The push-pull technique is a very useful element of drum technique. It helps develop speed when playing , especially double strokes. In one down-up hand motion, the stick produces two strokes. On the downward motion, the fingers open so the stick can rebound after the first stroke. Then the fingers close, producing the second stroke, and the wrist immediately lifts the stick back to the starting position.
You do not have to practice this with doubles in both hands right away. Start with one hand. You can leave a pause between double strokes equal to one or two strokes. Then repeat the same thing with the other hand. After that, you can practice triplets using a push-pull double in one hand and a single stroke in the other: RRL and LLR, as well as RLR, LRR, LRL, and RLL.
This technique works very well together with Gladstone accent strokes.