Part 9 of a series; the fourth of fifteen chapter-by-chapter articles. Part 1: 10.5281/zenodo.23587879 · Part 2: 10.5281/zenodo.23587670 · Part 3: 10.5281/zenodo.23526074 · Part 4: 10.5281/zenodo.23609857 · Part 5: 10.5281/zenodo.23610607 · Part 6: 10.5281/zenodo.23682055 · Part 7: 10.5281/zenodo.23684537 · Part 8: 10.5281/zenodo.23684996
Chapter 4 of The Kuriyama Protocol moves inside the body's boundaries to the skeleton, which both transmits force and constrains motion. Eight sections, each with claim, verbatim field observations, derivation, literature check, verdict and prediction:
- The body is built to lose in force: muscle tension = external force × (external moment arm / muscle moment arm), and hand speed = muscle speed × the same ratio.
- Required torque = weight × horizontal distance, so position, not effort, sets joint demand.
- Rotation is shared by foot, knee, hip, thoracic spine, upper cervical spine and eyes; the lumbar spine should contribute little, and whatever the others lack is passed to it.
- The knee is a helix: relative rotation (tibia − femur) has a normal range, and collapse occurs on both sides, distinguished by the toe–knee direction relation, with opposite corrective interventions.
- Rotation is always coupled with lateral flexion and counter-rotation.
- Bone takes compression, soft tissue tension (tensegrity as metaphor only).
- Joints have close-packed and loose-packed directions, so effective degrees of freedom change by configuration rather than command.
- Five observation points; vertical is the minimum-torque, minimum-signal state, so people cannot sense their own tilt.
Five gaps found while writing, not stated in the book: (1) "consciousness cannot instruct which muscle to use" overstated Part 6 — a muscle-focus cue is a few-bit setting that raises target EMG at 20–60% 1RM but not at 80% (Calatayud et al., 2016); (2) "larger joint moment ⇒ larger activity of that joint's muscles" is not supported by the high- vs low-bar squat data cited (Wretenberg et al., 1996); (3) the knee was missing from the list of rotation sites; (4) "knees-together is a close-packed hip position" only half fits, since the close-packed position includes abduction; (5) a book prediction contradicted its own claim that upper segments compensate.
Five falsifiable predictions are registered (numbered 39–43, continuing the series):
- P39. Bar position changes the gluteal/quadriceps EMG ratio more than the cue "use your glutes"; the cue works at 50% 1RM and fades at 85%.
- P40. Smaller hip and thoracic rotation range predicts larger lumbar rotation in the same task; increasing hip range reduces it.
- P41. Inward knee collapse splits by toe–knee relation; each subgroup improves only with its matched intervention.
- P42. Squatting with knees outward yields greater maximum hip flexion than with knees inward.
- P43. A wedge under one foot displaces the head much less than tilt × height, with person-specific compensatory segments; a light head load reduces the deviation of eyes-closed "stand straight" posture from vertical.
Refutations are welcome. The author has no formal research training. Corrections will be issued as new versions, with earlier versions kept retrievable.
The article body is in Japanese. An English summary, the registered predictions and the reference list are included in the document.
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