Analysis of the sperm tail movement

This analysis, which nowadays is computerized as well, provides information on the pattern and strength of the tail movement [18, 157]. 

This approach involves the measurement of the distribution of swimming distances made by the spermatozoa in various chambers, such as curved microchannels in microchips [87] or cervical mucus-fiUed capillaries [3, 82, 106]. The swimming distances are a measure of the progressive velocity and the percent motile cells in the sperm population. 

This approach involves determination of the extent to which spermatozoa can migrate through a membrane (e.g., a Nucleopore membrane with 5 xm pore size). This extent correlates primarily with the fraction of fast and straight-swimming cells in the sperm sample and with the sperm progressive velocity [68]. 

Measurement of the intrinsic motility forces of individual spermatozoa is carried out by optical trapping. Individual spermatozoa are optically trapped by means of laser tweezers, and the minimal trapping power required to hold the sperm cell in the optical trap (that is, the power below which the spermatozoon escapes from the trap) is measured ([85] and references cited therein). 

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