Biomechanics and Movement Analysis
Biomechanics and movement analysis examines forces, levers, stability, projectile motion and angular motion in sport. The exam expects you to describe movement using correct planes, axes and muscle roles, then explain performance or injury risk.
Core rules
- Newton’s laws: inertia (mass resists change), acceleration (F = ma), reaction (equal and opposite). Impulse = force × time; follow-through increases impulse.
- Levers: first class (neck extension), second class (calf raise), third class (biceps curl). Most human levers are third class, favouring speed and range over force.
- Stability: increased by larger base of support, lower centre of mass, and centre of mass over the base.
- Projectiles: range depends on velocity, angle and height; 45° maximises range only when release and landing heights are equal and air resistance is ignored.
- Angular motion: angular momentum conserved unless external torque acts; ice skaters pull arms in to reduce moment of inertia and increase angular velocity.
Worked example
A volleyball player jumps to spike. At take-off, she swings her arms upward. Reasoning: the arm swing increases vertical impulse and raises the centre of mass. In flight, angular momentum is conserved; tucking the legs reduces moment of inertia and increases spin rate. A lower centre of mass at landing and a wider base improve stability and reduce injury risk.
Traps
- Confusing distance with displacement, or speed with velocity.
- Naming a lever class without locating fulcrum, load and effort.
- Claiming 45° is always optimal; release height changes the optimum.
- Describing extension when the joint angle is decreasing (that is flexion).