Der Einfluss einer Schuheinlage aus Karbonauf die plantare Druckverteilung im Radschuh

Abstract

Background: Several equipment inter- ventions like optimizing seat position or optimizing shoe/insole/pedal interface are suggested to reduce overuse injury in cycling. Data analyzing clinical or biome- chanical effects of those interventions is sparse. Foot orthoses out of carbon fiber are one possibility to alter the interface between foot and pedal. The aim of this study was therefore to analyze plantar pressure distribution in carbon fiber foot orthoses in comparison to standard inso- les of commercially available cycling shoes. Materials and Methods: 11 pain- free triathletes (Age: 29±9, 1.77±0.04 m, 68±5 kg) were tested on a cycle ergometer at 60 and 90 rotations per minute (rpm) at workloads of 200 and 300 Watts. Sub- jects wore in randomized order a cycling shoe with its standard insole (control condition CO) or the shoe with carbon fi- ber foot orthoses (Condition CA). Mean peak pressure out of 30 movement cycles were extracted for the total foot and spe- cific foot regions (rear, mid, fore foot (me- dial, central, lateral) and toe region). Three-factor ANOVAs (factor foot ortho- ses, rpm, workload) for repeated measu- res (α = 0.05) were used to analyze the main question of a foot orthoses effect on peak in-shoe plantar pressure. Results: Peak pressures in the total foot were in a range of 70–75 kPa for 200 Watts (W) (300 W: 85–110 kPa). The carbon fiber foot orthoses reduced peak pressures by -4,1% compared to the standard insole (p = 0,10). In the foot regions rear (–16,6 %, p < 0.001), mid (–20,0 %, p < 0.001) and fore foot (-5.9 %, p < 0.03) CA reduced peak pressure compared to CO. In the toe regi- on, peak pressure was higher in CA (+16,2 %) compared to CO (p < 0,001). The lateral fore foot showed higher peak pres- sures in CA (+34 %) and CO (+59 %) compa- red to medial and central fore foot. Con- clusion: Carbon fiber can serve as a sui- table material for foot orthoses manufac- turing in cycling. Plantar pressures do not increase due to the stiffness of the carbon. Individual customization may have the potential to reduce peak pressure in cer- tain foot areas. Keywords: Carbon, Cyc- ling, Foot orthoses, In-shoe measure- ment, Plantar Pressure Distribution