One of the best ways to become functionally strong from your training is to include a heavy dose of single limb training, also known as unilateral training. While bilateral training is better known and also important, there are several unique advantages that unilateral training offers that makes it a must to include in your program. Before I get into their five main advantages, though, let me clear up a common misconception.
Simply using dumbbells does not constitute unilateral training. Even though both limbs are moving independently, using both of them at the same time is still bilateral training. True unilateral training means that you are either doing one side at a time or at least alternating between the two sides. For example, a regular dumbbell bench press is still considered bilateral training while doing only one side at a time falls under the unilateral category.
Now on to the five main indispensable advantages of unilateral training:
1) More specific to life and sport – The main advantage of unilateral training is that it is far more specific to the functions of daily life and athletics. Skating, walking and running occurs on one leg at a time, most upper body actions occur one arm at a time, and the list goes on and on. Since most daily and athletic actions require each limb to act alone it only makes sense to include exercises that require the same thing.
2) Injury rehab and prevention – Another advantage of unilateral training is that it helps to rehab and prevent injuries. After an injury it is extremely common to find that the injured side is weaker than the non-injured limb. When this happens it is impossible to restore that balance without using unilateral training. Even if you are not rehabbing an injury, making sure that you have balance between your limbs is also one of the best ways to decrease your future injury potential.
3) Recruit more muscles – Without getting too technical into anatomy, when performing unilateral exercises you are forced to use stabilization muscles that are simply not recruited during bilateral training (and no, standing on a wobble board or balance ball does not do the same thing). As an example, unilateral leg exercises require that the adductors and abductors (the inner and outer thigh muscles) to fire in a synchronized manner in order to maintain balance. In fact, this is the main reason that many people feel so unbalanced when starting unilateral leg exercises; they simply have not used those muscles in that way before and the body does not know how to efficiently accomplish the movement. Getting the body used to the demands placed on it by unilateral training will make for more fluid, athletic movement in your sport.
4) Build strength in a “spine friendly” manner – Just like anything in life, overuse of something will start to cause problems and while I love the squat and deadlift, after a while they will start to put undo stress on the spinal column. Using a unilateral version of these lifts will not only give you all of the previously mentioned advantages, they will allow you to do so with literally less than half the stress on the spinal column. Over the years this will add up to far fewer back problems and injuries. This aspect will also breathe new life into the training program of those who have suffered a back injury since it allows them to train hard enough to elicit strength gains in a way that does not greatly increase their chance of re-injury.
5) Bilateral Deficit (probably the most important)
The bilateral deficit is a phenomenon where the total force production of a bilateral lift (using two legs) will not be greater than the sum of individual efforts of a single limb.
Example from an ASP athlete:
Barbell Front Squat (2 Legs) = 285lbs for 6 reps
Barbell Front RFESS (Single Leg) = 185lbs for 6 reps
Scientific research shows that the front leg gets 90% of the load and the rear leg absorbs 10% when performing Rear Foot Elevated Split Squats (RFESS)
185lbs – 10% = 167lbs Load on the front leg
167lbs x 2 Legs = 334lbs Total load
334lbs (Total RFESS load)
-285lbs (Two leg squat)
49lbs (Bilateral Deficit)
Not only are you training each leg to work independent but you’re also working the stabilizers of the hip and pelvis, this help prevent strength leakage. Using a small base of support increases proprioceptive input (think balance). If you’re strong and have balance on a single leg, imagine how you’ll be on two legs!
Add all of these up and you must include unilateral exercises if you are serious about getting everything that you can out of your training program. Some of my favorite unilateral exercises are the unilateral dumbbell alt bench press, unilateral shoulder press, unilateral DB deadlift, rear foot elevated split squat (RFESS) and the unilateral squat (or if you have the strength and mobility a full pistol squat).
Be forewarned, though, since unilateral training will produce some muscle soreness in places that you did not know you had and has also been known to increase performance to previously unattainable levels.