Gait Characteristics of Children with Spastic Cerebral Palsy during Inclined Treadmill Walking under a Virtual Reality Environment

Table 2

Segment coordination systems.

Segment	Definition of the segment coordination system
Pelvis	Origin	Midpoint between hip joint centers
	X	Unit vector of cross product between the -axis and the vector from right hip joint center to left hip joint center
	Y	Unit vector defined by the -axis and -axis to create a right-hand coordinate system
	Z	Unit vector parallel to the line from S1/L5 to the midpoint between left and right shoulder joint centers
Torso	Origin	Thoracolumbar joint center
	X	Unit vector perpendicular to the plane formed by the -axis and the vector from right shoulder joint center to left shoulder joint center
	Y	Unit vector defined by the -axis and -axis to create a right-hand coordinate system
	Z	Unit vector parallel to the line from S1/L5 to the midpoint between left and right shoulder joint centers
Thigh	Origin	Hip joint center
	X	Unit vector perpendicular to the -axis lies in the global sagittal plane and points anteriorly
	Y	Unit vector defined by the -axis and -axis to create a right-hand coordinate system
	Z	Unit vector from knee joint center to hip joint center
Shank	Origin	Knee joint center
	X	Unit vector perpendicular to the -axis lies in the global sagittal plane and points anteriorly
	Y	Unit vector defined by the -axis and -axis to create a right-hand coordinate system
	Z	Unit vector from ankle joint center to knee joint center
Foot	Origin	Subtalar joint center
	X	Unit vector perpendicular to the -axis lies in the global sagittal plane and points anteriorly
	Y	Unit vector defined by the -axis and -axis to create a right-hand coordinate system
	Z	Unit vector from toe joint center to subtalar joint center