Kristin McGee on Instagram: "Core on fire try this no equipment cardio core workout! Years ago I filmed a weight loss Pilates dvd and created a cardio-type Pilates mat workout where we alternated between bursts of cardio and Pilates exercises. This combo mixes up the series of 5 with prone ab moves to keep your heart pumping as you jump back and forth from each exercise. I LOVE doing this when I’m short on time. Want more workout inspo like this?!"