Speed.

[crazy legs]

What muscle is more important in running; Quads, hamstring or calves?tnx.

[sqad617]

Ambiguous question, but here is AN answer. They all are equally important as if one set of muscles are damaged then running is extremely difiicult or impossible. If I have missed the point here then do please excuse me.

[Davy_Ewing]

All part of the same well oiled machine you need them all some are more involved than others but each plays their part without one you couldn't do running at all. It also depends on what kind of running is it long distance? cross country, uphill downhill sprinting?

[crazy legs]

Thanks. I guess I should have made it clearer. I want to increase my speed on flat grass( I play rugby) and I wanted to know which muscle I should pay the most attention to when doing weights,tnx.