Component 1: Fitness and Body Systems Study Guide

Lever systems are fundamental to human movement, acting as simple machines within the body to produce force and movement. Each lever consists of a rigid bar (bone), a pivot point (fulcrum/joint), an effort (muscle contraction), and a load (resistance or weight being moved). The three classes of levers differ in the relative positions of the fulcrum, effort, and load, which in turn determines their mechanical advantage. Mechanical advantage describes how effectively a lever amplifies the applied force or increases the range and speed of movement. A high mechanical advantage means a small effort can move a large load, prioritising strength. A low mechanical mechanical advantage means a large effort is needed to move a load, but it allows for a greater range or speed of movement, which is often crucial in sports.

The body primarily uses two energy systems during physical activity: aerobic and anaerobic. Aerobic exercise, meaning 'with oxygen,' relies on oxygen to break down glucose and fat for sustained energy production. This system is efficient for longer-duration activities at moderate intensity, such as long-distance running or swimming. Anaerobic exercise, meaning 'without oxygen,' generates energy rapidly for short bursts of high-intensity activity, like sprinting or weightlifting, by breaking down glucose without oxygen. However, this produces lactic acid, leading to muscle fatigue. Understanding when each system is predominant helps athletes tailor training for specific performance goals, optimise recovery, and promote overall health.