If instead , you stick with 21 strokes per length .
If instead , you decide to go for a faster stroke rate e.g. from 1.7 to 1.6 s you go 2.1 seconds faster .
If instead , you stick with 21 strokes per length and decide to go for a faster stroke rate e.g. from 1.7 to 1.6 s you go 2.1 seconds faster .