The relationship between lower limb biomechanical
variables during common screening tasks

Alenezi, FS

Abstract

Abnormal lower-limb mechanics during functional activities have been reported as being associated with several knee injuries. Hence it is important to develop screening tests to identify healthy individuals who may be susceptible to knee injury and then to design individual intervention programmes. There is limited literature exploring the associations between lower-limb biomechanical variables during athletic tasks associated with knee-joint injuries. A better understanding of inter-task performance would offer insights into the consistency of motor patterns employed by healthy individuals during common screening tasks.

This thesis comprises four themed studies. The first study aimed to examine the reliability of using 3D motion analysis to measure the biomechanical variables during single-leg squats (SLS), single-leg landing (SLL), running and sidestep cutting tasks. The findings of first study revealed that within-day measurements are more reliable than those between days across all tasks, while transverse-plane variables are less reliable compared to other planes of movement.

The second study established reference values for lower-limb biomechanical variables during these tasks in a large population sample (90 healthy participants). Furthermore, gender differences in biomechanical variables were also assessed. Significant differences were noticed in knee-flexion, knee-valgus and hip-adduction peak angles across all tasks and both genders.

The third study examined the relationships between lower-limb biomechanical variables during these tasks. A significant relationship has been reported across all tasks between the following variables: peak knee-abduction angle and moment, hip-internal and hip-adduction rotation angles. The findings support the hypothesis that those individuals who exhibit misalignment strategies, specifically in frontal and transverse planes, during SLS & SLL will also show the same movements during running and cutting tasks. However, it must be stressed that the use of squat or landing alone should not be considered as a replacement to find individuals at risk of running or cutting mechanics since several variable showed weak or no correlation.

The final study aimed to examine the effectiveness of an augmented feedback protocol on SLS performance and if changing squat performance would be reflected in a change in performance in SLL, running and side-step cutting tasks. Training resulted in a significant reduction in knee-valgus angle and moment and hip-flexion angles during single-leg squatting. Additionally, these improvements remained a few days later, proposing motor patterns might have improved and these improvements would sustain, thus reducing the risk of injury in the longer time. Furthermore, significant reductions in knee-valgus angle and moment were also noticed in landing after squat feedback training, but no significant improvements were transferred to run and cut tasks.

This thesis has expanded the understanding about using 3D movement-analysis systems and established reference values when performing common screening tasks. Furthermore, feedback was used to improve performance strategies, which could reduce the risk of knee injuries in a quick and easy manner. However, the results of this study do not confirm that the alterations reported in biomechanical variables were solely due to the SLS feedback-training programme.

Citation

variables during common screening tasks. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Sep 2, 2016
• Publicly Available Date: Sep 2, 2016
• Additional Information: Funders : Ministry of Health, Kingdome of Saudi Arabia
• Award Date: Jan 1, 2016