Our boxing gym has put up dozens of videos...30, 45, and 75 minute classes. I don't have a heavy bag at home, but if you put in the work, shadowboxing is a great workout. They've also put up several 30 and 45 minute kettlebell videos. Between those, my T25 videos, and my own weightlifting/body weight movement routine, I'm maintaining my weight/fitness/strength. I probably haven't made any gains, and I know that once I can go back to the boxing gym and hit the 95 lb.heavy bag, it will probably take me a week or two to get over the inevitable soreness, but otherwise, I should pick up right where I left off.