Table 1. Walking analysis parameters.

	Term	Description	Reference
1	Backtracking	Total distance that legs slip backwards divided by total distance travelled. Indicates efficiency of motion.
2	Slipping Angle	Average angle of slipping for a given leg.
3	Stride Period	Average time elapsed during a complete cycle of the stride and stance phases of motion.	[50]
4	Period Coefficient of Variation	Standard deviation of stride period divided by average of stride period. Indicates variability in motion timings.
5	Stride Duration	Average time elapsed during the stride phase of motion.	[51]–[53]
6	Stance Duration	Average time elapsed during the stance phase of motion.	[51]–[53]
7	Interstep Lag	Average time elapsed between initiations of stride in a given pair of legs.	[50]
8	Interleg Stride Overlap (%)	Average percentage of time two given legs are simultaneously in stride.	[53]
9	Cross Correlation Coefficient	Similarity in the motion-time waveforms of two given legs. Describes regularity of motion in terms of each of 15 leg pairs.
10	Leg-body distances	Average distances between the legs and the center of the body.
11	Leg-leg distances	Average distances between the tips of two given legs.
12	Stance Angle Deviation	Deviation in relative leg positioning from an equilateral triangle during stance. Minimal during normal motion.
13	Anterior Extreme Position (AEP)	Touchdown distances of the fly legs, expressed in a body-centered coordinate system	[54]
14	Posterior Extreme Position (PEP)	Takeoff position of the fly legs, expressed in a body-centered coordinate system	[54]
15	AEP\PEP Variability	Vector sum of standard deviation of AEP or PEP positions. Indication of variability in foot positioning.	[53]
16	Step Amplitude	Average stride leg movement relative to body center, normalized to body length. Independent of speed.	[52]
17	Step Distance	Average stride length, in body lengths. Dependent on speed.	[50]
18	Step Distance Coefficient of Variation	Standard deviation of stride length divided by average of stride length. Indicates noise in stride lengths.

The table lists the parameters that are calculated from the frame-by-frame acquisition of coordinates. Reference appears whenever a parameter has been used before.