Given that propelling a bicycle requires the transfer of power from the legs through the feet to the pedals, it is not uncommon for a cyclist to experience pain, numbness and/or tingling in the forefoot area. A common cause of forefoot symptoms in cyclists is an inter-digital injury called Morton's neuroma.
The nerve that innervates the foot originates from the inner aspect of the ankle and passes under the mid-foot. This nerve subdivides into a number of branches, which extend toward the toes between each of the MTP joints of the toe (knuckles of the foot). The nerve splits to innervate each side of each toe. Repeated compression of the forefoot (either from pressure from underneath the foot or from the sides of the foot) can cause irritation and inflammation of the nerve at the branch point between the MTP joints.
Nerve irritation and inflammation results in typical symptoms of pain, often localized between the affected MTP joint. There can also be an associated feeling of radiation of pain, numbness and tingling into the web-space and toes of the affected nerve. Once the symptoms develop during a bicycle ride, they can progressively worsen to the point that one must stop cycling. Squeezing the foot from the sides, wearing narrow foot wear or high-heeled shoes, running, jumping, and even prolonged walking often also bring on one's symptoms.
The diagnosis of a Morton's neuroma is usually made after clinical symptoms and physical examination findings have been considered. Sometimes, a diagnostic ultrasound or MRI can be used to aid in the diagnosis of a neuroma.
The treatment of a Morton's neuroma is used to reduce the pressure in the forefoot and calm the inflammation around the nerve. Ways to reduce the pressure in the forefoot include:
1. Adjusting the forward-backward position of the shoe relative to pedal axle.
2. Adjusting the side-to-side position of the cleat on the shoe.
3. Selecting large size pedals and/or shoe cleats.