Lower extremity joints and their contributions to whole limb extension

J W Fox,A E Jagodinsky,C M Wilburn,L Smallwood,W H Weimar

doi:10.1080/23335432.2019.1695540

Abstract

ABSTRACT Lower extremity multi-joint strength curves tend not to evaluate individual joint contributions to endpoint force in maximum effort isometric whole limb extension. Therefore, the purpose of this study was to measure the contribution of the hip, knee, and ankle to vertical ground reaction force in maximum effort isometric whole limb extension at various postures. An effect of posture on the contributions of the hip, knee, and ankle to vertical ground reaction force was found (F(3,96) = 85.31, p < 0.0001; F(3,96) = 21.32, p < 0.0001; F(3,96) = 130.61, p < 0.0001 for the hip, knee, and ankle, respectively). The hip and knee contributed most to vertical endpoint force when the lower limb was in a flexed posture, and their contributions decreased when posture was extended. Conversely, the ankle contributed least when the limb was flexed, but its contribution increased as posture was changed from flexed to more extended. In comparison to recent research involving induced acceleration analysis, it appears that the hip, knee, and ankle utilize the same force allocation strategy in multi-joint maximum effort isometric leg extensions and activities of daily living.

Highlights

Strength has been measured via single-joint strength curves for various joints throughout the body (Kulig et al 1984; Bober et al 2002; Anderson et al 2007)
The purpose of this study was to measure the contribution of the hip, knee, and ankle to vertical ground reaction force in maximum effort isometric whole limb extension at various postures
The purpose of this study is to quantify the force contributed by the whole lower limb, hip, knee, and ankle to vertical ground reaction force while performing a multi-joint maximum effort isometric leg extension task

Summary

Introduction

Strength has been measured via single-joint strength curves for various joints throughout the body (Kulig et al 1984; Bober et al 2002; Anderson et al 2007). Single joint strength curves take on one of the three different shapes: ascending, descending, or ascending-descending (Kulig et al 1984). The characteristic shapes of single-joint strength curves reflect the portion of the length-tension curve over which the muscle or muscle group operates (Kulig et al 1984; Anderson et al 2007). Despite the importance of single-joint strength curves, many activities of daily living are multi-joint efforts. While statistical perspectives on joint contributions to lower extremity endpoint force are useful, a clear mechanical description of joint contributions to endpoint force across postures is lacking

Objectives

Methods

Results

Conclusion