as far as weights are concerned-you don't want to do things such as punching with dumbells in your hands fast. This will damage joints tendons and ligaments. Light weights are ok, and when using heavier weights, do the technique slow.
Ok, on to explosiveness-powerlifting builds explosive power-research this.
So do sprints.
Shock power is done with the body and arm very relaxed, otherwise, the speed is not there. The strike is not a follow through, otherwise it becomes a push. It is a pulse, or a quick jolt, that shocks the body, and sends a tremor. If you hit someone and they move back, the body is dissapating the force of the strike. When you use shock power, the body absorbs the full impact internally.
The power comes from having correct structure, otherwise there is no penetration, as the shock is simply reabsorbed back into the body.
Third, you need to have the correct mindset. Calm, focused, with aggreessive intent to do damage. These seem contradictory, and that is the riddle.
One more thing-Kevin Thompson, who was an amazing point fighter, was small, and his nickname was "The Mongoose." He was very quick and explosive. Kinda "twitchy," in his movement if you get my meaning.
BTW- he did this from a pretty wide low stance.
People asked him how he developed his explosive speed, and he said."I do everything fast. I try to move fast, think fast. Everything."