# PWR-003 — Isometric strength: learner worksheet Release: Revision 7T · Full Tutorial Edition Estimated time: Estimated 16 min reading; practical time is provider-set Difficulty: Intermediate Equipment: Common household or practice equipment — Calibrated force or torque device with a live target display; Stable supports and provider-approved restraints; Metronome or spoken ramp-hold-release cues; An isometric record showing device, side, joint angle, lever setting, force target, hold time, release time, validity flags and separate steadiness values. Space: Room-scale practice space Automated structural checklist: 10 of 10 structural checks present Evidence quality/context: G4; Focused research depth Automated method-quality band: Comprehensive Method-rating basis: Structure coverage, instruction/check specificity, alternative distinctness, source troubleshooting, comparison depth and whether purpose/check fields are authored rather than derived. Editorial review: Pending manual editorial sign off ## Before you begin - [ ] I read the tutorial authority and stop conditions. - [ ] I have the required equipment/space or a declared accessible alternative. ## Canonical source context Learn to hold a steady, submaximal knee-extension force inside a target band for eight seconds. A qualified provider sets posture, joint angle, target, rest and eligibility. You learn to enter the band smoothly, keep the knee still, breathe, make small corrections, leave on the tone, and recognise overshoot, drift and pulsing. This is force-control practice, not a maximum-strength test. Target outcome: Across three supervised submaximal plateaus, the learner enters a provider-set force ribbon without an overshoot, keeps at least the declared dwell time with the knee visibly still, and distinguishes force level from steadiness. ### Authority and setup conditions - Confirm the movement, side, exact joint angle and whether the goal is peak force or steadiness. - Tell the provider about pain, cardiovascular concerns, recent surgery and reactions to straining. - Set the dynamometer and limb to the written angle, then let the learner find the pad without pushing. Begin only when the device, joint angle and zero-force start match the setup sheet. - Rehearse finding zero force and ramping smoothly into the visible band at submaximal effort before any recorded hold. ### Required or supplied materials - Calibrated force or torque device with a live target display - Stable supports and provider-approved restraints - Metronome or spoken ramp-hold-release cues - An isometric record showing device, side, joint angle, lever setting, force target, hold time, release time, validity flags and separate steadiness values. ## 1. Lock the geometry and clear the trace Settle into the recorded seat and lever settings while the provider confirms the knee angle. Let every muscle soften until the live line rests on the stored zero; do not preload the pad. Why: A hidden preload shifts every later ribbon calculation and makes the acquisition time false. Success check: The baseline stays within the device's zero tolerance for three quiet seconds. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The baseline stays within the device's zero tolerance for three quiet seconds.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 2. Read the whole target ribbon Before pressing, point to the lower boundary, centre line and upper boundary. Repeat the hold duration and the provider's rule for when scoring begins. Why: Knowing only the centre encourages large corrections; the ribbon defines an acceptable plateau. Success check: The learner names both boundaries, the centre value and the scoring window without looking away from the setup. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The learner names both boundaries, the centre value and the scoring window without looking away from the setup.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 3. Use a three-beat entry At the start tone, raise pressure in three smooth beats: leave zero, approach the lower boundary, then settle near centre. Never punch through the upper edge and drop back. Why: A staged ascent separates controlled recruitment from a ballistic spike. Success check: The line crosses the lower boundary once and reaches the ribbon without an upper-edge overshoot. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The line crosses the lower boundary once and reaches the ribbon without an upper-edge overshoot.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 4. Settle before correcting Once inside, wait for one display update before changing pressure. If the line sits low, add a tiny squeeze; if it sits high, ease a tiny amount. Why: Reacting to every pixel creates a saw-tooth trace because visual feedback has delay. Success check: Corrections become small and infrequent instead of alternating above and below the ribbon. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Corrections become small and infrequent instead of alternating above and below the ribbon.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 5. Keep a quiet breathing rhythm Use easy breaths while holding the submaximal plateau. Maintain jaw, shoulders and hands relaxed; pressure should come from the declared knee action, not a whole-body brace. Why: Breath-holding and accessory tension can alter the trace and add unnecessary strain. Success check: Speech remains possible after release and observation shows no gripping, shoulder lift or facial strain. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Speech remains possible after release and observation shows no gripping, shoulder lift or facial strain.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 6. Guard the angle as a separate channel Keep the kneecap, ankle pad and trunk landmarks aligned while watching the force ribbon. If the number looks good but a landmark moves, tell the provider rather than rescuing the score. Why: A stable force value cannot validate a hold performed through changing geometry. Success check: The provider's angle check stays inside tolerance for the complete scored window. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The provider's angle check stays inside tolerance for the complete scored window.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 7. Leave the ribbon on the end tone When the end tone sounds, taper pressure directly back to zero over the agreed release interval. Do not add a final squeeze or extend the plateau. Why: An extra pulse changes duration and can hide loss of control near the end. Success check: The line returns once to baseline with no rebound peak and no delayed pressure. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The line returns once to baseline with no rebound peak and no delayed pressure.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 8. Label the trace before resting Call the attempt clean, overshot, drifted, pulsed or moved, then compare that label with the provider's trace review. Fully relax for the prescribed recovery. Why: Immediate trace classification teaches error recognition without turning recovery into another contraction. Success check: Learner and provider identify the same main feature before the next plateau begins. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Learner and provider identify the same main feature before the next plateau begins.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 9. Score control, not just magnitude Report acquisition time, dwell percentage, centre-line bias and coefficient of variation alongside average force. Keep invalid movement trials visible but out of the summary calculation. Why: These values reveal slow settling, one-sided drift and oscillation that an average alone conceals. Success check: The session ledger contains separate columns for force level, dwell, bias, variability and validity. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The session ledger contains separate columns for force level, dwell, bias, variability and validity.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 10. Match trace shape to one correction Classify the plateau as overshoot, slow acquisition, centre drift or rhythmic pulsing. Choose only the matching response for the next familiarisation: soften entry, clarify three beats, make one micro-adjustment or wait longer between corrections. Why: Different control errors have different causes; a generic instruction to squeeze harder can worsen all four. Success check: The next trace shows less of the named shape without changing ribbon, duration or knee geometry. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The next trace shows less of the named shape without changing ribbon, duration or knee geometry.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## 11. Use the ribbon dose matrix Record ribbon width, plateau seconds and visual, auditory or haptic feedback mode. When authorised, change only one cell and compare dwell, centre bias and pulsing with the previous plateau. Why: Simultaneous ribbon, duration and feedback changes make loss of control impossible to diagnose. Success check: The ledger names one changed ribbon variable and retains matched dwell, bias, pulsing and geometry results. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “The ledger names one changed ribbon variable and retains matched dwell, bias, pulsing and geometry results.” If an adaptation changes the measured task or configuration, record it as a different configuration rather than an equivalent attempt. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## Reflection What changed? ________________________________________________________________________________ What remains difficult? ________________________________________________________________________________ What will I repeat, adapt, ask for help with, or stop? ________________________________________________________________________________ --- Completion of this worksheet demonstrates tutorial participation only. It does not establish capability, qualification, safety clearance, diagnosis, treatment or independent validation.