An athlete performs a vertical jump on a force plate. The graph shows the recorded ground reaction force of the athlete.

[Source: adapted from American Journal of Physics 69, 1198 (2001),
with the permission of the American Association of Physics Teachers]

State what happens to the athlete between C and D.

Outline power, a performance-related component of fitness.

Evaluate the vertical jump test as a method of assessing power in volleyball players.

Athlete is in flight / in the air ✔

it is the combination of speed and strength
OR
the ability to perform a maximum effort within the shortest period of time ✔

Strengths:
easy to administer / limited training required ✔

limited cost / equipment required ✔

athlete can conduct test on their own ✔

relevant to the actions of a volleyball player ✔

good for assessing lower limb power ✔

Limitations:
requires timing of the participant to mark at the peak of their jump ✔

performance could improve with practice ✔

can only test one person at a time ✔

reliability decreases with fatigue with repeated, continuous trials ✔

Award max [3] if only strengths or limitations are provided.

Award max [3] if the answer does not make reference to volleyball.