Supercompensation

Hey Everyone,
I was previously part of a track team and had my workouts planned out for me, but I now train by myself and am trying to construct a training program.
Specifically I would like to know:
1.If I did three weeks of training which included tempo and weekends off in order to promote recovery from high intensity workouts, would I still treat the three weeks as a “workout” and take the fourth week off for recuperation purposes to achieve a supercompensation effect?
2.If I continually do the same type of sprint workout, such as 8*30m sprints for example, will I plateau or will I continue to improve (at least over the 30m distance) since as I get faster each 30m sprint will place progressively more stress on my body so I am always challenged?