From Opinion to Certainty

Michael Goulden

Last updated: 

2 Dec 2024

2 min. read

Biomechanics is the study of forces and motion in living systems – in our case, the human body. But what does this mean for personal trainers and coaches? Simply put, it provides real, tangible, and objective data to inform training decisions for each client.

Beyond Opinion to Certainty

Biomechanics is rooted in physics and mathematics. Unlike many aspects of fitness, it offers something close to certainty: 1+1 will always equal 2, regardless of opinion or tradition.

Many of us began our fitness journey looking to magazines, athletes, or friends for exercise guidance. Over time, certain exercises developed loyal followings, with devotees attributing specific benefits or even magical properties to them.

But how do we know that exercise A will truly deliver outcome X?

The Power of Measurement

Biomechanics allows us to map forces, motion, and demands placed upon the body rather than relying on tradition and protocol. By understanding these forces, we can identify which tissues – muscle, ligament, joint – we’re actually stimulating.

Consider these examples:

Chest Development

Do you love the dumbbell (DB) fly? The numbers tell a different story. During significant portions of the movement, the resistance profile doesn’t match the strength profile, ranging from minimal to non-existent.

Quad Development

Want to create optimal tension through a full range of motion? Consider this:

• Squats: At specific points, the line of force runs directly through your knee joint, creating zero moment arm – meaning no tension, even with bands or chains
• Lunges: When mapping ground reaction forces and friction, we find the same issue – points of zero moment arm, meaning minimal stimulation

Shoulder Training

Have you ever noticed people throwing dumbbells upward during lateral raises? This isn’t just poor form – it’s a response to a mismatched resistance profile. The speed of movement affects resistance, but the underlying biomechanical truth remains unchanged.

Moving Beyond Guesswork

That doesn’t mean we should stop performing the DB fly, squat, or DB lateral raises. It allows us to understand the impact of our exercise designs.

Understanding biomechanics and exercise mechanics helps deliver results more efficiently. It allows us to:

• Select exercises based on evidence rather than tradition
• Match resistance profiles to strength profiles
• Understand why certain compensations occur
• Make informed decisions about exercise selection and progression

All exercises exist on a continuum and should be utilised for the right client, the right goal, and at the right time. We don’t have to guess what will be effective with biomechanics – we can measure it.

The beauty of biomechanics lies in its objectivity. It’s not about opinion or tradition. It’s about understanding the fundamental principles that govern human movement and applying them intelligently to achieve specific outcomes.

Discover more about the fundamentals of exercise mechanics.