Biomechanics session


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Whether you are new to cycling or triathlon, or you've been doing it for a few years, you've probably heard more than once about cycling biomechanics or "bike fitting".

It is, in essence, about adapting the bike to your particular characteristics. Because we are all made (or badly made) in a totally different way. Two people of the same height can be totally different when riding a bike, as everything depends on aspects such as leg length, torso or flexibility.

But a biomechanics session is not only about adapting to your bike, but also seeking advice on finding the right model if you are in the market for a new frame. And that's what I did a few weeks ago.

Usually the main reason to undergo a biomechanical study is because of discomfort on the bike, and although it is the most common reason for consultation, fortunately I have never suffered such discomfort.

Yes, like everyone else, there have been days when for whatever reason my neck is bothering me more, or that an hour sitting in the saddle can seem like torture. But that's just it, days that are punctual, not a general trend as many people suffer. In that sense I can say that I am lucky.

So why did I do a biomechanical study? Well, there are several reasons, all of them perfectly valid for everyone.

1.- Finding the right position

It's one thing if you don't feel any pain or discomfort, but it's quite another if your position on the bike is the ideal one, the one with the most power to the pedals, or the one that best relates an aerodynamic position to a comfortable one.

In fact, it's the main reason I've wanted to do the biomechanics session for a long time.

2.- Have a position that can be repeated

Another one of my recurring problems: I find a position, I use it for many months and I'm totally satisfied with it. For whatever reason I have to make any variation in the configuration, and automatically everything is disrupted.

The moment you have a biomechanical study with certain measurements, you have something to refer to when you are getting back on the bike. And you will also have that security of knowing that where you have placed everything you have placed, is where you should.


Maybe the same thing has happened to you as it has to me. Going back to a position that is the same as before, but you are not totally sure. And then come the doubts and the indecisions, thinking that before you were more comfortable than now. And every time you do a route you can't help but go eating your head thinking whether you should move the saddle forward 2mm or not.

3.- Goat search

Finally, I was in the market for a goat. In the past my road bike did the complete service for me, thanks to being very versatile. It allows me to reverse the seatpost, so with a specific saddle and a complete triathlon handlebar I could have a two-in-one relatively easily. And, above all, very economical.

But let's be honest. No matter how much you adapt to a road bike, even if it's an aero one, it doesn't have the geometry of a goat. You can make the fix, but you're not in the best position. And obviously, every time you had to change position the task became quite tedious.

Having to run all the wiring inside the frame is not difficult, but it does take time, if you don't lose any of the wires, because if you do, it will be hard to get it out the other end. But the mechanical adaptation is the least important, the worst thing is to make all the adjustments again, not only of brakes and gears, but also of position on the bike.

Marking a clearly differentiated season between drafting and non-drafting events may be an option. But if in the middle of the "non-drafting" season you have a race in which you are not allowed to ride a wheel, you will hate the bike mechanics.

What does a biomechanics session consist of?

If you are interested in going through the hands of a biomechanist, it is convenient that you know what a bike fitting session entails and what you are going to find.

Previous study... of the cyclist, not the bike

The first thing they will do to you is to submit you to an extensive questionnaire to find out what your ailments are or the particularities of your cycling style. In my particular case, the only thing to note is a clear difference in power distribution, which is usually 45-55 in favour of the right leg. The most likely reason is a meniscus operation on the left leg a few years ago, which is not a bad thing, but it does not hurt to confirm that there are no other problems related to the position on the bike.

Then it was time for specific body assessments: flexibility, muscle power, etc. We have been in session for almost an hour and I still haven't got on the bike. But before we can assess the bike, we have to assess the rider.

The result is that I'm a chromium. Some limited flexibility in the pelvis, contracted right pyramid, with slight dysmetry and shortened right psoas. It's like going for an analysis thinking that you're like a bull and that you get problems everywhere.

But here's the beauty of this kind of testing. Now I know my characteristics and I can act accordingly.

Preparation before starting to pedal

Before you start pedaling, there is another essential aspect to check: the placement of the cleats in the shoe. You have to make sure they are placed in the right spot, that is, in the area between the ball bone of the foot and the bunion area (which I can tell you more technically, but you wouldn't know it). Not only is the cleat placed in that area, but also the angle of rotation must be correct. A badly placed cleat can lead to injuries, for example, to the knee. You are already realizing that adjusting a bicycle goes beyond raising or lowering the saddle, right?

With the cleats already placed in the shoes, it's time to put on the sensors. The dynamic test is done thanks to high-speed cameras (many fps to be able to capture each and every movement), so they place several lights in specific points of the body. These lights turn on in different colors, according to the coding that the analysis program needs.

And finally the time has come to start pedalling. The application will then follow the movements of these light points, thus determining the angles of each extremity at all times. And this is where the technological part comes in, because the data itself means very little, and it is all up to the biomechanic to interpret it.

Work done

These are all the changes we made to the configuration of the bike which, as I say, did not pose any kind of physical problem for me.

  • Correcting the position of the cleats in the shoe
  • Increase the height of the saddle
  • Correct the location of the saddle, moving it forward in the seat post as much as possible

Visually, as far as my position on the bike is concerned, there is hardly any difference. Comparing both images you have to spin very fine to see where the gears are.

This is the before.

Home right

And now after the changes.

End right

But in terms of sensations there is quite a difference in how I am positioned on the bike: less tension in my arms when I am closer to the handlebars and the feeling of pedalling with my legs stretched out.

And as I say, I now have some data that can be repeated, so if I have to dismantle anything on the bike (which is not unusual with the amount of stuff I end up trying and analyzing), I have data to go to.

After fixing the route position, it was time to make the changes to establish the goat position, with two objectives: to be able to use the same bike in one way or another, and to value a size when acquiring a new triathlon bike.

Here I have fewer problems, because it is a position in which I have always been totally comfortable, and unlike what usually happens with other people, in my case when I am coupled I am more comfortable than when I am in the road position.

Goat position

I actually have less hip movement on the saddle, which is more pronounced in the riding position, although the saddle has a lot to do with it too.

Hip position

Hip position


In short, a test that I had to carry out for quite some time, and not because I suffered discomfort on the bike, but mainly to find a good position on the bike and that can also be easily repeated and even comparable to other bikes.

And with that... thanks for reading!

Eduardo Mateos

I've been surrounded by electronic devices of all kinds for more than 25 years. Using them, testing them, taking them apart and dissecting them. Long distance triathlete: I swim, run and cycle for a long time. Maybe too much.

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