Squats and Knees
Training the legs is sometimes a daunting thing. I’ve seen people balk at the squat rack in powerlifting competitions, but not at the bench press. Even at the local gym, it seems that there is often more of a line at the bench stations than there is at the squat rack. Read that again and take note how I wrote that. At my gym there are two flat free weight bench press areas and one power-tower for squatting. There are also hybrid machines for other benching work, but one leg press machine. It seems that people shy away from training their legs, to a degree.
Here, let’s think about the types of muscle that are getting trained. Whether you are doing squats for power, strength, endurance, or for the sheer squatting joy you will train either Type I or Type II muscle fibers.
Since I am now more of a power athlete, I will begin Type II. Type II muscle fibers are used for power and strength events. As a result, they fatigue more quickly than their type I counterparts. The type II are the fast twitch muscles. The Type II fibers support powerful, quick movements including sprinting, powerlifting, and weightlifting. Weightlifting in this sense is Olympic-style weightlifting which includes snatch and the clean and jerk
Both powerlifting and Olympic lifting are styles in which the lifter is moving the maximum amount of weight from point A to point B. The difference is that in Olympic Weightlifting the liter uses explosive movements to accelerate the weights from one point to another. Meanwhile, the Powerlifter uses brute strength to move the weight from one point to another. Then, there are the hybrid anomalies of the Strongman Competition and the CrossFit Games, both of which are beasts unto themselves. Both require training regimens unique to those fields. Honestly, they look like a world of fun, but not enough of a draw to me to try it out. Maybe next year.
Type I muscle fibers are used in endurance events. Think 12 to 15 repetition sets and swimming for 25 to 30 minutes minimum or running/jogging for 45 minutes to start. These are endurance training events. My endurance competition events were cross country running, 5ks in high school and 10ks in college, and swimming the 400 meter in high school. Again, I was built lean and thin. At 6’2” tall I weighed 135 to 140 pounds. To say I was thin was an understatement. After lifting for several years, I am now 245 pounds. Between age and infantry I’ve lost an inch in height, but that’s my problem.
The chart below will detail the muscle fibers in greater fidelity.
Muscle Fiber Type Comparison Chart
|
Characteristic |
Slow-Twitch Type I |
Fast-Twitch Type IIA |
Fast-Twitch Type IIX or IIB |
|
Activities |
Marathons, distance running, swimming, cycling, power walking, endurance training |
Powerlifting, sprinting, jumping, strength and agility training |
Powerlifting, sprinting, jumping, strength and agility training |
|
Muscle Fiber Size |
Small |
Large |
Large |
|
Force Production |
Low |
High |
Very High |
|
Resistance to Fatigue |
Slow |
Quick |
Very Quick |
|
Contraction Speed |
Slow |
Quick |
Very Quick |
|
Mitochondria |
High |
Medium |
Low |
|
Capillaries |
High |
Medium |
Low |
|
Myoglobin |
High |
Medium |
Low |
|
ATPase Level |
Low |
Medium |
High |
|
Oxidative Capacity |
High |
Medium |
Low |
https://blog.nasm.org/fitness/fast-twitch-vs-slow-twitch
This seems like a ton of information to boil down to ask one question. That question being, is squatting deep safe for the knees? Let’s start with where the concept of deep squatting being harmful to the knees came from. Let me first answer the question, no. Deep squats, ass-to-the-grass, ass-to-ankles, or however you want to describe it, squats are not bad for the knees
Now, let’s look at the history of where that myth came from, then we will look at how the anatomy of the knee protects and strengthens itself through squatting.
I am 50 years old and have been squatting on and off, to depth, since I was 23. That is when I really got into lifting weights and started to see the benefits from lifting. My knees are still good. I run and swim and still squat after 27 years of squatting and deadlifting deep. As I always say, talk to your doctor first. If your medical professional has a reason for you to not squat or not lift weights or to do something else before you lift, then follow your doctor’s orders.
Am I built like a fireplug? No, I was an endurance athlete in high school, my first four years in the military, and into college. I weighed no more than 145 until my mid-20s. That was when I finally peaked 180 thanks to deep squats and deadlifts. I say this as illustrative points, that the big compound lifts can add size and strength and not do damage. So, where did deep squats get their bad rap?
According to Dr. Aaron Horschig at Squat University (https//:squatuniversity.com) it all started in the 1950s with Dr. Karl Klein. He was looking into why his football players were coming in with serious knee injuries. This was a worthwhile question that needed answering. Injured players, knees going bad, find a common cause, fix the problem. It all makes sense, in a way. Unfortunately, he used self-made equipment that was inaccurate. It seems that he may have had a preconceived notion about things and found “evidence” to support that notion. His published articles eventually got picked up by mainstream publications including one issue of 1962 Sports Illustrated.
Then, the American Medical Association looked at his results. Eventually, even the Marine Corps took an exercise called the “squat jumper” off their training schedule for recruits and their physical training program (https://squatuniversity.com/2016/01/22/debunking-squat-myths-are-deep-squats-bad-for-the-knees/). By the mid-1960s, others were coming onboard with Dr Klein’s theory, such as Dr John Pulskamp. By the 1970s, full depth squats were all but removed from institutionalized regimens.
Unless you already have injured knees, squatting deep does not injure your knees. Let’s look at the anatomy and stresses throughout the squat. The sheering forces inside the knee are felt by the Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL). These ligaments limit forward and backward movement of the upper and lower leg bones as well as hold the knee together internally (ibid). The stresses on these ligaments are greatest, according to research, when the knee is flexed up to 20 to 25 degrees (https://barbend.com/deep-squats-bad-for-knees/). This is found at the top of the squat range. If you see someone doing ¼ squats note that this is the range of the greatest stress on the ACL/PCL. The deeper you go after this range, the more support you get from the other muscles and ligaments that surround the knee. At the same time, your hamstrings and quadriceps also balance the push-pull forces experienced in your knees. Thus, supporting the ACL/PCL in their job of limiting the shearing forces on and within the knee.
The meniscus is between the bottom of the femur and the top of the patella. The compressive forces, those that are felt when we stand upright with our legs straight or nearly straight, are cushioned by the meniscus. The only time that the meniscus is under stress is when we stand straight legged under this type of weight stress. Think of it as weight being piled on top of your head. The pressure from it increasing on the crown of your head every few moments. That is the sort of stress that is being applied to the meniscus.
While deep in the squat, at beyond 90 degrees, science has shown the ligaments inside the knee are under decreasing stress. At the bottom, the ACL comes under the least amount of stress at this point. The PCL is under its highest stresses just above parallel. Even these points of stress, the levels are a small percentage of the maximum. It is in the 15% to 20% of maximum range. Well within the safe stress range.
Those scientists who have replicated Dr. Klein’s studies, even using replicated equipment, have been unable to replicate the results Dr. Klein had. What sports scientists have found is that, through training, ligaments and muscles attached to and surrounding the knee have become stronger through proper and consistent training. Even at the 20% of maximum stress range, the ligaments are at a higher performance rating after being consistently trained for a period of time. In short, they tendons are stronger at the point of higher weights than at the beginner times of lower weights. This results in better support to the knee. Furthermore, scientists have been unable to find compression damage from increased forces against the meniscus, as alluded to earlier.
Squat depth for optimal training should be as far below parallel as possible. This will be dictated by each person’s anatomical differences. Think about a baby learning to walk and when they see something on the ground, they are interested in. Pow! That baby squats down, butt to heals, perfectly. That is the form we should strive for. Of course, there may be legitimate reasons which prevent us from getting there, ego is not a legitimate reason. Lower the weight on the bar to lower your body into the proper squat. I have had to do this time and time again, always to my benefit.
If you’re still unsure, find a strength coach or trainer to teach you and help you out as you learn how to squat properly. I have also written another article on how to squat, which you can read here.
BIBLIOGRAPHY
https://squatuniversity.com/2016/01/22/debunking-squat-myths-are-deep-squats-bad-for-the-knees/
https://barbend.com/deep-squats-bad-for-knees/
https://www.physio-network.com/is-it-safe-to-squat-deep-what-does-the-evidence-say/
https://themusclephd.com/are-squats-bad-for-your-knees/
