Source file: docs/models/technogym-selection-700-leg-press.md · rendered from the repository
Technogym Selection 700 Leg Press (MNAC)
Status: Parametric – formula ready, inputs must be measured
Confidence of outputs: estimated · method: mechanical-model · built: 2026-10-17
Mechanism: pulley / cam ratio model (stack weight × cable ratio, plus pulley friction)
Model
F_footplate = W · R · η^n with R = Δs_stack / Δs_footplate
Why no full numeric estimate: Doubling-pulley direction not determinable from the official figure.
Inputs
| Symbol | Input | Value | Status | Uncertainty | Source (verbatim quote) |
|---|---|---|---|---|---|
| W | Selected stack label Note: The product page says "190 kg | 380 lbs"; 190 kg is 419 lb, so the page's lb figure is inconsistent. |
— | ⚙️ user setting | — | manufacturer_manual p. 13: “MNAC- LEG PRESS … Standard weight stack 190 kg (419 lb) Increased weight stack 250 kg (551 lb)” · retrieved 2026-10-17 |
| R | Cable ratio (doubling pulley present) Note: The service guide confirms a doubling pulley, so R ≠ 1, but the routing figure (p. 58, Fig. 56) does not show whether the movable pulley rides on the stack (R = 0.5) or on the carriage (R = 2). We do not guess. How to measure: Push the footplate/carriage 20 cm; measure the stack rise. R = stack rise / carriage travel. |
— | 📏 to measure (Maxime) | — | manufacturer_manual p. 213: “ADJUSTING THE TENSION OF THE CABLE WITH DOUBLING PULLEY This operation applies to MNAC- LEG PRESS, …” · retrieved 2026-10-17 |
| n | Pulleys in the path How to measure: Count on site (photo). |
— | 📏 to measure (Maxime) | — | — |
| η | Efficiency per pulley | — | ✅ sourced | [0.96 … 1.0] — crane-sheave table | engineering_reference: “Ratio A Bronze Brushed Sheaves | Ratio B Anti-Friction Bearing Sheaves | Number of Line Parts … .96 | .98 | 1” — Table header and first row (1 line part) · retrieved 2026-10-17 |
Validation by Maxime
Follow docs/protocole-mesure-fr.md. Geometry/ratio to measure: R, n. Once measured, the inputs are entered and the curve is computed with the same code (research/models/build_models.py).