Section 276 of 440
Complete canonical tutorial. This reader section contains the same teaching body as PWR-094 · Body schema. Open the Power dossier.
PWR-094 · SELF GUIDED full tutorial
Estimate one body-part-to-target relation, move normally and correct the map
Body schema is an action-oriented representation of where body parts are relative to each other and the task. This low-risk lesson uses a seated reach to a benign target. The learner estimates direction and distance before moving, reaches normally with visual or tactile support allowed, compares the endpoint with the estimate and updates one error. It is not a neurological or body-image assessment.
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
- Stable chair and table, six large soft target cards and a start marker for the hand.
- Ruler or grid mat, estimate sheet and optional tactile or verbal position cues.
- Usual posture and mobility supports.
Before you start
- Choose a pain-free arm and comfortable table-height reach, or use the diagram route.
- Place targets within normal supported range with no hot, sharp or breakable objects nearby.
- Declare whether vision stays available; keep the same rule for scored trials.
3 · The method
Follow these steps in order
- Fix the body and task frame
Mark the seated position, starting hand position, target plane and vision rule.
Why: A stable reference makes estimates comparable.
Check: Chair, hand start and target area are marked.
- Calibrate the external scale
On two unscored targets, view or feel the grid distance and say the matching centimetres or squares. Return to the marked hand start after each.
Why: A shared scale prevents number unfamiliarity from being mistaken for body–target error.
Check: The learner correctly links near and far examples to the declared measurement units before scored estimates.
- Estimate direction
Before moving, point on a diagram or say whether the target is left, right, near, far, above or below the starting hand.
Why: A pre-movement estimate exposes the current body–target relation.
Check: One direction category is committed before reach.
- Name the segment relation
State where the hand is relative to the elbow and where the elbow is relative to the shoulder at the start, using ordinary words such as forward, bent or supported.
Why: Body schema concerns linked body segments, not only the hand’s location in room space.
Check: The start record describes both hand-to-target and hand–elbow–shoulder relations without pain or forced posture.
- Estimate distance
Mark the expected travel distance in centimetres or grid squares without moving the hand.
Why: Distance and direction can fail differently.
Check: A numerical or ordinal distance estimate is saved.
- Reach normally
Move at a comfortable speed to the target using the declared supports. Stop at first contact; do not search around it.
Why: One natural reach tests the estimate without added correction movements.
Check: The endpoint and any support are observable.
- Compare and update
Measure endpoint difference and classify the error as direction, distance or both. State one corrected relation before returning to start.
Why: Naming the error updates the action map rather than merely repeating.
Check: Every trial has a measured discrepancy and one correction sentence.
- Delay and change target
After 48 hours, use six targets in new safe positions while preserving seat and start. Score categories without rereading old answers.
Why: New positions test the relation method beyond memorised endpoints.
Check: Delayed novel-target results are separate.
4 · Worked example
See the whole method used once
Scenario
Seated at a table, Dev estimates a soft card placed forward-left of his marked right-hand start.
Walkthrough
- Dev keeps vision available and marks the same chair and start position.
- He predicts forward-left and 22 cm before moving.
- He reaches once and contacts the card at 27 cm without searching.
- He records correct direction and a 5 cm underestimation, then states “the target is farther than my first map.”
- Two days later he applies the same estimate–reach–compare sequence to six changed target positions.
Result
Dev corrects a distance relation in this seated task. The exercise does not measure neurological integrity or durable whole-body schema change.
5 · Right and wrong
Compare correct or safer execution with the common wrong version
| Moment | Right / safer | Wrong / riskier | Why it matters |
|---|---|---|---|
| Estimate | Commit direction and distance before movement. | Reach first and then claim what was expected. | A post-action estimate cannot show prediction error. |
| Reach | Use one comfortable movement and stop at contact. | Search back and forth or stretch beyond comfort. | Searching adds feedback and strain. |
| Support | Keep normal visual and posture supports. | Remove vision or back support to make the test pure. | Support removal changes risk and configuration. |
| Interpretation | Report error for this body–target setup. | Call a small error proof of normal neurology. | A simple reach is not a clinical assessment. |
6 · Common mistakes
Spot the error and apply the correction
| Mistake | Fix |
|---|---|
| The hand start drifts. | Use a tactile or drawn start marker every trial. |
| Direction and distance are merged. | Score category and magnitude in separate fields. |
| The target is placed at painful end range. | Bring it inside ordinary comfortable reach or use the diagram version. |
| Repeated targets are called transfer. | Change safe positions after a delay and hide old records. |
7 · Practice
Turn the steps into a usable skill
First session
- Set one stable seated frame.
- Complete two unscored estimates.
- Run six target trials.
- Classify direction versus distance errors.
- Finish with a comfortable movement check.
Repeat plan
Use one six-trial session twice a week for two weeks. Keep seat and hand start fixed, then vary target positions. Do not add eyes-closed standing or unstable surfaces.
Progress when
- All estimates precede movement.
- Direction and distance errors on changed targets are reported separately and are stable or lower without added searching.
- Distance error declines without extra searching or symptoms.
Do not progress when
- Pain, dizziness, body-image distress or unusual sensory symptoms occur.
- The task requires reduced support or greater reach.
- The goal becomes diagnosis or rehabilitation without a clinician.
8 · Check the result
Measure what changed
Pre-movement direction accuracy and absolute distance error.
How: For six targets, count correct direction categories and calculate absolute centimetre or grid-unit difference between estimated and actual travel, with support and symptoms recorded.
Good result: All estimates are committed before movement, direction and distance errors are both retained, and any lower median distance error repeats on a second novel set without strain or added correction movements. No fixed correct-count is a neurological pass score.
This does not prove: It does not diagnose body-schema disorder, neurological health, body ownership or general movement safety.
Self-check
- Was the estimate made before moving?
- Are direction and distance scored separately?
- Did you use one reach without searching?
- Were delayed targets actually new?
9 · Stop, adapt or get help
Keep the safety boundary practical
Stop and get help
- Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
- Seek clinical review for sudden or function-changing misreaching, sensory change or body-recognition difficulty.
- Do not continue if stable seating or a safe target range cannot be maintained.
Accessibility and adaptations
- Use tactile target cards and a raised-line distance grid.
- Give verbal left/right/near/far response options or use eye gaze.
- Use the diagram-only relation task when reaching is not appropriate.
10 · Evidence and limits
Why these instructions are here
- primary research
Tool use produced short-term morphological updating effects in a defined body-schema experiment, not a durable general training result.
Tool-use induces morphological updating of the body schema - primary research
A small rubber-hand-illusion study linked self-representation and external-object judgement but cannot support broad clinical claims.
Rubber hand illusions and size-weight illusions: self-representation modulates representation of external objects
Limits
- Short laboratory after-effects do not establish durable functional change.
- Body schema, body ownership and body image are distinct constructs.
- Results belong to the declared seated reach configuration.
Open the complete canonical research register
- Primary empirical supportLimiting / contraryTool-use induces morphological updating of the body schema
Lucilla Cardinali; Francesca Frassinetti; Claudio Brozzoli; Christian Urquizar; Alice C Roy; Alessandro Farnè · 2009 · Primary research
- Primary empirical supportLimiting / contraryRubber hand illusions and size-weight illusions: self-representation modulates representation of external objects
Patrick Haggard; Shyma Jundi · 2009 · Primary research
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.
Fix the body and task frame
Mark the seated position, starting hand position, target plane and vision rule.
A stable reference makes estimates comparable.
Chair, hand start and target area are marked.
I’m stuck on this step
Reset: Re-read this authored instruction — “Mark the seated position, starting hand position, target plane and vision rule.” — and its success check, then attempt only this step.
Possible snag: The result from “Mark the seated position, starting hand position, target plane and vision rule.” does not yet meet this declared check: Chair, hand start and target area are marked.
Correction: Return to the start of “Fix the body and task frame”, reduce complexity or pace, and repeat only the part needed to satisfy: “Chair, hand start and target area are marked.”
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Calibrate the external scale
On two unscored targets, view or feel the grid distance and say the matching centimetres or squares. Return to the marked hand start after each.
A shared scale prevents number unfamiliarity from being mistaken for body–target error.
The learner correctly links near and far examples to the declared measurement units before scored estimates.
I’m stuck on this step
Reset: Re-read this authored instruction — “On two unscored targets, view or feel the grid distance and say the matching centimetres or squares. Return to the marked hand start after each.” — and its success check, then attempt only this step.
Possible snag: The hand start drifts.
Correction: Use a tactile or drawn start marker every trial.
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Estimate direction
Before moving, point on a diagram or say whether the target is left, right, near, far, above or below the starting hand.
A pre-movement estimate exposes the current body–target relation.
One direction category is committed before reach.
I’m stuck on this step
Reset: Re-read this authored instruction — “Before moving, point on a diagram or say whether the target is left, right, near, far, above or below the starting hand.” — and its success check, then attempt only this step.
Possible snag: The result from “Before moving, point on a diagram or say whether the target is left, right, near, far, above or below the starting hand.” does not yet meet this declared check: One direction category is committed before reach.
Correction: Return to the start of “Estimate direction”, reduce complexity or pace, and repeat only the part needed to satisfy: “One direction category is committed before reach.”
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Name the segment relation
State where the hand is relative to the elbow and where the elbow is relative to the shoulder at the start, using ordinary words such as forward, bent or supported.
Body schema concerns linked body segments, not only the hand’s location in room space.
The start record describes both hand-to-target and hand–elbow–shoulder relations without pain or forced posture.
I’m stuck on this step
Reset: Re-read this authored instruction — “State where the hand is relative to the elbow and where the elbow is relative to the shoulder at the start, using ordinary words such as forward, bent or supported.” — and its success check, then attempt only this step.
Possible snag: The result from “State where the hand is relative to the elbow and where the elbow is relative to the shoulder at the start, using ordinary words such as forward, bent or supported.” does not yet meet this declared check: The start record describes both hand-to-target and hand–elbow–shoulder relations without pain or forced posture.
Correction: Return to the start of “Name the segment relation”, reduce complexity or pace, and repeat only the part needed to satisfy: “The start record describes both hand-to-target and hand–elbow–shoulder relations without pain or forced posture.”
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Estimate distance
Mark the expected travel distance in centimetres or grid squares without moving the hand.
Distance and direction can fail differently.
A numerical or ordinal distance estimate is saved.
I’m stuck on this step
Reset: Re-read this authored instruction — “Mark the expected travel distance in centimetres or grid squares without moving the hand.” — and its success check, then attempt only this step.
Possible snag: The result from “Mark the expected travel distance in centimetres or grid squares without moving the hand.” does not yet meet this declared check: A numerical or ordinal distance estimate is saved.
Correction: Return to the start of “Estimate distance”, reduce complexity or pace, and repeat only the part needed to satisfy: “A numerical or ordinal distance estimate is saved.”
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Reach normally
Move at a comfortable speed to the target using the declared supports. Stop at first contact; do not search around it.
One natural reach tests the estimate without added correction movements.
The endpoint and any support are observable.
I’m stuck on this step
Reset: Re-read this authored instruction — “Move at a comfortable speed to the target using the declared supports. Stop at first contact; do not search around it.” — and its success check, then attempt only this step.
Possible snag: The target is placed at painful end range.
Correction: Bring it inside ordinary comfortable reach or use the diagram version.
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Compare and update
Measure endpoint difference and classify the error as direction, distance or both. State one corrected relation before returning to start.
Naming the error updates the action map rather than merely repeating.
Every trial has a measured discrepancy and one correction sentence.
I’m stuck on this step
Reset: Re-read this authored instruction — “Measure endpoint difference and classify the error as direction, distance or both. State one corrected relation before returning to start.” — and its success check, then attempt only this step.
Possible snag: Direction and distance are merged.
Correction: Score category and magnitude in separate fields.
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
Delay and change target
After 48 hours, use six targets in new safe positions while preserving seat and start. Score categories without rereading old answers.
New positions test the relation method beyond memorised endpoints.
Delayed novel-target results are separate.
I’m stuck on this step
Reset: Re-read this authored instruction — “After 48 hours, use six targets in new safe positions while preserving seat and start. Score categories without rereading old answers.” — and its success check, then attempt only this step.
Possible snag: Repeated targets are called transfer.
Correction: Change safe positions after a delay and hide old records.
Stop / get help: Stop for pain, dizziness, new numbness, weakness, neglect-like errors, loss of balance or distress about the body.
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.
Commit direction and distance before movement.
Reach first and then claim what was expected.
Use one comfortable movement and stop at contact.
Search back and forth or stretch beyond comfort.
Keep normal visual and posture supports.
Remove vision or back support to make the test pure.
Report error for this body–target setup.
Call a small error proof of normal neurology.
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.