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BIOMECHANICS

There are a few things to remember about the relationship between the body and the bicycle:
 

  1. The cycling position, even one “bent over the handlebars,” should not be uncomfortable. It is based on the same classic “athletic stance” used in almost all sports. When it is seen in skiing or tennis or baseball, it is achieved by finding a point of balance and weight distribution over your feet to leave your pelvis rolled forward, your spine neutral, and your legs and hips spring-loaded to react. This then allows your shoulders, arms, and neck to relax and you able to hold onto whatever is called for out front, whether poles or racquet or bat, or handlebars. On the bike, the pelvis is rolled back to open your hip angle for pedaling clearance, supported by the lower abdominals, and the neutral spine arcs forward and down into a relaxed, aerodynamic position.

  2. The cyclist will find the most sustainable performance when balanced comfortably in this variation of “athletic stance.” As you move away from it you move into problem zones, because the shift in weight distribution puts more strain on weaker areas, or muscles you want to be contributing towards forward motion. Sitting on the bike with the pelvis rolled too far forward, the spine straightens out, forcing your lower back to take over, to the point that the arms have to be locked out front on the bars to hold the upper body up....a position which almost always explains lower back pain, sore neck and numb hands. Even while reading this blog, you have the choice of sitting upright in your chair with a conscious, aligned, posture which will ensure long-term comfort, or slouching in the same chair, which will lead to lower-back, neck, and shoulder strain. The bike, like your chair, should be set up as a neutral support system, and the fitting process should adjust your bike to this point while coaching you into a comfortable, balanced, posture…even in a low position. You don’t want to fight the inclination to shift from one position to the other, as the body knows what it wants to optimize its efficiency. You’re just looking for an awareness of how and why to work within that range of motion.

  3. Virtually any discomfort or pain while on a bike can be addressed through proper bike-fitting. Even though the fitting process begins with the general, effective “athletic stance,” its focus is on matching your bike to the specifics of your body’s particular strengths and limitations, allowing the bike-fit coach to chase the biomechanical problems specific to you.

 
Think of the pedaling biomechanics as being your body’s way of applying its inate hard-wired motor program for running-gait to the closed-gait limits of the equipment.  Of course, we change our stride lengths naturally to adjust to the grade going up- or down-hill, or as we change pace, but we will always go back to the default, normal stride pattern. Imagine being asked to add or subtract three inches from your stride length while you are walking or running – all the time. It would be possible for a while, like making the adjustment on a hill, but it would leave you exhausted if continuous! The point of the bike fit is to match the equipment to how your legs want to move through the equivalent of your stride, plus leave enough wiggle-room that you can self-adjust depending on conditions.

For some cyclists, fine-tuning their position is all about improving performance. But for many, especially as they age, proper bike fit is essential in avoiding or eliminating injury. Even though cycling is often a recommended form of exercise because it is low impact, injury can result from the high number of repetitions. If something is a little off, your body can adjust up to a point, but has to deal with it for many thousands of repetitions per ride.

In most sports it is up to the athlete to self-adjust within his or her body’s very wide range of motion, to stay within the zone that keeps the skeletal system aligned and muscles optimally extended. For example, a hiker on a rocky trail must consciously adjust her gait and footfall to avoid losing her balance or spraining her ankle. In contrast, the cyclist’s position is virtually fixed in place to the contact points of pedals, seat, and handlebars. The placement of those points determines joint alignment and muscle extension/contraction. If the contact points determine a poor position, the body looks for ways to compensate elsewhere, leading to discomfort, greater fatigue, or injury.

From a therapeutic, or corrective standpoint, having the contact points determine your alignment means that problems can be remedied by making specific adjustments to those points of contact.  It is worth getting the points right because, like after any repetitive motion injury, you still have to get back to the motion of the activity and not have the injury recur.


Important reminder:  

Obviously, not every problem is solved through proper bike fit. Sometimes referral to a medical professional is necessary. Pain is a warning signal for something being wrong and should be respected. As long as it is clear that bike-fitting is the appropriate route, well-considered adjustments to the bike and rider posture often avoid a trip to the PT, doctor, or surgeon later.

PEDAL

GUIDE

HANDLE BAR

GUIDE

SADDLE

GUIDE

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