Jillian Michaels is no stranger to a tough workout. Not only did she put her team members through vomit-inducing sweat sessions on The Biggest Loser, but the trainer and fitness expert loves challenging herself. She put together what she calls a challenge circuit that targets strength and balance, and it's definitely not beginners.

Jillian started off by balancing on an inflatable stability ball. She then did sit-ups on a punching bag, performed a modified burpee, balanced on two medicine balls while doing sumo squats with a dumbbell, and finished by doing single-leg deadlifts with a dumbbell while balancing on a foam roller.

This circuit is for more advanced gym-goers, but if you feel up to the challenge, incorporate this into your routine to work on your balance and core strength. Just be careful; these moves are probably best done with a spotter nearby.