Jump & Power
Countermovement Jump Test
Countermovement (CMJ) vertical jump height measurement.
The Countermovement Jump (CMJ) Test analyses, on video, a vertical jump performed from standing with a quick dip followed immediately by take-off. It calculates jump height from flight time and reflects lower limb power and use of the stretch-shortening cycle.
What Is It Used For?
- Quick, practical assessment of lower limb power
- Monitoring performance and neuromuscular fatigue during training
- Tracking power gains during rehabilitation
- Comparison with the Squat Jump to examine use of elastic energy
Measured Parameters
- Jump height (cm)
- Flight time (ms)
- Best and average value across trials
Setup and Camera Placement
- Fix the camera to the side of or in front of the client; take-off and landing of the feet must be clearly visible.
- The camera should be about 3 metres away at hip height.
- The whole body must stay in frame including the top of the jump; leave enough space above.
- The floor should be flat, firm and non-slip.
Tips for Accurate Measurement
- Keep hands on hips; arm swing raises the result and undermines comparison between trials.
- Dip depth should be self-selected and similar on every trial.
- Knees should not be tucked in the air; land with legs extended.
- Keep the camera steady and the room well lit; the feet should not be in shadow.
- When monitoring fatigue, test at a similar time of day with a similar warm-up.
How Is the Test Done?
- The client starts upright, feet hip-width apart and hands on hips.
- Start recording.
- The client dips quickly and, without pausing, jumps as high as possible.
- The client lands on the forefoot and stands balanced.
- 3 trials are performed with rest in between.
What Will I See on the Results Screen?
- Jump height and flight time for each trial
- Best trial and the average of trials
- Measurement history stored in the profile and change over time
Interpreting the Results
- A higher jump may indicate greater lower limb power; values vary widely with age, sex, sport and training level.
- A clear drop from the client's usual value can be considered in terms of fatigue or recovery status.
- The difference between CMJ and Squat Jump can give an idea of how well the stretch-shortening cycle is used.
- Flight-time-based calculation is affected by landing technique; the most meaningful comparison is with earlier measurements under the same protocol.
Clinical Use Example
In an in-season football squad, CMJ is measured weekly on the same day and time. When a player's value falls clearly below their own average, this is considered together with other data when reviewing training load.