the partnership between chris and heidi powell is not for the faint of heart. between their four kids, multiple businesses, and working out, this dynamic duo never seems to sleep. >> raise your knees to your chest, we're going 20 seconds. >> the personal trainers and diet and fitness experts became household names during abc's "extreme weight loss." >> you are a champ. 240 pounds. >> i love it. >> but the scope of that show limited them to only help as few people each year. >> one of the biggest struggles for us was on the show. we could work with 15 people in a season. that's it. but the problem, though, is that when every single episode starts off with i wrote a letter to chris and heidi and they