Preventive Insights On Shoewear And Bike Fit For Cyclists
- Volume 25 - Issue 10 - October 2012
- 7327 reads
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Subtle offsets here can make huge impacts at 50 or 60 miles, and thousands of leg rotations into a bike ride. This is where shoe positioning on the pedal and cleat placement become very important.
How Footwear Rotation And Placement Fit Into The Equation
In general, the rider should place the bike shoe on the pedal in such a way that a vertical line dropped from the tibial tuberosity would intersect the foot at the level of the pedal spindle. This should be around the first metatarsophalangeal joint for most people and is a good starting point.
Sprinters may move their foot position back so the pedals are farther forward toward the toes. Touring, long-distance cyclists may slide the pedal slightly farther back. Achilles tendon pain may be the result of the cyclist placing the pedal too far forward on the shoe and moving the pedal to a slightly more posterior position may relieve this pain.
Some cleats allow for medial and lateral shift of the cleat on the bike shoe while others only allow fore/aft displacement. Typically, the cleat should be relatively centered under the bike shoe. One may address lateral knee pain that occurs during riding by moving the cleat medially and address medial knee pain by moving the cleat laterally. The knee should track directly over the foot. If the knee is tracking outside the midline, then one should move the cleat laterally. The reverse is true if the knee tracks inside the midline.
Rotation also plays a role in appropriate bike fit. This is referred to as float. The alignment of the cleat on the shoe plays a role in the amount of pressure that the knee experiences. A good fit will keep the knee tracking straight. This can be somewhat tricky to identify with a short ride on an indoor trainer during the setup process. What feels fine for a few minutes on the trainer may not feel well over a couple of hours and 40 or 50 miles. To accommodate for this, there is some amount of internal and external rotation (float) that is available within the pedal.
Some cleats such as Look (Look Cycle USA) come in fixed floats of 0, 4.5 and 9 degrees. Speedplay (Speedplay, Inc.) cleats allow up to 15 degrees of float with some models allowing the rider to customize the amount of float to his or her comfort level.
In addition to internal and external rotation, varus and valgus tilt can also cause problems on the bike. This can manifest itself in either knee pain or foot pain. If there is a significant genu valgum, the knee fixed onto a bike cleat may cause the knee to track inappropriately. Adding a varus wedge between the cleat and the shoe may realign the knee.
If the genu valgum and tracking problem are the result of a pronated foot, a posted orthotic may alleviate the problem. Similar shims are also available for riders to place between the cleat and the shoe to accommodate a limb length discrepancy.
Key Pointers On Correct Bike Shoe Fit
Anyone who has ridden extended distances or even century rides (100 miles) will tell you things that feel fine at the 30-minute mark may not feel so fine at the three-hour mark. This is most true in the feet. Subtle problems in shoe fit or mechanics will show up over time.
In addition to setting the rotation and position of the cleat on the shoe, one must consider the shoe fit itself.
Cycling shoes usually have a stiff plastic or carbon sole that has very little flex. Flex becomes wasted energy and prevents full transmission of power to the pedals. The shoe should fit snugly and is secured by a variety of methods, but more commonly two or three straps across the midfoot. The heel should be locked into the shoe and not rise out of the shoe with the pedal stroke. Many of the shoes run slightly narrow but some shoe lines such as those made by Bont and Sidi America (with their Mega versions) offer some wider fitting shoes.