Total Body Strength plus Cardio Using Just a Backpack. Laugh yourself fit, that’s our goal. This is our third backpack (anyone else think of Dora the Explorer?). I love this format because the shifting of the backpack and its contents really changes the way you train the body and you can load as much weight as you want. Rilde and Christina will encourage, motivate and challenge you. Make sure to subscribe to our channel so you get all the live updates of videos as we create them!