Want more bang for your exercise buck? Interval cardio training is an awesome addition to any strength-training routine because it burns a ton of calories, works the cardiovascular system, and builds muscle. It's all about doing short bursts of cardio with an intense amount of effort. You should do intervals in between your weight-training exercises if you want to really maximize your workout. Here are two of my favorite interval cardio moves to get you started:
Start in a plank position on the floor, with your feet hip-width apart. Bend your right knee and, with a springing movement, bring your right thigh under the right side of your torso. Quickly spring back to the starting position while jumping your left knee forward under your torso. Repeat, keeping your pace as fast as possible. Besides being a cardiovascular exercise, this move trains the chest, shoulders, lower abs, and transverse abs.
Start in a plank position on the floor, with your feet hip-width apart. Bend your knees and jump both feet toward your hands so that you're in a crouching position. Quickly jump both feet back behind you to the starting position. Repeat, making sure you keep your abs tight — and don't let your lower back sag or drop.
Remember, "interval" is the key word here. These exercises are meant to be done in 30-second to 5-minute bursts, not half-hour sessions. The exercises are demanding, so warm up before doing them.