Strength Power Tests: The Squat Jump Test

The Squat Jump (SJ) is a simple way of measuring lower-body power. There are two common variations of the SJ test: Static SJ Test and Dynamic SJ Test.

The Static SJ Test variation requires the athlete to pause in a semi-squat state, before the concentric phase of the jump. This is in contrast with the Dynamic SJ Test variation whereby the athlete descends, without a pause, in one continuous, rapid movement.

This test can be used by loading various weights in order to test the athletic power production. These loads could be 20%, 40% and 60% of the athlete 1RM back squat. A power-load curve can then be created to identify the athlete peak power output.

The historical belief is that power production can be increased by applying training at the peak power load. However, recent research has shown that this is becoming out dated as the curve may change on a daily basis. In recent years, researchers are beginning to implement a technique called “force-power-velocity profiling” (1).

Power

To perform the SJT, a loaded bar or unloaded bar can be used. Although a barbell could be used for an unloaded bar, an Olympic barbell weights 20kg and therefore a wooden dowel can be substituted if the load of a barbell exceeds the athletes 40% limitations.

The Static SJ Test variation requires the athlete to pause in a semi-squat state, before the concentric phase of the jump. This is in contrast with the Dynamic SJ Test variation whereby the athlete descends, without a pause, in one continuous, rapid movement.

Performing the Test

The counter movement depth at the start of the test has no prescribed or ideal depth. However, this does need to be consistent when performing each test.

Source: Canadian Sport Institute Calgary (link)

During the flight of the jump, it is important that the athlete maintains extension of the hip, knee and ankles and does not attempt to gain additional flight time by bending knees.

It is important to note that test results can be affected if the athletes does not land in the same position that they took off. This can be supported by placing tape or markers on the floor.

When performing the test, the dynamic squat jump test must be performed with a 2-3 second pause at the semi-squat phase.

The athlete performs 3 jumps, which are then used to take an average or best scores.

Outcomes

In most cases, the SJ test is calculated as a jump height (cm or inches), or relative peak power (w.kg). The most valid method of calculating jump height is by flight time. This starts when the athlete leaves contact with the floor and ends when contact with the floor is made again.

References:

1 Morin JB, Samozino P. (2016). Interpreting Power-Force-Velocity Profiles for Individualized and Specific Training. International Journal of Sports Physiology and Performance, 11 p 267-272.

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