The thing about cardio is that it can bore you to tears in, like, a second (looking at you, elliptical). But you can get it done without slaving away on a treadmill and subsequently wanting to kill yourself.
Exhibit A: Jumping jacks. This classic exercise is an awesome way to activate just about every muscle in your body, including your heart. Take these moves to the next level with modifications designed by CosmoBodyfitness trainer Astrid McGuire to fend off boredom. Perform 20 reps of each exercise, then move on to the next without resting. For a full cardio workout, repeat the set two to four more times, resting 30 to 60 seconds between sets.
1. Rotational Jacks: Stand upright with your feet together and hands together at your chest. Jump up and land with your feet slightly wider than shoulder-width apart with your toes turned slightly outward. As you lower into a squat, twist from the waist as you reach straight up toward the sky with your left hand and straight down to the floor with your right hand. Tap the floor with your right hand, then jump back to starting position. Repeat the jump squat, this time reaching up toward the sky with your right hand, and touching the floor with your left hand. Return to starting position to complete one rep.
What they work: Your core, quads, hamstrings, butt, and back.
2. Floor Jack Splits: Lie on the floor with your thumbs interlocked, arms and legs outstretched, and feet together. Brace your core as you lift your arms and feet off the floor, keeping knees and elbows locked. Exhale as you lift your legs up and out to form a V and you lift your entire upper body off the ground. As you come up, swing your hands straight forward through the V. With control and without touching the floor, release your arms and legs and lower back to starting position. That's one rep.
What they work: Your upper and lower abs, chest, and quads.
3. Plank Jacks: Start in a modified plank position with your shoulders stacked over your wrists and feet together. Keeping your butt as low to the ground as possible, jump both legs out to the sides. Jump back to starting position. That's one rep.
What they work: Your arms, abs, quads, and back.
Photo Credit: Getty Gallo Images, Cosmo Body