Rodale

Monday, March 28, 2011

Health: Insoles can be crucial for comfort and performance

Walking and running come naturally to us but pedalling isn’t a normal state of affairs. “Our feet work by our arches collapsing and energy being stored like a leaf-spring,” says Sean Madsen, a biomechanist at the Boulder Center for Sports Medicine in Colorado and an expert in Specialized’s Body Geometry (BG).

“That energy is returned during the push-off, when we propel forward. None of that happens with cycling. Riding is a forefoot oriented activity, meaning the arch collapses and stores energy precisely at the point when we want to deliver it.”

This is what makes an insole a useful tool for providing support to your arches. “It provides stability to the foot and allows the best possible power transfer,” says Madsen. “BG insoles have three levels of arch support. This is to accommodate the variety of arches out in the general population.” Red insoles are the lowest, blue are mid-height and green are the highest.

“Blues are the most common arch height,” says Madsen. This doesn’t come as a surprise; most of the population have Rectus arches, somewhere between flat (Planus) and high ones (Cavus). “The insoles have a metatarsal button for spreading the metatarsal heads, which are the ends of the bones that connect to the toes. This helps to reduce the incidences of hot foot and numbness.”

As well as the insoles, you can also get a varus wedge to correct forefoot varus, which Madsen says affects up to 90 percent of the population. “Forefoot varus is a condition in which the big toe is elevated over the little toe when the foot is unweighted, meaning the front half of the foot rotates outwards,” explains Madsen.

“In cycling we need the front half of the foot to rotate inwards to make contact with the insole and apply power to the pedal. Therefore, forefoot varus can cause a loss of power, and injuries to the knee due to excessive internal rotation of the tibia.” A varus wedge can counterbalance this by angling the foot, bringing it into contact with the pedal and stopping rotational movement of the knee.

A study published in 2003 takes the claim for insoles even further, stating that they don’t just prevent injury and make you more efficient through positioning but can also cause a reduction of blood lactate levels and an increase in time to exhaustion. “The goals of insoles are capturing the arch, improved stability at the foot and increased power transfer,” says Madsen. “Find out your foot shape and arch height by drawing around your feet or, more accurately, going to see a specialist, and see the difference proper insoles can make to your ride.”



Via: BikeRadar.com Road Fitness

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