. 2020 Jun 26;9(6):138. doi: 10.3390/biology9060138

Table 2.

Eigenvectors of principal components (PCs) * for kinematic variables of bull sperm in three commercial extenders.

Extender	OptiXcell^®			Triladyl^®			Tris-EY
Variable	PC₁	PC₂	PC₃	PC₁	PC₂	PC₃	PC₁	PC₂	PC₃
VCL		0.960			0.915			0.899
VSL		0.737		0.819			0.728
VAP		0.888		0.723			0.761	0.610
LIN	0.931			0.977			0.827
STR	0.641		0.621	0.737					0.844
WOB	0.899			0.909			0.942
ALH	−0.646	0.624			0.912			0.884
BCF			0.801			0.952			0.668
Var Exp	37.51	35.26	16.59	46.50	29.18	14.48	38.14	30.51	21.33

Var Exp: variance explained in each PC. Total variance explained: OptiXcell^® = 89.36%; Triladyl^® = 90.16%; Tris-EY = 89.98%. *Expresses the more important variables in each PC. Only eigenvectors >0.6 are presented. VCL: curvilinear velocity; VSL: straight-line velocity; VAP: average path velocity; LIN: linearity of forward progression; STR: straightness; WOB: wobble; ALH: amplitude of lateral head displacement; BCF: beat-cross frequency.