Figure 3

Simulated COM sway signals (top panel) and corresponding summary statistics (four lowest panels). The three columns present three simulated test subjects. The blue COM signals are the original three signals that were simulated with known parameter values. The red COM signals were simulated using parameters that were sampled from the joint posterior PDFs that were inferred from the original COM signals by the SMC-ABC algorithm (see Section Methods: Statistical inference of the model parameters). The lower panels show the summary statistics: amplitude -, velocity -, and acceleration histograms and spectra. In each panel, the blue line is the true summary statistic calculated from the original COM signals (average of the three), and the blue shadowed region presents 95% CIs that were calculated from the COM signals simulated using parameters that were sampled from the inferred marginal posterior PDFs. Leftmost column: true parameters: m = 54 kg, h = 0.85 m, P = 124 Nm/rad, D = 8.7 Nms/rad, Δ = 0.16 s, σ = 0.22 Nm, C _ON  = 0.63; estimated parameters: P = 119 Nm/rad, D = 24 Nms/rad, Δ = 0.18 s, σ = 0.23 Nm, C _ON  = 0.67. Mid column: true parameters: m = 80 kg, h = 0.78 m, P = 128 Nm/rad, D = 37 Nms/rad, Δ = 0.16 s, σ = 0.16 Nm, C _ON  = 0.75; estimated parameters: P = 126 Nm/rad, D = 37 Nms/rad, Δ = 0.14 s, σ = 0.16 Nm, C _ON  = 0.82. Rightmost column: true parameters: m = 82 kg, h = 0.96 m, P = 237 Nm/rad, D = 29 Nms/rad, Δ = 0.16 s, σ = 0.44 Nm, C _ON  = 0.59; estimated parameters: P = 244 Nm/rad, D = 22 Nms/rad, Δ = 0.12 s, σ = 0.45 Nm, C _ON  = 0.59.