Explain the joint actions that occur at the knee and ankle when performing a vertical jump. (4 marks)
--- 8 WORK AREA LINES (style=lined) ---
Show Answers Only
Sample Answer
- During the preparation phase, the knee flexes and the ankle dorsiflexes. Lowering the body’s centre of gravity through these actions creates a countermovement. As a result, muscles are pre-stretched, storing elastic energy.
- In the propulsive phase, powerful knee extension occurs simultaneously with ankle plantar flexion. Such coordination causes rapid force generation against the ground. Maximising vertical force production is achieved through this synchronised joint action.
- Following this, the sequential extension from proximal (knee) to distal (ankle) joints creates a kinetic chain. Therefore, force transfers efficiently upward through the body. The outcome is maximum jump height through coordinated joint actions.
Show Worked Solution
Sample Answer
- During the preparation phase, the knee flexes and the ankle dorsiflexes. Lowering the body’s centre of gravity through these actions creates a countermovement. As a result, muscles are pre-stretched, storing elastic energy.
- In the propulsive phase, powerful knee extension occurs simultaneously with ankle plantar flexion. Such coordination causes rapid force generation against the ground. Maximising vertical force production is achieved through this synchronised joint action.
- Following this, the sequential extension from proximal (knee) to distal (ankle) joints creates a kinetic chain. Therefore, force transfers efficiently upward through the body. The outcome is maximum jump height through coordinated joint actions.