Revision notes written to the specification, with examiner tips and the required practicals. Every point here has flashcards in the Stickwise app.
Lever systems & mechanical advantage
A lever system in the body has three parts. The fulcrum is the joint the lever turns on, the effort is the force produced by a muscle contraction, and the load is the resistance being moved, such as a limb or an object.
First class leverIn a first class lever, the fulcrum sits between the effort and the load. An example is the extension of the elbow by the triceps during the follow-through of a throw.
Second class leverIn a second class lever, the load sits between the fulcrum and the effort. An example is a calf raise, where the ball of the foot is the fulcrum, body weight is the load, and the gastrocnemius pulling up the heel is the effort.
Third class leverIn a third class lever, the effort sits between the fulcrum and the load. An example is the flexion of the elbow by the biceps during a bicep curl, or when pulling an opponent in a tackle.
Mechanical advantage shows how effectively a lever magnifies force, and is calculated by dividing the effort arm length by the load arm length. A value above 1 favours force, while a value below 1 favours speed.
mechanical advantage = effort arm length ÷ load arm length
Third class levers are the most common in the body. Their effort arm is shorter than their load arm, giving a mechanical advantage below 1, which sacrifices force for a greater range and speed of movement at the load. Second class levers are rarer, but their load arm is shorter than their effort arm, giving a mechanical advantage above 1, which favours force and suits powerful movements such as a calf raise.
🎯 Examiner tip: When a question gives a sporting action and asks for the lever class, identify the fulcrum, effort and load first, then judge which one sits in the middle. Naming the lever class alone rarely earns full marks without a labelled, named example to go with it.
Planes, axes & movement types
A plane is an imaginary flat surface passing through the body in a particular direction, and an axis is an imaginary line the body rotates around as it moves through that plane.
Sagittal planeThe sagittal plane divides the body into left and right halves. Movement within it turns around the transverse axis, such as the flexion and extension of a forward roll or a running stride.
Frontal planeThe frontal plane divides the body into front and back halves. Movement within it turns around the sagittal axis, such as the abduction and adduction of a cartwheel or a star jump.
Transverse planeThe transverse plane divides the body into upper and lower halves. Movement within it turns around the longitudinal axis, such as the rotation of a twist on a trampoline.
The transverse plane is also called the horizontal plane, because it divides the body into upper and lower halves running horizontally, unlike the vertical sagittal and frontal planes. Recognising which plane a movement happens in also identifies its matching axis, since each plane pairs with only one axis of rotation.
🎯 Examiner tip: Exam answers on planes and axes are marked for correctly pairing the plane with its matching axis, not just naming one or the other. Always finish with a named sporting movement that actually happens in that plane, such as a cartwheel for the frontal plane.
Turn these notes into memory. 12 flashcards cover this topic. Short daily sessions, spaced repetition up to your exam date, quizzes with friends. Free during the beta.Practise Movement Analysis in the app ↗