What defines a depth/drop jump?

A depth/drop jump is defined by the process of a lengthening action followed by ground contact and then an explosive jump. This type of jump is primarily used to improve an athlete's reactive strength and power. The athlete typically steps off a platform or a box, allowing gravity to create a stretch in the muscles upon landing. This stretch-shortening cycle enhances the explosive power produced during the subsequent jump.

In this context, the first option describes a jump from a static position, which does not capture the essence of the drop component inherent in a depth jump. The third option mentions a jump requiring no preliminary motion, which is contrary to the mechanics of a depth jump, as it focuses on how the rapid transition from the land into an upward jump is critical. Lastly, the fourth option highlights a slow jump that prioritizes height over distance, which is misaligned with the explosive action and speed required for an effective depth jump. Thus, the correct definition emphasizes the dynamic engagement of the muscles and the immediate transition to a jump after the grounding phase, establishing why the lengthening action followed by ground contact is essential.