Advances in Functional Training Excerpt: Classifications of Single-Leg Exercises

Advances in Functional Training: Training Techniques for Coaches, Personal Trainers and Athletes
Michael Boyle, Classifications of Single-Leg Exercises Excerpt, pages 216-219

One of the major changes of the last decade in the fields of strength and conditioning and personal training has been an increased emphasis on exercises considered both functional and multi-planar. Where many strength coaches and trainers previously relied on bilateral exercises like squats and leg presses, we now regularly use exercises like lunges and one-leg squats. We’ll next look at the menu of single-leg exercises to classify the relative differences and benefits of each exercise, and evaluate where these exercises might best fit into our programs.

As we use more and more single-leg exercises with our athletes, we’ve broken these exercises into categories and placed the exercises in progressions. One of the drawbacks of having a broad range of exercises available is determining which exercise is appropriate for which individual, and at what point in training should each be used.

We often see an advanced exercise like lunges capable of producing extreme soreness recommended as a cure-all for nearly every lower-body issue. The current thought in some circles seems to be when in doubt, lunge. Yet prescribing an advanced single-leg exercise for a beginner can be a crippling introduction to the world of unilateral training. Using lunges initially can make sports practice difficult for the next few days.

When looking at single-leg exercises, it’s apparent they can be broken into knee-dominant exercises, variations of a squatting movement, and hip-dominant exercises, or those that prioritize the glutes and hamstrings and are variations of straight-leg deadlifts or bridging exercises.

Further investigation of the demands of single-leg exercises makes it necessary to break single-leg knee-dominant exercises into static exercises like one-leg squats, and dynamic exercises such as lunges and slideboard lunges.

In static single-leg exercises, there is no movement of the feet. One or both feet stay in contact with the ground. The body moves up and down in the sagittal plane or potentially side to side in the frontal plane, as in a lateral squat. Static knee-dominant exercise can further be broken into either static unsupported or static supported exercises.

Static Supported Exercises

Single-leg supported exercises describe a one-leg exercise done with some support from the remaining leg. The non-working leg could either be in contact with the floor as in a split squat or on a bench. These are not dynamic exercises as they lack translation. The center of mass stays in the confines of the base of support and the feet do not move.

A split squat is what we call a single-leg, static, supported exercise. It’s static: We’re not moving. It’s not a lunge. There is no step. It’s supported: We have the back foot in contact with the ground, a box, bench, or something else. Other examples would include the one-leg bench squat, the lateral squat and the rotational squat.

The rear-foot-elevated split squat, while harder, is still a static, supported exercise. All we’ve done is shifted the load more onto the front leg. This is a harder exercise than the split squat, and probably a better exercise for the more advanced athlete. This is a really important single-leg strength exercise, but it’s still static.

The pelvic implications of supported exercises are very different from the pelvic implications found in single-leg squatting, or other unsupported exercises. It’s very different in terms of what it’s asking the pelvis to do.

Single-leg supported exercises are a great introduction to single-leg training and should always precede the dynamic variations. An additional benefit of single-leg supported exercise is these exercises are excellent for flexibility.

Static Unsupported Exercises

Static unsupported single-leg exercises consist of single-leg movements done on one leg only. The non-working extremity is not allowed to touch the ground or any other object such as a bench. The only true static unsupported exercises are variations of one-leg squats. These may be referred to as one-leg squats, balance squats or step-downs in various texts.

The single-leg squat is an excellent example of knee stability. We won’t find an example better than that. As we look at a single-leg squat, we should think knee stability; this is the ability to exist in what we would call a single-leg, unsupported environment. Many of the single-leg unsupported exercises are frequently used as dynamic warm-up exercises, and are excellent for more experienced trainees in that function.

Carryover Limitations

Until recently, I did not distinguish between static unsupported and static supported exercise. Strength and conditioning coach Karen Wood convinced me otherwise. Wood’s rational is the limited functional carryover from the single-leg supported category to the single-leg unsupported category. In other words, performance of exercises like splits squats or rear-foot-elevated split squats did not carryover to performance in a true one-leg squat.

In static supported exercises, the hip rotators, adductors and glute medius do not take as active a role in stabilizing the femur. In true static unsupported exercises, the hip rotators, adductors and glute medius must actively work to prevent internal rotation of the femur. Static unsupported exercises are essentially tri-planar, as the movement may be sagittal, but the stabilizers must also prevent movement in the frontal and transverse planes.

A static unsupported exercise becomes a tri-planar movement automatically as the stabilizers work as anti-rotators. Wood’s thought process has caused me to program exercises in a manner we now define as progressive range of motion.

Progressive Range of Motion

Earlier in my career I would have scoffed at the idea of using partial movements. However, as I became involved in the rehabilitation of athletes with patella-femoral problems, I came to realize range of motion in the lower body needs to take a back seat to femoral control. Often in static supported exercises like a split squat or a one-leg bench squat, the athlete can move through a full range of motion, perhaps with significant loads, but still be unable to control the motion of the femur in an unsupported environment. In this case, lower-body strength is wasted because it does not fulfill its obligation to control the motion of the femur.

To illustrate the concept, in our facility, a single-leg squat will be done only to a pain-free range that demonstrates control of the femur relative to adduction and internal rotation. In other words, it is not enough to squat low. The trainee must squat low while maintaining control of the femur from the hip musculature.

In progressive range of motion training, the bodyweight load remains constant, while the range of motion is progressively increased. Once the trainee demonstrates full, controlled range of motion, the programming reverts back to basic progressive resistance concepts.

In the same program or in the same workout, we may simultaneously be using a single-leg unsupported exercise with progressive range of motion as in partial one-leg squats, followed by a single-leg supported exercise done through a full range of motion.


Split squats should precede lunges; lateral squats should precede lateral lunges; and rotational squats should precede rotational or transverse lunges. Failure to do this will result in exceptional soreness, possible disruption of the training program, and often a loss of confidence in the coach or trainer by the athlete or client.

The reason for the exceptional soreness lies in the sagittal emphasis of most training programs. Many times range of motion is consistently gained in the same plane of motion; motion out of the sagittal plane involves muscle fibers and action not previously encountered.

Athletes often report unusual levels of soreness in an area that appears to be the adductors or the medial hamstrings and it sometimes seems even worse with lunges. Rolfer and author Thomas Myers describes the adductor magnus as the fourth hamstring, and in fact the adductor magnus is the third most powerful hip extensor.

Adductor magnus assists in hip extension by providing a counterbalance to the external rotator capability of the glute max, the most powerful hip extensor. The combination of extreme knee and hip flexion in a single-leg exercise stresses the anti-rotator and extensor capabilities of the adductor magnus in a way completely unfamiliar. This causes unusual soreness that can be injurious or even confused with an actual groin strain.

Many athletes don’t use the adductor magnus as a hip extensor until they begin to squat low or begin performing walking lunges. When they do these exercises, they activate the adductor magnus. The response is usually a painful one. The adductors, primarily the adductor magnus, plays a critical role in sprinting, acting as both a powerful hip extensor and a counterbalance to the external rotating capability of the glute max.

Dynamic Unsupported Single-Leg Exercise

The remaining single-leg exercises would be classified as dynamic exercises. In dynamic single-leg exercises, the body is translated in either the sagittal plane (lunge, slideboard lunge, Valslide lunge, TRX lunge or walking lunge), frontal plane (lateral lunge), or transverse plane (rotational lunge).

Dynamic single-leg exercises are among the most significant soreness producers in the coach’s toolbox, and should be implemented with great care. A static supported version of the exercise should precede the dynamic version for a three-week period. Lunges should not be used until the trainee has done at least three weeks of split squats.

Accelerative and Decelerative Patterns

It is further necessary to categorize dynamic single-leg exercises into accelerative and decelerative patterns. Accelerative patterns would be walking lunges and slideboard lunges. Accelerative exercises are pulling actions that mimic the mechanics of an athlete accelerating toward an object. These have high transfer capability to running.

Decelerative patterns would include conventional lunges, lateral lunges or any multi-planar, transverse or rotational version. The decelerative patterns have more application to braking and direction-change skills. Decelerative exercises are excellent for injury prevention, whereas accelerative exercises will greatly enhance movement capability. Both types are necessary, but they should not be viewed as either strongly related or interchangeable since they are markedly different.

The accelerative dynamic single-leg exercises have been inappropriately named and misclassified. Walking lunges, Valslide lunges and slideboard lunges are actually hip-dominant exercises that look knee-dominant.

Although the action in a walking lunge or slideboard lunge appears to be the identical movement to a conventional push-back lunge, the muscle actions are entirely different. Conventional lunges are knee-dominant and quadriceps-oriented and don’t produce unusual soreness. Any of the walking, slideboard and Valslide variations will produce exceptional soreness, particularly in the long adductors as noted above.

Effectively programming single-leg exercises takes on an entirely new dimension in light of this. In our programming, I have relied far too heavily on the static versions and have not used enough of the dynamic. In fact, the accelerative options may be the best one-size-fits-all choice.

Advances in Functional Training

Excerpted from Advances in Functional Training: Training Techniques for Coaches, Personal Trainers and Athletes

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