HMS, BM EQ-Bank 22

Describe how the coordination of joint actions at the hip, knee and ankle contributes to the generation of power in a vertical jump. Use biomechanical principles in your response. (3 marks)

--- 8 WORK AREA LINES (style=lined) ---

Show Answers Only

Sample Answer

Preparation phase:

Concurrent flexion at hips, knees and ankles lowers the centre of gravity. This creates a countermovement, initiating the stretch-shortening cycle in leg muscles to store elastic energy.

Propulsive phase:

Sequential triple extension follows a proximal-to-distal pattern – hips extend first, then knees, finally ankles. This kinetic chain transfers force upward, with each joint adding velocity to the movement.
Ground reaction forces peak when all joints extend together. Coordinated timing maximises vertical impulse at take-off.

Show Worked Solution

Sample Answer

Preparation phase:

Concurrent flexion at hips, knees and ankles lowers the centre of gravity. This creates a countermovement, initiating the stretch-shortening cycle in leg muscles to store elastic energy.

Propulsive phase:

Sequential triple extension follows a proximal-to-distal pattern – hips extend first, then knees, finally ankles. This kinetic chain transfers force upward, with each joint adding velocity to the movement.
Ground reaction forces peak when all joints extend together. Coordinated timing maximises vertical impulse at take-off.