Cyclic Jump Test
Significant for capturing the ankle plantar flexors’ ability to quickly and effectively change from an eccentric to a concentric contraction.
What is a cyclic jump test?
Like the “10/5 RSI test”, the cyclic jump (CJ) test represents an athlete's ability to effectively utilize the stretch-shortening cycle and explosive capacity during dynamic jumping activities. This is important for various athletic activities and to see changes in fatigue or optimal performance. A practitioner can perform the CJ test to evaluate the following areas of functional movement performance:
Muscle strength reserves and power
Propulsive and absorptive strategies with foot-ground interactions
Degree of inter-limb asymmetry for all of the above components of movement performance
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Tip: Instruct the person you're collecting data on that this test aims to evaluate their ability to use the stretch-shortening cycle in their leg muscles. Most of the power should come from the calves, and the movement should be primarily through the ankles. The person being tested should perform 20 cyclic jumps. Cyclic jumps are characterized by repetitive hops with stiff legs and a slight knee bend. The person being tested should try to jump as high as they can and spend as little time on the ground as they can, like they're "hopping on a hot stove."
1. Tester navigates to the measure page of the Plantiga app and selects the Cyclic Jump Test.
2. Tester selects the subject that will be performing the activity. Address any warnings that may come up once they have been selected.
3. Tester instructs the subject to stand still with feet planted firmly on the ground.
4. Tester starts the Cyclic Jump Test in their plantiga.io web application and the subject remains still as the stopwatch counts down from 5.
5. Subject will perform 20 cyclic jumps with their hands on their hips.
6. Once the jumps have been performed, the tester instructs the subject to stop and plant their feet firmly on the ground.
7. The tester stops the stopwatch once still, and the subject remains still for 5 seconds.
8. Tester fills out optional information (RPE, Pain, Floor type...) and saves the Cyclic Jump Test.
What does Plantiga measure?
Jump height (max): the highest height achieved from all successive cyclic jumps during a single test.
Low cyclic jump heights indicate poor muscle strength reserves.
Reactive strength index (RSI): the ratio between the height jumped and the average ground contact time during a successive jump. It is a reliable indicator of strength and explosive power capabilities.
An individual with a high RSI during the cyclic jump (>1.0) can either jump higher, or have shorter ground contact time or both, in comparison to low RSI (<0.5) cyclic jumpers.
Vertical take-off acceleration (VTA) asymmetry: a comparison of how quickly the left vs. right foot swings immediately after toe-off between jumps
High VTA asymmetry (> 10%) occurs when the opposite limb ankle musculature and surrounding tissues are fatigued, weak, or experiencing pain.
Vertical landing acceleration (VLA) asymmetry: a comparison of the ability of the left vs. right to absorb impact when the foot lands on the ground between successive jumps.
High VLA asymmetry (> 10%) occurs when landing more abruptly on one limb than the other.
How can my athletes benefit from CJ testing with Plantiga?
To simplify data interpretation and provide actionable movement insights to our users for better rehabilitation and performance outcomes, we’ve created instant and customizable activity reporting tools that can be accessed and shared within minutes.
