The force developed by actively lengthened muscle depends on different structures across different scales of lengthening. For small perturbations. the active response of muscle is well captured by a linear-time-invariant (LTI) system: a stiff spring in parallel with a light damper. The force response of muscle to longer stretches is better represented by a compliant spring that can fi... https://www.ldartstudio.com/product-category/scar-gel/