## 4 Discussion  
The current preliminary research investigated the relationship between muscle activity and hip and knee torque data during stance and swing phases in non-symptomatic adults. As hypothesized, our results demonstrated that VLO, BF, TA, and GCM muscle activities were related to hip and knee torques. Most importantly, the present baseline normative data would provide insightful information to clinicians when treating gait impairments utilizing RAGT in individuals with neurological impairments or conditions because our novel results revealed optimal or normative (physiological) motor control patterns elicited during Walkbot RAGT by means of adjusting gait speed and BWS parameters. Moderate relationships between hip and knee torques and biceps femoris activation data were statistically significant, ranging from \(r=0.241\) to \(-0.590\), \(p<0.05\). Importantly, inverse relationships between hip torques and vastus lateralis oblique, biceps femoris, and tibialis anterior activation data correlations existed, respectively. Specifically, the correlation analysis showed a moderate relationship of the VLO with gait speed and BWS (\(r=-0.383\)). The current results demonstrated that BF EMG activity was related to gait speed and BWS. In a previous study involving 35 healthy women, a moderate (\(r=0.50\)) correlation was reported between BF EMG muscle activity and gait speed [25]. Gait phase prolongation may have enforced modifications in neuromuscular control to accommodate the altered task constraints implied by changing the natural relationship between gait speed and BF muscle activity [25]. Another study on the intentional modification of the preferred step-frequency-to-amplitude relationship suggested that such alterations in the temporal step pattern are accompanied by reorganization of the underlying muscle activity, including the quadriceps and hamstrings [6]. [PERSON] et al. (2012) [26] showed that modular organization of neuromuscular activity characteristics to bipedal human locomotion was compatible between the overground walking and RAGT conditions and \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Spearman’s rho (\(r\))** & **VLO** & **BF** & **TA** & **GCM** \\ \hline
**Experimental conditions** & \(-0.383\)** & \(-0.190\)** & \(-0.072\)** & \(-0.243\)** \\ \hline
**STANCE hip torque** & \(-0.108\)** & \(0.412\)** & \(-0.168\) & \(0.116\)** \\ \hline
**STANCE knee torque** & \(-0.211\)** & \(-0.590\)** & \(-0.335\)** & \(0.069\)** \\ \hline
**SWING hip torque** & \(-0.214\)** & \(-0.412\)** & \(-0.240\)** & \(0.119\)** \\ \hline
**SWING knee torque** & \(0.180\)** & \(0.241\)** & \(0.136\)** & \(0.120\)** \\ \hline \hline \end{tabular}  
* \(p<0.05\). VLO, vastus lateralis oblique; BF, biceps femoris; TA, tibialis anterior; GCM, gastrocnemius medialis.  
\end{table} 
Table 3: Correlation between electromyography and torque data during different robot-assisted gait training conditions. largely unaffected by changes in gait speed and BWS. Interestingly, the overall temporal patterning of muscle activity was maintained regardless of the different BWS and gait speed conditions, which supports the role of the central pattern generator in RAGT as evidenced in EMG muscle activation patterns [26]. Similarly, [PERSON] and colleagues reported moderate (\(r\) = 0.48) to strong (\(r\) = 0.71) correlations between the hamstring muscle activity and torque at different positions in 19 healthy adults [25] because, neuromechanically, hamstrings involve in the hip and knee torques as a two-joint muscle. A possible rationale for these results is related to the neurophysiological effect of decreasing the EMG activity at greater muscle length, together with the mechanical effect of increased force by passive parallel elastic components; this may account for the constant torque and is associated with EMG activity of the lengthened muscle. A previous study reported that promoting early task-specific RAGT with bottom-up integration could improve gait recovery in patients with neurological disorders [2,27].