Complete the 100 repetitions as quickly as you can, with good form.
Time yourself and make a note of how long it takes you to complete the 100 reps.
20 PRESS UPS
20 SQUAT JUMPS
20 SIT UPS
Then, without rest RUN for the same amount of time.
For example, if it takes you 3 minutes 24 seconds to complete the 100 reps, then you must run for 3 minutes 24 seconds.
(the quicker you complete the repetitions, the less time you have to run for)
Once you finish the run, rest for 1 minute then aim complete another 3 rounds. (4 in total)