The role of landing foot orientation on linear traction in stop and stop-jump tasks
Date
2021
Authors
Taylor, Laura Thistle, author
Reiser, Raoul F., II, advisor
Fling, Brett W., committee member
Blanchard, Nathaniel, committee member
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Abstract
Introduction: The incidence of lower extremity injury has been shown to be greater on artificial turf (AT) than on natural grass across a variety of sports. Injury risk and performance are influenced by the traction characteristics of the foot-surface interface shortly after initial foot contact. The foot's orientation relative to the ground upon landing potentially contributes to these traction characteristics. Although landing foot orientation has been shown to be predictive of lower extremity injury risk on hardcourt surfaces, it remains unclear if foot orientation influences landing ground reaction forces and traction on AT. This information could contribute to modifications in athlete technique, cleat design, and surface characteristics to optimize athlete performance and reduce injury risk. The primary purpose of this investigation was to examine how foot orientation upon landing on AT during stop and stop-jump tasks influences linear traction and foot loading characteristics. Secondary goals were to investigate differences in landing strategy between males and females and the effect of subsequent task demands between the two movements. Methods: Twenty-nine collegiate club-level or higher athletes (15 females) accustomed to competing on AT participated. A third-generation AT was prepared over a foam shock pad to manufacturer specifications with a sand base and crumb rubber performance infill. Isolated panels were secured over two side-by-side force platforms. Subject kinematics were measured using optical capture with reflective markers. Subjects performed six acceptable trials of a stop task and a stop-jump task. Each limb was analyzed separately from initial foot contact through the landing phase. The representative average trial of each subject was used to determine differences between the limbs and sexes within and between each movement. Individual trials were used to explore the relationships between the initial foot progression angle and traction. Due to the limited number of forefoot landings for the two analyzed movements, correlations were only performed on the initial foot progression angles ranging from rearfoot to flatfoot. Results: This investigation is especially novel since most reported literature on foot orientation has been conducted on hardcourt surfaces, not on AT. We found that initial foot progression angle was strongly correlated with the horizontal displacement of the foot before the cleat fully engaged with the AT but had limited influence on early ground reaction forces. We found no differences in initial foot progression angle between sexes or between movements, although horizontal ground reaction forces were greater for males than females and greater for the stop task compared to the stop-jump task. Conclusion: Landing foot orientations, ranging from rearfoot to flatfoot, contribute to the horizontal movement across AT. The relationship between horizontal foot movement on AT and injury risk needs to be further analyzed, specifically by examining the joint loading mechanics at the ankle, knee, and hip.
Description
Rights Access
Subject
foot orientation
traction
foot progression angle
artificial turf