The drop jump, also called the depth jump or box jump, is a fitness test of leg strength and power which requires the athlete to "drop off" a box and immediately jump as high as they can. There is also an Incremental Drop Jump test used for measuring reactive leg strength, where the athlete jumps after dropping from a series of different heights. There is also a drop jump assessment as part of the Bosco Ergo Jump System. See about other vertical jump tests.
purpose: to measure the explosive force of the lower limbs
pre-test: Explain the test procedures to the subject. Perform screening of health risks and obtain informed consent. Prepare forms and record basic information such as age, height, body weight, gender, test conditions. Check and calibrate timing mat measurement. Subject to perform an appropriate warm-up. See more details of pre-test procedures.
procedure: This test is performed from a pre-set box height. The heights used can be between 20 cm and 100 cm. The athlete stands on the box, adjacent to the timing mat. Hands are placed on the hips, and stay there throughout the test. The athlete then drops down off the box onto the mat, bending the knees on landing, then immediately performs a maximal vertical jump. The athlete jumps vertically as high as possible, and lands back on the mat with both feet landing at the same time, returning to the takeoff spot. Several trials can be performed, with adequate rest between trials.
scoring: Depending on the equipment, there may be measurements of contact time, flight time, height of the jump, power of the jump, and ground reaction forces. The jump height time is the time between the participant's feet leaving the timing mat or force platform and when they contacted it again. Vertical jump height can be calculated using this formula: jump height = 4.9 x (0.5 x Time)2. Ground contact time is the time between the first foot contact with the force platform and when the participant's feet left the mat. Reactive strength index (RSI) can be calculated by dividing the jump height by the ground contact time.
- The standard size boxes are not readily available, and may even need to be custom made.
- Results can be easily influenced by body position during take-off and landing. If an athlete bends their legs when landing the flight time and therefore jump height calculation can be affected.
- This test requires athletes with good degree of leg strength, as the forces through the body are much higher than for a standard vertical jump test.
- This test can be used to assess ACL injury risk.
- Make sure the participants do not jump off the box, rather than simply 'stepping-off'.
- no arm-swinging is allowed.
- Drop Jump (Bosco) — the athlete jumps after dropping from heights of 20 cm, 40 cm, 60 cm, 80 cm and 100 cm.
- Drop Jump (Incremental) — the athlete jumps after a drop from a series of heights, starting from a 30cm box and working upwards to a 75cm box.
- Force Plate Vertical Jump
- Vertical jump using a timing mat
- No arms vertical jump
- Reactive Strength Index — the ratio between the height jumped and the ground contact time.
- A discussion about the various vertical jump equipment available
- A discussion about other vertical jump techniques
- See the list of anaerobic tests for other fitness tests of leg strength and power.