[BerntR]

This is basically a training of the nervous system. It is not a muscle builder. You will be training coordination and most important training towards firing more cylinders (muscle fibres) more often.

You need 100% quality to get good results from speed training. If the workouts are too long or the restitution period too short you will not get max benefit.

The only thing I know is that you should feel faster and stronger immediately after each session. If you work until you start feeling tired you are no longer training speed but endurance.

I suspect that 7 days a week is too much. But you should ask the man himself, Miyahira. You could also check how often Hussain Bolt runs with 100% speeed.