Kinetic requirements of sudden slip-like anteroposterior perturbation recovery: a joint level perspective

Abstract-Text (inkl. Referenzen und Bildunterschriften)

Introduction

Sudden slip-like anteroposterior perturbations (SLAPs) during running pose a significant challenge to dynamic stability and joint loading. Joint kinematics and kinetics in SLAPs and the following recovery steps have not been studied much. However, studies focusing on perturbations during walking show that joint loading increases during perturbation recovery.

Objectives

To investigate how a SLAP in running affects the lower limb kinematics and kinetics during several steps within the perturbation compared to a non-perturbed baseline.

Methods

Fifteen recreational runners (12 males) underwent a series of two treadmill runs (2.5 m/s) with ten SLAPs each. Three-dimensional motion capturing and ground reaction forces were used to calculate joint biomechanics. SLAPs started at midstance and ended two steps later (Fig. 1). Before each perturbation, it was ensured that the participants maintained a regular running style.

Results

During the accelerated step (P+1), an increased maximum ankle plantarflexion (Tab. 1) and decreased maximum knee extension moment (Tab. 1) compared to baseline were necessary. During the decelerated step (P+2), increased maximum ankle dorsiflexion (Tab. 1) and maximum hip extension moments (Tab. 1), while reduced maximum ankle plantarflexion moments (Tab. 1) were required to recover from the perturbation. At P+1, positive ankle power was increased (Tab. 1), whereas at P+2, positive hip power was increased (Tab. 1).

Summary

SLAP recovery occurs over multiple steps and requires increased joint moments and power output of the hip and ankle joints. The biomechanical mechanisms that underlie these increases will be investigated in future research.

Figure 1: Predefined belt velocity for a SLAP, separated into four steps. Baseline step (B), initial Perturbation step (P), first post perturbation step (P+1), second post perturbation step (P+2), third post perturbation step (P+3).

Table 1: Statistical results.