Undergraduate Honors Theses

Thesis Defended

Spring 2017

Document Type

Thesis

Type of Thesis

Departmental Honors

Department

Integrative Physiology

First Advisor

Rodger Kram

Second Advisor

Herbert Covert

Third Advisor

David Sherwood

Abstract

Purpose: Vertical Kilometer (VK) races, in which runners gain 1000 m of elevation in <5000 m of total distance, are becoming popular, yet there are few studies on steep uphill running. Previously, we determined that ~30° is the optimal angle for uphill running, costing the least amount of energy for a given vertical velocity. In the present study, we quantified the metabolic cost of walking and running at various velocities at a 30° incline.

Method: At a 30° incline, eleven experienced runners (7M, 4F, 30.8 +/- 7.9 years, 1.71 +/- 0.08m, 66.7 +/- 9.4 kg) walked and ran for 5 minute trials with 5 minute rest between. Starting at 0.3 m/s we increased treadmill velocity by 0.1 m/s for each successive trial until subjects were unable to maintain the set velocity. We measured oxygen uptake (mlO2/kg/min) and metabolic rates (W/kg) and calculated the costs of walking (Cw) and running (Cr) (J/kg/m).

Result: Oxygen uptake and metabolic power increased linearly with velocity (W/kg walk= 1.452 + 21.848V, W/kg run=5.351 + 17.586V). At the five slowest velocities (0.3, 0.4, 0.5, 0.6, and 0.7 m/s), Cw was less than Cr. However, at 0.8 m/s there was no difference between the two, and extrapolation suggests that at faster velocities, running likely cost less than walking.

Conclusion: Running quickly up steep inclines requires more energy than running slowly does. Furthermore, at slower speeds, walking costs less than running. Thus, VK racers should pick a specific gait based on their racing speed.

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