, ,

The Importance of Unilateral Exercises

, ,

Most movements can be divided into two categories: unilateral or bilateral. Unilateral exercises are asymmetrical, in which one side of the body (e.g. one leg) is performing an action that the other side does not. Bilateral exercises are more symmetrical, in which both sides of the body are doing roughly the same thing. Both types of exercises are important and functional, but unilateral exercises will facilitate certain benefits that cannot be obtained from bilateral exercises alone. Some examples of unilateral exercises are: reverse lunge, single-leg bridge, single-arm overhead press, split squats, and single-leg deadlift. Examples of bilateral exercises include a squat, deadlift, barbell overhead press, push up, and bridge. In real life, we engage in both types of movements extremely often.

But, because life is rarely symmetrical, unilateral exercises tend to be more relevant to daily life.

Standing on one leg to pull your pants on. Reaching for the glass on the top shelf. Walking. Running.

Bilateral and unilateral exercises both serve a crucial role in functional fitness. While more force and power can be created with bilateral exercises, unilateral exercises require greater balance and stability. They can bring awareness to compensations and imbalances between sides of the body that can easily be overlooked during bilateral movements.(1)

For example, if one has weakness in the left leg characterized by a difficulty in distributing and generating forces, maintaining balance, or moving through a functional range of motion under load, a unilateral exercise will make this extremely clear. If one only ever did regular, bilateral squats, the right leg would continue to overwork, perpetuating a compensatory pattern that could contribute to issues down the road. While we should not expect that our two sides should be equal in their ability, it is helpful to be aware of our unique characteristics and engage in movements that will provide a stimulus for positive adaptations to occur. 

It is important to recognize that with most unilateral, “single leg” exercises, both of your legs continue to carry out an important job. Put simple, one is the mover, and one is the stabilizer. Contrary to what might be evident visually, it is the leg that is not moving that actually has the more difficult job. One leg is weight-bearing, and one leg is non weight-bearing (or bearing less weight than the other leg). The leg that is holding our weight is responsible for maintaining our balance and control of the movement, while the other leg is free to move through space. Consider walking. At each moment in time, one leg is holding your weight, foot on the ground, allowing you to move your other leg forward. By becoming more aware of where we are holding our weight, and which leg is free to move, we can refine our coordination, balance, and efficiency of movement. 

Mime Walking Example

Mime walking is a standing movement lesson that almost all Wellness Station clients learn early on. Many of us begin to have difficulty gliding our pelvis to shift our weight, which can be evident from a forward-flexed posture, short step length, and difficulty standing on one leg. This lesson helps to bring about greater elegance and ease to walking by teaching awareness of weight shifting from one leg to the other. The basic idea is to glide the pelvis to one side (e.g. right) so one leg holds your weight while the other leg lightens up, and then repeat on the other side. Once this concept is learned and felt in the body, countless variations and progressions can emerge that will translate into improved function and ease of walking.

Single Leg Stand to Reverse Lunge

To further progress mime walking, we can apply this motion into a single leg stand. We become aware that one leg is holding us up and controlling our movement and stability, while the other leg is free to move through space. Applying this into a single leg stand to reverse lunge flow is a dynamic way to improve balance, strength, and awareness of our differences from side to side. 

If lacking in steadiness and ease, gently hold on to a support surface with a hand (put your hands in the kitchen sink!), or don’t move the non weight-bearing leg through such a large range. 
If more challenge is desired, move in slow motion, increase the range of motion of the non weight-bearing leg, and/or hold a dumbbell.

Sit to Stands and Squats: Unilateral Bias

A basic squat or sit to stand movement can be changed to have a unilateral focus by holding more weight through one leg intentionally. Coming up onto the tip toes of one foot is a way to do this. 

If lacking in steadiness and ease, use a higher chair, and/or don’t come up as high onto the tip toes (keep more of the non weight-bearing foot grounded). Or, hold on to the kitchen sink as you do this motion. 

If more challenge is desired, use a lower chair or squat through a deeper range, move in slow motion especially on the way down, hold a dumbbell at the chest, or even practice hovering the tip toes off the ground.