How do our muscles and bones act as levers?
A lever is an object with a pivot point (fulcrum), used to multiply the force which can be applied to an object in order to lift it. There are 3 classes of lever, all of which can be found in the human body. For example, the action of lifting an object in your hand by bending your elbow is a 3rd class lever – the force (the attachment point of the biceps brachii in the forearm) is located between the fulcrum (the elbow) and the resistance (the object in the hand). Tilting your head upwards is an example of a 1st class lever – the fulcrum (the point at which the joints between your top vertebrae move) is located between the force (the attachment points of the upper trapezius in the base of the skull) and the resistance (the weight of your head). Standing on tip toes is an example of a 2nd class lever – the resistance (the weight of your body) is located between the force (the attachment of your calf muscles through the achilles tendon) and the fulcrum (the joints between your metatarsal
