The kinetics, kinematics and energy requirements of distance running: Implications for footwear design
As the primary interface between the runner and the road, athletic footwear has a potentially important role to play in the reduction/management of chronic injuries and enhancement of performance. Over the past thirty years the running shoe has changed considerably. However, despite significant advances in footwear technology, the incidence of injury in distance runners has not altered meaningfully. It has been postulated that poor footwear selection is the mechanism behind this, whereby running shoes are incorrectly selected/inappropriate for the populations and situations in which they are worn. The investigations and results obtained from this thesis aim to attenuate this, and provide runners and footwear manuafacturers with new knowledge regarding the application of footwear to different populations and conditions in order to improve both injury occurence and performance. In addition to a significant amount of developmental analyses, four principal examinations were conducted as part of this thesis. Study 1 aimed to determine the kinetic and 3-D kinematic differences between treadmill and overground running, in order to determine whether the treadmill replicates overground running and whether different footwear is necessary during treadmill running. It was observed specifically that treadmill running was associated with significant increases in eversion and tibial internal rotation whilst overground runners exhibited greater peak tibial accelerations. It was concluded that treadmill runners are likely to require footwear with additional medial stability properties, aimed at reducing rearfoot eversion whilst overground runners should consider footwear with more advanced midsole cushioning properties designed to reduce the magnitude of impact transients. Study 2 examined the gender differences in the kinetics and 3-D kinematics of running in order to determine whether females require running shoes specifically tailored to their running mechanics. Females were associated with significant increases in eversion and tibial internal rotation; reaffirming the notion that they are more susceptible to overuse injuries than males. It is reccommended that females select running footwear with design characteristics aimed towards the reduction of rearfoot eversion in order to reduce the incidence of injury. Study 3 investigated the kinetics and 3-D kinematics of running: barefoot, in conventional running shoes and in barefoot inspired footwear in order to determine the efficacy of barefoot running in comparison to shod and also the ability of barefoot inspired footwear to closely mimic the 3-D kinematics of barefoot running. Barefoot running was associated with significant increases in impact parameters. It was also observed that barefoot inspired footwear does not closely mimic the 3-D kinematics of barefoot running. This leads to the final conclusion that barefoot running may not serve to reduce the incidence of injury. Study 4 aimed to examine the influence of footwear with different shock attenuating properties on the energy requirments of distance running and to investigate the biomechanical parameters which have the stongest association with running economy using regression analyses. Whilst footwear with different shock attenuating properties did not influence running economy, it was observed that a significant proportion of the variance in running economy could be explained by kinematic and EMG parameters. The thesis has provided information not previously available regarding the injury prevention and performance aspects of running footwear. It is clear that footwear cannot be universally prescribed and that the population and circumstances in which different shoes are used are key when selecting and designing appropriate running footwear.
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