If you are a fan or watching bicycle races often, you have probably noticed that racers (besides being in a good shape for race) care about every detail when it comes to decreasing frontal air resistance. You can notice a new bike shapes – models, innovative helmets – equipment in general… But have you ever been worried why they have always been in a bent (curled) position?
Beside of reduced frontal air resistance reason OF COURSE, there is a one more simply – but big reason for that (in my opinion).
So, what should be the most important cyclist’s ability beside an endurance? It’s ability to produce as much force as possible with almost every single pedal kick – especially with sprinting phases (strength + endurance = success).
Therefore, they need to find the best possible position for doing that. Of course that strong m. quadriceps femoris is important (more info below), but the hip extension pattern almost nothing less. With bended torso position (bent over position), cyclists have better position for making a bigger forces in hip extensors (mostly glutes and hams) because these muscles are initially more lengthened and capable for producing more force/strength consequently. More muscle length = more muscle concentric force in cyclist case. There is no full hip extension of course – which would be the best. But you can’t find a better cycling body position for reducing frontal air resistance and good force producing both.
When you take a look at any racing bike, the seat is on the higher level (spot) than steering wheel. That’s the advantage because the torso is bended more and it means the chance for the higher muscle force potential – among the other things of course (my opinion).
Plus, it’s definitely make sense that torso position mentioned above is valuable because in FAST cycling manner as close the thigh is to torso (when one thigh is up) as better elastic (passive) muscle component is, therefore it helps initially to reach and produce the max possible concentric force faster and easier – which is the main goal in almost any racing phase (rate of force development is important – especially in sprinting phases). There is no injury risk because glutes are big muscles and can’t be torn easily with fast transferring from eccentric to concentric muscle contraction.
Ok, know let mi take a look at m. quadriceps femoris a bit. Bended torso position is easier position for producing force because imaginary vertical gravity line (the center of gravity of the body) is much closer to the knees than hips (lever arm is small) and producing force is easier for that muscle (extension of knees is present non-stop, but NOT torso). An easy function of that muscle is very present while torso is bended. Can you imagine doing squat but with constantly bended torso position while moving up (just extending knees)? It would be very easy for quads, this is the same mechanism like cycling – we push the pedals vertically down (take a look at the cover photo). This is why the bended torso position is, among other things, so perfect for cyclists. On the other side, hip extensors are more (the most) important in running because of horizontal moving component). I just wanted to explain why bended torso position is so comfortable for quads (comparing with the front squat for example, where your quads are the most important muscles because vertical center of gravity line is closer to hips – quads require much more tension). Understanding this and small trick mentioned above is almost everything you need when it comes to understanding the cycling mechanic. Last but not least, riding a bike with upright torso position means that your quads are also dominant (more burdened muscles) like with front squat just mentioned above (undesirable position for cyclists).
One more interesting thing, you have probably noticed a jerky forward-backward movements (when torso is upright) on yourself while trying to maintain some speed during uphill driving. That’s unconscious striving/tendency for increasing pushing force. If you think for a moment, you will figure out that your torso is leaning down in the same time while your leg is pushing pedal down. Yeah buddy, it’s the same mechanism – your body knows how to push the pedal stronger.
The only thing I don’t like here is rounded lower and upper back with many of them (it’s not spine healthy – friendly position). They should strive to get it more flat because if we know functional anatomy – we know that we make our important hip extensors even more lengthened on that way (because of anterior pelvic tilt of course), which means chance for producing the highest muscle force. Making more flatten (if not perfect neutral) lower spine (and consequently upper spine) is not easy at all because of structural or other lacks of hip mobility with many cyclists in that very specific body position – but that’s another HUGE topic. Also, the cervical spine is not neutral because they need to look forward of course – but that’s something you can’t prevent (maybe only if they look down at some GPS on the steering wheel (but there would be a many accidents 🙂 ). The latest is not a big deal because the human spine is mobile the most at cervical part (the smallest vertebrae).
So, if you are a recreational cyclist – give it a try next time. Try riding with more upright and bent torso and feel the difference in hip extensors force producing. When your torso is bent – it should be easier.
Last but not least, if you bend over torso EXCLUSIVELY by flexing low back spine, your pelvis stays in upright tilt position and there is no benefit on increasing muscle length – and potential muscle force consequently. Plus, you could feel a low back pain after a while…
Thanks for reading and all the best,