text: It is when a runner is on base. The pitcher has to "hold" the runner on, meaning keep him close to first so he doesn't steal second. If he was in the wind-up (his regular motion), the runner could get an enormous jump to steal second. In the stretch, he holds the runner better. \n\nThe stretch is basically pitching without the wind-up. The pitcher comes to a set (hands come down to a point and he pauses) before raising his leg and going home. Compare that to a full wind-up and you'll notice a huge difference.