Biomechanics Concepts: Mechanical Advantage · CSCS Accelerator Community

Biomechanics Concepts: Mechanical Advantage

Definition: Mechanical advantage describes how effectively a muscle or external load can produce torque around a joint, based largely on moment arm length.

In resistance training:

When a muscle’s internal moment arm is large relative to the external moment arm, the muscle has a mechanical advantage and can produce force more efficiently.
When the external moment arm is large, the muscle is at a mechanical disadvantage and must produce more force to move the load.

Example: At the bottom of a squat, changes in hip and knee moment arms can shift mechanical advantage between the glutes, quadriceps, and spinal extensors, influencing which muscles are stressed most.

Why This Matters for Coaches

Explains why exercises feel harder at certain joint angles
Guides exercise selection and modification
Helps manage joint stress and tissue loading
Clarifies how changes in stance, grip, or range of motion alter difficulty without changing load

So when you change body position or setup, you’re changing mechanical advantage and how much force the muscle must generate. This—along with individual anthropometric variation—is one reason why certain variations of a lift are harder or easier for various athletes.

Question: What are some exercise variations or setups you use to alter mechanical advantage for yourself or your athletes?

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