IB Biology HL 3.3.3 Antagonistic Muscles Question Bank
Practise IB Biology HL 3.3.3 by explaining antagonistic elbow muscles and how titin supports sarcomere recoil and relaxation.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Practise IB Biology HL 3.3.3 by explaining antagonistic elbow muscles and how titin supports sarcomere recoil and relaxation.
The diagram shows a section through part of the leg of an insect and antagonistic muscles X and Y . The tibia moves in the direction shown by the arrow when the muscle is flexing.

Outline a reason for the muscles being described as antagonistic.
cause opposite movements / pull in opposite directions / when one contracts the other relaxes;
Describe the role of muscle Y.
a. flexor/flexion;
b. bends/flexes the leg/limb/joint;