Table:
Input Signals	Explanation
grfL	vertical ground reaction force of the left foot (N)
grfR	vertical ground reaction force of the right foot (N)
grfDiff	average absolute difference between grfL and grfR in the past 50 samples (N)
COPyL	longitudinal coordinate of the center of pressure for the left foot (starting from the toes to the heel) (mm)
COPyR	longitudinal coordinate of the center of pressure for the right foot (starting from the toes to the heel) (mm)
sumAng	the sum of all knee and hip angles (°)
gyroL	angular velocity of the left foot in the sagittal plane (rad/s)
gyroR	angular velocity of the right foot in the sagittal plane (rad/s)

Parse the following content of the table in markdown code: | Input Signals | Explanation | 
 | --- | --- | 
 | grfL | vertical ground reaction force of the left foot (N) | 
 | grfR | vertical ground reaction force of the right foot (N) | 
 | grfDiff | average absolute difference between grfL and

grfR in the past 50 samples (N) | 
 | COPyL | longitudinal coordinate of the center of pressure for the left foot (starting from the toes to the heel) (mm) | 
 | COPyR | longitudinal coordinate of the center of pressure for the right foot (starting from the toes to the heel) (mm) | 
 | sumAng | the sum of all knee and hip angles (°) | 
 | gyroL | angular velocity of the left foot in the sagittal plane (rad/s) | 
 | gyroR | angular velocity of the right foot in the sagittal plane (rad/s) |