A countermovement jump (CMJ) is a vertical jump where the athlete starts standing tall, dips quickly into a partial squat, and immediately jumps as high as possible. It is one of the most widely used tests of lower-body explosive power because it is quick, needs no equipment to perform, and correlates well with sprint and jump performance, and more loosely with change of direction.
This guide covers how to run the test, what each result means, the mistakes that throw off the numbers, and how to measure it without force plates.
What the countermovement jump measures
The "countermovement" is the quick dip before takeoff. Dipping first lets the leg muscles build up force before the push-off starts, and stores some elastic energy in the tendons. Together, this stretch-shortening cycle lets athletes jump higher than they can from a paused squat.
That makes the CMJ a test of more than leg strength. It shows:
- Explosive power. How much impulse (force applied over a short time) the legs produce, which sets takeoff speed and jump height.
- Elastic ability. How well they use the stretch-shortening cycle.
- Readiness. The athlete's neuromuscular readiness, meaning how fresh or fatigued they are on a given day.
- Landing control. How well they absorb force on the way back down, if you watch the landing too.
How to run the countermovement jump test
- Warm up. Five minutes of light movement plus a few practice jumps at building effort.
- Starting position. Stand tall with feet about hip- to shoulder-width apart and hands on hips. Keeping the hands on the hips removes the arm swing, so the test measures the legs.
- The jump. Dip quickly to a comfortable depth, then jump straight up as high as possible without pausing at the bottom.
- In the air. Keep the legs straight and the hands on the hips. Don't tuck the knees.
- Landing. Land on both feet in the same spot you took off from, with the legs as straight as at takeoff, toes first, then bend at the hips and knees to absorb.
- Reps. If you're measuring by hand or with a jump mat, do three jumps with 30 to 60 seconds of rest and record the best or the average. Use the same choice every time.
Countermovement jump vs. squat jump
The squat jump starts from a paused bottom position, with no dip. Because it can't use the stretch-shortening cycle, athletes almost always jump higher in the CMJ.
Comparing the two can be useful. A big gap suggests the athlete makes good use of the countermovement. A small gap suggests they rely mostly on raw strength and may benefit from plyometric work. Treat it as a hint, though: research on this ratio is mixed, and squat jumps are hard to standardize because a small hidden dip inflates them.
What the results mean
Jump height
The headline number. Higher jumps mean more explosive power. Compare athletes against their own baseline first. Comparing them to norms is only useful if every test used the same method, because force plates, jump mats and video apps calculate height in different ways and their results don't line up exactly.
Flight time
How long the athlete is in the air. Most jump mats and many apps calculate jump height from flight time, so the two numbers move together. That method assumes the athlete lands in the same position they took off in, which is why tucking the knees or landing with bent legs inflates the result.
Takeoff depth
How deep the athlete dips before jumping. A deeper dip can raise height a little while lowering the force and power behind it, so tracking depth keeps retests comparable.
Landing
How the athlete absorbs the landing: knee and hip bend at touchdown, whether the knees cave inward, and whether both sides land evenly. Stiff, straight-legged landings and knees caving in are the patterns most linked to knee injury. Our guide to landing mechanics covers these in detail.
Using CMJ to monitor fatigue
Because the CMJ is quick and does not tire the athlete out, many coaches test it once or twice a week. Jump height alone can hide fatigue, because tired athletes often dip deeper or slower to reach the same height. Track takeoff depth and timing alongside height, and only act on drops bigger than the athlete's normal day-to-day variation. A real drop is a cue to adjust the session, not a diagnosis.
Common CMJ testing mistakes
- Swinging the arms. Arm swing adds height. Fine for training, but it makes the test inconsistent.
- Tucking the knees. Pulling the knees up in the air lengthens flight time and inflates jump height on flight-time-based tools.
- Pausing at the bottom. A pause turns it into a squat jump and removes the stretch-shortening cycle.
- Changing depth. A much deeper or shallower dip from test to test changes the result.
- Landing somewhere else. Drifting forward or landing on one foot first changes flight time and hides landing problems.
- Testing when tired. Test before training, after the same warm-up each time.
Why the CMJ matters for sprint speed
Both jumping and sprinting depend on how much force the legs can apply quickly, which is why they correlate, even though sprint ground contacts are far shorter, single-leg and more horizontal. Research by Loturco and colleagues found a strong relationship between CMJ height and sprint performance in elite sprinters. The link is weaker in team-sport athletes, but it is still there.
That's why the CMJ is a useful check on speed training. A 40-yard time tells you an athlete is slow. The jump helps show why, and whether power training is carrying over.
Measuring the countermovement jump without force plates
Force plates are the lab standard. They measure the force behind the jump, not just its height, but they cost thousands of dollars and stay in one place. Jump mats are cheaper but only give flight time.
Demotu measures the countermovement jump with a phone camera. Set the phone 7 to 8 feet away facing the athlete, have them stand with feet shoulder-width apart and hands on hips, press record, and have them dip, jump and land. Results come back in seconds.
Demotu tracks the athlete's whole-body center of mass in 3D and calculates jump height from how high it rises, instead of estimating it from flight time like most jump mats. That keeps a knee tuck or a bent-leg landing from inflating the result.
Each jump breaks down into:
- Performance. Jump height, flight time, takeoff depth and a landing score, with a percentile against the athlete's age and gender.
- Angles. Knee and hip angles for each side, plus trunk lean and sideways tilt, at touchdown and at the deepest point of the landing.
- Mechanics. An 11-point landing check covering foot width, foot symmetry, toe-to-heel contact, knee and hip bend at touchdown, trunk position and knees caving in, each marked pass or fail.
- Breakdown. How each part feeds the overall score, with a written analysis of the jump.
So one test gives you jump performance and landing quality together. A force plate measures landing forces but not what the knees, hips and trunk are doing, which normally needs a separate video screen. Retests plot against the athlete's baseline, so a drop from fatigue or a gain from a training block shows up in numbers.
Try it yourself: start a free 7-day trial and run the countermovement jump from your phone.
Frequently asked questions
What is a good countermovement jump height?
It depends on age, sex, sport and how the jump is measured. Different tools give different numbers for the same jump. The most useful comparison is an athlete against their own baseline. Demotu also shows a percentile for the athlete's age and gender.
What's the difference between a countermovement jump and a vertical jump?
A countermovement jump is a type of vertical jump. "Vertical jump" usually means a jump-and-reach test with an arm swing. A CMJ test usually keeps the hands on the hips so it measures the legs alone.
Why keep the hands on the hips?
Arm swing adds height and varies from rep to rep. Hands on the hips makes the test more consistent and isolates the legs.
How often should you test the CMJ?
Monthly works for tracking progress over a training block. For monitoring fatigue, many coaches test once or twice a week before training, using the same warm-up each time.
Do you need force plates to test the countermovement jump?
No. Force plates add force-time detail, but jump height, flight time, takeoff depth and landing mechanics can all be measured from video with a phone.