Investigating footwear biomechanics concepts in ‘health and well-being’ footwear
Health and well-being’ footwear positions itself in the footwear market between high street footwear and specialist therapeutic footwear. Manufacturers in this footwear category promote benefits when compared with standard footwear. However, the full exploration and validation of such proposed benefits requires scientific exploration through the application of footwear biomechanics concepts and techniques. The studies herein were undertaken to assess these biomechanical concepts in ‘health and well-being’ footwear, particularly in FitFlopTM footwear. The studies are experimental studies with repeated measures designs. A total of 128 individual participants volunteered, 28 of which were included in two publications. Variables were quantified using an in-shoe plantar pressure measurement system (with a bespoke insole), electromyography, 3D motion capture, force plates, accelerometers, a modified questionnaire and a custom-made mechanical drop-test device. The research identified that ‘health and well-being’ footwear can be manipulated to increase shock absorption, namely reducing the heel-strike transient magnitude (-19%) compared with a flip-flop. ‘Health and well-being’ footwear does induce instability at specific phases of the gait cycle, which is specific to the outsole shape of the footwear. For example the MBT shoe increased muscle activity relating to controlling sagittal plane motion. The biomechanics of gait are also altered compared to standard footwear styles, such as reducing the frontal plane motion of the foot in stance (-19%) and the magnitude (-86%) and duration (-98%) of gripping with the Hallux in swing compared with a flip-flop. The tested ‘health and well-being’ footwear was subjectively rated equally as comfortable as a control shoe with increased regional pressures in the midfoot (≈25%) and decreased peak pressures in the heel (-22%). Therefore ‘health and well-being’ footwear may influence the biomechanics of wearers however further exploration of meaningful differences and individual population differences is required. The studies emphasise the importance and relevance of testing walking, as well as running, footwear to the wider footwear biomechanics field and demonstrate how this may be integrated into research and development processes within a footwear company.