Description
Return muscle PCSA and ideal pennation-projected force.
Mechanical inertia, torque and muscle-force projections require compatible axes, origins and geometric assumptions. A parallel-axis contribution, planar moment or ideal pennation factor is one local model term rather than a full anatomical load or muscle-activation calculation.
Return muscle PCSA and ideal pennation-projected force.
When to use this tool
Use Muscle Physiological Cross Section Force Term when evaluating the stated segment, moment, inertia or ideal muscle-geometry term.
How to use the tool and how it works
- Enter volume, fiberLength, specificTension, pennationRadians. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read pcsa, fiberForce, tendonForce. Use the output convention below.
Return muscle PCSA and ideal pennation-projected force. Require volume/specificTension >= 0, fiberLength > 0 and pennation in [0,pi/2]; pcsa = volume/fiberLength, fiberForce = pcsa*tension, tendonForce = fiberForce*cos(angle).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| volume | Volume | Required. Finite number; minimum 0. |
| fiberLength | Fiber Length | Required. Finite number; strictly above 0. |
| specificTension | Force per PCSA area on compatible units. | Required. Finite number; minimum 0. |
| pennationRadians | Pennation Radians Unit: rad. | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| pcsa | Volume/fiberLength under this convention, before pennation projection. | Required. Finite number. |
| fiberForce | Fiber Force | Required. Finite number. |
| tendonForce | Tendon Force | Required. Finite number. |
{
"input": {
"volume": 100,
"fiberLength": 10,
"specificTension": 3,
"pennationRadians": 0
},
"output": {
"pcsa": 10,
"fiberForce": 30,
"tendonForce": 30
}
}Limitations and assumptions
- PCSA here excludes the projection factor; properties and uniform-fiber assumptions are supplied, without predicting actual activation or safe force.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use verified anatomy and calibration, a consistent coordinate frame and a complete appropriate mechanical model for actual loading or clinical interpretation.
References
Similar or alternative tools
- Muscle Moment Arm Torque Factor
Return projected tendon force and signed moment-arm torque.
- Force Plate Cross Axis Reference Sign Tool
Calculate force plate cross axis reference sign from explicit caller-supplied inputs.