• Bill Gaylor

CrossFit WILL Injure You + DEEP Squats = BAD Knees

Updated: Aug 23, 2020

Two statements you may have seen on numerous occasions. CrossFit will injure you and it's dangerous to do deep squats. Studies aside there were some great points made on the podcast from a realistic common-sense perspective. If you want to listen to the podcast episode on this topic then scroll to the bottom for the full episode!

CrossFit WILL Injure you. Let's start with something Tom mentioned at the start of the episode and that is the availability of media on the internet. When CrossFit first started as a "sport" it wasn't so mainstream so of course, no one was really a "pro" CrossFit athlete. Take a look at the video down below. By no means the worse thing I've ever seen but when these types of videos were coming out it was all new. You'd have people from traditional training modalities look at that and essentially laugh at it. I and Tom are guilty of this! Back way before I started CrossFit we'd have a pop simply because it was different and something that we didn't partake in. Now that is tunnel vision!

Another great point that was made was that let's remember this is a competition. Lose the tunnel vision for a second and think when does a 1 rep max deadlift ever look good in competition? Look at the Olympics. Yes, it still looks pretty good but when the athletes are hitting PBs they don't exactly look technically sound. When you compete you go 100% so the form is naturally going to break down. If you're training properly you very rarely work at 100% and only do so when in competition mode. Also, let's be honest. If you google sport XYZ injury you are going to find it all. Just because a video exists of someone getting injured doing a particular sport doesn't mean the injury rate is astronomically high.

Let's fast forward a bit to an issue that may be happening today. Andy made a really good point on the podcast that doing CrossFit on you're own at home/home gym is becoming more common. This could be down to the preference of training at home, the cost of CrossFit box membership or even the intimidation factor. Especially now if you were to google CrossFit it's all super-fit men and women throwing weight around, walking on their hands, swinging from bars and for a newbie, this could be quite intimidating. In reality, though the CrossFit community is very friendly and accepting of people at all levels. So why is this an issue? CrossFit is an extremely complex training modality if you take into account the various different movements and the intensity you are expected to perform at. An example Andy used was that if someone sees the workout "Fran" 21-15-9 pullups and thrusters FOR TIME and is new to CrossFit then injuries may occur. You go 100% on a movement like thrusters that is essentially a combination of a front squat and push press and you're new to it so lacking the adaption then yeah you are at a significantly higher chance of getting injured. Especially during COVID, we've seen more home "WODS" than ever. It's absolutely crucial that during your first year of any new training modality, not just CrossFit that you are progressive and sensible. Get the right guidance and allow the body to adapt to this new stimulus. I would love to see some data on injuries in CrossFit participation since COVID started.

Let's move onto some studies. Now in the podcast, we use 3 sources in regards to stats quoted. What it did identify is that you can essentially cherry-pick stats and studies to support your bias. Let's start with study 1.

Strength and Conditioning 2013

"CrossFit is a constantly varied, high intensity, functional movement strength and conditioning program which has seen a huge growth in popularity around the world since its inception twelve years ago. There has been much criticism as to the potential injuries associated with CrossFit training including rhabdomyolysis and musculoskeletal injuries. However, to date no evidence exists in the literature to the injures and rates sustained. The purpose of this study was to determine the injury rates and profiles of CrossFit athletes sustained during routine CrossFit training. An online questionnaire was distributed amongst international CrossFit online forums. Data collected included general demographics, training programs, injury profiles and supplement use. A total of 132 responses were collected with 97 (73.5%) having sustained an injury during CrossFit training. A total of 186 injuries were reported with 9 (7.0%) requiring surgical intervention. An injury rate of 3.1 per 1000 hours trained was calculated. No incidences of rhabdomyolysis were reported. Injury rates with CrossFit training are similar to that reported in the literature for sports such as Olympic weight-lifting, power-lifting and gymnastics and lower than competitive contact sports such as rugby union and rugby league. Shoulder and spine injuries predominate with no incidences of rhabdomyolysis obtained. To our knowledge, this is the first paper in the literature detailing the injury rates and profiles with CrossFit participation."

Hak PT, Hodzovic E, Hickey B. The nature and prevalence of injury during CrossFit training. Journal of Strength and Conditioning Research. 2013 Nov. DOI: 10.1519/jsc.0000000000000318.

So looking at those numbers, 73.5% sustained an injury. That's a massive percentage. If I saw that and took it as gospel I'd think wow CrossFit has a high injury rate. Now let's take a look at how this injury rate of 3.1 per 1000 hours trained is used in context.

This table is from strength and conditioning research. Now compare that 3.1 to the other training modalities on the table and it's really not that bad. The next study is an example of something that makes CrossFit look very safe and I believe this was in direct response to this 2013 study as this next one was done from 2013-2017.


Background: High-intensity functional training (HIFT) is a new training modality that merges high-intensity exercise with functional (multijoint) movements. Even though others exist, CrossFit training has emerged as the most common form of HIFT. Recently, several reports have linked CrossFit training to severe injuries and/or life-threatening conditions, such as rhabdomyolysis. Empirical evidence regarding the safety of this training modality is currently limited.

Purpose: To examine the incidence of injuries related to CrossFit participation and to estimate the rate of injuries in a large cross-sectional convenience sample of CrossFit participants from around the world.

Study Design: Descriptive epidemiology study.

Methods: A total of 3049 participants who reported engaging in CrossFit training between 2013 and 2017 were surveyed.

Results: A portion (30.5%) of the participants surveyed reported experiencing an injury over the previous 12 months because of their participation in CrossFit training. Injuries to the shoulders (39%), back (36%), knees (15%), elbows (12%), and wrists (11%) were most common for both male and female participants. The greatest number of injuries occurred among those who participated in CrossFit training 3 to 5 days per week (χ2 = 12.51; P = .0019). Overall, and based on the assumed maximum number of workout hours per week, the injury rate was 0.27 per 1000 hours (females: 0.28; males: 0.26), whereas the assumed minimum number of workout hours per week resulted in an injury rate of 0.74 per 1000 hours (females: 0.78; males: 0.70).

Conclusion: Our findings suggest that CrossFit training is relatively safe compared with more traditional training modalities. However, it seems that those within their first year of training, as well as those who engage in this training modality less than 3 days per week and/or participate in less than 3 workouts per week, are at a greater risk for injuries.

Feito Y, Burrows EK, Tabb LP. A 4-Year Analysis of the Incidence of Injuries Among CrossFit-Trained Participants. Orthop J Sports Med. 2018;6(10):2325967118803100. Published 2018 Oct 24. doi:10.1177/2325967118803100

A big difference in numbers. You have to read more than one article/study to get a better picture of the truth. I like this study due to the large numbers used. (3049 vs 132) Interestingly in the conclusion, it supports something I said earlier. "However, it seems that those within their first year of training, as well as those who engage in this training modality less than 3 days per week and/or participate in less than 3 workouts per week, are at a greater risk for injuries." As I said earlier it's crucial that in the first year you are coached, progressive and basically sensible. What's also interesting is the mention of if you do it less than 3 days or 3 workouts per week then the risk is heightened. I would say this is due to the body not doing enough to adapt to the arduous stimulus.

Even if you take the first study and it's higher injury stats look at the 3.1 injuries per 1000 trained hours and it's still showing that CrossFit is not worse than more traditional training modalities. I think this boils down to the social perception of the sport. If you look at it it's very complex and you will automatically think that looks dangerous. Reality is that especially at a higher level you will have excellent coaching with correct training cycles, recovery and more importantly your body has adapted to the stimulus thus reducing the chance of injury.

To summarise: There is no real evidence to support that CrossFit will injure you more than other training modalities however we would recommend that due to its arduous nature you take care in recovery, training cycles and ensure you are receiving the correct guidance in terms of exercise form and volume. Example being don't do 30 clean and jerks for time on day 1 of starting CrossFit hurt your back and then say CrossFit injured me.

DEEP squats = BAD knees. We need to go back in time for this one. Dr Karl Klein. Back in the 1960s, Dr Klein released a study which suggested that deep squats stretch the ligaments, therefore, causing knee pain/injury. So why did this take off? Shortly after it appeared in popular media and even the US army took note by removing the squat jump from training due to fear of ligament damage. It became widely accepted that the tools and methodology were somewhat subpar. One of his actual subjects wrote,


It's not looking good for Dr Klein. Following on from this "Todds Paper" written in the 1980s noted the spurious nature of Klein’s measuring equipment, noting that examiners could manipulate the results quite easily. Let's try and defend Dr Klein for a moment. Tom brought something to our attention on the podcast and that is that the original study is actually really hard to find. We live in a digital age of so much information so easily accessible yet back in the 1960s it would have been paperback. Now Tommy Suggs revisited the research and actually got eyes on the original book. (He has actually met Dr Klein as well) This is from page 30 of the book.

"The depth of the squat position should be controlled, with the thighs just breaking the parallel position (Figure 7). Much beyond this point, the reaction between the hamstrings and calf muscle begins to act as a pry to force the joint apart at the front, as well as on the sides, stretching the ligament"

The actual picture shows someone squatting slightly below parallel! It's important to note he's not saying do 1/4 squats but just don't go deeper than what he shows in his book. Essentially what seems to have gone on here is a case of Chinese whispers! Here's an example Tommy gave for a breakdown of communication.

"On page 57 Klein gives an example of the acceptance of his theory by quoting an article by a person considered a lifting authority of the day: “Murray, in his editorial comments on the article “Full Squats or Half Squats” makes the following comment: ‘You will be well advised not to squat below the parallel…’” Suddenly “just breaking parallel” became “not below parallel.” And the beat went on and on, and now a half- or quarter-squat is the order of the day.

Let's move on to what we think now. Greg Nuckols - Stronger by Science released a good article talking about specificity. It's something we agreed on in the podcast. If you are 70 years old just trying to keep active is there really any need to force your mobility to get the deep squat? However, if you're a weightlifter it's crucial you can recover heavy cleans from the deep squat position so yes deep squatting is useful in training. Usefulness aside Greg also states "Now, before we proceed, I do realize the full squat is the safest for the knees, with increased hamstring activation countering anterior translation of the tibia (it reduces the stress on your knees)." So everything else aside to say deep squats = bad knees is simply wrong due to what Greg has just stated there. They do in fact offer more safety. I'd highly recommend you check out Greg's squat guide if you are really into your squats. https://www.strongerbyscience.com/how-to-squat/

Now, this is where it gets interesting/ slightly comical. Another point that we made in the podcast was that the back squat (Full-depth) is actually great for growth. With a study, we mentioned claiming a 10% increase in quad growth and a 5% increase in glute growth over the hip thrust.

Barbalho et al. 2020. Back Squat vs. Hip Thrust Resistance-training Programs in Well-trained Women. 10.1055/a-1082-1126

So there we were raving about this study claiming XYZ and then big Grek Nuckols comes along literally yesterday and throws a 10-ton spanner into the works. Down below is the article in question.

Essentially researchers have discovered some statistical anomalies and basically things that don't make sense with Matheus Barbalhos studies. Specifically, in regards to the study we mentioned, Greg notices that the strength gains from the back squat in Barbalhos' study seemed questionable. Greg then discovered some atypical results in two prior studies from Barbalhos so he began taking a closer look finding more issues. We will keep an eye on this (mainly Tom the study man) and see how it unfolds. As I said this literally came out yesterday as if we had known that it certainly would have changed how we addressed back squat being greater than hip thrusts for growth.

This just goes to show how much of a rapidly changing world it is in the health and fitness sector. Studies are constantly coming out so you need to be open to new information all the time. We recorded the episode on a Thursday with information that we thought was genuine and then by Sunday it was all put into question. Comical but exciting.

To summarise, deep squats will not lead to knee injuries (even evidence to suggest reducing risk) HOWEVER what will lead to injuries follows the same tune as with the CrossFit segment. Too much too soon, lack of correct guidance on squatting correctly, incorrect weight cycling and general overuse of the muscles worked.

If you want to hear everything we had to say on this topic then join me, Tom and Andy, down below for the full podcast episode.

Final point. What are you thoughts on this? Were you on of those who perhaps looked at CrossFit and thought "that's so stupid!" Because I and Tom certainly were back in the day. Education is key! I'd love to hear if you this article may be changed the way you look at it? Maybe you still don't agree with what's been said? Whatever the case drop us a message as we always love engaging. Back next week with more health and fitness related information to wrap your brains around! Speak soon.

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