Unilateral Leg Exercises. Where Do They Fit In?

With the multitude of exercises that we can choose from, there is something so fun about single limb work that I like to incorporate in almost every lower body session. From split squats, pistol squats, and different variations similar, I find that including unilateral work can help tremendously for understanding how our body moves in space. But that’s not the only thing unilateral exercises can help with as there other parts to our athleticism that have yet to be trained. From testing our balance, mobility, and stability around the hip, ankle, and knee, using unilateral exercises can come in handy for the many individuals interested to try them.

Bilateral vs. Unilateral

However, does this mean unilateral work should only be done if we want to improve our athleticism in this respect? I would argue no as there are other options to choose from that may improve our performance to a greater degree. For example, the squat, leg press, deadlift, and any other bilateral movements specifically tend to do wonders for improving our strength & performance given their ease of use (relatively speaking) and progress-ability so to speak (e.g, our ability to add larger increases in weight/intensity overtime).

As a result, this improvement will most likely carry over to any unilateral movement that we attempt (and vice versa), but still might miss certain features if trained separate. This is why including unilateral exercises on their own can still be helpful, specifically for the legs, as they have their own unique features and benefits to offer.

Why Include Unilateral Exercises

Although bilateral work will typically be the foundation to most exercise programs, unilateral exercises are still a great addition. Whether you’re an athlete or someone generally interested in exercise, you may find these movements helpful for improving how you feel and move.

Balance & Mobility

For starters, unilateral leg exercises can be very onorthodox and challenge your balance/mobility depending on the movement. A Cossacks squat, for example, is a unilateral movement that requires a degree of mobility around the hip, ankle, and knee. It also requires a sense of balance when lowering into the squat on one side as your other leg stays stretched while you sink into the bottom position.

As a result, although a person may be strong in a traditional barbell squat, performing one clean Cossacks squat (either with one’s bodyweight or additional weight) may be difficult given these other variables. However, working to improve in this movement can help not only with any tightness, but may help improve your depth and range of motion in any other squatting movement that you attempt.

Other exercises, like pistol squats and split squats, will also be challenging in a similar fashion. As your knee, ankle and hip will need to work in unison, performing these reps in a clean and controlled manner may take some time as you get accustomed to the movement. Regardless, try them out and see where you stand while using easier progressions, and specific stretching, to advance in the movements.

Bringing Up A Smaller Muscle

If there’s a certain muscle that is smaller to a significant degree (or perhaps being compensated for by the other limb), incorporating a span of training that aims to work that muscle may benefit slightly from programmed unilateral work (however, this may not be completely necessary). Although bilateral exercises can help to correct any significant asymmetry over time, completing more volume on one side might help to expedite the process in the short term.

Keep in mind, however, that it’s completely normal to have a dominant muscle, as well as different shapes to the bilateral muscles themselves (nobody is perfectly symmetrical), but if you do find that you have trouble contracting one limb in unison with the other (e.g, a barbell squat feels like a single leg squat), then try out the following approach:

1. Drop the weight of your bilateral movement to a load that feels challenging to the weaker side (or at least until you feel both legs working together). Progress with this new weight over the following weeks keeping each rep consistent with the reps at the lighter load. Try to keep your fatigue low as well by leaving 2-3 reps left in the tank. You may also include some tempo work while doing this, like a 3 count eccentric, to get better accustomed to evenly using both legs.

2. Add in a unilateral movement specifically to the less engaged side - try 1-2 sets to begin with. In conjunction with the lighter bilateral movement, you should start to notice a bit of a difference.

Complete these exercises in a controlled fashion until you find the contraction you’re looking for in each set. In the case of the legs, try a unilateral movement that closely mimics the bilateral movement causing you trouble. If it’s a squat that is the issue, try a single leg hacksquat or leg press while going as deep as you can with comfortable form.

Bulgarian split squats can also be a good choice, but depending on your familiarity with this movement, the former may be more convenient (completely up to you). Try this approach for 3-6 weeks on your leg days and try implementing some hip, ankle and knee mobility/flexibility for both legs. If this doesn’t help, seek out a good coach or talk with a health care provider to see what the problem might be.

Adding Training Variety

If you’ve ever felt your workouts becoming a bit stale, sometimes adding a little training variety can keep you motivated for the next few months (or at least give you a new challenge to work on). Unilateral exercises can do just that as there are many variations that you can experiement with. For the legs, a pistol squat can be combined into a jump (see here) while a step back lunge can be completed on an elevated surface for the working leg (see here).

If these exercises are too difficult or perhaps feel off, use easier progressions or focus on the eccentric phase of that movement. For example, if you lack the mobility for a pistol squat on the way down, try working a decel step down on small box (see here). You may increase the height of the box overtime once the reps on the smaller box become nice and smooth. Here’s an example of how to go about it:

• A. Leg press: 3 x 10 reps. 3 count eccentric

• B. Decel step down on 15” box: 3-4 x 3-10 reps

• C. Ankle Mobility/Leg Mobility

Leave 3 reps in reserve on the step downs to ensure each rep isn’t grinded out. If the 15” box is challenging to begin with, start with 3 reps and increase your volume slowly from here. If you decide to add reps over the next few weeks, begin adding them after you notice your form improve (e.g, you don't wobble on the way down and come up quicker than compared to day 1).

This might take a few weeks to notice a difference, but completing the same amount of repetitions with better form is still an indication of progress being made. After this point is reached, slowly add more sets or reps. If you exercise your legs twice per week, then complete this sequence on the second day with the option to omit the 3 count eccentric. See where your progress stands after ~3 weeks and work to andvance the movement to a higher box/platform. Be sure to progress with your leg press exercise as well while working in any necessary mobility for the ankle and/or leg.

Some Ways To Include Unilateral Work

When including unilateral work, you may find it helpful to consider tweaking a few variables upon getting started. For example, the load that you use, as well as when to include the exercise in your workout can both be helpful when attempting to make progress.

Use Lighter Loads

Since only one limb is involved/targeted in the exercise, using less weight will typically be needed to achieve a good stimulus [5]. Despite looking like the movement would be easy, lighter weights can surprisingly be challenging especially when using your full mobile capacity. This deeper range of motion may also be beneficial for muscular hypertrophy when compared to a more partial range - e.g, half reps [8].

Through doing this, your connective tissues may also become stronger within that range making you less prone to injury and better equipped to handle more complex movements [2][3][4]. Using less weight, relatively speaking, will also be helpful for completing the exercise safely and efficiently given the other variables such as maintaining your balance. However, as you practice the exercise and hone in on your technique, you’ll likely be able to handle more weight over time.

Add Them In The Later Part Of Your Workout

Sometimes referred to as an accessory exercise, this allows you to complete the heavier, bilateral movements at the beginning of your routine while leaving the single-limb exercises (which tend to be lighter) for the end. As a result, we get to train our heaviest/hardest movement first when our fatigue is low, while leaving any lighter, less fatiguing exercises for later.

Plus, if you are doing an exercise like a split squat that requires a deeper stretch, your muscles and connective tissues should be fairly warm by this time to attempt any deeper range of motion required. This can help save you time in your workout as putting these exercises first might require a more thorough warm up.

Do More Repetitions Initially

Doing more repetitions initially can help in many respects as you become accustomed to the movement while improving on your technique. Plus, with aspects of balance and stability often coming into play, trying to work within a lower rep range (1-5) may be difficult to accomplish smoothly.

In this case, completing a bilateral movement may be a better investment of your time as handling these loads with two limbs involved may be a smoother process. However, as your strength improves and your comfort within these movements increases, upping the load and dropping the repetitions is a great goal to shoot for so long as you feel comfortable. Try to keep it in the 6-7+ rep range to allow for better form while still providing a good stimulus.

Exploring More With Your Exercise

Although not mandatory for you to include, unilateral exercises can spark a lot of creativity within a given workout, and over the span of a new training block. They allow you to test your athleticism, give you the chance to move in a different plane, and perhaps can introduce a weakness you didn't know you had. In addition to any solid training program, including unilateral exercises is something to consider overtime.

References

1. Reiman, M. P., & Lorenz, D. S. (2011). Integration of strength and conditioning principles into a rehabilitation program. International journal of sports physical therapy, 6(3), 241–253.

2. Afonso, J., Ramirez-Campillo, R., Moscão, J., Rocha, T., Zacca, R., Martins, A., Milheiro, A. A., Ferreira, J., Sarmento, H., & Clemente, F. M. (2021). Strength Training versus Stretching for Improving Range of Motion: A Systematic Review and Meta-Analysis. Healthcare (Basel, Switzerland), 9(4), 427. https://doi.org/10.3390/healthcare9040427

3. Mayo Foundation for Medical Education and Research. (2020, January 31). Stretching is not a warm up! find out why. Mayo Clinic. Retrieved January 31, 2022, from https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/stretching/art-20047931

4. Gummelt, D. D. (2015). The impact of flexibility training on performance. ACE. Retrieved January 31, 2022, from https://www.acefitness.org/education-and-resources/professional/expert-articles/5598/the-impact-of-flexibility-training-on-performance/

5. Eliassen, W., Saeterbakken, A. H., & van den Tillaar, R. (2018). COMPARISON OF BILATERAL AND UNILATERAL SQUAT EXERCISES ON BARBELL KINEMATICS AND MUSCLE ACTIVATION. International journal of sports physical therapy, 13(5), 871–881.

6. Costa, E., Moreira, A., Cavalcanti, B., Krinski, K., & Aoki, M. (2015). Effect of unilateral and bilateral resistance exercise on maximal voluntary strength, total volume of load lifted, and perceptual and metabolic responses. Biology of sport, 32(1), 35–40. https://doi.org/10.5604/20831862.1126326

7. Accessory exercises – what are they and why do we need them? ISSA. (n.d.). Retrieved February 28, 2022, from https://www.issaonline.com/blog/index.cfm/2020/accessory-exercises-what-are-they-and-why-do-we-need-them

8. Schoenfeld, B. J., & Grgic, J. (2020). Effects of range of motion on muscle development during resistance training interventions: A systematic review. SAGE open medicine, 8, 2050312120901559. https://doi.org/10.1177/2050312120901559