Jump & Power

Repeated Jump Test

Reactive strength and fatigue assessment over repeated jumps.

The Repeated Jump Test analyses consecutive vertical jumps performed without pause on video. By measuring the height and ground contact time of each jump, it shows reactive strength and how performance changes across repetitions.

What Is It Used For?

Assessing reactive strength and stretch-shortening cycle efficiency
Monitoring fatigue-related performance decline during repeated effort
Following readiness for and progress in plyometric training
Functional follow-up in late-stage ankle and Achilles rehabilitation

Measured Parameters

Height (cm) and flight time (ms) for each jump
Ground contact time (ms)
Reactive Strength Index (RSI): jump height / contact time
Average values and change between first and last jumps (fatigue indicator)

Setup and Camera Placement

Fix the camera to the side of or in front of the client, about 3 metres away.
Foot contact with the floor and the top of the jump must be clearly visible in frame.
The client should stay on the same spot throughout; a floor marker can help.
The floor should be flat, firm and non-slip.

Tips for Accurate Measurement

Cue the client to jump "fast and high, as if the floor were hot".
Avoid excessive knee bend; the movement should be a stiff rebound mainly through the ankles.
Hands should stay on the hips.
Use the same number of repetitions at follow-up.
Make sure the feet are not in shadow and the camera is steady.

How Is the Test Done?

The client starts upright with hands on hips.
Start recording; the client jumps consecutively without pause (e.g. 5–10 repetitions).
The aim of each jump is to spend as little time on the ground as possible while jumping as high as possible.
After the last jump the client stands balanced and recording stops.
Review the results and save them to the profile.

What Will I See on the Results Screen?

Height, flight time and contact time for each jump
RSI value and its trend across repetitions
Average, best value and rate of performance decline
A record stored in the profile and comparable with earlier tests

Interpreting the Results

A higher RSI may indicate that greater height is produced with shorter contact, i.e. better reactive strength.
Falling height or lengthening contact time across repetitions can be considered in terms of fatigue tolerance.
RSI values depend on the protocol (repetitions, cueing); only measurements made with the same protocol should be compared.
Results should be interpreted in the context of the client's sport and training history.

Clinical Use Example

In the final phase of Achilles tendinopathy rehabilitation, the repeated jump test is performed every two weeks before return to running. Shorter contact time and rising RSI are taken into account, together with symptom response, when progressing plyometric loading.