4 step or 5 step approach.

[sully_51]

4 step for me. It feels completely un-natural and awkward stepping with my right foot first (I'm a lefty).

[glen290]

I changed about 12 months ago from a 5 step to 4 as my timing was way out, but by pushing out as I take my first step brought everything back in to line, as has been mentioned in previous posts, its entirely what you feel most comfortable with.

[K3ntFIN]

4 step or 5 step makes little to no difference as long as the timing is correct. This girl has pretty much perfect timing going in to the last step. http://www.flickr.com/photos/k3ntfin...57628812810241

One thing that is quite often noticeable with 4 steppers is that the support leg is still sliding as the release happens, this is an accuracy killer. It also inhibits sufficient kinetic energy being transferred from the body into the ball itself. A good metaphor is a javelin thrower, imagine what would happen to the distance if their support leg was still sliding when they release the javelin. It would decrease quite a bit.
Bowling needs a little bit of slide, but it has to stop before the release. Physics. Can't work around it.

Another thing that is quite often seen is the usage of the "free" hand (I assume a right-hander). Where is the left arm going after the start of the swing? If it flips straight out to the left, you will create quite a bit of elastic tension in your upper body which will a) shorten the swing radius b) accelerate the downswing, throwing the timing off c) long-term effect will be pains and "throwers arm" most likely.

Look again at the picture of the girl, her free arm stays in front until the release, only when the release starts will the left arm move out to the side. This helps keeping the swing and release relaxed to enable maximum release speed and accuracy. And, does not wear you out, even after long periods of bowling.