*4.2. Experimental Traumatic Spinal Cord Injury (TSCI) Causes Perturbation of Electromyographic (EMG) Data*

The experimental TSCI resulted in both a physiological and histopathological perturbation [4]. In this analysis, there was a difference in the *RP* values when comparing the pre- and post-lesion data; this was statistically significant. Specifically, the low frequency (LF) sub-bands (D4, D6, and A6) were increased significantly during the post-lesion period on both sides. Also, the high frequency (HF) sub-bands (D1 and D2) were decreased significantly during the post-lesion period on the right side. These results are consistent with the literature [14]. As a general construct, neurological disease is associated with abnormalities in the firing of the motor units and leads to a lower discharge frequency [14,15,52]. This, in turn, can affect the distribution of the high and low-frequency components of EMG signals. This shift in the *RP* value may be related to the disorganized, spontaneous firing of single or multiple motor units, which affect the frequency distribution. Speculatively, a component of these abnormalities was be related to spasticity; in TSCI, there may preferentially affect the recruitment of Type I or Type II motor units, which could also distort the frequency content. The elucidation of these relationships requires further research. With this method, the change in recruitment behaviour post the TSCI might be detectable even before the clinical evidence.
