It can take a few sets to get the hang of it, but the kettlebell windmill is a super effective core-strengthening exercise. With the weight positioned overhead, your rectus abdominis and obliques have to work double time to keep the kettlebell stabilized. And because of that stabilization, you’re gonna feel this move in your shoulders, glutes, and hamstrings tomorrow morning, too.
First, pay attention to the setup, since getting a kettlebell over your head can be tricky if you don't know what you're doing. Start with a kettlebell that’s much lighter than what you would use for kettlebell swings. Stand behind the kettlebell with your feet shoulder-width apart and, with a flat back and soft knees, hinge at the hips, press the butt back, and use the left hand to deadlift the kettlebell up.
Hinge the hips again and allow the kettlebell to swing back through the legs. Your thumb should be pointing behind you. As the kettlebell comes forward, thrust the hips, rotate the wrist, shrug the shoulders, and catch the kettlebell in a rack position. In this position, the elbow is bent, the thumb is in line with the collar bone, and the base of the kettlebell is resting in the crook of your arm.
Maintaining a tight core, press the kettlebell overhead. Be sure the wrist is neutral and stacked directly over the elbow, and that the elbow is stacked over the shoulder. You want to be tight and straight from shoulder to wrist. Widen your stance slightly and turn both feet 45 degrees to the right. Keeping your eyes on the kettlebell at all times, hinge at the hips so that your glutes are moving left, away from your midline, and your shoulders are moving toward the floor. It’s okay to soften the knees if you need to, but the back should stay flat as you trace the inside of your right leg with the back of your right hand. Hinge as deeply as you can without compromising your flat-back position (some guys will be able touch their fingertips to the floor; others won’t be able to reach past their knees). Once you’ve gone as far as you can go, squeeze the glutes, tighten the core, and return to a standing position. Repeat for eight to 12 reps before switching sides.