Dissecting the 1-Leg Squat

With the increased attention paid to the benefits of single-leg training, 1-leg squats have worked their way into more and more programs. Similar to traditional squatting, there are multiple ways to perform and progress a 1-leg squat. An understanding of the advantages and disadvantages of each approach will allow coaches to select the best methodology for their athletes.

Before programming 1-leg squats for your athletes, it's best to progress up the exercise using exercises with similar patterns, but less of a stability challenge. In other words, athletes should demonstrate proficiency in hinging at the hips, maintaining neutral spinal alignment, loading the posterior chain, and controlling dynamic valgus (knee collapsing in) prior to performing 1-leg squats. A simple build-up progression could be:

1. 2-Leg Squat (Back, Front, or Goblet Grip)
2. Split Squat
3. Back Leg Raised Split Squat
4. 1-Leg Squats

Performance Variations
The traditional way to perform a 1-leg squat is with the “up-leg” extended in front of the body. This tends to shift the weight a bit more anteriorly and allows for a high degree of knee flexion ROM. In essence, this is a 1-leg version of a front squat. Because both hips are flexed in this version, I find that most athletes tend to hit hip flexion end range and enter into lumbar flexion before they reach the bottom.

1-Leg Squat (Pistol Variation)

This realization raises two questions:

1. How are we determining “full” depth?
2. Is there a better way to perform the exercise to avoid undesired lumbar motion?

Regarding the former, full depth is typically defined as the femur of the squatting leg(s) reaching parallel to the ground. As a basic definition, this is fine; but following this as an unconditional necessitation without consideration to individual limitations can be dangerous. For example, an athlete with CAM impingement will not have hip flexion past 90° because of a bony restriction. Pushing past this ROM will cause labral damage. Instead, full depth could be defined as the ROM that allows optimal alignment of all the involved joints, including a neutral lumbar spine and minimal hip rotation in transverse or frontal planes. This definition minimizes the risk of lumbar and hip damage as a result of pushing excessive ROM and places the core musculature in optimal positioning to stabilize the torso and pelvis.

To address the latter question, simply moving the non-working leg into a hip extended position can go a long way in improving the quality of the squat. Having the up-leg behind the body creates a counterbalance, allowing athlete to shift their weight back more. This will lead to an increased loading of the posterior chain, and provides the option of allowing the athlete to squat with a more vertical tibia, which can be an effective strategy when attempting to both reduce and train in the presence of anterior knee pain.

1-Leg Squat (Up-Leg Back) 

Progressions

Exercises can be progressed in three basic ways:

1)    Speed of movement
2)    Range of motion
3)    Load

In general, all of our lifts are performed with a controlled eccentric phase and an “intent to move rapidly” concentric phase. Range of motion is a great way to progress the 1-leg squat initially, as people continue to develop the strength and stability necessary to reach their full depth. With traditional squatting and the pistol style squat, you can easily determine depth by using a box. When the athlete's butt lightly touches the box, he/she has reached full depth. This is a great strategy to ensure consistency between reps. With the extended up leg 1-leg squat variation, it's possible to apply this same concept using stacked weight plates as an implement and having the athlete touch their knee lightly. As an athlete gets stronger and/or develops better control of the movement, you can increase the depth of the squat by using less plates or by changing the top plate from a larger weight to a smaller one (e.g. 10 lb plates are thinner than 45 lb plates).

1-Leg Squat (Partial ROM)

After experimenting with several loading methods, I've come to the conclusion that a “goblet” loading style is the best. Holding a kettlebell or dumbbell in this position engages the core and forces the athlete to maintain an upright posture. If athletes are able to perform sets with the heaviest dumbbell in the facility, load can be furthered progressed with weight vests.

1-Leg Squat (Goblet Loaded)

1-leg squats are an effective exercise for improving lower body and hip strength and stability. As with any exercise, it's important to have sound progressions in place to ensure the athlete continues to adapt. The parameters above will allow coaches to effectively incorporate 1-leg squats into their programs, while minimizing the risk of deleterious hip and lumbar compensations/injuries.