± 6 vs 50 ± 6 and 50 ± 4 ml*kg-1*min-1,p < 0.05) and greater at maximal velocity (66 ± 7 vs 61 ± 7 and 58 ± 8 ml*kg-1*min-1, p,0.05) but not different between 90% and 100% BM. Fractional utilization of O2 measurements were lower at 80% BM at 9 and 10mph than at 90% and 100% BW (67 ± 8 vs 74 ± 9 and 77 ± 10 and 74 ± 9 vs 82 ± 8 and 83 ± 6%, respectively, p < 0.05) but not different between 90% and 100% BM. HR responses were lower at 80% BM at 10mph than at 90% and 100% BM (155 ± 14 vs 169 ± 13 and 172 ± 10 bpm, respectively, p < 0.05). CONCLUSION: The results are predicated on the fact that the participants in this study were actually tested at 94%, 90%, and 80% of their BM. The 100% setting produces positive lifting pressure on the participant resulting in a mean 6% reduction in BM. The metabolic demands of running at 80% BM is significant less than running at 90% and 100% BM and minuscule differences in the metabolic demands while running at the same velocity at the 90% and 100% BM settings on the BT