Metabolic, cardiovascular, and kinematic responses to running on sloping surfaces.
Leo J. D’Acquisto, Jared Dickinson, Vince Nethery. Department of Health, Human Performance, and Nutrition. Central Washington University, Ellensburg, WA. 98926 acquisto@CWU.edu
PURPOSE: The purpose of this study was to compare metabolic, cardiovascular, and kinematic responses to running on sloping surfaces between two groups of runners who varied in performance ability.
METHODS: Trained collegiate runners were divided into a top (T; N = 7) and non-top (NT; N = 6) group based on 8-km performance time. Metabolic (indirect calorimetry), heart rate (HR, telemetry) and stride frequency (SR, stop watch) and length (SL) were monitored during the following: 1) 20 min level run at 14.4 km·hr-1 followed by a run to exhaustion, 2) sloping-surface run at 14.4 km·hr-1, and 3) a 3 km performance run over sloping surfaces.
RESULTS: VO2max for T (65.17 ± 1.85 mL·kg-1·min-1) was greater than NT (58.59 ± 0.44 mL·kg-1·min-1) (P<0.05). T maintained a faster velocity (4.77+0.08 m.s-1) compared to NT (4.04+0.18) (P<0.05) during the 3-km performance run with T sustaining a greater %VO2max (86.1 ± 1.7 vs. 80.8 ± 1.4%) (P<0.05); however, both groups had a similar oxygen cost per distance covered (T, 195.9 ± 3.4; NT, 196.7 ± 6.0 mL·kg-1·km-1) (P>0.05). Relative to level running, downhill and uphill running similarly decreased and increased VO2 and HR in both groups (P>0.05), although T reached steady-rate quicker (P < 0.05), suggesting a faster rate of metabolic adjustment. Overall, uphill running increased VO2 1.5 times more than downhill running decreased VO2, suggesting the decrease in metabolic load during downhill running does not compensate for the increased metabolic demands of uphill running. SL was longer (P < 0.05) and shorter (P < 0.05) during downhill and uphill running, respectively, compared to level running for both groups.
CONCLUSIONS: This study suggests uphill and downhill running similarly affect runners of different abilities, and that superior running performance over sloping surfaces is not attributable to running economy, but rather to a greater VO2max and ability to sustain a high %VO2max.