BS	biofeedback system
GC	gait cycle
GP	gait phase
Performance Dir	user’s performance regarding the direction of human-robot interaction
Performance Mag	user’s performance regarding the magnitude of human-robot interaction
Performance Mag Thr	user’s performance regarding the magnitude of human-robot interaction with a threshold
PID	Proportional Integral Derivative
PRTR	pre-training
PSTR	post-training
RMS	Root Mean Square
RMSE	Root Mean Square Error
TGP	training gait phase
TR	training
Thr	user-adaptive threshold