Now since we understand body leverage, understand the purpose of an approach. I promise you it has nothing to do with consistency and accuracy. The reason we have an approach is because the pins are 60 feet away. We use the approach to create the momentum we need to provide the optimal energy at the pins. I bring this up because it is not a constant.
Lets use the extreme examples here to paint a picture.
That would be humanly impossible. Now imagine bowling on an ice rink. If the surface friction was as low as it is in an ice rink we would not need an approach at all. As a matter of fact we would benefit by having less build up of momentum. And just the opposite on dirt or grass.