Abstract
Repetitive landings as well as variations in foot posture have been suggested to be risk factors for the development of lower limb overuse injuries. It is believed that variations in foot posture may affect the foot’s ability to attenuate landing forces, via the foot spring mechanism, leading to increased force experienced further up the limb. Experiencing these increased forces during repetitive landings, and the accumulated load over time, leads to the development of lower limb overuse injuries, most commonly affecting structures surrounding the ankle and knee as force is transferred up the kinetic chain. This thesis aimed to quantify the foot’s contribution to recycling mechanical energy during landing tasks, and whether this energetic function could be increased using an exercise intervention.To address the thesis aims, four studies were conducted. Firstly, a cross-sectional study (n = 61) was conducted to quantify the mechanical work and power done by the foot during four common landing tasks. Additionally, differences between males and females, as well as among supinated, neutral and pronated foot postures were investigated (Chapter 3). Results revealed that the foot exhibited increased negative and positive work and power during single-leg and drop jump tasks, compared to double-leg and drop landing tasks, and that pronated feet had decreased peak negative power compared to supinated feet. Further, work done during the single-leg tasks was not twice that of the double-leg tasks, suggesting the foot may reach a maximal threshold, beyond which it can no longer do mechanical work.
As no previous literature had sought to modify the foot’s energetic function, via the foot spring mechanism, a systematic review and meta-analysis was conducted to identify and review exercise interventions that have previously been used in the literature to modify foot function (Chapter 4). Exercise selection and prescription targeting foot function is highly varied, with over 50 exercises prescribed and with different intervention duration, session frequency, and training volume used within the literature. The results of this study highlighted the need for specificity in exercise prescription, as exercises that mimicked the outcome measure tended to yield improvements.
Once intervention exercises and their prescription parameters had been identified and reviewed, a modified Delphi study sought to reach consensus of opinion on exercise selection and prescription specifically targeted at increasing the foot spring function of the foot (Chapter 5). Participants (experts on the topic) agreed that an intervention targeting the foot spring function during landing would need to include multi-joint, functional, dynamic exercises with a strength and plyometrics focus. Participants agreed that the protocol should be 12 weeks in duration, include three sessions per week, and should follow a progressive overload model, in agreement with ACSM guidelines. Additionally, participants agreed that exercises should be completed barefoot where possible, and equipment such as resistance bands and additional mass should be used.
Finally, a randomised controlled study (n = 30) was conducted to evaluate the effectiveness of the exercises and prescription parameters determined in Chapter 5 on foot spring function during four landing tasks (Chapter 6). Participants were randomised to either a control or intervention group, and the latter completed the intervention protocol developed based on Chapter’s 4 and 5. Results revealed that there were no significant changes in the foot energetic function following the intervention protocol. However, medial longitudinal arch angle during landing decreased following the intervention, suggesting an increased resistance to deformation. The findings from this thesis extend our understanding of the foot’s energetic role in landing and provoke further research questions in the pursuit of a deeper understanding of its function during human movement.
| Date of Award | 2025 |
|---|---|
| Original language | English |
| Supervisor | Wayne SPRATFORD (Supervisor), Phillip NEWMAN (Supervisor) & Nicholas Brown (Supervisor) |