All you need for a stronger back and core is a kettlebell and a chair

The best workouts are the ones that give you the most bang for your buck in the shortest amount of time. It’s why people have begun flocking to megaformer workouts, which offer cardio, strength training, and flexibility at the same time, and why we’re so excited about this week’s Trainer of the Month workout, which works your forearms, back, and core in only four easy moves.

Trainer Roxie Jones has put together a simple seven-minute series that will fire up all three major muscle groups with nothing more than some kettlebells and a chair. The workout utilizes unilateral movements that work both sides of your body evenly for some serious all-over strength, and will leave you sore for a full 24 hours.

Jones suggests grabbing a light kettlebell, anywhere from 10 to 25 pounds. To make sure you’ve got the right weight, rack the kettlebell and see if you’re able to lift it properly in one hand—without swinging it or relying on the other hand for support. Once you’ve got that done, cycle through these four moves. Repeat the entire series for a total of three rounds, which you will definitely be feeling tomorrow.

1. Assisted single arm bent over row: Place one hand on a chair with a kettlebell in your other hand. Keep your hips back and your back flat, tightening your core, and plant your feet hips width apart. Pull the kettlebell up as if you’re trying to tuck it into the pocket of your armpit. Squeeze your lats as you lift, and hold for a beat at the top of the move. Repeat on the other side.

2. Bent over tricep kickback: Holding onto your weight in one hand, place your other hand on the chair and stagger your feet. Kick your arm back, extending your arm out as if you’re trying to touch the back wall and squeezing your tricep throughout the move. Repeat on the other side.

3. Standing single arm bicep curl plus single arm iso hold: Stand with your feet hips-width apart and a kettlebell in each hand. Hold one arm at 90 degrees, and use the other to cycle through 12 full bicep curls from your hip to your shoulder, squeezing your bicep at the top. Repeat on the other side.

4. Renegade row: Start in a high plank position with your wrists stacked under your shoulders and core engaged. Before you grab your kettlebell, become comfortable with the movement of lifting your hand toward your shoulder. Then, add the weight. Holding a kettlebell in one hand, lift it up toward your armpit, keeping your hips square. Repeat on the other side.

Forget the dumbbells—the kettlebell rack is where it’s at. Here’s how to use them in an abs workout, and why they should be a part of your arms workouts, too.