Unilateral vs. Bilateral
Single leg split squats. Two legged dead lifts. The turbulent debate between unilateral and bilateral work has merits on both sides. I believe much of it hinges (pardon the pun) on what a lifter/trainee values. As someone who’s had 25+ years of gym training experience and a myriad of injuries, the value of unilateral strength work has a much higher upside for me. I still perform loaded, multi-joint bilateral work, but I often do it after mya single leg work (body- weighted-double legged plyometrics, however, are still completed with my unilateral work at the forefront of my workout).
Since I’ve done a lot of rotational sports throughout my life (baseball, basketball, soccer, tennis, golf), my muscle imbalances have been the underlying root of low back tightness, hip snapping, shoulder “popping” and a host of other nagging injuries. Although I’ve skirted any major injuries, these smaller issues have led to constant discomfort as I glided to age 40. Well, maybe more shuffled toward 40… in any event, I realized that finding muscle stability and addressing my lack of mobility could only be maximally obtained with unilateral work.
One of the foremost reasons I favor unilateral work is it’s ability to create a stronger level of stability in the frontal plane. The majority of heavy-loaded bilateral work operates in the sagittal plane and it’s often our strongest linear movements. But these ubiquitous and popular exercises overwork our primary muscles. Think of your musculature as your own little militia: the sagittal plane muscles are your front line. However, after many battles with the same heavy bilateral squat and deadlift patterns, the casualty cost (muscle fatigue) is high. Call in the reserves: your frontal plane stabilizers. These stabilizers (think gluteus medius, gluteus minimus, internal and external obliques and adductors) become an added force to help support the front line. The more available, faster and stronger the neuromuscular response the stabilizers can create the greater the support system for your primary muscle movers.
In order to create a more powerful, clean and injury-free squat, for example, exercises that focus on our flanks will help create the stabilizing supportive muscles that will assist the primary movers (quadriceps, gluteus maximus, erector spinae). Active lateral planks highlight the gluteus medius with ipsilateral (same side) oblique muscles. The Copenhagen Adduction exercise will target the adductors with contralateral obliques. The key with both of these is to not allow the pelvis to dip: you should maintain a constant push from the ground with your hips in order to maximize the internal and external obliques. In addition, the continuous contraction of the abductors and adductors creates a stronger neural connection that will establish a robust base of support for your big lifts (bi-lateral squat, deadlift, cleans, etc).
Naturally, the loading mass cannot nearly be as heavy in unilateral work as one leg cannot handle the same workload as two legs. However, single leg work doesn’t need to be about heavy resistance, but rather enhanced range of motion and controlled movements. Larger range of motion correlates to a more balanced recruitment of more muscle for a joint or joints for complex movements. A focus on one-leg eccentric movement—such as rear foot elevated split squats, reverse lunges and bowlers squats— can make the exercise extremely challenging and flush out twisting and torquing during two-legged closed chain work. The shifting/twisting during the lowering phase of squats and deadlifts can be cleaned up with specific one legged exercises combined with abdominal stability.
Finally, unilateral and split stance work can assist in repositioning the body for better breathing techniques by inhibiting certain areas of the body that can often be under constant contraction. Many athletes have what I call the “standing on the edge of the cliff” syndrome: people who complain of sensitive calves, hip flexors, vastus lateralis (outside quads), anterior deltoids (front shoulders), tight chests and posterior neck are just a few indicators of overworked sagittal plane muscle groups that don’t get any buttressing in normal, everyday life. Simply spending time in one-legged exercises as a focal point can help ease discomfort and create a more balanced and efficient movement capability.
I’m not saying to complete overhaul your workouts to just do unilateral work, but there are advantages to beginning one-legged work from a fresh starting point. You may find that spending a couple months of intensive single leg work can greatly improve your bilateral squats, deadlifts and even Olympic lifts.