Counter-movement jump (CMJ), squat jump (SJ), and drop jump (DJ) are all types of jump tests that can be used to assess an athlete’s power, explosiveness, and lower body strength.
The choice of which jump test to use will depend on the specific goals of the assessment and the characteristics of the athlete being tested.
Counter-movement jumps
Also known as CMJs, involve starting in a standing position and quickly bending the knees before jumping as high as possible.
This type of jump is a good measure of an athlete’s ability to use the stretch-shortening cycle (SSC), which is the process by which the muscles stretch and then quickly contract to produce force. This can be an important ability for activities such as jumping, running, and throwing.
Squat Jump
SJ, on the other hand, involve starting in a squatting position and then jumping as high as possible without any counter-movement.
This type of jump is a good measure of an athlete’s strength and power and can be useful for activities that require high amounts of them.
Drop jump
The DJ is a test that involves jumping down from a height (such as a box or platform) and then immediately jumping as high as possible after landing.
This test is suitable for assessing an athlete’s ability to absorb and then quickly re-use the energy from the landing to generate a powerful upward jump and thus assessing SSC under ballistic conditions. It also tests the neuromuscular reaction of the lower body musculature.
To summarise
In general, CMJ test is best to assess power, explosion, and ability to utilize stretch-shortening cycle. While squat jump is good to assess strength, SJ and DJ both assess both strength and power, with DJ also assessing an athlete’s ability to use the energy from the landing for a quick upward jump.
It’s important to note that these tests should be performed under the supervision of a qualified professional, and that proper technique should be used to ensure accurate and reliable results.