Prosthetic Running Blade Spring Calculator
Prosthetic biomechanics & athletic engineering: Determine carbon fiber running blade dynamic stiffness ($k$), elastic strain energy return ($U$), and natural cadence resonance.
Athlete & Running Kinematics
Mass including residual limb
Sprinting peak ~2.8 to 3.5 × BW
Prosthetic Blade Mechanics
Vertical compression at midstance (typically 60–90 mm)
Hysteresis loss ~6–10%
Sprinting cadence ~180–220 steps/min
Spring-Mass Model of Running
The athlete-blade system acts as a spring-mass oscillator where dynamic stiffness is:
$$k_{\text{leg}} = \frac{F_{\text{peak}}}{\Delta z}$$
Strain energy stored: $U_{\text{stored}} = \frac{1}{2} k \Delta z^2$. Rebounding energy returned during toe-off: $U_{\text{return}} = \eta \cdot U_{\text{stored}}$.
Stiffness & Energy Return
Required Dynamic Stiffness (k)
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Energy Returned per Stride
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Forces & Resonance Frequency
Peak Ground Force (F_peak)
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Midstance vGRF
Blade Natural Frequency (f_n)
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√(k / M) / 2π
Biomechanical Tuning
Manufacturer Category Rating:
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Resonance Cadence Match:
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Stiffness Evaluation:
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