Knowledge of the three dimensional shape of the human foot is important in the design of shoes to facilitate correct fit. Currently only the static shape of the foot is considered despite the fact that the foot undergoes changes in its shape, particularly in athletic pursuits, due to associated movements and loadings. Attempts, presented in research, have been made to measure dynamic foot shape. However, to date, measurements have been limited in detail as well as restricted to walking gait, as a result of the method. The work of this thesis aimed to develop a methodology that would be capable of measuring the three dimensional shape of the human foot during the stance phase of gait, in locomotion speeds associated with running.

The research contained within this thesis formed part of an Engineering and Physical Sciences Research Council (EPSRC) funded project based at Loughborough University, which aimed to investigate the use of additive manufacturing (AM), and in particular sintering technologies, for the production of running footwear sole units. Laser sintering (LS) is an AM process which produces parts directly from a computer aided design (CAD) file by selectively fusing successive layers of powdered material using a CO2 laser. LS imparts significant advantages over traditional manufacturing techniques including extensive design freedom, the ability to manipulate the local properties of a single material part as well as economical manufacture of bespoke items due to the elimination of tooling. Modifying the mechanical properties and/or geometry of sole units has been shown to provide benefits in the areas of performance, injury risk reduction and comfort, especially when considering elite athletes on a subject specific basis. Given the attributes of LS outlined above, the technology offers significant potential to produce sole units offering high added-value compared to conventional counterparts which are limited by the constraints of traditional processing techniques such as injection moulding. However, the mechanical capacity of LS polymers in context of such application was unknown. Accordingly, this research investigated the suitability of a laser sintered elastomer (LSE) material, in view of key selected mechanical properties, for the manufacture of running shoe midsoles. The midsole is the primary functional component in the sole unit of a running shoe used for distance running on hard surfaces. Following a preliminary assessment of the selected LSE (TPE 210-S), a new dynamic test method was designed to assess the compressive, fatigue and time dependent recovery properties of midsole material specimens under loading conditions representative of in-service use. The method was successfully implemented on an electro-mechanical test apparatus (previously unreported upon in literature) and used firstly, to benchmark the aforementioned properties of a range of ethylene vinyl acetate (EVA) and polyurethane (PU) midsole foams representative of the range currently used in production, and secondly, to establish the same property set for TPE 210-S specimens produced across a range of laser powers (LP's). Initial cycle operating ranges in terms of key compressive properties were established for EVA and PU materials. All conventional variants showed considerable deterioration from these initial values over the 125,000 cycle test regime, but subsequently demonstrated partial recovery when left unloaded post-test. PU grades generally exhibited better fatigue performance and findings were consistent with those of previous studies. Whilst variation in LP facilitated linear variation in displacement and stiffness properties for TPE 210-S, all specimens yielded a stiffer and more elastic response than that of conventional foams at the outset; initial compressive operating ranges, whilst within close proximity, did not overlap. However, fatigue performance was found to be superior with only relatively small property changes occurring over the test regime regardless of LP. Furthermore, no signs of catastrophic specimen failure (e.g. cracking) were visually apparent. In this respect the material showed good suitability for midsole applications, but further work is required to address increasing the available compressive property range which fell outside the scope of this work.

The main problems concerning birth of running injuries is their unclear ethiopathogenesis and high frequency. Injuries are often lined with forces affected on tread-down which have to be defused by running shoes. There are also opinions that currently used footwear can cause injuries on the contrary. This work explores impact of particular types of running shoes for influencing of stability. Methods: There are compared two groups of runners: minimalists and classic runners. Their stability is examined with help of posturography in three versions: barefoot, classic and minimalistic footwear. Thereafter there is analyzed relation among stability, used footwear, training usage and frequency of injuries. Results: Minimalists and classic runners have the same stability while they are barefoot. Usage of footwear does not cause significant deterioration of stability in any of groups. Nevertheless most of runners subjectively evaluate the variant of testing barefoot as the simplest. There is more frequent occurence of flat foot among classic runners in comparison with minimalists. Flat foot increases risk of formation injuries, on the contrary, regular compensation motion activity decreases this risk.

Accelerometers and gyroscopes are used to detect foot strike (FS), i.e., the moment when the foot first touches the ground. However, it is unclear whether different conditions (footwear hardness or foot strike pattern) influence the accuracy and precision of different FS detection methods when using such micro-electromechanical sensors (MEMS). This study compared the accuracy of four published MEMS-based FS detection methods with each other and the gold standard (force plate) to establish the most accurate method with regard to different foot strike patterns and footwear conditions. Twenty-three recreational runners (12 rearfoot and 11 forefoot strikers) ran on a 15-m indoor track at their individual running speed in three footwear conditions (low to high hardness). MEMS and a force plate were sampled at a rate of 3750 Hz. Individual accuracy and precision of FS detection methods were found which were dependent on running styles and footwear conditions. Most of the methods were characterized by a delay which generally increased from rearfoot to forefoot strike pattern and from high to low midsole hardness. It can be concluded that only one of the four methods can accurately determine FS in a variety of conditions.

This work explores the fusion of bio-technology and sports footwear design and envisions a future where people enhance their physiology to meet their specific needs. Through tissue engineering, the wearer’s own biomaterials are utilized to optimize performance and customization. It seeks to redefine the enhancement of long-distance running by creating a physical bond between footwear and feet. Based on both design fiction and industrial design, the project speculates on the impact of biotechnological advances. It reflects a curiosity-driven exploration of the human body and its potential transformation. The thesis concludes with reflections on such innovations in footwear design and the role of design fiction in imagining future possibilities. It forms a contribution to Design Ecologies and illustrates the intersection of design, ecology, biology, and fiction, in addressing contemporary challenges.