A good baseline is 15 reps of a bodyweight exercise – it shows competency with the movement and sufficient strength. 15 minutes is a solid period of time to get benefits from your running.
This is why this workout is the Spartan 15; It helps with strength and athleticism and requires no gear.
75 Jumping Jacks
75 Seal Jacks
Repeat 2-5 times.
Run/cycle/row/jump rope 15 minutes at high intensity