OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

During which action does the biceps muscle relax?

1. When extending the arm

2. When flexing the arm

3. When pulling an object

4. When throwing an object

The correct answer is: When extending the arm

The biceps muscle relaxes when the arm is extended. This is because the biceps is primarily responsible for flexing the arm at the elbow joint. When you extend your arm, the triceps muscle, located at the back of the arm, contracts to straighten the elbow while the biceps relaxes to allow this movement to occur. This coordination between the biceps and the triceps is essential for smooth and controlled movements of the arm. Additionally, during the actions of pulling or throwing an object, both the biceps and triceps may be actively involved, often resulting in the biceps being contracted rather than relaxed.