Squatting is a normal everyday task; we squat to pick up an object from the floor, to tie our shoes or to sit down in a chair.
Most runners who follow a strength-training regime will perform the squat as part of their program. Squatting is also widely used as part of knee rehabilitation after injury or surgery. The squat engages most of the lower-body muscles as well as abdominal and back muscles, in total more than 200 muscles are activated when you squat.
A lot of controversy exists as to how the squat should be performed, especially when discussing safety of squat depth and optimal muscle activation.
So is squatting bad for my knees?
Some research suggested that regular deep squats could cause knee laxity, leading to an increased incidence of knee injuries. More recent articles refuted these findings and showed that those who perform deep squats have increased knee joint stability.
In a review published by Schoenfeld, he concluded that there is inadequate evidence to show that deep squats are contraindicated in those with healthy knee function. Deep squats do not contribute to increased risk of injury to soft tissues. He suggested that the decision as to how low to squat should therefore be based on an individual’s performance-oriented goals and considered in conjunction with any pathological issues that may be apparent.
There are in fact fewer loads on the ligaments during the squat compared to walking and running. Given enough time for adaptation regular resistance training will also increase tendon and ligament strength. Stronger ligaments, muscles and tendons will increase knee stability that will in effect further protect the joint, reducing risk of injury.
So contrary to popular belief the deep squat IS NOT bad for your knees. Having said that, there are many variables that can affect your squat safety and risk for injury.
Any resistance exercise when performed incorrectly may result in injury. Most injuries occur because athletes increase volume or weight too quickly, not allowing the tissues time for adaptation to the increased load. Incorrect form or technique when performing the exercise also increases risk of injury, however when performed correctly, squat-related injuries are uncommon.
Healthy runners should follow these rules when squatting:
- Set a goal: What do you want to achieve through squatting?
During the squat, the Quadriceps’ activation peaks between 60 and 90 degrees knee flexion while Gluteal EMG (muscle activity) continues to increase past 90-degree knee flexion. So to build Quadriceps power, perform partial to parallel squats and for Glute power aim for deeper squats.
For me the main aim of squatting is to build the Glute engine that powers my running. Therefor I regularly perform deep squats with powerful upward drive for power. I also incorporate single leg squats to improve knee stability during mid stance.
- Make sure you have adequate joint mobility:
Aim for normal ankle, knee, hip and low back mobility to allow you to achieve optimal form.
When the ankles are too stiff, the heel will lift during the deep squat, causing an unwanted increase in load at other joints. Decreased hip and knee mobility will limit squat depth.
Before you attempt a squat, first perform your basic joint-mobility checks (as demonstrated at RUNeasy Running Clinic).
- Aim for perfection:
If you are new to squatting, ask a professional to help you learn correct squat technique. As mentioned above, poor technique increases your risk of injury.
Correct squat technique:
- Stand tall with an upright posture, looking straight ahead.
- Stand with your feet shoulder width apart and toes slightly pointed out.
- Keep your low back neutral.
- Tighten your core muscles.
- Slowly lower your butt back and down.
- Drive the knees out in line with your shin towards the second toe.
- Don’t let the knees roll inside the foot or push over the toes.
- Keep the feet flat on the floor; do not allow your heels to lift.
- Lift your arms out and up as you descend.
- Don’t allow the lower back to bend as you move further down.
- Don’t look down at your feet, but keep looking straight ahead.
- Squat only as low as your form allows.
- Squeeze glutes and hamstrings and rise without leaning forward or shifting balance.
- Power from the glutes to drive the hips up and forward.
- As you return, fully extend your hips and knees and stand as tall as you possibly can.
- Watch this video of Chris Spealler performing the Air Squat.
Once you have achieved perfect form with the Air squat, progress to more challenging squats. Remember to keep in line with your set goals:
- Single leg squats
- Bosu squats
- Pistol squats
- Barbell squats
- Kettlebell swings
- Stop when form starts to deteriorate:
Only perform as many reps as you can without breaking form. Form starts to deteriorate when muscle fatigue sets in and that should be your cue to stop. More isn’t always better. You will gain more strength from low reps performed with perfect form compared to high reps performed with poor form. Poor form also leads to faulty movement patterns that might translate into bad running.
- Allow time for adaptation:
Progress slowly to allow your muscles and joints time to first adapt to a new load (weight or squat depth) before you take it up a notch.
Deep squats and loaded squats should be seen as the end goal not necessarily the starting point. Some runners might need a lot of time and work before they are ready to perform advanced squats and some might never be able to perform loaded or deep squats, and that’s okay.
What if I have a history of knee pain, injury or surgery?
If you have a history of knee or back pain, injury or surgery, consult a professional for evaluation and guidance before you embark on a squat regime.
Pain during or after performing squats:
Get an expert opinion. Consult with a medical professional who will perform a thorough mechanical evaluation to determine the cause of pain. If you find the cause (injury, stiffness, weakness, poor form) you will most likely be able to implement the correct treatment strategy (time for healing, mobility/strength exercises, correct form) to help eliminate knee pain and prevent future episodes.
Allow time for healing of the soft tissues and start rehabilitation as soon as possible. The Squat (as a closed-chain exercise) is often used in knee rehab as it engages a wide range of leg muscles that increase stability of the knee. Your physiotherapist will be able to guide you in determining safe squat ranges and progressions to weights and squat depth. The evidence suggests that there are minimal contraindications to squat after knee surgery as long as you progress slowly as not to cause harm.
After a low back pain episode or lumbar surgery you should follow normal return to function rehabilitation and regain normal lumbar range of motion and function. To be able to squat is a normal human activity.
Increase in lumbar flexion or extension away from neutral increases compressive loads on the spine during squatting (especially if you squat with weights). Therefore it is important to maintain a neutral spine throughout the squat (stable upright posture) to avoid excessive compressive forces on the spine. Unless you are able to maintain optimal neutral spine position, avoid loaded squats (weights) after back surgery. Regular body weight squats done with correct technique should not place extra strain on the intervertebral/ lumbar structures. Make sure you follow the guidelines as prescribed by your physiotherapist and surgeon.
Some last thoughts:
Most modern humans lost their ability to perform basic human movement due to lifestyle changes.
The human knee was designed for use into full range but the modern human seldom use full knee flexion and seldom squat down past childhood.
We sit in chairs that promote stiff knees, hips and spines and we squat less and less as we get older.
Will we not have less pain and injury if we actually start using our bodies for what they were designed for?
As they say:
“If you don’t use it, you lose it.”
Happy Running (and Squatting)
- Klein K. The deep squat exercise as utilized in weight training for athletes and its effects on the ligaments of the knee. J Assoc Phys Ment Rehabil 15: 6–11, 1961
- Escamilla RF. Knee biomechanics of the dynamic squat exercise. Med Sci Sports Exerc 33: 127–141, 2001.
- Schoenfeld BJ. Squatting kinematics and kinetics and their application to exercise performance. J Strength Cond Res 24: 3497–3506, 2010
- Steiner M, Grana W, Chilag K, and Schelberg-Karnes E. The effect of exercise on anterior-posterior knee laxity. Am J Sports Med 14: 24–29, 1986.
- Hartmann, Hagen, Klaus Wirth, and Markus Klusemann. “Analysis of the Load on the Knee Joint and Vertebral Column with Changes in Squatting Depth and Weight Load.” Sports Medicine 43.10 (2013): 993-1008.
- Escamilla RF, Fleisig GS, Zheng N, Barrentine SW, Wilk KE, and Andrews JR. Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises. Medicine & Science in Sports & Exercise. 30:556 – 569. 1998.
- Caterisano A, Moss RF, Pellinger TK, Woodruff K, Lewis VC, Booth W, and Khadra T. The effect of back squat depth on the EMG activity of 4 superficial hip and thigh muscles. Journal of Strength and Conditioning Research. 16(3):428 – 432. 2002
- Bloomquist, K., H. Langberg, S. Karlsen, S. Madsgaard, M. Boesen, and T. Raastad. “Effect of Range of Motion in Heavy Load Squatting on Muscle and Tendon Adaptations.” European Journal of Applied Physiology 113.8 (2013): 2133-142.