trainlog/docs/domain/exercise_equipment_interpretation.md

Exercise and equipment interpretation

Scientific knowledge is keyed to existing stable exercise and equipment identities. Display labels are identification clues. They are not anatomical proof, runtime classification rules or grounds for merging identities. catalog/exercise-knowledge-v1.json separates reviewed interpretations from conditional candidates; catalog/equipment-knowledge-v1.json describes physical apparatus and its exercise capabilities.

The reviewed inventory contains 23 exercise identities and 41 equipment identities: 38 supplied definitions and three durable custom entries. No manufacturer or model has been confirmed for the local apparatus. Available manufacturer examples remain examples; their ratios, trajectories and outcome claims are not transferred to the local inventory.

Reviewed exercise families

The following are biomechanical interpretations using the stated execution. They are qualitative classifications, not measurements of individual force contributions. Anatomy and the references linked below support the rationale.

Actual catalog exercise	Interpretation	Existing primary / secondary BODY ZONES	Main qualification
Abdominal crunch	Resisted spinal flexion; rectus and obliques	core	Confirm that movement is not predominantly hip flexion
Arm curl	Elbow flexion; biceps, brachialis and brachioradialis	arms	Grip and shoulder support change participation
Back extension	Spinal extension; erector spinae and multifidus	back / core	Pelvic restraint determines hip involvement
Converging Shoulder Press	Overhead push; deltoids with elbow extension	shoulders / arms	Plane, seat support and scapular freedom unresolved
Diverged seated row; Seated row	Horizontal pull; humeral extension and scapular retraction	back / arms	Elbow path determines lat/scapular/posterior-deltoid emphasis
Diverging lat pulldown; Lat pull	Vertical pull; shoulder adduction/extension and elbow flexion	back / arms	Grip and linkage do not establish regional isolation
Hip abduction	Abduction involving medius/minimus and other abductors	glutes	Tensor fasciae latae and superior maximus contributions vary
Hip adduction	Resisted thigh approximation by hip adductors	thighs	Hip and knee angles affect individual muscles
Leg extension	Resisted knee extension by quadriceps	thighs	Rectus femoris also crosses hip
Leg press	Combined knee/hip extension	thighs / glutes	Machine, depth and foot placement alter moments
Prone leg curl	Knee flexion with prone support	thighs	Distinct length context from seated curl
Seated Leg; Seated leg curl	Knee flexion with seated support	thighs	Two existing identities retained; common family does not merge IDs
Rear Delt	Reverse fly: humeral horizontal abduction with scapular contribution	shoulders / back	Distinct from Pec Fly on the same device
Rotary torso	Relative thorax-pelvis rotation; paired oblique action	core	Compatible supplied equipment is not proven occurrence linkage

Chest Press priority is addressed through a complete conditional anterior press interpretation: pectoralis major as a primary mover, anterior deltoid and triceps as synergists, shoulder horizontal adduction with elbow extension, and horizontal_push. The custom Chest press and Converting chest press identities have not independently established that execution. Their retained chest/shoulders/arms relations are plausible historical mappings; the scientific candidate stays uncertain until apparatus and motion are confirmed. NIH pectoralis anatomy, OpenStax upper-limb anatomy

The custom Abdominal entry similarly retains a conditional crunch candidate, not an asserted execution. Both generic warm-up identities remain unresolved. Marche has a conditional walking interpretation; a continuous/duration profile and an aggregate treadmill inventory do not establish all execution details or a specific occurrence association. Unknown new custom exercises remain unclassified until evidence is added explicitly.

Seated versus prone curl has direct longitudinal evidence: the studied seated condition produced greater growth of biarticular hamstrings. This supports retaining length context while avoiding a universal machine or outcome ranking. Maeo and colleagues

The leg-press review concerns EMG. It supports quadriceps involvement but does not establish a robust universal foot-placement recipe or prove that hamstring coactivation replaces knee-flexion training. Martín-Fuentes and colleagues

Reverse pec-deck and row/pulldown investigations concern selected EMG tasks. They corroborate plausible posterior-deltoid and scapular contributions without ranking long-term growth. Divergent/convergent machine labels add no independent outcome evidence. Franke and colleagues, Lehman and colleagues

Pelvic stabilization changes lumbar-extensor excitation. A Back Extension execution dominated by hip motion may deserve different muscle roles from the spinal-extension interpretation; that decision requires actual geometry and execution evidence. Lee

Multifunction and unrestricted equipment

A Rear Delt / Pec Fly device supports at least two distinct tasks. Rear Delt uses shoulder horizontal abduction and a shoulder/back projection. Pec Fly uses horizontal adduction, with a chest emphasis and possible anterior-deltoid assistance. Pec Fly has no verified local exercise ID. It remains an unlinked capability, not a fabricated catalog exercise.

The assistance device likewise supports separate assisted dip and assisted chin/pull-up capabilities. Neither has a verified local exercise ID. The legacy assisted_dip and assisted_chin strings in the equipment manifest are not creator exercise identities. Chin-up and pronated pull-up also require specific grip/execution context. Manufacturer catalogs demonstrate that such combination products exist, not that these examples identify the local model. Life Fitness equipment catalogue

Functional trainers, adjustable pulleys, dumbbells, kettlebells, bags, medicine balls and suspension straps require the actual exercise. Their presence cannot establish a primary BODY ZONE. Cable height and routing, attachment, stance and line of pull determine the task. A documented example with a 4:1 cable ratio illustrates why local ratios must be verified separately. Precor RUD0915

Benches and guided squat machines require support and movement details. Cardio apparatus requires mode, speed/cadence, resistance and support context. A rowing ergometer includes a leg/trunk/arm cycle and is not the same exercise as a seated resistance row. Battle ropes have mass and inertia: their existing bodyweight catalog category is retained as legacy metadata, not a calibrated physical load model. Any future vocabulary change needs a separate explicit compatibility decision.

BODY ZONE audit result

No reviewed finding justifies an automatic persisted-zone change. Existing assignments are compatible with the identified families or remain conditional where observation is missing. Additional potential synergists are documented at muscle level. A future correction must state its evidence, affected stable identities and explicit migration separately; enrichment never silently rewrites historical mappings.