There is a difference between "strides," and sprints.
Strides are something you can do before and after runs. You could do them every day. Ours were usually about 60 meters and that included the acceleration and the slow down.
Sprints are something all distance runners should do one day per week.
These are something you do to "develop," speed. That's something that is foreign to many distance runners. The distance for those could be anywhere from 30 to 100 meters. You could even do "broken 200/300s/400s" and call them speed development. However there should be some changes of gear and at least one of them should be at 99% so you develop some greasy speed.
>>>This is not a complete description of speed development of course.