Stand with your feet wider than hips-width apart, toes slightly pointing out. Squat down, and pick up a kettlebell with both hands. Allow it to hang between your legs. If you don't have a kettlebell, use a dumbbell instead.
With a flat back and your core engaged, inhale to bend the knees and push your butt back. The weight should be back in the heels so your knees are in line with the toes.
Keep your abs strong and the arms straight. On an exhale, press into your feet, squeezing the legs and glutes as you aggressively explode up, extending through your hips and legs to stand, which drives the kettlebell overhead. If you have mobility issues in the shoulders or lower back or an injury, do a Russian kettlebell swing instead, where the bell only raises to shoulder height.
Inhale, and with control, come back to the starting position, allowing the kettlebell to swing back between your legs.
This counts as one rep.
Complete 20 seconds of kettlebell swings rest for 10 seconds.