Levers in Biomechanics

Basic Understanding

Levers are simple machines that assist in moving a load with lesser effort.
A lever is composed of a rigid bar, a fulcrum (pivot point), an effort (input force), and a load (weight or resistance to overcome).
The human body functions using various lever systems, crucial for physical activities and sports movements.

There are three types of levers: First class, Second class, and Third class levers.
First class levers have the fulcrum placed between the effort and the load (like a seesaw). In sport, an example is the elbow extension during a tricep dip.
Second class levers have the load between the effort and the fulcrum (like a wheelbarrow). In sport, an example is the plantar flexion of the foot to raise the body onto the toes.
Third class levers have the effort located between the load and the fulcrum (like tweezers). In sport, an example is the upswing during a bicep curl.

The type of lever used can impact the speed, range of motion, and force the athlete can generate.
First class levers are useful in activities where balance is required, as the fulcrum can be moved according to the weight distribution.
Second class levers favour power as a large load can be moved with a relatively small effort, suitable for weightlifting or shot put.
Third class levers are common in the human body and often increase speed and range of movement, beneficial in games like tennis or cricket for maximum precision and speed.

Understanding leverage can greatly help improve an athlete’s technique across a variety of sports.
Variance in the fulcrum position can change the output, affecting factors like speed or accuracy.
Accurate manipulation of levers and hinges in the body can lead to more efficient energy use, enhancing overall performance and minimising the risk of injury.
Knowledge of lever systems allows for tailored training programs that focus on specific lever types for specific sports.