High rep squatting is brutal. When done correctly they offer numerous benefits for bodybuilders, athletes, strength enthusiasts and general gym-goers. There are few exercises that rival the squat in terms of the number of muscles worked and the mental toughness needed to get through a difficult set. High rep squats will hit your quadriceps, hamstrings, calves, glutes, lower back and core muscles and leave you gasping for air and with legs like jello.

Muscular Endurance

To improve muscular endurance you typically need to perform sets of 15 or more repetitions using a weight that's less than 60 percent of your single rep max (the heaviest weight you can lift for one rep with good form.) Your sets should last at least 45 seconds, notes David Adamson, powerlifter and strength coach at the University of Texas at El Paso. This means that if you're performing 15 reps each one needs to take at least three seconds. By gradually increasing the time under tension, number of repetitions and the load, you'll build up muscular endurance.

Muscle Growth

Your quadriceps are composed mainly of type 2a muscle fibers, which are more aerobic than type 2b fibers and therefore respond better to higher reps, claims Charles Poliquin, author of "The Poliquin Principles." The time under tension applied during a set of high rep squats can quickly pack on lower body muscle, he adds. Just make sure the load is heavy enough -- you should have to take at least three deep breaths between reps when you're nearing the end of your set.

Rib Cage Expansion

The most common high rep squat program is the 20-rep squat routine. This isn't just a simple 20-rep set though. You need to load the bar with your 14-rep maximum and try to hit 20 reps. While this sounds impossible, you can rest for as long as needed at the top of each rep, giving your legs a brief rest opportunity. Dr. Ellington Darden writes in "The New High-Intensity Training" that 20-rep squats can help expand your rib cage and grow your chest as you have to take very deep breaths once you get to the 12-rep mark.

Mental Strength

High rep squats are just as mentally challenging as they are physically, if not more so, claims David Whitley, personal trainer and Russian Kettlebell instructor. Before planning your high rep squat routine or workout you need to prepare your mind for what's in store. Once you get to the 10-rep mark, your whole body will be "screaming" for you to stop, but the key to developing mental toughness is mind over matter. If you get it right, a high rep set of squats will be the most challenging thing you've ever done in the gym.