A hot topic of discussion between us strength coaches is the benefits of unilateral and bilateral training. For years now, and we have been taught “if we can’t do it on two, we shouldn’t be doing it on one!” There is merit to this, no doubt. What your body does to accommodate loading on one leg is a totally different neural pattern compared to two legs, and it will lead to different training adaptations. Bilateral exercises such as the squat, deadlift, and RDL have been proven to be useful exercises to improve strength and power that transfers to on field performance. Unless you participate in a bar sport like powerlifting, you may not be getting as much out of these lifts as you think.
We are asymmetrical creatures, we are never going to perfect balanced no matter how hard we to strive to attain symmetry. When you play an asymmetrical sports such as baseball, the asymmetries are further attenuated. While your body adapts to these asymmetries, the possibility of injury tends to increase. While a lot of movements in the weight-room are performed on two limbs, athletes can hide asymmetries in these bilateral movements. Over time something will give on the field or in the weight-room that causes an injury. In unilateral movements, hiding compensation patterns is almost impossible! It can actually highlights the flaws in the system. While we may never be symmetrical (maybe we aren’t supposed to be) if I can close the gap between left and right, the total system benefits.
The majority of athletic activity takes place on one leg. Running, cutting, jumping all take place on one leg; the amount of time spent on two limbs is not as often as your would think. The body relies on each individual limb to produce force to propel the body forward; while the opposite leg prepares for ground contact. Bilateral movements like the squat train the appropriate muscle groups required to improve performance, however it is not a movement athletes often experience on the field. A big counter argument is that you are stronger/ more powerful on two legs compared to one, and this is true… in the moment of the lift.
The bilateral deficit is a term used to describe the sum of two limbs lifts has a greater total load compared to using two legs at the same time. For example, athlete A can back squat 300lbs. But, he can single leg squat 155lbs on each limb individually and this totals to 310lbs. If the rep and set scheme is the same between the two exercises, total tonnage will be greater with the single leg squat compared to the back squat; which would elicit greater adaptation (maybe).
Finally, two limb movements do not always equal improvements with one limb movements, while one leg movements can further improve the ability of two limb movements. In my experience, my athletes have trained primarily on two limbs, while often neglecting unilateral movements. With that being said, their RDL strength and coordination completely exceeds their Single Leg RDL ability (most cannot even get into the position). This is troublesome because we ask these athletes to perform single leg plyometric exercises such as a sprint on a daily basis. The Single Leg RDL almost directly mimics the requirements of the sprint, and if these guys can hardly get in the correct position in a controlled, unloaded environment… I cannot expect them to have any type of advanced sprint ability. I want to change our current mindset that you should be able to perform a movement on two limbs before you attempt it on one. I think we should train single limb ability before attempting bilateral movements.
Thanks for your time!
Coach Nate Garcia