What Is Unilateral Training and Why Is It Important?

Adding unilateral exercises to your routine can help you avoid muscle imbalances.

Unilateral Training

What do Bulgarian split squats, tossing a frisbee, and the single-box stretch of hopscotch all have in common? They all technically qualify as unilateral training — the underrated, highly beneficial style of exercise that involves working one side of your body at a time.

"Unilateral training is one of the most overlooked training styles there is, but it's so important," says Alena Luciani, M.S., C.S.C.S., a certified strength and conditioning coach and founder of Training2xl. "Yes, it can build a more symmetrical body, but it can also help prevent injury, give you the extra strength you need to bust through a plateau, and improve stability and mid-section strength." Not too shabby.

But, what exactly is unilateral training and why is it so damn effective? Here, Luciani and other strength experts share the 411 on unilateral training — including how to add it to your workout regime.

What Is Unilateral Training?

If you took Latin in high school — or know what a unicycle is — you likely understand that "uni" means one, and therefore can deduce that unilateral training entails using one of something.

"It's any training that entails isolating and using the muscles on one side of the body at a time — as opposed to distributing the workout evenly between both sides as you do with traditional, bilateral training," explains Luciani.

For example, a pistol squat (also called a single-leg squat) entails keeping one leg raised in the air, then squatting all the way to the floor using the strength of the single, standing leg. That's a unilateral exercise. On the other hand, the basic air squat or barbell back squat are bilateral moves that work both sides at the same time.

Why Unilateral Training Is So Important

Everyone has a dominant (stronger) and non-dominant (slightly less strong) side of the body. Think about raising your hand in grade school during roll call; whichever arm you raised is likely your dominant side.

"We are all naturally stronger on one side of our body than the other," explains Luciani. For instance, "if you write with your right hand, your left arm is weaker and if you always take your first step upstairs with your right leg, your left leg is weaker."

These strength imbalances are typically more pronounced in athletes, says Luciani. For instance, if you're a runner, the leg that you accelerate off of is stronger than the other. If you're a pitcher or tennis player, the arm you use to pitch or serve is going to be more muscularly developed.

Yes, it happens naturally, but the trouble is muscular asymmetry isn't ideal. "Right to left, side to side, imbalances in the body are bound to happen, but you want the muscle tissues on each side of your body to be evenly strong and mobile," says Erwin Seguia, D.P.T., C.S.C.S., a board-certified specialist in sports physical therapy and founder of match fit performance.

And if they're not? Well, two things can occur. First, the stronger side can overcompensate for the other, further widening the strength gap between the two sides. Often, during bilateral movements such as the bench press, push press, deadlift, or barbell back squat, the stronger side will do slightly more than fifty percent of the work, explains Allen Conrad, B.S., D.C., C.S.C.S. If you've ever squatted heavy and been more sore on one side compared to the other, that's because that side likely did more work. Basically, the dominant side picked up the slack. This can prevent the weaker side from catching up, strength-wise.

The second possibility is that instead of the stronger side overcompensating, different muscles on the weaker side get recruited (that shouldn't get recruited) to help complete the movement. Let's use a heavy bench press for example: It primarily works the chest and triceps, with the shoulders and back acting as secondary muscles. If during the very end of the movement, one side is lagging behind — even if it's just an inch or two — your body may recruit more of your shoulders or back (and possibly even, yikes, your lower back) to complete the rep.

The potential consequences of imbalances are major, hence the importance of unilateral lifts. "The muscles on the stronger side can fall victim to overuse injury," says Luciani. "And the joints and muscles on the weaker side of the body become more vulnerable to injury."

There's another v important benefit of unilateral training: improved core strength. "In order to keep you stable while you do these single-limbed movements, your trunk has to go into overdrive," says Luciani. "Any time you load one side of the body, it's going to work and strengthen the core."

How to Test Your Muscular Imbalances

To reiterate, almost everyone has some degree of muscular imbalance because of sport or just life. If you're really concerned about being uneven, you can always consult a trainer or physical therapist for an evaluation. Otherwise, here's a rudimentary way to determine how imbalanced you are and learn how much you'd benefit from unilateral training.

Let's say you can bench press 100 lbs. You might think you should theoretically be able to press half of that weight with your right and left arm individually, but it doesn't usually work that way, says Grayson Wickham, D.P.T., C.S.C.S., physical therapist and founder of Movement Vault, a mobility and movement company. "It requires a lot from your stabilizing muscles to move weight on just one side and it takes more coordination with one arm at a time, as opposed to two," says Wickham. "Most people can lift closer to 30 percent when doing the one-limbed version of an exercise vs. the two-limbed version."

So, how do you test your muscle imbalances and decide whether you need unilateral exercises? Test each side separately. Try the single-limbed version of the movement, building up in weight very, very slowly to see which side is stronger, says Wickham.

Try this test with the single-leg deadlift, as an example:

  • Start with a bare barbell or relatively light dumbbell and do three reps in a row, per side.
  • If all reps on both sides were performed in good form, go up in weight, says Wickham.
  • Then, repeat. Continue adding weight until one side can't go any heavier with sound form.

More than likely, you'll be able to use a heavier weight on one side than the other. "If you still have gas left in the tank on one side and think you can lift heavier...don't," says Wickham. Instead, as soon as your form starts to deteriorate, stop and note how many pounds you were able to lift and which side felt strongest. Don't be surprised if this weight is lower than you expected. "Single-leg deadlifts are way more challenging than deadlifts where both of your feet are on the ground because of the balance required," says Wickham. The same can be said for many unilateral exercises such as pistol squats, lunges, and step-ups, among others.

The goal here isn't necessarily to PR, but to see if the strength on each side of your body is equal. If you don't lift regularly, you can also test each side of your body with bodyweight moves too, keeping tabs on how many reps you can do on each side. (That will more specifically test your muscular endurance vs. muscular strength.) Remember, the goal of this test is to how you might be able to benefit from doing unilateral movements — you don't want to get injured in the process.

How to Incorporate Unilateral Training Into Your Workouts

Good news: Adding unilateral movement exercises to your routine isn't rocket science. Any movement that entails moving just one side of your body at a time is a unilateral exercise and, when done in good form, can help fix these imbalances. Here are some of the best unilateral exercises.

Upper-Body Unilateral Exercises: Seguia recommends the single-arm overhead press, single arm chest press, single-arm row, bottom-up kettlebell press, and single-arm overhead walk.

Lower-Body Unilateral Exercises: In addition to single-leg squats and deadlifts, "any lunge is a great option," says Seguia. Try experimenting with walking lunges, reverse lunges, front rack lunges, rear elevated lunges (also called split squats), and curtsy lunges. Luciani adds that single-leg step-ups, single-leg weighted step-ups, and single-leg glute bridges are effective.

Full-Body Unilateral Exercises: Try Turkish get-ups, windmills, and walking single-arm front rack carries. "I can't recommend them enough, because they tax and strengthen the whole body, one side at a time," says Seguia.

When you're first getting started with unilateral training, stay within the 5-12 rep range and let your weaker side determine the weight you use, says Seguia. "The goal here is to help the weaker side catch up to the stronger side, not necessarily to make the stronger side even stronger." Noted.

Two more tips: Start with your non-dominant side. "Load your less-strong side first so that you're tackling the weak side when your body is fresh," says Luciani. And keep the number of reps the same on each side, she says. (See above paragraph for a reminder as to why).

As for how to implement these moves into your routine? It doesn't reallyyy matter, according to Luciani. "Truthfully, unilateral training could replace all your bilateral training because it's only going to make you even better at those bilateral movements," she says. So, "there isn't really a right or wrong way to incorporate unilateral training into your practice, especially if you're currently not doing it at all," she says. Good point.

If you need some guidance, consider turning three of the above unilateral exercises into a circuit two days a week.

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