Fig. 2. Motility versus time. Sperm maintained in low pH (6.91±0.02; filled squares) or high pH (9.72±0.03; open squares) SI buffer prior to water activation. N=5 for each data set. Earliest motility measurements were within 1 min of combining semen and SI buffers. If the t=0 data point is taken as 70±0% (the earliest motility value in high pH SI), all low pH motility values are significantly different from t=0. (Motility of sperm in high pH SI at 60 min was 70±0%, N=5.)