Compared with a flat orthosis, contoured orthoses increased the contact area of the plantar surface during stationary cycling, and influenced the perception of greater support in the midfoot while increasing relative pressure through the hallux, according to study results published in Journal of Science and Medicine in Sport.

“While there is some research regarding the distribution of plantar pressures using orthoses in walking and running, this issue has not been addressed in cycling,” the researchers wrote. “The primary aim of this study was to evaluate the effect of orthoses on plantar contract area, plantar pressure, perceived comfort and support of the foot plantar surface.”

Orthosis use during cycling

Using a contoured orthosis and a flat insert of similar hardness, 12 cyclists performed steady-state seated cycling at a cadence of 90 rpm and rated perceived comfort and support using a visual analogue scale. Researchers measured contact area (CA) and plantar mean pressure (PP) using the Pedar system, determined for seven discrete plantar regions and represented as the percentage of total CA and PP.

Overall, study results showed the contoured orthosis produced a significantly greater CA percentage at the medial midfoot and the lateral midfoot and a significantly greater PP percentage at the hallux. Repeated measures analysis of variance indicated a statistically significant interaction between plantar region and orthosis condition, according to comfort and support perception data. Researchers found a significant increase in the perceived/reported support visual analogue scale at both the arch and the heel during follow-up tests of simple effects of orthosis condition for each comfort and support aspect.

“Contoured orthoses spread contact area underneath the foot, while improving support without compromising comfort,” Bill Vicenzino, BPhty, GradDipSportsPhty, MSc, PhD, professor of sports physiotherapy at the University of Queensland, Australia, said. “If a cyclist had a need to move the pressure away from the ball of the foot, then a contoured orthosis will achieve this without any loss to comfort and improving the feeling of stability within the shoe.”

Limitations, future studies

While the results of the study provide initial evidence supporting the role of orthoses in cycling to initially influence plantar surface contact and pressure profile, the researchers acknowledged several limitations. First, although cadence was standardized among all participants, resistance was constant for each participant but varied among participants. Also, resultant pedal force was not recorded. The researchers believe it would be ideal in future studies to record pedal force to allow for control over potential force variations that may result between participants and conditions. Researchers also did not mold the contoured orthosis to the participants’ foot, nor did they measure foot posture in fitting the orthosis.

Similar to previous walking and running research, researchers noted no difference of perceived comfort between the contoured orthosis and flat insert, which could be due to the similar hardness of the orthosis and insert or to the lack of a sufficiently strenuous bout of exercise, since the testing period was relatively short and of a comfortable exertion level. The researchers believe future studies should evaluate the response in perceived comfort ratings to different hardness of EVA material of orthoses in cycling shoes during longer periods of cycling time with increased training intensity since current research indicates that foot pain and paraesthesia typically occur after a more extensive period of riding time. In future studies, the researchers also plan to investigate what happens when wedges or posts are added to the orthosis in terms of pressure, contact area and comfort. — by Casey Murphy

For more information:
Bousie JA. J Sci Med Sport. 2013;16:60-64.

Disclosure: Vicenzino has no relevant financial disclosures.

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