Figure 2. Example of (A) an electrical signal recorded on the patella and of (B) a vertical platform acceleration signal illustrated in the time domain (upper panel) and Power Spectral Density (PSD, lower panel) for one representative subject. The ratio
![](volume14/iss1/images/jssm-14-54-e005.jpg)
for the patella signal illustrated in (A) was γ = 0.80.