"Like most moms with un-potty-trained children, the must-haves include diapers, wipes, changing pad, sippy cup, and emergency snack (for both of us). I also keep everything I would need if I get the opportunity to shower (which rarely happens). I also want to be prepared for any workout, because I never know how I'll feel once I walk in the door. So you'll find everything from swim goggles to cycling shoes in my bag, and another important item: an extra sports bra. You never know."
Our fave: The baby and the dog—will they both fit in the bag? Kara Thom, triathlete, mother of four, and author of Hot, Sweaty Mamas blogs at Mama Sweat.