You squat.

This is the most common error I see. For some reason, guys want to "sit" when the bell goes between their knees. But the swing is not a squat, it's a hip hinge.

The difference? During a squat, your hips and knees maximally bend. During a hip hinge, your hips maximally bend and your knees minimally bend.

Hinging at your hips until your torso is almost parallel to the floor allows you to engage your hamstrings, large muscles that let you powerfully swing the kettlebell back up to top. Bending your knees won't let you do that.

Your lower back hurts.

After a swing workout, your hamstrings should be sore. But if you're lower back is bothering you instead, the problem is probably your hinge.

Some hinging pointers: Guide the kettlebell toward your groin as it falls. (I know that sounds scary, but trust me.) As it nears your zipper, bend at your hips and reach your arms back like you're deep snapping to a punter. This keeps your back in a neutral position and effectively engages your hamstrings.

You don't plank.

Think of the swing as two distinct movements: the hip hinge and the vertical plank. I've already cued how to hinge, but the plank at the top of your swing is equally important.

You want to be a straight line from your head to your feet. Pull your shoulders away from your ears, squeeze your glutes and quads, brace your abs, and push your feet through the floor. Pretend as if the top of your head is stretching straight to Zenith. It should look like you're performing a plank on the ground, but you're standing.

Your eyes wander.

When you look up or look down, you throw your form out of alignment. Keep your eyes on the horizon, and continue to look at that point throughout the entire move.

You lack control.

The kettlebell is heavy, so you need to generate a large amount of power to manage the weight. If you don't control it, it will control you—and that leads to injury.

Here's how to put some serious power behind your swing: After you hinge, forcefully explode your hips forward like you're performing a football tackle. Pretend as if you're throwing the weight in front of you. (Just think it. Don't actually release it!) As you hinge back, toss the weight toward your zipper. Do this every rep.

You get fancy.

Although single-arm swings are great for cardio and increasing grip strength, the uneven load can cause you to sway or twist. Unless you have a StrongFirst certified kettlebell instructor taking you through the basics of a single-arm swing, just stick with the standard two-handed version. It hasn't failed me yet.

Your arms go above your head.

At the top of your swing, the kettlebell should end somewhere between belt and shoulder height. You'll know it's high enough when you feel the bell "float" or go weightless for a second. The heavier the bell, the lower the peak of your swing.

You only concentrate on the swing.

The start and finish of the swing deserve just as much respect as the move itself.

The better your setup, the better your first swing will be, so don't just throw the bell back without first getting into the proper stance. Before every set, I make sure my feet are gripping the floor, my hips are hinged back, my back is flat, my lats are engaged, my hands are creating torque by trying to break the kettlebell handle, and my eyes are on the horizon.

When finishing, don't just dump the bell on the floor. Instead, guide it gracefully to the floor in front of you. This shows mastery and means you're in control of the weight the entire time.

You're still struggling.

No article or video can take the place of hands-on coaching. If you really want to learn how to master the swing, train with a StrongFirst certified kettlebell instructor. They can offer regressions and corrections based on your background and challenges.