• Chris

The Biomechanical Problems of Cycling



So you've played sport all your life, you like running, but lately the pain has gotten too much. It's time to ditch the running shoes and jump on the bike, it is zero impact after all. A wise choice?


Well, yes and no. You're right, it is less impact and less damaging on your joints than running in your current form, and you will no doubt feel some temporary relief because you've stopped aggravating the pressure points on your body you've been pounding over and over again for years. However, this isn't the full story; the negative effects of cycling will catch up with you eventually. The good news is that there are some things you can do to mitigate such issues.


This article is a good summary of some of the more mainstream ways of looking at the issue, and it has some excellent advice about some things you may be doing on the bike that aren't helping you. The article specifically covers knee injury while cycling, but the advice to avoid such injury is sound and is excellent information to find the best set-up on the bike, the best technique, the best equipment, and simple strategies to avoid pain generally while riding.


If you are a serious cyclist, someone who likes to cycle week-in week-out, or you are a bicycle tourer like me who may spend multiple days, weeks, months, or even years in the saddle, an often overlooked aspect of injury prevention - and also rehab after injury - is the effect cycling has on your posture.


This is particularly relevant to people cycling on racing bikes where the seating position encourages a more severe rounded-back position, but also applies to those cycling in a more upright position.


In a previous blog post, I delved into the importance of connecting exercise with evolution. We obviously haven't evolved to sit on a bike and exercise, and remember that animals have evolved to fill a niche; if we have evolved to principally run and walk, adaptations our body goes through to cycle aren't going to help this, and eventually (it may take months or years depending on the individual) we'll pay for it. Our bodies are biomechanically adapted for walking and running, these movements keep our joints healthy and we walk a lot in our lives; if you mess-up the way you walk and run, there will be consequences.


So how does cycling mess up the way you walk and run (your gait cycle)? In a nutshell, walking and running are simple, our legs move forward and back and our upper torso rotates slightly, producing a slinging effect that works reciprocally with the lower body. How does cycling differ from this? Firstly, the upper thoracic is fixed on the handlebars on the bike, there is no rotation. Without the rotation, the reciprocal relationship between the upper and lower body is switched-off, and with the stress of exercise, myofascial fibres will become dense and dehydrated in the upper thoracic over time, causing a decreased ability to rotate. When you then go to walk and run, your body will compensate for your restrictions; if you can't rotate in your upper thoracic, you will rotate somewhere else. Where this will be can depend on a variety of other factors unique to your body type and the postural history of your life when it comes to the stresses and strains you have put on your body. You may, perhaps almost imperceptibly begin to rotate or shift in your hips, lower back (lumbar region), knees, ankles, maybe even all of the above. This is not good news for your body.


The lack of thoracic rotation when cycling is just one example I have probed in a bit of depth here, but there are a number of other issues also that I will list rather than get too in-depth at this stage: - Bent-over position causes tight hip-flexors, making it hard to complete your gait cycle without incorporating hyper-extension of the lower back, which in turn leads to poor glute function.


- Because of the position on the bike and the nature of cycling as opposed to running or walking, the motion of pedalling half-mimics the gait cycle but without fully completing it. The back is not straight and one leg does not straighten or go back behind the body to naturally stretch the hamstrings and glutes, this can cause stiffness in the back line of muscle and fascia which includes the calves, hamstrings, glutes, lower and upper back (adaptive muscle shortening).


- More of a problem on a stationary bike because of the lack of necessity to balance, but also could be present on a normal bike, is the tendency to push with more force on one side of the pedals. This can be difficult to detect and may cause imbalances over time.



Much of the above is already understood, but what is not currently common knowledge is that without correcting the dysfunctions caused by cycling - or many other forms of sport and exercise - the result will be a change in the way you move in every day life, most notably your gait cycle (the way you walk and run), but also in the way you pick things up or throw something, and eventually will lead to changes in your standing and sitting posture as well.


For an example, let's use a common injury I have been noticing in gyms my whole life, rotator cuff tears. Before I give this example, note that there is not any current evidence that bad posture is even a contributing factor to rotator cuff injury, but my experience had led me to believe that without a shadow of a doubt it does. The people at https://www.mayoclinic.org have the following to say about this subject:


Rotator cuff disease may be the result of either a substantial injury to the shoulder or to progressive degeneration or wear and tear of the tendon tissue. Repetitive overhead activity or heavy lifting over a prolonged period of time may irritate or damage the tendon.

What this doesn't tell you is why there is progressive degeneration and wear and tear other than some specific activities. But lets imagine a scenario; you have spent years cycling; because of the tendency for the human body to adapt to stress, that position on the bike has caused significant fascial thickening in the areas of your upper back and shoulders, restricting you ability to rotate optimally. Tight hip flexors mean that you can also not complete your gait cycle without hyperextending your lower back, causing a anterior pelvic shift and tilt. This shift forwards in your hips has to be counter-balanced by a forward head posture and a rounding of the shoulders (something you may have been prone to before even jumping on a bike). Your shoulder is now pronated forwards causing impingements in certain movements, creating wear and tear on the joint. Then one day your mate from the cricket club wants you to fill-in and play a match for them; you are in the field, the ball comes to you, the batsmen takes a quick run and you rush in and throw the ball forcefully towards the stumps and BANG, there's your torn rotator cuff.


I used a game of cricket for an example, but the final straw for your shoulder could be a variety of things. Maybe it was when you reached behind you to the back seat of your car to grab something, you picked-up a grandchild, reached-up to get something heavy from a high shelf, or perhaps in an attempt to save someone or something from falling you reached-out suddenly and bore too much weight. Instead of your bigger muscle groups handling the strain in each case, because of poor shoulder positioning caused by bad posture, your tiny rotator cuffs, already strained, took the brunt of the work and couldn't handle it.


A torn rotator cuff is merely one example, and an example of a possible acute injury. However chronic injuries, like lower back pain, will be even more common as a result of long hours in the saddle combined with a lifestyle of too many hours sitting and working.



Adaptive Muscle Shortening


Definition: With adaptive shortening, one muscle or muscle group becomes tight and hyperactive, while the opposing muscle or muscle group becomes loose and underactive.


Adaptive muscle shortening has become a bit of a popular term lately and is often associated with cycling, and indeed with running. Most websites will advise a stretching regime for the overly tight muscles, but this won't work, in fact it will likely make the situation worse in ways that might seem unrelated. The reason adaptive muscle shortening occurs is that the activity you are doing has switched-off the relationship between muscle groups. Unfortunately, because not many people are taking a whole-body approach to training, they will narrowly focus on two groups at a time; for example the hamstrings and the quads. Taking this approach does not factor in that the problem is much deeper. The reality is that if you are exercising with bad posture, or doing an activity which puts your body in an unnatural postural position, you are switching-off relationships between muscles ALL OVER YOUR BODY. You can create this effect with almost any activity you do, including running with poor gait, but cycling will certainly do it too. The solution is to improve the way you move and the starting point of this is improving your posture.



The message is this; if you exercise and live a lifestyle out of sync with how you evolved, you have to take some measures to prevent the inevitable deterioration, especially as you will likely live a much, much longer life than your ancestors. Tight hip flexors or a kyphosis in your upper back are less of an issue if you are dead at 30; if you live until you're 80 though, these warning signs unchecked and ignored are going to make you seriously miserable later in life. Ask yourself, is this my fate? And if I knew how to make this less likely, would I take measures to prevent it?


Most of these issues can be prevented, but it takes some dedication. It will require hours of myofascial release (self-massage or massage from a therapist) followed by intelligent corrective postural exercise, and this is an almost daily routine you will need to build into your life. Easy to learn, hard to apply and maintain in our crazy daily lives, but this site, along with my YouTube channel - and I strongly recommend Functional Patterns, who are the best in this field as far as I can tell - is here to teach you how to do it.


Sucks right? I mean, you are busy enough already, but how else do you expect to remedy a problem you have spent most of the years of your life creating? Did you expect a trip to the physio once a month and a few lame exercises a couple of times a week would do the job? Deep down you know better than that; I'm not selling you an easy way to fix your problems, no such thing exists. I am offering you the red pill, it will take you down a rabbit hole that only you can dig your way out of, and this will require some suffering and diligence. But since when was anything worth doing any other way?





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