The long-term effects of shoe flexibility on a child’s foot development and gross motor skill performance

Abstract

A barefoot childhood results in improved foot morphology, as well as superior gross motor skills, compared to a shod childhood. Acute effects of conventional shoes are detrimental to children’s foot and ankle biomechanics. There is no consensus amongst foot health professionals on how the midfoot part of the shoe should be made for children. To date, no research into the long-term effects of shoe design on children’s foot health has been conducted. This thesis aimed to establish: a link, if any in the literature between toe flexor strength and balance in children, a flexible shoe comparative to a standard school shoe via laboratory 3D motion capture testing, a new reliable toe flexor strength testing protocol for children, the long-term effects of wearing flexible versus stiff school shoes on foot and gross motor skill development in children aged 9-12-years (randomised controlled trial – RCT), and finally, children’s shoe design preferences. These aims were achieved by establishing that toe flexor strength is correlated to balance in older adults (> 60 years) in the literature, and this same correlation exists in children (RCT results). Flexible shoes resulted in substantially more mid-foot power output with plantarflexion compared to standard school shoes in the laboratory. The novel dynamometer setup and protocol was highly reliable for test-retesting of children’s toe flexor strength. The longitudinal RCT provided the first evidence that flexible shoes over time substantially improve children’s semi-dynamic balance and moderately improve foot muscle size and strength. Children prefer flexible and cushioned shoes for comfort. The overarching aim of this thesis was to benefit children; and children’s shoe manufacturers, foot health professionals and parents should consider increased shoe flexibility as a beneficial and preferred aspect of shoe design for children’s comfort, improved foot strength and gross motor skill development.