Cycling Injuries Can Often Be Related To An Improper Bike Fit
Honey, I Need a New Ride!!

My wife has heard these words, and answered with common sense (Damn!) "Maybe your bike (like my old pants) doesn't fit you anymore." Decreased flexibility with age and prior injury can change the way our body interacts with our bike, producing discomfort.

Triathletes often get into triathlon as a means of continuing to train while recovering from an injury due to overtraining in one of the three disciplines (swim, bike, run). For example, cycling allows someone suffering from plantar fascitis to maintain their aerobic base without placing as much stress on the fascia.

Competing in triathlon requires high volume training in three disciplines, not just one as with running. While each discipline stresses the body in different ways, the overall volume can still predispose an athlete to overuse injuries. In the last issue I made some recommendations to help prevent shoulder injuries due to swimming. This month I will talk about improper bike fit and how it may contribute to overuse injuries.

In general, when considering cycling injuries related to improper bike fit they can be separated into upper and lower body segments, and the spine. Upper extremity injuries are usually related to weight bearing on the handlebars and vibration transmitted via the handlebars. Lower extremity and spinal injuries are caused by the effects of highly repetitive lower extremity movements. Small errors in bike fit and anatomical variations are magnified by long hours on the bike, causing repetitive microtrauma which can lead to injury.

Upper extremity injuries like carpal tunnel syndrome, as stated above, are usually caused by too much weight on the handlebars and road vibration. This force may add enough additional stress to that already placed on the hands and wrists by computer usage at work, resulting in symptoms. Having too much drop between the height of the seat and the height of the handlebars will contribute to this situation. One test I like to use is can the rider relax their arms and wiggle their elbows while riding. Locked arms make poor shock absorbers and cause more stress on the wrists and hands. If the arms are locked while riding it will also cause tension to increase all the way up the arms to the shoulders and contribute to neck and shoulder pain.

Too much drop between the seat and the handlebars can also place added stress on the spine. This is a common problem for serious cyclists who believe a large drop is necessary for increased aerodynamics. If this position causes flexion of the lower back and rounding of the spine (see figure I), it will cause increased recruitment of the lower back muscles with exertions and place added stretch on the spine. This position is more common in cyclists with tight hamstrings (occurs with age) that pull the pelvis backward and cause increased rounding of the lower back. A straight or neutral spine (see figure II) allows better belly breathing and gluteal muscle recruitment which ultimately leads to increased power output.

While improper bike fit can affect many things in the lower extremity, we will concentrate on the ones that are most common in runners. Having a saddle that is too low or too far forward will lead to problems in the patello-femoral joint very similar to runner's knee. This seat position will cause increased recruitment of the quadriceps muscles on the front of the thigh and subsequent increased pressure under the knee cap. Increased quadriceps recruitment will also predispose the rider to Patellar Tendinitis or pain just below the knee cap on the front of the knee. A saddle position that is too high or too far back will place added stress on the back of the knee and can lead to Iliotibial Band Friction Syndrome or hamstring tendinitis.

Improper foot to pedal contact can cause Achilles Tendinitis if the foot is situated too far back on the pedal, the ball of the foot should be positioned directly above the pedal's attachment to the crank arm. Pedal positioning can also cause problems with knee rotation and alignment throughout the pedal stroke. This can lead to the development of "float" with clipless pedals that allow the foot to rotate on the pedal (heel can go side to side). Improper pedal alignment can lead to patello- femoral pain, Hamstring Tendonitis and IT Band Syndrome.

While this article dwells on the negative effects of improper bike fit, cycling is a very useful tool in aerobic cross training for injury prevention, rehabilitation and sanity preservation. If you find that time in the saddle is aggravating a painful condition, try getting a professional bike fit (or, if you're a guy, use it as an excuse to get a new toy!), it may help prevent future episodes.

Dr. Ken Sheridan is a local road and trail runner who competes in a variety of local events. He practices at Active Care Chiropractic and Rehab in Golden. To ask him your injury questions, call 303-279-0320.