Influence of stance width and step frequency on gait initiation in healthy young adults.

Tijs, C. (2010) Influence of stance width and step frequency on gait initiation in healthy young adults. thesis, Human Movement Sciences.

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Abstract

Gait initiation, which starts with an intentional balance perturbation, is usually carried out without problems in a healthy population. However, it may be problematic in pathological populations. Insight in the process of gait initiation is therefore important. The role of spatiotemporal variables during gait initiation is not always taken into account, whereas these variables can influence relevant parameters, which can result in within subject variability. For investigating gait initiation in pathological populations, it is critical to dissociate spatiotemporal effects from pathological effects. Therefore, this study will focus on the effects of gait initiation speed and stance width on relevant bilateral kinematic, kinetic and electromyographic (EMG) parameters during gait initiation in order to gain insight of these effects on gait initiation in healthy young adults. Step frequency was used for controlling initiation speed. Subjects were asked to place the medial sides of both feet at several distances from each other (5, 20, 35 ern) and initiate gait with a certain step frequency (40, 60, 80, 100 beats/min). Each trial started with a 4 second baseline measurement, whereupon subjects walked for a distance of 3 m. Data was analyzed using Repeated Measures ANOV A's with p<0.05 to determine statistical significance. Results demonstrate an absence of bilateral Tibialis Anterior (TA) and leading limb Gluteus Medius (GM) activity before onset. Step frequency influenced the time of step events (heel-off, toe-off and heel-strike), leading limb step length, bilateral step duration, step velocity, CoM displacements and it increased the backward CoP displacement and lateral CoP displacement toward the leading limb. There is also increased bilateral TA, GM and Gastrocnemius (GA) activity and an earlier onset of leading limb T A and GM. In addition, increasing step frequency resulted in increased kinetics in all three directions (Fx, Fy, Fz) for both leading limb and trailing limb and it resulted also in increased bilateral knee flexion and hip flexion, increased leading limb ankle dorsal flexion and trailing limb ankle plantar flexion. Variation in stance width resulted in increased Fx and Fy before onset, trailing limb step length and step velocity, leading limb step duration and CoM displacement in mediolateral direction. It also increased lateral CoP displacements and it increased trailing limb ankle dorsal flexion, knee flexion and hip flexion before leading limb heel-off. Moreover, activity of leading limb GA is also increased before leading limb heel-off. Finally, stance width resulted also in increased Fy indicating that stance width can influence the forward velocity. Results also suggest that stance width and step frequency influence each other during gait initiation resulting in interaction-effects. All these results emphasize the roles of stance width and step frequency during gait initiation in a group of healthy young adults. This information can be useful in research toward people with gait impairments that typically have narrowed stance width and lowered gait speed.

Item Type:	Thesis (Thesis)
Supervisor name:	Otter, Dr. R. den
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:44
Last Modified:	25 Jun 2020 10:44
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/598

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