Lever Systems
Physical Education: AQA GCSE, topic 2.1.1
First Class Levers
A first class lever has its fulcrum (joint) lying in between the effort (muscle) and the resistance (load that needs moving).
The neck when raising the head
- An example of this would be the neck when the head is being raised.
- The neck muscles are the effort. The neck itself is the fulcrum. The load/resistance is the weight of the head.
Second Class Lever
A second class lever has its fulcrum at one end and the effort at the other. The resistance is then in the middle of the effort and the fulcrum.
The ankle
- An example of this would be the ankle. The ball of the foot would be the fulcrum, the gastrocnemius (calf muscle) is the effort and the weight of the person going through the middle of both is the resistance.
- The effort is applied by the gastrocnemius, which moves the ankle joint to plantar flexion (points toes).
Sprinter
- This would be used when a sprinter explodes out of the blocks in a race. They would push off the ball of their foot, using the gastrocnemius to produce plantar flexion of the foot.
Third Class Lever
A third class lever has its fulcrum at one end and the resistance at the other. The effort is then in the middle of the fulcrum and the resistance.
Elbow joint
- An example of this would be seen in the elbow joint (hinge).
- The elbow joint is the fulcrum, the hand is the resistance and the effort is the bicep pulling through the middle of the lever.
- The effort is applied by the bicep to the radius and ulna (bones in the forearm) to flex the arm.
Tennis forehand
- This would be used when a tennis player follows through on a forehand shot. They would flex their elbow by using their bicep to pull the hand (resistance) upwards.
Test yourself on Lever Systems
What does the fulcrum of a first class lever lie in between?
What type of lever is the neck joint when raising the head?
Where is the resistance in a second class lever?
What are the 3 main components allowing the second class lever in the ankle to function?
Which of the following is an example of a second class lever?