Sprint like there’s no tomorrow
10 Sprints for time…
100 yards with 1:3 work/rest ratio
100 yards with 1:4 work/rest ratio
50 yards with 1:5 work/rest ratio
So, if it takes you 20 seconds to run your distance, 1:3 would get 60 seconds of rest, 1:4 would get 80 seconds of rest, and 1:5 would get 100 seconds of rest before the next interval. Track separate intervals and overall time.
These are all out sprints. You are not pacing for the later intervals early on. Your times might (and probably will) get slower. This is okay. The point is to stress the system at maximum output.