*Author, Joshua Nackenson squatting 391lbs in the 165 weight class
The timing of this article is fitting, given the epidemic sweeping gyms across the world — people squatting too high.
By definition, a full squat is just below parallel, where the hip joint is lower than the knee joint. At the bottom of the squat, if you were to put a marble on your thigh, it should roll down towards your hip — not your knee.
In actuality, most people perform half squats or quarter squats (referring to the range of motion) for various reasons. Some can’t due to mobility issues, while others simply resist because they claim squatting to full depth is “bad for your knees and back.” The knee excuse is so common that I’m often warned by casual gym-goers that I’ll be in a walker by age 60 if I continue to squat below parallel.
If you think about the very bottom position of a squat, it’s the same position that many babies assume while they’re playing; in the third world, it’s the way a lot of people eat their meals and go to the bathroom. That’s all well and good, but in neither situation is there an external load on the person’s back. Surely that’s got to change things.
Fortunately, we can look to science — specifically a recent study published in the journal Sports Medicine1 — for a definitive ruling on the squat depth debate.
Researchers essentially did a review of all current literature on knee and back health, as it pertains to squat depth at various loads. The researchers reviewed a total of 164 articles and found some very interesting data. Not only are full depth squats not dangerous, they actually cause less stress on your knee joint and spine. “When compared with half and quarter squats, in the deep squat [less] knee joint and spinal joint stress can be expected.”
Not only are full depth squats not dangerous, they actually cause less stress on your knee joint and spine.
Major Takeaways Noted in the Study —
Supportive tissue (ligaments and tendons) will adapt to increased loads, and concerns about degenerative changes in the knee are unfounded.
At the turning point of a half squat, there is morecompressive stress on the knee and a smaller support surface for the quadriceps tendon (when compared with a full squat).
Full squats do not have any negative effect on the stability of knee ligaments.
The spine adapts to squat training by A) increasing bone mineral density, B) increasing tensile strength of ligaments, and C)strengthening back muscles — this contributes to a protective effect.
When half squatting, a significantly greater load is necessary to create the same training stimulus (when compared to the full squat) — this requires MORE compressive force on the back and knee to produce the same effect.
Verdict: Squat Deep.
If you can’t squat deep because of mobility/flexibility limitations, it’s probably a good time to start prioritizing mobility — a good place to start is with the book Becoming a Supple Leopard by Kelly Starrett, as well as www.mobilitywod.com.
As with any exercise, start light and slowly add weight as you build up your strength. Just because full-depth squats are safer than half squats doesn’t mean you’re bulletproof — use common sense and standard safety practices when lifting.
Joshua Nackenson, CSCS, is a medical student at the University of Miami Miller School of Medicine with a passion for all things related to fitness and nutrition.
His primary athletic focus is powerlifting, where he competes in the 165lb and 181lb weight classes. In between powerlifting training and competitions, he stays fit by competing in local 5ks and Tough Mudder events.