Why the Medicine Ball Slam Is a Great Cardio and Strength Exercise

Josephine Skriver and Jasmine Tookes, the models behind @JoJa on Instagram, are more like fitness spouses than fitness pals. They work out together all over the world and share their sweaty fun on Instagram, whether it's a glutes move for one or some partner abs work.

The models' most recent Instagram post featured Skriver standing in a victorious pose holding a medicine ball overhead. (Standing on what looks like a rooftop, somewhere with palm trees, naturally.) She elaborated on the move in the caption: "Saturday Slam! Let’s get moving this morning with some ball slams! Have you guys ever tried these? Such a great full-body workout. I’m using an 8-pound ball for 20 slams x 3."

Check it out here, via @joja:

We asked trainers how to recreate this ball slam move, and more importantly, why you would want to pick up a medicine ball and try this exercise in the first place.

Turns out medicine ball slams are great for working many different muscle groups at once and getting your heart rate up.

"The medicine ball slam is a great total-body exercise," says Danielle Barry, certified personal trainer and CrossFit coach at Solace New York. "They engage your core, shoulders, triceps, back, glutes, hamstrings, and quads," she adds. Barry says that she turns to medicine ball slams when a client is looking to develop power, strength, and speed.

That's because the motion of medicine ball slams can teach an athlete to "become explosive," says Barry. So if you have trouble with fast, high-power moves (box jumps, squat jumps, speed skaters) like I do, this move can be a great way to ease your way in. Even better, Barry says medicine ball slams have a "low learning curve," which means they're really straightforward, and thus, beginner-friendly.

Here's how to do a ball slam with proper form:

• Stand with your feet between hip- and shoulder-width apart, and hold the medicine ball at waist height.

• Raise the ball up over your head, rising up on your toes as you do, instructs Barry. This is basically the wind-up to the fun part: the slam.

• Keep your abs tight and glutes squeezed as you slam the ball down to the ground in front of you as hard as you can. At this point, you should naturally bend your knees a bit.

• From here, squat down, by pushing your butt back and bending your knees, so that you can grab the ball as it bounces back without dropping your chest and rounding your shoulders forward. You want to keep your back as flat as possible throughout.

• Stand back up and bring the ball overhead to immediately go into the next rep.

Start with a light ball until you get comfortable with the movement. Once you have the basics down, Harold Holness, certified personal trainer at Diakadi, suggests doing 10 to 12 reps with a medium-weight ball, like Skriver's 8-pounder. Depending on your current strength, you may want to stay with a lighter ball, and that's totally fine. You should be able to lift the weight above your head without arching your back, feel some resistance during the slam but not anything that strains your back and shoulders, and be able to lift the ball back up off the ground from a squatting position. If the ball you're using makes it too hard to do any of those things successfully, go lighter. (As always, before starting this or any other new exercise, it's a good idea to check with your doctor to make sure the move is safe for you.)

Holness offers two ways to incorporate a slam into your workout regimen—either to improve conditioning or to build strength and power.

If cardio conditioning is your goal, "use a lighter ball to get as many reps as possible within 20-30 seconds," he says. When you work for speed, your heart rate will really get up there. Just make sure to use something light (like 2-3 pounds) so you can work quickly without sacrificing form.

For strength and power, "incorporate the medicine ball slam after heavy lifts and use a heavier medicine ball. For strength building, perform between 5-10 repetitions," Holness says. The exercise can really complement any routine, so feel free to add it into your workouts whenever you're looking for a nice burst of strength, cardio, and power.