Question

what kind of lever is arm flexion?

Answer 1

There are three types or classes of levers, according to where the load and effort are located with respect to the fulcrum.

Class 1 has the fulcrum placed between the effort and load

Class 2 has the load in-between the effort and the fulcrum

Class 3 has the effort between the load and the fulcrum.

Arm flexion is a class 3 Lever. The pivot is at the elbow and the forearm acts as the lever arm. The biceps muscle provides the effort (force) and bends the forearm against the weight of the forearm and any weight that the hand might be holding.

Force(Effort)-Biceps Muscle

Fulcrum(pivot)-Elbow

Load-Weight of the fore arm and any load held by the hand

Lever-Forearm

In a flexed Elbow ,The Force(Biceps Muscle) is between the Fulcrum (Elbow Joint) and The Load.Hence this is a 3rd Class lever