Why Side lunges alone are not an effective way to train in the Frontal Plane
What is the Frontal Plane
Movement in the frontal plane occurs when the center of mass is shifted from side to side and is concentrated onto one leg (Stance Leg) at a time. This movement can be seen in many athletic movements as an ability to load into the stance side hip and then explode out of it. An Ice hockey player must do this in a side to side fashion and the more efficient and explosive they are in getting into and out of that stance side hip, the faster and more agile they will be. Similarly, both pitchers and hitters in baseball do this in a more linear fashion by loading into their stance hip and then explode out of it in order to apply a force on the ball. In the case of the pitcher, the energy travels from the lower extremities up to the throwing arm and a hitter from the lower extremities to the bat.
My experience with side lunges
Unfortunately, I started seriously training to be a better baseball player at the start of my freshman year of college after I getting cut trying to walk on to the baseball team. Naturally, I began the process of learning the best method for training. Probably in that first few months, I learned that it is necessary to train outside the sagittal plane as baseball is a sport where the prime movements occur on one leg and in the frontal plane. It has now been two years since I started training and side lunges and medicine ball throws have been the main way I have trained in the frontal plane.
In doing these side lunges the main sensory feedback was feeling a stretch in my opposite side (Leg opposite to the stance leg) adductor. I didn’t realize that it is also important to feel that stance side hip so as I said earlier I went on doing this for almost two years not knowing I was missing a major element of the moment.
What I recently learned
Fast forward two years and I have finally realized that the most important part of training in the frontal plane is feeling a loaded stance side glute/hip. There are two simple positions that helped me find this stance leg glute/hip. The first is a retro step with stance leg elevated. To get into this position start with both legs together then take one leg and step it back so it flat against an elevated surface, this is the stance leg. While keeping that toe facing forward load into that leg until you feel your hip light up. This is a frontal plane exercise that will help you feel the loading of the stance leg hip/glute. Once you are comfortable in this position you can throw medicine balls out of it. This will teach the body to explode out of a loaded hip position as would need to be done in an athletic scenario.
Another exercise has given me the same sensory response of a loaded stance leg glute is a lateral lunge onto an elevated surface. Once in this position drive your stance leg knee inwards, reach your arms out straight and rotate them towards your stance leg until you feel that stance side glute/hip. To exaggerate the feeling hold a weight or medicine ball in your outstretched arms. Again you can throw a medicine ball out of this position once you are comfortable with it.
Feeling that stance side glute/hip in this position that I described above has actually made my side lunge more effective. Instead of only feeling a stretch in my opposite side adductor I can now feel a loaded stance side glute and use the lateral lunge to further work on exploding out of that position. Similarly, my other medicine ball throws have gained a new purpose as I can now use them to achieve this same function. Some people may already feel this hip in there lateral lunge and I am sure with the proper cueing I could have too. However, some people might have a hard time achieving this sensory feedback so it is important to have a bank of exercises like I went over above to force them to feel that proper loading pattern.