In order to improve speed, an athlete must do 3 things:
Apply more mass specific force into the ground
In the proper bio-mechanical positions
In ever decreasing increments of time
Increments of time: This means that an athlete is manifesting force QUICKER, aka their rate of force development is improving
This is why training explosive strength through various means has such value for athletes who want to be powerful and fast
Appropriate volume of alactic jumping, med ball throws, and using the all important dynamic method are great tools for improving explosive strength
Speed is a skill. It can be trained. By consistently training all three improvements, an athlete can make massive strides in their speed!