Parameter

Definition

Unit

Total Motility (TM)

Percent of sperm showing any movement

%

Progressive Motility (PM)

Percent of sperm moving rapidly and in a straight path

%

Rapid Motility (RAP)

Percent of sperm travelling at a speed of 25 µm/sec or faster

%

Curvilinear Velocity (VCL)

Time-average velocity of sperm head along its actual path

µm/s

Straight Line Velocity (VSL)

Time-average velocity of sperm head projected along straight line

µm/s

Average Path Velocity (VAP)

Time-average velocity of sperm head projected along its spatial trajectory

µm/s

Linearity (LIN)

Ratio of projected length to total length of curvilinear trajectory; LIN = VSL/VCL

%

Straightness (STR)

Ratio of projected length to average velocity of sperm head along a spatial trajectory, STR = VSL/VAP

%

Wobble (WOB)

Expression of the degree of oscillation of the curvilinear path about its spatial average path; WOB = VAP/VCL

%