The Drop Jump Test
The Drop Jump is a brilliant test for measuring athletes reactive strength. As the test requires the athlete to step off from a platform, the coach has the option to adjust the height of the platform to test how well the athlete maintains there reactive strength when more force has to be accounted for (higher platform). This test should be a fast stretch-shortening movement (under 250ms), so the athlete should perform the jump as quickly as possible for a true test of eccentric control into concentric strength.
Drop Test – Step by Step
1. Drop Phase
To begin, the athlete starts from a platform above the plates; the platform height can be recorded directly into our capture engine. The athlete then steps off the plate with the aim of landing on the plates with both feet at the same time. This phase ends the moment the feet touch the plate.
2. Braking Phase
As soon as the athlete hits the plate, the aim is to quickly decelerate the centre of mass by absorbing the impact of the landing with hip, knee and ankle flexion. As this phase immediately transitions into the propulsive phase, the aim is to complete this deceleration and braking as fast as possible while still being in control of the movement. The leg muscles will be working eccentrically as they stretch and prepare for the jump.
3. Propulsive Phase
After the athlete’s centre mass has stopped moving downwards, the propulsive phase begins. This phase is sometimes referred to as the “concentric” or “push-off” phase. In this phase, the athlete will rapidly extend their hips, knees and ankles to propel the body vertically which results in the Jump. By definition, this phase begins when the Centre of Mass velocity becomes positive and ends as soon as the athlete has left the plate.
4. Flight Phase
The Flight Phase begins once the athlete has fully left the force plate, also known as the instant of take-off. This phase then ends at the instant of touchdown whereby the athlete first re-contacts the plate.
5. Landing Phase
The Landing Phase begins when the athlete re-connects to the plate from the jump. This phase requires the athlete to absorb the forces of the landing by flexing the hips, knees and ankles (not doing this will result in higher landing forces) with the goal of coming to complete stop in the shortest time possible.
The Test Results
Who should do the test?
As a pure reactive strength test, this is ideal for sports that are won and lost in rapid, explosive movements and movements and quick directional changes.
Which metrics are recorded?
Over 30 metrics. The most commonly used are reactive strength index, jump height, contact time, braking and propulsive forces and velocity
How long does the test take?
4-6 seconds from the drop phase to the landing.
Where do I learn more?
Please call 01344 623 883 for further information.