Mechanical Advantage Lever Systems Provide in Movement

In biomechanics, a lever refers to a rigid bar that rotates about a fixed point, known as the fulcrum. It can assist with movement by magnifying an applied force or altering the direction of the force.
Three classes of levers exist, depending on the locations of the fulcrum (F), resistance (R) and effort (E): First class levers have the order as FRE, second class levers have the order as FER and third class levers have the order as EFR.
First class levers: The fulcrum is positioned between the effort and the resistance. It can generate speed and range of motion, as seen in movements like heading a football where the neck acts as the fulcrum.
Second class levers: In these systems, the resistance is located between the effort and the fulcrum. These provide greater force at the expense of movement speed and are commonly found in the body, such as during a push-up.
Third class levers: These are the most common lever systems in the human body. Here, the effort is placed between the fulcrum and the resistance. Third class levers provide a greater range of motion and speed, sacrificing force.
Levers can help in movement by altering the mechanical advantage. This refers to the amount of force that can be generated by a lever system. Levers with a mechanical advantage greater than one amplify force, but they decrease speed and range of motion.
In contrast, levers with a mechanical advantage of less than one will increase speed and range of motion at the cost of force. Most movements in sports and physical activities use third class levers enhancing speed and range of motion over force.
The leverage system in our body is an example of structural efficiency, enabling us to make complex movements using less muscular effort. This is significant for performance as it allows for quicker, precise, and energy-efficient movements.
Understanding these principles can be beneficial for analysing and improving technique in various sports and for understanding injury mechanism and prevention.