Simple Concept to Help Acceleration: Hand Speed, Power, and Push
If Acceleration equals Force divided by Mass, then the level of force that you put into the grown will move your bodies mass. Now body positioning, body weight, and force required are important factors but we can discuss later when we have more time.
In the process of pushing away from the blocks head is down and body is at an angle. Hands must pump back and forwards as fast as possible. What I like to teach is a concept that I call, "Feed Your Face." Fire your hands backwards and then forward as fast as you can towards your face as if you are feeding your face.
Knees must be high even in acceleration phase. That gives the perfect position to fire down into the ground and then return to high knee position. I like to teach my athletes to strike with what they have on the single leg squat or single leg press machine. Remember force must affect your body mass. So use that Power.
The finishing move for my athletes is a push concept on the back end if their power. Basically using dorsiflexion, we finish our strike where our leg is straight after each push. We are able to dram a straight line through the toe/ankle all the way through the shoulders/head.