Ron...a noted urologist which I could PM you and give you his name, who specializes in this says that the long...even 8 seconds are a form of Isometric exercise that strengthens the PC muscle. THE quick ones, he says, are okay but the longer ones give power and strength. I have found that he is right and over the years...15, have found that when doing the longer ones, I have harder erections and can last longer and longer than I could when doing the short ones. Try it and see. Proof comes with seeing what works. GS