Figure 3. Power and coherence of muscle and kinematic data recorded during a single 4 km h⁻¹ rear-end collision (experiment 1).

Left panel, average power spectra for the left and right SCM muscles, left and right PARA muscles, head forward acceleration (Head a_x) and head angular acceleration (Head α_y). * denotes the secondary peak in the power of the head angular acceleration signal between 5 and 10 Hz. Right panel, average coherence between the left and right SCM and PARA muscles. The dotted lines represents the 95% confidence limit for the coherence estimates. Note the significant peaks in coherence at 15.6 Hz (SCM) and 17.6 Hz (PARA) depicted by * and the power associated with these increases in the averaged power spectra (left panel).