haha. car terms in fitness
You can learn to open up more with each stride but that only helps if you learned to run with a smaller stride. your stride length really is not going to change by much though because its something fairly genetic.
Now, you have to realize that how fast you run is all genetics. you can not take a 5.0 40yd person and get them into the low 4s. The way that speed training helps is by making each stride you take more efficent. there are numerous exercises to teach you how to control your stride more efficently which creates a faster person. I would say that a more efficent start when running will yield the best results.
You dont really need super strong muscles to run fast.