Why Personal Trainers Should Study Biomechanics

Michael Goulden

Last updated: 

2 Feb 2024

3 min. read

Biomechanics is the study of forces and motion on living systems, in our case, the human body.

For the personal trainer/coach, what does biomechanics give us that could possibly be useful?

Real, tangible and objective data to inform your training decisions for each client.

Biomechanics, in essence, is derived from physics. And when we are talking about physics, we are now talking about mathematics. Biomechanics is the closest thing to certainty that we have within the body: 1+1 will always be 2, no matter what your opinion is.

For most of us, when we started to learn exercises, we looked to magazines; to athletes; to our friends and family, for inspiration on which activities to choose. Over the years, exercises develop their own little tribes of people who love them and attribute magic or specific benefits to them.

But how do we know that exercise A is really going to deliver out come X?

Rather than relying on tradition and protocol, we can map out forces, motion and the demands placed upon the body. Understanding these forces means we can start to piece together which particular tissues within the body (muscle, ligament, joint, etc) we are stimulating.

Want to fully stimulate your pec? That dumbbell supine fly won’t do it. But don’t take my word for it, go measure it. The resistance profile does not match the strength profile. You might love this exercise, but you can’t get away from the fact that during a significant portion of it the actual resistance will be too light to non-existent.

Want to develop your quads?

If you wanted to create a full range challenge to the quads, with the goal of optimal tension and stimulation – how would you do this? Which exercises would you choose?

Squats? There’s a point in that exercise when the line of force is running through your knee joint. When this happens, the moment arm is effectively zero. No tension. Even if you add bands or chains.

Lunges? When you map out the line of force coming at you from ground reaction forces AND from forces occurring due to friction, which means we have the same issue: zero moment arm at one point in the exercise – creating low stimulation.

Want to develop your deltoids?

Have you ever noticed that you witness some individuals throwing the dumbbells up in the air? Kinda swinging the dumbbell to reach the top? Perhaps we need to look at the strength profile again, does this exercise offer a matching resistance profile? (No). Does the speed at which you move affect the resistance (Yes).

It’s all mapped out. It’s not my opinion.

Understanding biomechanics will help you deliver results more efficiently.

I choose exercises that I use both for myself and with many of my clients. All exercises exist on a continuum and are utilised for the right client, the right goal, and at the right time. We don’t have to guess at what will be effective.