# PWR-004 — Eccentric strength: learner worksheet Release: Revision 7T · Full Tutorial Edition Estimated time: Estimated 12 min reading; practical time is provider-set Difficulty: Intermediate Equipment: Specialist equipment — Clinician-controlled isokinetic or resistance apparatus with emergency release and assisted reset; Stable seating plus fitted pelvic, thigh and lower-leg supports; Start, middle and finish markers; Velocity display or tempo cue; Descent worksheet for angle bins, torque continuity, speed, unload point, reset mode and symptoms; Delayed-response log plus a separate supported step-down sheet Space: Specialist setting 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 Eccentric work happens when muscle produces force while lengthening. Here, quadriceps activity brakes a machine arm as a seated knee bends. This is neither a slow lift nor a static hold. Learn receive-lower-unload: accept supported tension, allow continuous descent, resist from first marker through final marker, unload, then relax for passive return. Curve-reading exercises expose four failures—catch-and-drop, stall, mid-arc hole and end-range dump. A rehabilitation clinician selects apparatus, range, velocity, resistance, repetition count and recovery. Target outcome: In one authorised appointment, a participant performs a continuously resisted knee-extension descent, completes passive return without lifting, logs later response and distinguishes full-arc control from an impressive but invalid torque spike. ### Authority and setup conditions - Report recent injury, operation, swelling, instability, unexplained weakness, severe soreness or any previous unusual response to lengthening exercise. - Describe today's action: apparatus starts with lower leg raised, then travels downward while quadriceps acts as a brake. - Sweep through planned angles without working resistance. Identify beginning, midpoint and finish; mention pinching or guarding immediately. - Practise three commands. Receive means meet supported tension. Lower means allow movement while resisting. Unload means stop resisting for mechanical removal. - Rehearse once lightly. The lever must keep moving during lower; a frozen arm signals a different contraction. - Agree how same-day and next-morning effects will reach the responsible clinician. ### Required or supplied materials - Clinician-controlled isokinetic or resistance apparatus with emergency release and assisted reset - Stable seating plus fitted pelvic, thigh and lower-leg supports - Start, middle and finish markers - Velocity display or tempo cue - Descent worksheet for angle bins, torque continuity, speed, unload point, reset mode and symptoms - Delayed-response log plus a separate supported step-down sheet ## 1. Map travel direction Point from start angle to finish angle. Say, 'My knee bends while I brake this arm.' Name midpoint as a separate landmark. Why: Direction determines whether quadriceps fibres shorten, hold length or lengthen. Success check: Participant identifies correct limb, direction and three landmarks without looking at torque. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Participant identifies correct limb, direction and three landmarks without looking at torque.” 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. Fit supports and rehearse Sit against backrest while clinician aligns knee axis, secures pelvis and positions shin pad. Perform an unloaded sweep, then a light receive-lower-unload rehearsal. Why: Stable geometry keeps measured work inside a repeatable arc and exposes uncomfortable contact before loading. Success check: No pelvic slide, thigh lift, knee twist, pinching or numbness appears. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “No pelvic slide, thigh lift, knee twist, pinching or numbness appears.” 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. Receive supported tension Remain relaxed while apparatus places its arm at start. On receive, meet already-supported resistance smoothly—no upward pull, kick or sudden catch. Why: Snatching produces an early torque spike without showing braking capacity. Success check: Curve begins without impact and arm waits at start until lower command. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Curve begins without impact and arm waits at start until lower command.” 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. Allow movement while braking On lower, permit knee flexion while maintaining pressure against moving arm, like controlling a heavy door. Avoid freezing or letting descent run away. Why: Lengthening control requires force during movement; stalling becomes an isometric hold, whereas runaway motion becomes a drop. Success check: Angular velocity remains inside its declared corridor and braking torque persists through first half. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Angular velocity remains inside its declared corridor and braking torque persists through first half.” 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. Brake through the final third Continue resisting beyond midpoint to finish. Keep pelvis level and torso supported. If control disappears, signal abort instead of catching a falling arm. Why: Strong early output can hide release near terminal angles. Success check: Final bins retain torque without acceleration, twisting or shortened travel. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Final bins retain torque without acceleration, twisting or shortened travel.” 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. Unload, then accept passive return At finish, follow unload command. Relax quadriceps while apparatus removes resistance and restores start position. Never lift during reset. Why: An active upward reset adds concentric work, changing dose and meaning. Success check: Trace shows a distinct unload boundary followed by assisted return with no participant-generated positive work. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Trace shows a distinct unload boundary followed by assisted return with no participant-generated positive work.” 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. Classify descent shape Before reading peak N·m, label each curve smooth arc, catch-and-drop, mid-arc hole or end-range dump. Check angular speed beside torque in every bin. Why: Peak magnitude cannot reveal missing braking elsewhere. Success check: Validity decision cites exact bin and velocity departure rather than overall impression. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Validity decision cites exact bin and velocity departure rather than overall impression.” 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. Log delayed response After recovery, document immediate symptoms and separate step-down observation. Add later-that-day and next-morning soreness, swelling and ordinary-activity change before another loaded decision. Why: Lengthening work may produce effects after departure. Success check: Both delayed entries exist and clinician reviews them before changing any parameter. Accessible alternative: Ask the qualified provider to adapt positioning, cue modality, pace, interface or rest while preserving this step’s declared check: “Both delayed entries exist and clinician reviews them before changing any parameter.” 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.