Repeating myself, there are two ways of developing more power.
Breaststrokers like to be very strong and apply that strength along a long pull and kick paths.
Or what I recommend that nearly everyone can do, is develop more power by a faster pull and strength. Power being strength x distance divided by time.
A faster pull and especially a faster kick (explosive fast) will get breaststrokers faster.
That is why I hate many drills, like holding a heavy weight and going slow egg beaters struggling to stay on the waters surface. Now can anyone explain how that helps? It doesn't and never will. Just a waste of precious time.
MY swimmers do explosive hands, but their explosive forwards all-out egg beater develops leg muscles that will fire much faster, and the drill does one thing that NO other drill does, work the muscles that pull the legs up to the butt. Remember it it the muscles that pull the legs up that get tires way before the muscles that are propulsive firing backwards.
It's not how fast you swim, it's how fast you slow down.
For competition breaststroke information visit: http://www.breaststroke.info/