Question

During the flexion of the elbow joint, the .......... muscle contracts while the .......... muscle relaxes.

Answer 1

• The large muscle of the upper arm flexes the arm and powerfully twists the forearm, turning the palm upward.
  
• This muscle extends from the head of the head of the humerus over the elbow to the ulna bone to help flex the elbow, and also enables pronation of the forearm.

So, the correct answer is 'Biceps, triceps'.