Figure 7

Experimental, fitted, and predicted forces from a typical subject's quadriceps femoris muscle at different constant shortening speeds during the model validation phase. (a): Fitting of the experimental force data in response to VFT20-VFT80 train combination at 40° of knee flexion (isometric) to determine the values of a, b, A₄₀, τ₁, τ₂, and K _m (b): Fitting the experimental force data in response to VFT20-VFT80 train combination at 200°/s to determine the value of V₁. (c)-(e): Comparison of experimental and predicted forces in response to CFT10, CFT50, and CFT100 (panel c), VFT30, VFT50, and VFT100 (panel d), and DFT30, DFT70, and DFT100 (panel e) at a shortening speed of -25°/s. (f)-(n): Comparison of experimental and predicted forces in response to the above stimulation trains at -75°/s (panels f-h), -125°/s (panels i-k), and -200°/s (panels l-n). The isovelocity model parameter values for this subject were: a = -0.00165, b = -0.0662, A₄₀ = 3.42686, τ₁ = 30.69527, τ₂ = 91.07621, K _m = 0.23564, R₀ = 2, τ _c = 20, and V₁ = 0.00074.