Single leg exercises do one thing especially well and that is hit the quatratus lumborum. One of the QL’s main functions is to laterally stabilize the pelvis in a single leg stance. One place this is important in everyday life is just simply walking. Each step requires the QL to hold the pelvis up so to speak. If the QL doesn’t do its job the pelvis will drop. When this begins to happen, low back problems aren’t far away.
There has been a lot of talk lately about choosing single leg exercises over bilateral exercises such as the squat or deadlift. Mike Boyle is one of the huge proponents of single leg work over double leg. One of the reasons stated for this change is less stress on the low back. Mike believes the low back is the weak link in all bilateral exercises, and by performing single leg work you eliminate the low back in the equation. In reality, according to Dr. McGill single leg exercises actually require much more out of the lumbar spine due to the higher levels of stabilization that have to occur. Now, don’t get me wrong, I’m not saying Coach Boyle is wrong in the training of his athletes, I’m only trying to provide a different perspective. He has been training athletes far longer than I have and has concrete reasons as to why he utilizes single leg work. You can find his opinions on the above topic in the link below. It’s a great video and I give Mike a lot of credit for his critical thinking.
Single leg exercises such as the split squat with the back foot elevated (Bulgarian Split Squat) require high levels of pelvic stabilization from the QL.
Another exercises that is great for QL as well as the surrounding torso musculature are suitcase carries. These are just like they sound. Athletes pick up a heavy dumbbell and walk with it. This is great exercise for lateral torso stabilization.
Having a strong QL is just one part of the equation when it comes to lumbar stabilization. Single leg exercises will always have a large part in the training of athletes and can go a long way in helping develop stabilization patterns for future health throughout the spine.