The effect of foot orthoses and in-shoe wedges during cycling: a systematic review

BACKGROUND: The use of foot orthoses and in-shoe wedges in cycling are largely based on theoretical benefits and anecdotal evidence. This review aimed to systematically collect all published research on this topic, critically evaluate the methods and summarise the findings. METHODS: Study inclusion criteria were: all empirical studies that evaluated the effects of foot orthoses or in-shoe wedges on cycling; outcome measures that investigated physiological parameters, kinematics and kinetics of the lower limb, and power; and, published in English. Studies were located by data-base searching (Medline, CINAHL, Embase and SPORTDiscus) and hand-searching in February 2014. Selected studies were assessed for methodological quality using a modified Quality Index. Data were synthesised descriptively. Meta-analysis was not performed as the included studies were not sufficiently homogeneous to provide a meaningful summary. RESULTS: Six studies were identified as meeting the eligibility criteria. All studies were laboratory-based and used a repeated measures design. The quality of the studies varied, with Quality Index scores ranging from 7 to 10 out of 14. Five studies investigated foot orthoses and one studied in-shoe wedges. Foot orthoses were found to increase contact area in the midfoot, peak pressures under the hallux and were perceived to provide better arch support, compared to a control. With respect to physiological parameters, contrasting findings have been reported regarding the effect foot orthoses have on oxygen consumption. Further, foot orthoses have been shown to not provide effects on lower limb kinematics and perceived comfort. Both foot orthoses and in-shoe wedges have been shown to provide no effect on power. CONCLUSION: In general, there is limited high-quality research on the effects foot orthoses and in-shoe wedges provide during cycling. At present, there is some evidence that during cycling foot orthoses: increase contact area under the foot and increase plantar pressures under the hallux, but provide no gains in power. Based on available evidence, no definitive conclusions can be made about the effects foot orthoses have on lower limb kinematics and oxygen consumption, and the effect in-shoe wedges have on power during cycling. Future well-designed studies on this topic are warranted.