Abstract
[Truncated] Perhaps not surprisingly, foot biomechanics has received significant attention in human locomotor studies as it affects not only foot function but also whole body biomechanics and energetics. Two key aspects of the foot that play an important role in dictating the mechanics and energetics of running are: 1) foot posture (rearfoot strike [RFS] and forefoot strike [FFS] techniques), and 2) its longitudinal arch mechanics. Despite considerable research in these areas, a detailed knowledge of their effect on joint and lower limb mechanics and metabolic energetics, and the interaction between arch mechanics and foot strike technique does not exist.
Disparities in lower limb biomechanics have been identified between runners using RFS and FFS techniques, yet it remains unclear which, if any, technique offers a mechanical advantage with respect to improved performance or injury reduction. Additionally, whether the joint-level characteristics and any associated benefits can be adopted by changing to an imposed (non-preferred) technique is not clear. One factor that may differentiate foot strike techniques is longitudinal arch mechanics. Compression/recoil of the foot’s arch is hypothesised to lower the metabolic cost of running due to recycling of elastic energy in the arch’s tendons and ligaments. However, no study has specifically assessed this during locomotion. Greater arch compression has been reported in FFS compared with RFS runners, although whether this facilitates an advantage is unknown, nor is it clear, how the arch spring influences other lower limb mechanics such as joint work. The aim of this thesis was to explore these questions, and in doing so establish an integrated understanding of the effect of foot strike technique and the spring function of the arch on running mechanics and energetics.
Study One provides a comprehensive analysis of the lower limb joint kinetics differentiating habitual RFS and FFS runners, as well as the mechanical consequences of switching techniques. Inverse dynamic analysis revealed that neither habitual technique offers a clear mechanical advantage, although variation in negative work distribution may have implications for injury, with RFS and FFS runners at potentially greater risk of knee and ankle injuries, respectively. Total limb positive average power (sum of the ankle, knee and hip rate of mechanical work production) suggests switching to an imposed FFS may be detrimental to performance (increases average power requirement), while switching to an imposed RFS may provide a useful rehabilitation strategy for reducing ankle loading without incurring an overall mechanical penalty.
Disparities in lower limb biomechanics have been identified between runners using RFS and FFS techniques, yet it remains unclear which, if any, technique offers a mechanical advantage with respect to improved performance or injury reduction. Additionally, whether the joint-level characteristics and any associated benefits can be adopted by changing to an imposed (non-preferred) technique is not clear. One factor that may differentiate foot strike techniques is longitudinal arch mechanics. Compression/recoil of the foot’s arch is hypothesised to lower the metabolic cost of running due to recycling of elastic energy in the arch’s tendons and ligaments. However, no study has specifically assessed this during locomotion. Greater arch compression has been reported in FFS compared with RFS runners, although whether this facilitates an advantage is unknown, nor is it clear, how the arch spring influences other lower limb mechanics such as joint work. The aim of this thesis was to explore these questions, and in doing so establish an integrated understanding of the effect of foot strike technique and the spring function of the arch on running mechanics and energetics.
Study One provides a comprehensive analysis of the lower limb joint kinetics differentiating habitual RFS and FFS runners, as well as the mechanical consequences of switching techniques. Inverse dynamic analysis revealed that neither habitual technique offers a clear mechanical advantage, although variation in negative work distribution may have implications for injury, with RFS and FFS runners at potentially greater risk of knee and ankle injuries, respectively. Total limb positive average power (sum of the ankle, knee and hip rate of mechanical work production) suggests switching to an imposed FFS may be detrimental to performance (increases average power requirement), while switching to an imposed RFS may provide a useful rehabilitation strategy for reducing ankle loading without incurring an overall mechanical penalty.
| Original language | English |
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| Qualification | Doctor of Philosophy |
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| Publication status | Unpublished - Apr 2015 |