I was thinking about how to start this post and well, simply put, speed is simple. Getting faster is simple. Allow me to clarify, getting faster is simple, I didn't say easy. There is a big difference between those two words.
In order to get faster, get stronger. There I said it, and I'll say it again and again. Of course it's all relative.
A guy that can squat 300 but also weighs just as much is not going to be as fast as the guy that weigh 150 and squats 300. See how simple it is? An athlete who can squat and deadlift double body weight has a much better foundation towards being faster than an athlete who can't.
To put another way, the force the lighter guy puts into the ground compared to his weight will be far greater than the force that the heavier guy puts into the ground.
There's the rub. Speed really amounts to force application. The stronger you are the more force you can put into the ground. However, if we stopped it there we would be missing the other half of the puzzle, and unfortunately a lot of us stop it there.
It's not just about the amount of force that is placed into the ground, we also need to consider the rate in which that force is applied.
In other words, I make an athlete strong, but now that athlete has to learn to use that strength. Well I can't think of a better way to apply force at a rapid rate than to make like House of Pain and Jump Around.
Please don't throw the baby out with the bath water and start jumping like crazy. There's a smart way to go about programming and performing jump training. That being said, I'm talking speed, not jumping but speed.
There you have it, make an athlete faster by making them stronger, getting them jumping around, and of course getting them to speed drills - sprinting, cutting, reaction, etc.
To quote the Legendary Strength and Conditioning Coach Dan John, when asked how he develops such good athletes, and how does he make his sprinters faster he simply replies "Sprinters sprint". If an athlete wants to be faster of course they need to do more speed drills and run around more. Besides, that's the best part of the whole thing.
P.s. I know I didn't mention Olympic lifts or absorbing force.
Absorbing force properly and rapidly is also an important factor, but also in regards to reducing the risks of injury not just speed. I feel it deserves its own post. Olympic lifts are helpful, but they are also just a method, personally I am more comfortable with jumps and have had very good success with those.