Description
Ideal force and length projection relative to a supplied tendon axis, excluding force transmission through a full muscle architecture.
Physiological models use measured signals, reference levels, rates, and physical balances. A content difference, normalized phase, or energy term depends on its unit system and model assumptions. Supplied coefficients and annotations define the calculation but do not establish biological plausibility or measurement accuracy.
Ideal force and length projection relative to a supplied tendon axis, excluding force transmission through a full muscle architecture.
When to use this tool
Use Muscle Pennation Force Projection Term when you need this explicit signal, content, phase, flow, or physical-balance term under compatible supplied units.
How to use the tool and how it works
- Enter fiberForce, pennationRadians, fiberLength. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read tendonComponent, transverseComponent, projectedLength. Use the output convention below.
For nonnegative fiberForce and fiberLength and pennationRadians within -pi/2 through pi/2 return tendonComponent=force*cos(angle), transverseComponent=force*sin(angle), and projectedLength=length*cos(angle).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| fiberForce | Fiber Force | Required. Finite number; minimum 0. |
| pennationRadians | Pennation Radians | Required. Finite number. |
| fiberLength | Fiber Length | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| tendonComponent | Tendon Component | Required. Finite number. |
| transverseComponent | Transverse Component | Required. Finite number. |
| projectedLength | Projected Length | Required. Finite number. |
{
"input": {
"fiberForce": 100,
"pennationRadians": 1.0471975511965976,
"fiberLength": 10
},
"output": {
"tendonComponent": 50.000000000000014,
"transverseComponent": 86.60254037844386,
"projectedLength": 5.000000000000001
}
}Limitations and assumptions
- Force and length outputs retain their respective input units. This is an ideal vector projection with signed transverse direction, not a full muscle-tendon model or measured load.
- 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. Signed zero is exported as zero.
Alternative or Complementary methods
Choose a physiological and measurement model suited to the signal or experiment. Verify coefficients, unit conversions, baseline definitions, and sampling support before combining local terms.
References
Similar or alternative tools
- Muscle Force Length Normalized Coordinate
Normalize supplied muscle length and active force to explicit references, without a force-length curve or physiological prediction.
- Muscle Pennation Tendon Axis Reversal Sign
Project a supplied fiber force using the supplied pennation cosine and explicit tendon-axis orientation.