You've probably heard about breathing squats, sometimes called the 20-rep squat challenge. It's simple... and brutal.

Basically, you load the bar with a weight you can lift for 10 good reps. Then you squat that sucker 20 times. How? By using a rest-pause approach. Without racking the bar, you just stand there and breathe until you can do another rep. The first 8-10 reps are pretty easy, then the "fun" begins.

Anyone who's done it can attest to its ability to challenge the mind and body... and the crippling leg soreness that comes after.

So could it get worse? Yes. Yes it can. If you thought the DOMS were bad after a 20-rep back squat, you're in for a treat now.

The challenge? Do 20 Bulgarian split squats holding half your bodyweight in your hands. (A 200-pound lifter would hold two 50-pound dumbbells.) Then immediately do it again for the other leg with no rest period between.

Remember, you can stop and catch a couple of breaths during the set as needed, but you can't put the dumbbells down until you hit 40 total reps (20 per leg).

Why Do It?

To get all these benefits:

• Muscular Endurance: Better muscular endurance means you don't run out of gas late in your workouts.
• Relative Strength: Being strong is cool, but being strong for your bodyweight is even better. Completing this challenge is a good sign that your relative strength is on point.
• Grip Strength: Holding on to two dumbbells that (together) weigh half your bodyweight for a total of 40 reps is a grind. You'll develop mad grip strength, which is necessary for elbow health and quite handy for big lifts.
• Hypertrophy: If you've been training in the 8-12 rep range for a while, you'll find some untapped growth potential by training this way. Muscle isn't just built in the 8-12 range. You can build dense, strong muscle from 5 reps up to 30.

These 40 reps will eat up your lungs and cause you to question your life choices. But if you can crush this challenge, it's a good sign that you're both strong and lean.