Question

62. A bicep curl is an example of which of the following type of lever? A 1st class B. 2nd class C..3rd class D. 4th class

Answer 1

CORRECT ANSWER:

C. 3rd class

EXPLANATION:

In biceps curl, elbow flexion is taking place and Biceps Muscles pulls the forearm weight. In these movement , elbow joint acts as the fulcrum and weight of the forearm acts as resistance and pull of the elbow flexors acts as effort. If the effort is present between the fulcrum and the weight then it is third class lever. It is the lever of speed and has mechanical disadvantage because the effort required to lift the weight is more

LEVER: Lever is rigid bar which is capable of movement about a fixed axis called fulcrum.

There are three types of levers in human body : 1st class lever, 2rd class lever, 3rd class lever

1st class lever: In first class lever fulcrum is present between the effort and the weight (resistance). This type of lever is also called lever of equilibrium because the effort and weight are almost equal.

Example: Atlantooccipital joint. (Nodding movement of head)

2nd class lever: In second class lever weight is present between the effort and the fulcrum. This lever has mechanical advantage. Less effort is needed to lift more weight.

Example: Calf raises . Here ankle joint acts as fulcrum , pull of calf muscles acts as effort and weight of the body is resistance.

3rd class lever: In third class lever effort is present between the fulcrum and the weight

Example: Biceps curl. Here elbow joint acts as fulcrum , weight of forearm acts as resistance and pull of biceps acts as effort.