Personally, I love bilateral lifts. There’s not a better feeling in the weight room than loading up the bar and PR-ing your squat. The world is starting to feel that excitement as well. Squats and deadlifts are becoming cool again and more people than ever have found their way to a barbell. So why am I writing about the single-leg exercise?
Because sports movements aren’t typically executed on two legs. Quite the opposite.
Sprint strides revolve around a single leg producing force into the ground while the other leg simultaneously recovers to do the same. Cutting occurs on one leg. For every one movement that you can demonstrate where each leg performs an identical movement, I could list 5 where they are doing very different things.
Now let’s back up. Science has shown us that bilateral exercises (squats, deadlifts, etc) are terrific for developing motor unit recruitment, strength, muscle mass, and all that good stuff we value as coaches and athletes. There are some drawbacks to these lifts, however.
Not even the most highly trained professional athletes in the world are entirely symmetrical. We all have a dominant hand or leg. Do you think Chris Sale can throw gas with his right hand like he can with his left? Nope. I’d be willing to bet a good deal of money that Shea Weber wouldn’t be able to rip bombs from the point if he was shooting left-handed. Even switch hitters are a little better on one side of the plate than the other.
These bilateral discrepancies get masked during bilateral lifts, particularly under max loads. Keen eyes will notice some lateral pelvic shift as an athlete relies on the stronger leg to help accelerate the bar on his final rep. As a result of increased use of one limb over the other, mobility can also become a concern. Muscle, mobility, and recruitment imbalances that remain unchecked can snowball into “injury-risk” territory.
Unilateral (single-leg exercise) variants take that favoritism out of the equation. They force the athlete (and coach) to address these strength and mobility discrepancies before they become bigger problems. They can also improve balance, increase joint and total body stability, and establish a mind-body connection between the athlete and the affected muscles.
Big bilateral lifts have their place. Squats and deadlifts establish motor unit recruitment patterns by placing the athlete under heavy loads. Strength and muscle mass adaptations will be enhanced when these big multi-joint lifts are followed by lighter multi-joint and single-joint exercises. It can look something like this:
A1) Squat 5×5
B1) Split Squat 3×8 L/R
B2) 1-Leg Barbell Hip Raise 3 x 10 L/R
Pre-fatigue of the muscle tissues paves the way for hypertrophy gains in the affected agonist muscles. Couple that with light CNS fatigue and you’ve forced the athlete to focus on his connection to the floor and heighten his spatial awareness in order to balance. This says nothing about the immense neurological adaptations and skill transfer that can come from single-leg hops and bounds.
Remember: athletes need to lift like athletes. The game occurs on one leg and having them lift like powerlifters will do them a vast disservice in the short-term and the long run. Focus on adding the single-leg exercise into your program to grab results on both sides of the body.