The Most Important Joint for Road Cyclists (Bike Fitter Explains...)

Summary

In this episode of the RCA Podcast, expert bike fitter and sports physiotherapist Neill Stanbury discusses the critical role of the sacroiliac joint in cycling performance. He explains how dysfunction in this joint can lead to significant issues, including pain and reduced endurance, particularly due to asymmetrical movement patterns. The conversation also covers corrective measures and exercises to address these issues, emphasizing the importance of maintaining symmetry for optimal cycling performance.

Takeaways

The sacroiliac joint is crucial for cycling performance.
Dysfunction in the sacroiliac joint can cause significant issues.
Asymmetrical movement patterns can lead to pelvic torsion.
Pain is a major detriment to cycling performance.
Symmetrical cyclists tend to have better endurance.
Corrective exercises can help address asymmetry.
Sacroiliac joint torsions are common among cyclists.
Understanding your own asymmetry is vital for performance.
The joint has a significant number of proprioceptive nerve endings.
Addressing these issues can improve overall cycling function.

Chapters

00:00 Understanding the Sacroiliac Joint
07:02 Addressing Asymmetry in Cycling

Online Bike Fitting Course: https://roadcyclingacademy.com/bike-fit-fundamentals/ 

Transcript:

Cam Nicholls (00:00.11)
Welcome back to the RCA Podcast where today I am joined by expert bike fitter and sports physiotherapist, Neill Stanbury. Just be aware that this conversation is also designed for YouTube. So please excuse any visual references. Let's get into it. Neil, what have you got in front of you there?

This is a spine, hopefully it's not a real one, right? I never thought about that before. Hopefully this is a plastic replication of a real one, otherwise I'm probably gonna get in trouble for this. no, purchased directly from eBay, this is almost certainly plastic and not real, but this is a spine and a pelvis. And I wanted to show you guys, I get asked this question a lot, like to do with, when we're sort of explaining asymmetrical movement patterns to people on the bike, and when people come in with really big, what we call pelvic,

This is a question that I get asked a lot. It's kind of interesting. So let me run you guys through a bit of anatomy I'm gonna try and describe to you why I think this joint here called the sacroiliac joint is probably the single most important joint for cycling in in terms of Its correct function if it's dysfunctional if this joint doesn't work well, you're in big trouble on the bike Now what is the sacroiliac joint? It is the joint between the sacrum and the ilium's there's two sides of the pelvis here the left and the right side

This joint is two in the body, one on the left, one on the right. It's a sliding or a gliding diarthrosis joint, which is a fancy way of saying it's not a joint like your shoulder or your knee or your finger. Basically, this is two faces of bone which sit in on each other like this. There's a massive collection of really strong ligaments across the front and the back. And this joint moves about five degrees or so, not much. It rolls forwards and backwards and on the inside faces of the joint, it's got kind of a knurled surface that kind of...

Interlocks the two the two sides got little valleys and depressions in it which interlock now the joint doesn't move much But why is it the most critical joint for cycling? Performance the reason being that this joint when it's dysfunctional it causes more havoc than any other joints in the body I've found for riding a bike Which is really interesting because it doesn't actually move that much the joint seems to be incredibly important

Neill Stanbury (02:09.634)
for proprioceptive function of the leg and for general kinematics of the rest of the leg. If it is dysfunctional, what happens is as you drive down on the pedal, for example here, if your left leg is driving down on the pedal, the sacroiliac joint, as the hip extends, is supposed to roll forward a little bit. And then as the hip comes up over the top of the stroke, it's supposed to roll back a little bit. So it's supposed to basically just move a little bit like this, forwards and backwards, forwards and backwards. Because of the planes that the two SIJs operate in, like this,

They go like this, rhythmically, as you're walking, running, cycling, all of that kind of stuff. Now if you operate asymmetrically on a bike for a long period of time, let's say you've got a rider who's dropping their right hip forward because their right leg is shorter than their left, for example. Typically what will happen is the right ilium will get a lot more forward rotation with very little rearwards rotation, and the left one will get the converse going on, is that it will have to rotate backwards a lot more than forwards with every pedal stroke.

Now we do this about 4,000 times an hour and some of us are doing 15 or 20 hours a week. You multiply it out, it's a lot of repetition, right? Over time, the pattern is that you can develop what we call a pelvic torsion, where the two, that's what I call it anyway, the two sides of the pelvis mutate relative to each other. So their neutral position, they're supposed to just be symmetrical, their neutral position starts to gravitate towards an asymmetrically dysfunctional, know, torsional position.

So when you're sitting in a seat for example watching TV, it'll be like

They're just sitting like that, right? The reason that they get like this is complicated, but basically the the muscle, the drag of the muscle system of all the large muscles which attach onto the pelvis, the quadriceps and the hamstrings and the glutes, the drag of them becomes sufficiently asymmetrical that the two iliac, the sacroiliac joints become torsion at rest to each other. Now when they get torsion at rest, this is starts to, this is usually where you start getting pain.

Neill Stanbury (04:02.466)
bike and this is why this joint is so so seriously compromised when it's really compromised it's so serious for your function on a bike because when they get torsion it's usually because you've got really large-scale asymmetry happening on the bike and it's affecting your muscular system which is then dragging the two sides of the pelvis out of plane with each other and as they go out of plane with each other what's embedded in the side of the pelvis your hip joint so as the two sacroiliac joints move like this

it changes the neutral position of the two hip joints. And the two hip joints, the ball and socket joints, they start to go out of plane with each other. And you'll see the person basically flaring one knee away from the bike and the other one's coming right in towards the top tube, which is a classic pattern of complicated asymmetry that we'll see all the time, typically because the person's been dropping their right hip forward a lot of the time. And this torsional effect is catastrophic for a lot of things. It causes most notably pain.

And as I've said many times before, pain is the single biggest detriment you'll ever have to your performance on the bike. If something is hurting, your nervous system is going to curtail your power output really significantly. Not only that, when the pelvis is torsioned, the complicated compensatory patterning which goes on really takes a lot of energy, a lot of neurological energy, which really hammers down your endurance. It really causes trouble. You basically end up utilizing a lot of calories compensating that you could have used for pressing down on

pedals. This is one of the reasons why highly symmetrical people tend to have better endurance than highly asymmetrical people. And the asymmetrical people will usually find that one hamstring blows out before the other one on a long hard ride or one quad or something like that. So this torsional effect is really really serious for your function on the bike. Typically the side effects if they go forward on the right back on the left is left-sided gluteal pain, left-sided ITB pain, left-sided lower back pain,

but the pain is what curtails your performance mostly on the bike. So the Sacroiliac joint, because it's such a critical joint, when it goes bad, I've never seen any other joint in the body cause as much trouble for a cyclist as this one does, which is really fascinating because it is such a, it's a joint which barely moves at all. Depending upon which textbook you read, you might see like five to eight degrees of rotation in the SIJs. So really, really unusual joint.

Neill Stanbury (06:28.992)
It seems to have a lot of proprioceptive nerve endings in it. I've heard, I've heard bandied about numbers that contain within the sacroiliac joints, you might have 30 or 40 % of all the proprioceptive nerve endings in your body contained within these joints. So they're really, really critical for posture, balance, general function, all that sort of stuff. And when one of them gets torsion backwards or jammed up, you're in big trouble.

Okay, so how often do you see that in your clinic with people coming through and then what can you do about it?

Ah, what can you do about it is a complicated question. Take up hockey. Take up hockey. What you want to do first is you want to correct for the asymmetry on the bike and then you want to give them corrective exercises off the bike which they vary between people but we give them isolated strength training to do for the weak muscle groups to try and correct the torsional drag that's happening on the pelvis because of that. But how often do I see it? We see it probably, I probably see three decently torsioned SIJs every week.

When they, and that would be out of potentially like 10 to 12 people that I fit in a week, something like that. So it's fairly common. Now there's different grades of how badly they get twisted. A lot of people just have a mild adaptive torsion and they haven't yet gotten to that end stage where when one of the iliums gets turned back a lot, it can actually get like jammed. They can actually get stuck. And that's when you get really big trouble is when they get stuck and they don't move. That's when a lot of the pain really starts.

But in terms of small adaptive torsions, yeah, probably about a third of people. It's really, really common. But when it gets really bad, and these are the ones which we're sort of referencing more here in this video, when it gets really bad and one side gets jammed and it won't move properly, that's when you're in big trouble. So sacroiliac joint torsions are really catastrophic for your function on a bike and in general in everyday life. But cycling, there is no other joint that affects your function as much as the sacroiliac joint in my experience.

Cam Nicholls (08:26.7)
Interesting. If somebody's interested in figuring out how they can deal with this from the comfort of their own home, you've put together a program called Bike Fit Fundamentals which has a tutorial on asymmetry.

I think it's think it's part six or seven. Yeah, we're right. Yep. That's the one mate It goes through a lot of the corrective or a lot of the what would you call it? Diagnostic methods of figuring out your asymmetry and it's pretty detailed and this is a good first step to try to prevent or Reverse this fun this this situation if it's starting to happen to you at home Because yeah this long-term effect of compensating asymmetrically on the bike is really problematic for this joint

with a downloadable guide.

Neill Stanbury (09:06.316)
and the flow down effects through the rest of your kinetic chain, really, really catastrophic. yeah, that is a really good first step is going through that asymmetry module to try and correct your own asymmetry and see how you go from there.

Hope you enjoyed that conversation with Neil Stanbury. We'll catch you in the next podcast.