How do levers in the body let muscles move heavy loads, and which lever is which?
The three classes of lever (first, second and third class), the components of a lever (fulcrum, effort and load), mechanical advantage, and examples of each lever in the body during physical activity.
A focused answer to OCR GCSE PE Component 01 on lever systems: the fulcrum, effort and load, the three classes of lever with body examples, how to identify a lever class, mechanical advantage, and how to calculate it for the second-class lever.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
OCR wants you to know the three components of a lever, classify the three lever types, give a body example of each, and explain and calculate mechanical advantage.
The components of a lever
The class of a lever depends on which of these three is in the middle, between the other two. Learn the order for each class and a clear body example.
The three classes of lever
A useful way to remember the order in which the middle component changes is the mnemonic 1-2-3 F-L-E: in a first-class lever the Fulcrum is in the middle, in a second-class lever the Load is in the middle, in a third-class lever the Effort is in the middle.
Mechanical advantage
The body trades force for speed. A second-class lever (calf raise) has a long effort arm, so a relatively small muscle force can raise the whole body weight, but the load moves a short distance. A third-class lever (biceps curl, throwing) has a short effort arm, so the muscle must work hard, but the end of the lever (the hand) moves a long way and fast, which is why third-class levers are good for generating speed in throwing and kicking.
Levers in physical activity
Knowing the lever class helps explain technique. A discus thrower extends the throwing arm to lengthen the third-class lever, increasing the speed of the hand and therefore the speed the discus is released. In contrast, the second-class lever of the calf raise lets a high jumper drive the whole body upward with a powerful but short ankle extension.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20193 marksWhen a performer rises onto the balls of the feet (plantar flexion at the ankle), identify the class of lever operating and label the positions of the fulcrum, effort and load.Show worked answer →
A Component 01 lever-identification question. Award marks for the class and for the correct order of the three components.
The ankle in plantar flexion (calf raise) is a second-class lever. The fulcrum is at the ball of the foot (the toes), the load (body weight) acts through the ankle joint in the middle, and the effort is at the heel where the gastrocnemius pulls up via the Achilles tendon. So the order along the lever is fulcrum, load, effort, with the load between the fulcrum and the effort.
Markers reward "second class" plus a correct statement that the load is between the fulcrum and the effort. A labelled diagram in the right order also scores.
OCR 20223 marksA second-class lever has an effort arm of 0.30 m and a load arm of 0.10 m. Calculate the mechanical advantage and state what this tells you about the lever.Show worked answer →
A calculation item. Award marks for the working, the value and the interpretation.
Mechanical advantage is the effort arm divided by the load arm: .
A mechanical advantage greater than 1 means the effort arm is longer than the load arm, so a small effort can move a large load. The trade-off is that the effort must move through a larger distance and the load moves slowly. Markers want the formula, the value 3, and a sentence saying a large load can be moved with a smaller effort.
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Sources & how we know this
- OCR GCSE (9-1) Physical Education J587 specification — OCR (2016)