Neck and Back Pain in Bicycling
Improper bicycle fit can lead to dysfunction, impaired performance, and pain.
hamstrings predispose to backward pelvic tilt. The Thomas test measures the degree of flexibility of the hip flexors, while the popliteal angle can objectively assess hamstring flexibility. Pushing large gears or extended hill climbing may fatigue the gluteus and the hamstrings, causing the pelvis to tilt backwards, aggravating the back musculature, causing pain. Also, the strength of the abdominal muscles is critical to maintaining stable pelvic positioning. Core muscle group strengthening and lower extremity stretching will help with proper pelvic positioning and lead to pedaling efficiency.
Researchers have reported that low back pain among men and women cyclists occurs at rates of up to 50% [Salai] and may be related to the cyclist's position on the bicycle. To help reduce the incidence of back pain some have suggested that a forward pelvic tilt is favorable as it decreases lumbar flexion and tensile stress to the longitudinal ligaments of the lumbar spine. [de Vey] Although there is evidence to show that anterior pelvic tilt would reduce the incidence of low back pain, it may increase pressure on the anterior perineum, and may also contribute to increased hyperextension of the neck and neck pain. [Bressel]
Abnormal pelvic tilt is not the only cause of lower back pain in cyclists. The lumbosacral junction, a point of support from which the power of the legs is generated and transmitted to the pedals, may also be a source of pain an injury when there is an improper fit between rider and bicycle. The cyclist's position on the bicycle compresses the anterior portion of the intervertebral disk and opens up the posterior side. This tenses the posterior ligamentous complex, leading to low back pain. During load-bearing activity, increased abdominal pressure can protect against this by increasing spinal stability and reducing discal load. [Nachemson] However, because of respiratory needs, the cyclist cannot employ this defense mechanism.
The virtual top-tube length is the most important fit factor for neck and back pain. Proper reach gives you easier breathing, better neck and lower back comfort, weight distribution, and bicycle handling. "Ideal position" varies here more than anywhere else for cyclists, depending on riding style, flexibility, body proportions, and frame geometry, among others. Unfortunately, there is no set formula for sizing the top tube and stem. The top tube length contributes to the distance from the seat to the handlebars, and therefore should vary with the rider's size. Both arm length and torso length figure into the proper distance from seat to handlebars. After the frame is constructed, the distance from seat to handlebars can be adjusted by replacing the stem. However, use of a stem shorter than 40mm or longer than 140mm alters the stability of the bicycle, so it is of some importance that the top tube length be as close to correct as possible.
One indicator of proper reach comes from glancing down at the front hub while riding in the drop handlebars; your view of the front hub should be obstructed by the handlebar. In another fit technique your elbows, bent at 65-70 degrees with your