6 Ways to Challenge the Single Leg Squat to a Box
As much as I love the traditional barbell squat movement, it’s not for everyone. Differences in hip structure (long femur, shallow hip socket), spinal issues, or comfort alone, may not make it the best choice for some people. That’s ok – It doesn’t matter what your favorite exercise is, find what works best for the individual in front of you.
The single leg squat to a box is one of my favorite exercises for athletes and knee rehabilitation. There are a good deal of progressions and regressions that make this a versatile movement to have in your arsenal. The box allows you to exaggerate sitting back to load the posterior chain more and focus on the eccentric component of the movement. A recent study found that being able to perform 22 single leg squats was favorable for an improved outcome in those athletes who had ACL reconstruction .
If tolerable, begin with accentuating the eccentric (lowering) portion of the movement. We know that eccentric contractions are heavily involved in deceleration and transfer of elastic energy . With eccentric contractions we can drive hypertrophy and strength (more than concentrics), improve flexibility (more than static stretching), and increase stiffness of the tendons, which can reduce the incidence of strains.
Because we produce more force during eccentric contractions, we can use a heavier load than if we were performing the concentric portion of the repetition as well. This is a simple way to prepare the tissue for full repetitions and increased loading. Eccentrics also slow the movement down, which can improve motor learning.
Exercise – Single Leg Squat to Box
– Opposite leg will be out in front
– Brace your abdominals and grip the floor with your foot
– Slowly begin sitting back onto the box
– Reinforce that they push back and load the hips
– Arms can be out front to counter balance or holding weight for resistance
– Stand up with good power and extend through the hips at the top
– I prefer starting with an eccentric block where they lower with one leg and stand with two, loaded and unloaded.
1.) Eccentric Single Leg Squat to a box with bilateral standing
This can be used in general development of a single leg squat and in a rehabilitation scenario. This exercise focuses on a slow eccentric (4-6 seconds) lowering on one foot and then standing back up with both legs. Reps are kept between 5-8.
The benefits of eccentric training are mentioned above but this can often be done by individuals who either aren’t ready to stand up with one leg or may experience pain if they did. This allows you to stress and change the tissue in a pain-free environment, eventually allowing you to progress.
2.) Loaded Single Leg Squat to a box
You can use a dumbbell front loaded, chains, dumbbells at the side or weight vests. Once you have gone through normal single leg squat progressions and can properly control the eccentric and concentric portion of the reps, add resistance for more of a challenge. This can be used as your main lift or an accessory.
3.) Single Leg Squat to a box with TKE
This exercise can be used in a prehabilitation or rehabilitation scenario. Finishing with the band helps reinforce proper hip and knee extension. While this exercise may not isolate the VMO as once believed, it’s still a nice movement to strengthen the quadriceps and improve knee stability. This will be done with higher repetitions and normal tempo. 1-2 sets of 15.
4.) Single Leg Squat to a Box from a Deficit
If you’d like to work in deeper ranges of motion, you can use a lower box or stand on pads. This allows you to strengthen the movement pattern below parallel. This is a great way to improve your pistol squat if you aren’t able to do a full rep yet.
Regression Options (Knee pain / Rehabilitation)
5.) Single Leg Squat to an elevated box
A lot of things change as we sit deeper into a squat. For some, there might be anterior knee pain the lower they go. Others might excessively flex at the spine due to their anatomy or some other restrictions. By adding an airex pad you can work within pain free ranges of motion where the athlete/patient can maintain postural integrity and avoid pain. Start with comfortable ranges, get really good at them and then progress.
6.) Single Leg Squat to a box with TRX assistance
This is the lowest level of the exercises described. The TRX provides stability and takes pressure off of the working leg. You can use this to reinforce proper technique, reduce stress level associated with the movement, or someone who lacks the eccentric control without support.
 Culvenor et al., (2016). Dynamic single leg postural control is impaired bilaterally following anterior cruciate ligament reconstruction: Implications for reinjury risk. Journal of Orthopaedic Physical Therapy. 46, 357-364.
 Franchi, Martino V., et al. “Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations.” Frontiers in Physiology, Frontiers Media S.A., 2017, www.ncbi.nlm.nih.gov/pmc/articles/PMC5495834/.
 O’Sullivan K, McAulifee S, DeBurca N. The effects of eccentric training on lower limb ﬂexibility: a systematic review. Br J Sports Med 2012;46:838–845
 Kay, A.D., et al. “Stretching of Active Stretching Elicits Chronic Changes in Multiple Risk Strain Factors. Medicine and Science in Sports Exercise, 2016.