The squat is arguably one of the best if not the definitive exercise for any serious trainer. Due to its movement pattern, many trainers are warned however about the dangers of squatting past 90 degrees or past parallel, and how damaging it can be for the knees. But is there any evidence supporting this idea? Are there any benefits to performing deeper squats or even half squats. This weeks Q & A will address the age old question of ‘How far down should you be squatting?’
But First Watch Our Video On Proper Squatting Technique
1. Should I squat to 90 degrees or lower? Will squatting past 90 degrees damage my knees?
The squat is a compound movement that often involves a weight and both knee and hip flexion to reach its end point. It is considered one of the best exercises to help boost the strength and muscle size of the legs (quads and hamstrings) and the buttocks, but also helps train and develop a range of accessory muscles such as: the core, abdominals, lower back, upper back and the trunk muscles just to name a few.
Over the years, concern over the squatting depth and its impact on the knees has always been an issue amongst trainers of all experience levels. This concern arises over the high degree of knee flexion and the amount of weight that placed on the joint during a squat. Initial studies looking at deep squats did notice that the collateral and anterior cruciate ligaments of deep squatters were more lax than control groups1, leading the researchers to suggest that ligament stability is compromised with deep squats. However, studies performed since have shown that deep squats doesn’t pose any significant greater risk than 90 degree squats.
In fact, deep squats may result in better stability of the knee2. Studies looking at forces on the ligaments have shown that the peak force for the ACL occurs at 15-30 degrees of flexion and actually decreases significantly at 60 degrees before maintaining itself after that. For the PCL, forces actually increase till peak levels are reached at 90 degrees of flexion, before decreasing sharply after that. So, theoretically, it might make more sense to squat deeper and past 90 degrees to help protect the ligaments3.
Rather, the menisci and the articular cartilage of the knee joints suffers the greatest risk with deep squats due to peak compressive forces occurring at about 130 degrees of flexion4. However there hasn’t been any evidence of greater injuries to these structures with deeper squats. In terms of muscle development however, deep squats appear to be better at improving glute muscle activity and growth, while peak muscle activity for the quadriceps occur at 90 degrees with no significant decrease thereafter. There doesn’t appear to be any major difference in hamstring development with deep or parallel squats5.
Take Away Point – Squat with Form
Provided you perform the squat with appropriate form, then squatting to 90 degrees or past 90 degrees won’t put you at any greater risk of injury. However, depending on the muscles you want to target, a deeper squat will help support glute development, whilst maximal quad development occurs at 90 degrees or more of knee flexion. Half or quarter squats on the other hand will not only result in poorer muscular development, you might be risking the knee and spinal joints in the long term6.
1. Klein K. The deep squat exercise as utilized in weight training for athletes and its effects on the ligaments of the knee. JAPMR. 15(1):6 – 11. 1961.
2. Chandler T, Wilson G, and Stone M. The effect of the squat exercise on knee stability. Medicine and Science in Sports and Exercise. 21(3):299 – 303. 1989
3. Li G, Zayontz S, Most E, DeFrate LE, Suggs JF, and Rubash HE. In situ forces of the anterior and posterior cruciate ligaments in high knee flexion: an in vitro investigation. Journal of Orthopaedic Research. 22(2):293 – 297. 2004.
4. Escamilla RF. Knee biomechanics of the dynamic squat exercise. Medicine and Science in Sports and Exercise. 33:127 – 141. 2001.
5. Wilk KE, Escamilla RF, Fleisig GS, Barrentine SW, Andrews JR, and Boyd ML. A comparison of tibiofemoral joint forces and electromyographic activity during open and closed kinetic chain exercises. American Journal of Sports Medicine. 24(4):518 – 527. 1996
6. Hartmann H, Wirth K, Klusemann M. ‘Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load.’ Sports Med. 2013 Oct;43(10):993-1008.