Since I started riding trials, I’ve witnessed a revolution when it comes to handlebar positioning: Jack Carthy began to rotate his handlebars extremely forward about ten years ago, and the rest of us followed. Witnessing evolutions and innovations are fantastic, it’s certain that by improving the means, the riders will be able to achieve even better performance, if the improvement goes in the right direction…
But, the question is: Are we going in the right direction? And to specify, I won’t go into the choice of materials or the way things are constructed, but I wonder if it’s appropriate to think, or rather rethink, the geometry of the handlebars. Let’s delve into it.
First, some definions to help you out:
- Upsweep: The angle between grips and the horizontal line on the frontal plane.
- Backsweep: The angle between grips and the horizontal line on the transversal plane.
- Frontal plane: The vertical plane that divides the body into ventral (front) and dorsal (rear) sections.
- Transverse plane: An imaginary plane that divides the body into superior (top) and inferior (bottom) parts.
- Lateral: The side of the body or a body part that is farther from the middle or center of the body. Typically, lateral refers to the outer side of the body part, but it is also used to refer to the side of a body part.
- Medial: Towards the middle or center. It’s the opposite of lateral. The term is used to describe general positions of body parts.
Ergonomics are defined, according to Oxford, as “The study of people’s efficiency in their working environment”.
All tools that are branded as “ergonomic” stem from this science, designed to adapt to the structure of the human body, favouring its natural movements without stressing them, and to reduce the risk of injuries from continuous repetitions of non-optimal movements.
A handlebar’s backweep and upsweep should ensure a physiologically correct transition between forearm and hand, to create a wrist and elbow position that allows for an ergonomical optimal position. This way the hard impacts that occur during trials riding can be absorbed as good as possible.
Now we’re getting closer to the crux of the matter: What kind of backsweep and upsweep angles are optimal for a correct positioning of the hand relative to the wrist, forearm and elbow?
The anatomy of the wrist
The wrist, in its neutral anatomical position, is rotated in two planes in relation to the forearm: On the frontal plane of the hand, the “grip” line is rotated about 15° relative to the forearm, and in the the transverse plane, the palm of the hand is rotated about 18° relative to the forearm. See figure below.
Note: Don’t take the angle measurement too serious, this is just to show you that the hand is rotated in relation to the forearm, both in the frontal and transversal plane.
The handlebar-hand relationship
If we look at the anatomy of the handlebar together with the anatomy of the wrist, we can find two relationships:
- The relationship between the frontal angle of the hand and the upsweep of the handlebar.
- And the relationship between the transversal angle of the hand and the backsweep of the handlebar.
But, there is an issue with the term “upsweep” and “backsweep” when you tilt the handlebar 90° forward from it’s upright position: Then the upsweep becomes the frontsweep, and the backsweep becomes the upsweep. Then I ask you: Do you think the handlebar-hand angle relationship is ergonomical now? As far as I can imagine, it’s not!
What does this entail? Clearly the hand will be internally rotated, therefore the physiological position of the wrist will not be taken care of. I can’t say for sure, but I suppose that this situation involves an altered distribution of the load in the palm of the hand, with increased pressure on the outer edge of the palm, increased pressure on the medial side of the wrist, and increased tension on the tendons that pass laterally between the hand and the the forearm. But, these statements are for now only a hypothesis, that needs further investigation.
I’ve now discussed the quality of the geometry of our handlebars, and it’s not meant to be a criticism of the manufacturers of trials components. I tried to show you my argumentation in a step by step manner, and the conclusion I ended up with is, considering a little anatomy and ergonomics, that a lot of the handlebars used in trials are not ergonomical efficient!
I can’t answer what’s the best handlebar geometry with precise degrees, but looking at the wrist anatomy, a proper handlebar should look something like the illustrations below. No more upsweep, but neutral or downsweep instead, because when we rotate the handlebars forward, this fits our wrist’s natural angle.
I hope this opinion has instilled some doubt in your mind, that is always good!
This article expresses the author’s personal opinions.