Effects of Carbon Fiber Foot Plate on Able-bodied Gait: Pilot Study

ABSTRACT Introduction Foot orthoses have injury prevention and human performance benefits. The carbon fiber foot plate (CFFP) is a possible orthotic intervention for preventing foot injury and enhancing sports performance. However, the cost of these devices is generally acceptable for developed settings but might serve as a barrier for use in developing settings. In this study, we aimed to develop an affordable locally custom-made CFFP and evaluate its function along with subjective feedback. Materials and Methods Three types of foot plates were designed each with a unique layup and fabric orientation. Carbon fiber preimpregnated with activated resin was used for foot plate fabrication. Three participants were provided with each prototype of the foot plate. Outcome measurements include walking speed (20-m walk test [20MWT]), treadmill jogging energy expenditure, and user feedback. Results The 20MWT self-selected speed increased for two participants with the CFFP. The maximum average walking speed increased in two participants with CFFP prototype B (8%–11%). Moreover, the average increase of walking speed for prototypes A and C were 2%–2.6% and 4%–4.6%, respectively. The third participant showed a 5% reduction of speed with CFFP prototype B and 3%–5% with prototypes A and B. For all participants, no improvements of energy expenditure were observed with all prototypes compared to without foot plate. Conversely, an increase in energy expenditure was found with all prototypes at all speeds. The subjective feedback in each prototype showed that all participants were satisfied with the CFFP prototype A, but the first participant was identified with metatarsal head pain. Prototype B also evidenced a consensus among participants with increased comfort compared with prototype A, especially at the metatarsal heads. Conclusions The study describes the development and effects of using three types of CFFPs. Although prototypes increased the energy expenditure, prototype B improved walking speed. Prototypes A and B were useful and accepted by all participants. Further exploration is required in a larger heterogeneous sample of able-bodied persons and sport-specific athletes. Clinical Relevance The study demonstrates the effect of the CFFP on walking ability, which can better inform the clinician when considering the prescription for patients with foot problems and sports activities.