Ten±1 s after transfer (=after activation) in the Makler chamber,
sperm motility was measured using the Stroemberg Mika cell motility
analysis program. About 100 spermatozoa were analyzed from each
sample and sperm motility was classified as follows: spermatozoa
with an average path velocity 20 μm/s as motile. From the motile
spermatozoa the linearity index (LI) was calculated as LI=SL/AL,
where SL represents the straight line between the measuring points
and AL the actual swimming path between the measuring points.
Spermatozoa were classified in linear when having a linearity
index ≤0.9 μm, in non-linear when having a linearity
index >0.9 μm, and in circular when swimming in circles with a
maximal radius of 20 μm. Finally, the percentage of linear, non-linear,
and circular motile spermatozoa was calculated in relation to the total
number of motile spermatozoa.