Section 196 of 440
Complete canonical tutorial. This reader section contains the same teaching body as PWR-013 · Reactive strength. Open the Power dossier.
PWR-013 · SUPERVISED full tutorial
Rebound quickly from a small supervised hop while keeping landing control
Reactive strength is the ability to switch rapidly from landing force to take-off force in a declared rebound. This lesson teaches a provider-controlled low-amplitude bilateral pogo hop on a force plate: establish a stable landing first, keep the trunk tall, contact through the forefoot and whole foot, rebound without a deep squat and stop when contact time, height or alignment deteriorates. The provider controls clearance, hop height, repetitions, rest and whether drop jumps are ever appropriate.
1 · Permission and limits
Know exactly what you may do
2 · Get ready
Gather what you need and check the starting conditions
What you need
- Force plate or validated contact-time and jump-height system
- Flat resilient non-slip surface with foot marks
- Video view of trunk, knees and feet
- Stable support outside the landing zone
- A rebound sheet showing task, surface, footwear, contact number, ground-contact time, jump height, alignment flag, stopping reason and invalid contacts.
Before you start
- Demonstrate a quiet two-foot landing and hold balance for two seconds before repeated rebound work.
- Report recent tendon, bone, knee, ankle or back symptoms and any long break from jumping.
- Agree on contact count and the exact stop rule for height loss, longer contact or alignment error.
- Mark the take-off and landing area and rehearse one quiet, low landing. Start the rebound series only when the learner can stay on the marks without stepping, collapsing or reaching for support.
- Rehearse the tall ready posture, a quiet landing and one small rebound before starting the provider-limited contact series.
3 · The method
Follow these steps in order
- Earn the landing first
Complete a provider-set low jump, land on both marked feet and hold for two seconds with hips and knees flexed.
Why: Repeated rebound is inappropriate when one landing is not controlled.
Check: The learner stays on the marks without a step or collapse.
- Set the rebound posture
Stand tall with feet on the marks, ankles ready and arms in the declared position. Keep the gaze forward.
Why: A repeatable start controls arm and trunk contributions.
Check: Feet, arms and trunk match the setup image.
- Use a small first hop
Rise only to the provider-set low height and return to the same marks; do not chase maximum height.
Why: The first contact should establish rhythm, not create an overload.
Check: The first landing is quiet, centred and within the target height range.
- Rebound from the ankle-led contact
On landing, allow the whole foot to load while ankles, knees and hips flex slightly, then push away promptly without a deep squat.
Why: A deep, slow countermovement changes the task from short-contact reactive work.
Check: Contact remains brief and the trunk does not fold.
- Keep contacts aligned
Track knees in line with feet and keep each contact on the marks. Do not let one leg take over or the feet drift.
Why: Drift and collapse show loss of a repeatable rebound pattern.
Check: Video shows centred contacts and similar left-right timing.
- Stop at the first failed rebound
End the set when contact becomes clearly longer, height falls outside the band, alignment breaks or symptoms appear; step out and settle rather than forcing one more hop.
Why: Technique failure is the endpoint, not exhaustion.
Check: No extra contacts occur after the first stop criterion.
- Calculate and interpret RSI
For valid contacts, divide jump height by ground-contact time using consistent units and report height and contact time alongside the ratio.
Why: The same ratio can hide different height-contact strategies.
Check: The record retains all three values and the exact hop condition.
4 · Worked example
See the whole method used once
Scenario
A strength coach prescribes five low bilateral rebounds on a force plate, hands on hips, with a 12–16 cm height band and a stop if contact exceeds 0.25 s.
Walkthrough
- The learner first demonstrates two stable single landings.
- Contacts one to three show 0.21, 0.20 and 0.21 s with heights of 14, 15 and 14 cm.
- Contact four lasts 0.27 s and the knees collapse inward, so the learner stops and does not perform contact five.
- The coach calculates RSI only for the first three valid contacts and keeps height and time visible.
- After rest, the coach ends the session rather than adding a replacement set because the predeclared failure occurred.
Result
The valid series is three controlled contacts, not five. The mean valid RSI describes this low hands-on-hips rebound; it does not establish repeated-sprint endurance, sprint speed or safe drop-jump capacity.
5 · Right and wrong
Compare correct or safer execution with the common wrong version
| Moment | Right / safer | Wrong / riskier | Why it matters |
|---|---|---|---|
| Entry level | Show a stable landing before repeated rebound. | Begin with a box drop to discover whether landing is adequate. | Box height adds unearned impact demand. |
| Contact: Reactive strength checkpoint | Use a small prompt rebound with slight joint flexion. | Sink into a deep squat and pause. | The task becomes a slower countermovement jump. |
| Set endpoint | Stop at first height, contact-time or alignment failure. | Continue until exhaustion to improve the score. | Extra poor contacts add risk and corrupt the measure. |
| RSI: Reactive strength checkpoint | Report height and contact time beside the ratio. | Report only the ratio and hide how it was achieved. | Identical ratios can represent different strategies. |
| Transfer: Reactive strength checkpoint | Call it performance in this rebound fixture. | Use it as proof of sprint or repeated-sprint ability. | Reactive rebound and sprint endurance are different constructs. |
6 · Common mistakes
Spot the error and apply the correction
| Mistake | Fix |
|---|---|
| The learner chases height and lengthens contact. | Reinstate the provider's height band and prioritise the declared contact task. |
| A deep knee bend replaces the ankle-led rebound. | Lower the hop height and rehearse two low contacts before another set. |
| Invalid contacts remain in the mean RSI. | Apply the contact-time, height and alignment rules before calculation. |
| The series continues after inward knee collapse. | End at the first failed contact and review the cause. |
| Repeated-sprint evidence is presented as rebound evidence. | Keep the dossier mismatch explicit and use direct RSI sources for this method. |
7 · Practice
Turn the steps into a usable skill
First session
- Provider checks readiness and teaches a stable single landing.
- Practise two low hops separated by a full reset.
- Complete one three-contact familiarisation series.
- After full rest, complete one short measured series with a declared failure rule.
- Review contact time, jump height, RSI and alignment for each valid contact.
Repeat plan
The qualified provider controls contact count, height, surfaces, rest and weekly plyometric exposure. Drop height, unilateral work or external load are new higher-risk tasks and require separate teaching and clearance.
Progress when
- Every rebound returns to the same foot marks with stable alignment.
- Height and contact time remain inside the declared bands for the full short series.
- Symptoms and next-day response remain acceptable under the provider's rule.
Do not progress when
- Contact time lengthens, jump height falls or alignment fails before the planned endpoint.
- Pain, swelling, stiffness, fear or asymmetry appears during or after the session.
- The learner needs a higher drop or more contacts to make the ratio look better.
8 · Check the result
Measure what changed
Jump height divided by ground-contact time for valid short-contact rebounds, with height, time and alignment reported
How: Use the same force plate, arm rule, hop or drop condition, foot marks and validity bands; calculate RSI only after excluding failed contacts.
Good result: All contacts in the declared short series meet height, contact-time and alignment rules with stable symptoms and a consistent ratio.
This does not prove: It does not prove sprint performance, repeated-sprint endurance, injury prevention or readiness for higher drop heights.
Self-check
- Can you demonstrate a stable landing before rebounding?
- Did you stop at the first failed contact?
- Can you calculate RSI and still show height and contact time?
- Can you explain why this is not repeated-sprint endurance?
9 · Stop, adapt or get help
Keep the safety boundary practical
Stop and get help
- Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
- End the series on the first contact-time, height or alignment failure; do not finish the count for completeness.
- Abandon rebound contacts after focal tendon or bone pain, swelling, instability or a visibly protective landing, and let the qualified provider decide whether impact testing remains suitable.
Accessibility and adaptations
- Use a provider-selected supported heel raise, rapid seated push or non-flight stretch-shortening task when hopping is not appropriate and label it separately.
- Use high-contrast foot marks and visual or tactile start-stop cues without reducing the landing area.
- Teach the landing and rebound shape with a side-view demonstration, tactile position targets or short sound cues, without relaxing the contact-time and landing-quality criteria.
10 · Evidence and limits
Why these instructions are here
- primary research
The cited study evaluates a modified reactive strength index based on jump height and time to take-off; that value should not be substituted silently for contact-time RSI.
Using the reactive strength index modified to evaluate plyometric performance - primary research
Drop-jump and hopping RSI did not show a consistent relationship with sprint measures in one primary study, limiting transfer claims.
Influence of Reactive and Maximum Strength Indicators on Sprint Performance
Limits
- The current canonical evidence register for PWR-013 is bound to repeated-sprint studies; those sources do not substantiate this rebound method.
- RSI depends on the hop/drop condition, technique and device.
- A higher RSI is not permission to add box height, contacts or load.
Open the complete canonical research register
- Primary empirical supportLimiting / contraryPerformance and physiological responses to repeated-sprint exercise: a novel multiple-set approach
Fabio R. Serpiello; Michael J. McKenna; Nigel K. Stepto; David J. Bishop; Robert J. Aughey · 2011 · Primary research
- Primary empirical supportLimiting / contraryThe Effect of Speed Endurance Versus Core Training on The Repeated Sprint Ability of Youth Male Soccer Players - A Randomized Controlled Trial
Olavo Maciel; Ricardo Martins; Fábio Y. Nakamura; Pedro Figueiredo; José Afonso; Ivan Baptista · 2024 · Primary research
- Limiting / contraryOfficial boundary contextWHO guidelines on physical activity and sedentary behaviour
World Health Organization · 2020 · Official guidance
Read the complete evidence interpretation on the Power dossier.
Tutorial delivery controls
Learn, adapt, troubleshoot and resume
Progress is saved only in this browser on this device.
Step-by-step learner mode
Each activity includes its success check, a nearby accessible alternative and an “I’m stuck” correction path. Alternatives preserve the target where possible; when they change the task, Titan labels them as related rather than equivalent.
Earn the landing first
Complete a provider-set low jump, land on both marked feet and hold for two seconds with hips and knees flexed.
Repeated rebound is inappropriate when one landing is not controlled.
The learner stays on the marks without a step or collapse.
I’m stuck on this step
Reset: Re-read this authored instruction — “Complete a provider-set low jump, land on both marked feet and hold for two seconds with hips and knees flexed.” — and its success check, then attempt only this step.
Possible snag: The result from “Complete a provider-set low jump, land on both marked feet and hold for two seconds with hips and knees flexed.” does not yet meet this declared check: The learner stays on the marks without a step or collapse.
Correction: Return to the start of “Earn the landing first”, reduce complexity or pace, and repeat only the part needed to satisfy: “The learner stays on the marks without a step or collapse.”
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Set the rebound posture
Stand tall with feet on the marks, ankles ready and arms in the declared position. Keep the gaze forward.
A repeatable start controls arm and trunk contributions.
Feet, arms and trunk match the setup image.
I’m stuck on this step
Reset: Re-read this authored instruction — “Stand tall with feet on the marks, ankles ready and arms in the declared position. Keep the gaze forward.” — and its success check, then attempt only this step.
Possible snag: Repeated-sprint evidence is presented as rebound evidence.
Correction: Keep the dossier mismatch explicit and use direct RSI sources for this method.
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Use a small first hop
Rise only to the provider-set low height and return to the same marks; do not chase maximum height.
The first contact should establish rhythm, not create an overload.
The first landing is quiet, centred and within the target height range.
I’m stuck on this step
Reset: Re-read this authored instruction — “Rise only to the provider-set low height and return to the same marks; do not chase maximum height.” — and its success check, then attempt only this step.
Possible snag: The result from “Rise only to the provider-set low height and return to the same marks; do not chase maximum height.” does not yet meet this declared check: The first landing is quiet, centred and within the target height range.
Correction: Return to the start of “Use a small first hop”, reduce complexity or pace, and repeat only the part needed to satisfy: “The first landing is quiet, centred and within the target height range.”
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Rebound from the ankle-led contact
On landing, allow the whole foot to load while ankles, knees and hips flex slightly, then push away promptly without a deep squat.
A deep, slow countermovement changes the task from short-contact reactive work.
Contact remains brief and the trunk does not fold.
I’m stuck on this step
Reset: Re-read this authored instruction — “On landing, allow the whole foot to load while ankles, knees and hips flex slightly, then push away promptly without a deep squat.” — and its success check, then attempt only this step.
Possible snag: A deep knee bend replaces the ankle-led rebound.
Correction: Lower the hop height and rehearse two low contacts before another set.
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Keep contacts aligned
Track knees in line with feet and keep each contact on the marks. Do not let one leg take over or the feet drift.
Drift and collapse show loss of a repeatable rebound pattern.
Video shows centred contacts and similar left-right timing.
I’m stuck on this step
Reset: Re-read this authored instruction — “Track knees in line with feet and keep each contact on the marks. Do not let one leg take over or the feet drift.” — and its success check, then attempt only this step.
Possible snag: The result from “Track knees in line with feet and keep each contact on the marks. Do not let one leg take over or the feet drift.” does not yet meet this declared check: Video shows centred contacts and similar left-right timing.
Correction: Return to the start of “Keep contacts aligned”, reduce complexity or pace, and repeat only the part needed to satisfy: “Video shows centred contacts and similar left-right timing.”
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Stop at the first failed rebound
End the set when contact becomes clearly longer, height falls outside the band, alignment breaks or symptoms appear; step out and settle rather than forcing one more hop.
Technique failure is the endpoint, not exhaustion.
No extra contacts occur after the first stop criterion.
I’m stuck on this step
Reset: Re-read this authored instruction — “End the set when contact becomes clearly longer, height falls outside the band, alignment breaks or symptoms appear; step out and settle rather than forcing one more hop.” — and its success check, then attempt only this step.
Possible snag: The learner chases height and lengthens contact.
Correction: Reinstate the provider's height band and prioritise the declared contact task.
Possible snag: The series continues after inward knee collapse.
Correction: End at the first failed contact and review the cause.
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Calculate and interpret RSI
For valid contacts, divide jump height by ground-contact time using consistent units and report height and contact time alongside the ratio.
The same ratio can hide different height-contact strategies.
The record retains all three values and the exact hop condition.
I’m stuck on this step
Reset: Re-read this authored instruction — “For valid contacts, divide jump height by ground-contact time using consistent units and report height and contact time alongside the ratio.” — and its success check, then attempt only this step.
Possible snag: Invalid contacts remain in the mean RSI.
Correction: Apply the contact-time, height and alignment rules before calculation.
Stop / get help: Stop for sharp tendon, bone, knee, ankle or back pain, a pop, swelling, giving way or inability to land normally.
Correct versus incorrect execution
These accessible process diagrams are built from the tutorial’s own right/wrong teaching. They are not anatomical illustrations and do not add technique beyond the canonical tutorial.
Show a stable landing before repeated rebound.
Begin with a box drop to discover whether landing is adequate.
Use a small prompt rebound with slight joint flexion.
Sink into a deep squat and pause.
Stop at first height, contact-time or alignment failure.
Continue until exhaustion to improve the score.
Report height and contact time beside the ratio.
Report only the ratio and hide how it was achieved.
Call it performance in this rebound fixture.
Use it as proof of sprint or repeated-sprint ability.
Method-structure checklist
10 of 10 structural checks present
- Ordered, Power-specific instructions — present
- Every activity has a success check — present
- Materials or supplied records are declared — present
- Measurement or assessment rule is present — present
- Tutorial-specific troubleshooting is present — present
- Stopping or escalation boundary is present — present
- Every activity has an adjacent alternative — present
- Correct-versus-incorrect comparison is present — present
- Evidence context is bound to the Power record — present
- Planning metadata is present — present
The method-readiness band and presence checklist assess tutorial presentation and are separate from evidence quality for the underlying Power. They are automated editorial aids, not human approval.
Manual editorial sign-off: Pending. This tutorial must not display a human-approved state until an identified editor signs the exact content hash.