The Influence of Altering Internal and External Factors Contributing to Metatarsophalangeal Joint Mechanics and their Effects on Running Economy
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Date
2019-09-18
Authors
Day, Evan
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Publisher
University of Oregon
Abstract
The metatarsophalangeal joint serves as the base of support during running once the heel lifts off the ground. However, it is often neglected as a contributor to forward propulsion. Despite being historically overlooked, advances in footwear technology have shown that the use of stiffer footwear may benefit performance in distance runners. Little is known however about how mechanical function of the metatarsophalangeal joint changes in response to varying external and internal factors contributing to its function. To address this, we had well trained runners run at a range of speeds from perceived easy to mile race pace, strengthen their intrinsic foot muscles, and run in shoes of varying longitudinal bending stiffness. This dissertation was divided into two projects. The first project consisted of running at speeds ranging from 3.69 to 6.11 m/s on an instrumented treadmill. Participants also completed a ramped protocol consisting of three-minute stages while expiratory gases were collected, in order to assess running economy. Half of the participants underwent an intrinsic foot muscle training program for ten weeks while half did not. Participants revisited the lab at five and ten weeks to test for changes in foot strength, gait mechanics, and running economy. Results indicate that metatarsophalangeal joint moment, range of motion, and dynamic angular resistance change across running speeds. Interestingly though, greater intrinsic foot muscle strength did not alter mechanics of the metatarsophalangeal or ankle joint or running economy. The second study consisted of having well trained runners run in shoes of varying longitudinal bending stiffness at 3.89, 4.70, and 5.56 m/s while joint and gross level mechanics were assessed. Running economy was assessed at 3.89 and 4.70 m/s. Results suggest that changes in joint and gross level mechanics and running economy in response to variable longitudinal bending stiffness of footwear is running speed dependent. Individual subject responses suggest that optimal tuning of the longitudinal bending stiffness of footwear should take speed into consideration. These findings may serve as a guide for how to construct footwear to improve performance in distance runners.
This dissertation includes previously published and unpublished co-authored material.
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Keywords
bending stiffness, footwear, gait, performance