Logic tells you ....muscle = power.
raquet head speed = power as well.
Watch Dani play. watch how far she takes her raquet back before she hits the ball.... you will notice she takes a VERY big swing at the ball.... thats why it is hit so hard.
For serena - just look at those massive arms and you will see why she cains the crap out of the ball.
V MELB...Serena's arms arn't massive...the female bodybuilders at my gym have arms 3 times the size of those...her arms appear to be big because they are pretty toned and she has bothered to work them somewhat. take a side view of them and they dont look big at all...her bi's look good but her triceps arnt even properly developed...if you want big arms you work your tri's more (naturally)...i should know im a fitness instructor :-) people that are skinny as can thump the ball...muscular power and muscular stregth are 2 different things jomar...to which are you referring?
V.melb...yes i am i am VICFIT accredited... i can send you a photo of my muscles if you want but you'll have to message me privately....yes serena has nice biceps ...very prominent....she is obviously no stranger to a gym...