SR rate is important for many things especially techinique, at lower stroke rates you also work the blade more, all sprint kayakers vary there training and work at different levels which are defined by stroke rate. I no the average 1000m paddler sits around 100SR per minute for the middle of the race but some at the start get as high as 150SR per minute. How this all relates to ocean racing well like Rob said you need to vary your SR high ratings when your chasing a swell but but very low while on the runs so you can recover a bit. Stroke Ratings are also affected by how good or bad your technique is. Get on you tube and have a look at some sprint kayak races you will see ratings through the roof