Question

Assume you are performing ‘curls’ with a 5-kg weight in your right hand, i.e. you are lifting the weight up until your forearm is vertical with the elbow while the upper arm remain close to the body.

What is the correct human movement term to describe this movement?

Which muscles are involved in this movement and what roles do the individual muscles play during the movement?

Is it easier to perform this movement with your forearm turned so your palm faces up or down? Why?

Answer 1

A. Flexion: decrease in body angle between two parts. When the forearm is vertical to the elbow, it means the elbow is flexed decreasing the angle between ulna and humerus.
B. Muscles involved with flexion: there are three main muscles of the upper arm and forearm involved with this movement. They are: biceps brachii, brachialis, brachioradialis. Biceps Brachii: flexes the arm at the elbow and supination of forearm, Brachialis: flexion at the elbow. Brachioradialis: flexion at the forearm, supination and pronation of forearm.
C. The right way to perform curls is flexion of the forearm with forearm supination i.e. the palm faces upward, which increases the strength of the core muscles. If the palm is facing down, then the weight is not held properly in the arm plus the forearm is not vertical with the elbow.