Smith, Jeremy D.
Heise, Gary D.
Ferris, Abbie E.
College of Natural and Health Sciences; School of Sport and Exercise Science: Biomechanics
University of Northern Colorado
Type of Resources
Place of Publication
University of Northern Colorado
In this dissertation, the measurement and impact of asymmetrical locomotion were investigated. In the first study, ten able-bodied individuals were asked to run on a treadmill from which interlimb symmetries of joint level kinematics and kinetics were measured. To obtain a stable measure of interlimb symmetry, an average of 15 strides were needed. However, no differences were found between averages from bins of consecutive and inconsecutive strides. Further, no differences were noted between the average interlimb symmetry and interlimb symmetries calculated from the first, middle, or last, strides. Although there were differences between symmetry calculations, neither measure required a greater number of strides to become a stable measure of interlimb symmetry. In study two, ten able-bodied individuals were asked to walk on a treadmill from which interlimb symmetries of joint level kinematics and spatiotemporal parameters were calculated. The interlimb symmetries became stable with an average of 8 strides. No systematic differences between subsets of three, five, or eight strides were noted. Further, no differences were noted between subsets when utilizing consecutive or inconsecutive strides. Finally, although it required eight strides to achieve a stable mean symmetry index, no differences were noted between the average interlimb symmetry index of the first three, five, and eight strides for all measures. In study three, the metabolic cost of walking asymmetrically was explored for ten able-bodied individuals. Walking with a unilaterally added 2kg mass at the ankle resulted in an increased metabolic cost of walking compared with normal walking. The asymmetrical swing times were calculated and replicated without the mass via an audible metronome that when matched to initial foot strikes resulted in asymmetrical swing times. This temporally asymmetrical swing time also resulted in an increased metabolic cost of walking compared with normal walking. Additionally, walking to a symmetrical metronome with the added mass increased the metabolic cost of walking. Forcing temporal symmetry when walking with a unilaterally added mass and forcing temporal asymmetry when walking without a unilaterally added mass were found to result in metabolic penalty compared with unmanipulated walking with and without a unilaterally added mass. The findings of this dissertation indicate that 15 and 8 strides should be collected when studying interlimb symmetries during running and walking, respectively. However, whether the strides are collected consecutively or whether these strides are collected early or late within a trial does not appear to effect results. Further, there does not appear to be a statistical difference between the strides required to achieve a stable mean and fewer strides in able-bodied locomotion. Lastly, forcing an unnatural temporal gait pattern will result in a metabolic penalty during walking. Without interlimb mass differences, an asymmetrical gait pattern results in a greater metabolic cost of walking than a symmetrical gait pattern. More importantly for persons with a unilateral amputation; when interlimb mass differences are present, a symmetrical gait pattern results in a greater metabolic cost of walking than an asymmetrical gait pattern.
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