The RFESS (rear foot elevated split squat) is an exercise I have been using in my training a lot recently. This exercise is quite challenging and works your whole leg musculature in a unique way, not to mention that after a few sets you can really get a good sweat going. The primary muscles worked during the RFESS are the quads but it also works the hamstrings and can hit the core quite well.
The RFESS is nice because you can make good strength gains without all the spinal loading of the traditional barbell squat. In addition it can be loaded several different ways, and the range of motion can be modified to make it easier or harder. As you can see above I am doing them on a 4 inch box allowing me to get a better range of motion. Also I loaded it goblet style with a kettle bell because I find I can maintain form easiest with this method. Holding dumbells at your sides is very popular, as well as using a weighted vest which is probably the best option but not necessary as long as you are consistent with loading techniques.
While doing the RFESS it is important to keep your chest up and spine in a neutral position, it is common for the upper body to lean forward in the down ward phase of the motion to compensate for flexibility/ strength deficits and this should be avoided. Lastly the foot that is elevated on the bench is simply their for balance and should not be used to drive back upwards. When done correctly this may be a good exercise choice for people with anterior pelvic tilt because with a full range of motion the opposing hip flexors will get stretched.