The rear-foot-elevated split squat, which I’ll abbreviate as RFESS, is oftentimes called the Bulgarian split squat (BSS). In other venues, it’s referred to as the Bulgarian lunge, despite the fact it didn’t originate in Bulgaria and isn’t a lunge.

The RFESS has numerous benefits. Beginners, for example, will develop balance and hip flexibility, along with strength, size, and the all-important ability to endure a high level of discomfort while training. The really dramatic results come when more advanced lifters load up the exercise. It allows you to apply huge weights to your leg muscles with limited spinal compression.

In fact, I think the loading capability of the RFESS is unmatched by any other exercise that primarily targets the leg extensors, including the squat. When my trainers and I started using heavy RFESS as the primary lower-body exercise for our athletes, we found they couldn’t work both legs without taking a break in between.

A couple of important technique points:

• Obviously, you can’t do the exercise without elevating your rear foot. An exercise bench works for most, but if you find the stretch to the quads and hip flexors of your elevated leg is too extreme or uncomfortable, switch to a slightly lower box or step. We find this necessary for some of our shorter lifters.

• The start of the exercise is a lot like a back squat, in that you position the bar on your shoulders in a squat rack, lift it off the supports, and take a step back. From there, lift one foot and place it on the bench behind you. You want to rest the top of your foot on the bench, even though it may be uncomfortable for you, especially if you’re used to doing this exercise with your toe on the bench. It may be easier for you to do it that way with lighter loads, but with heavier loads it’s not — the range of motion is longer, and your balance will be worse. Break this habit in week one.

• How deep should you go? We place an Airex pad or mat on the floor under the rear knee, and tell our athletes they have to touch the pad with their knee on each rep. This creates consistent depth, and also serves to cushion the knee. This is especially helpful when we’re testing our athletes’ strength on this exercise, which I’ll describe in the next section.

• As you would in a back squat or barbell lunge, you must keep your core tight and chest up. Core control is especially critical in the RFESS, as the elevated rear foot can create an unwanted back arch.