30 seconds work 30 seconds rest whole body workout.
https://www.instagram.com/fuelptuk/
https://www.facebook.com/Fuelpersonaltraining/
Interval timers
Apple:
https://itunes.apple.com/gb/app/intervals-interval-timer/id957586938?mt=8
Android:
https://play.google.com/store/apps/details?id=cc.dreamspark.intervaltimer&hl=en_GB