The elbow flexion performed by the brachioradialis muscle is an example of a third-class lever.
In a third-class lever, the effort is located between the fulcrum and the load. In the case of elbow flexion:
- Fulcrum: The elbow joint acts as the fulcrum.
- Effort: The brachioradialis muscle applies the effort.
- Load: The weight of the forearm and any object being lifted acts as the load.
This arrangement means that the effort is applied closer to the fulcrum than the load, which is characteristic of a third-class lever. Third-class levers are common in the human body and are designed for speed and range of motion rather than force.