Today we talk about CrossFit and injury. CrossFit is one of the most popular, and divisive, exercise modes of recent years. No one seems to have a moderate opinion – it seems to inflame passion both for and against it.
The controversial nature of the CrossFit creator Greg Glassman, muddies these waters further. Glassman got into trouble, then resigned as CEO of CrossFit, after some racist comments on social media.
He is also highly litigious.
I’ve reviewed CrossFit before on another site. My opinion at the time could be summed as: if you can tolerate it, and enjoy it, go for it. But if you have specific needs, it may not meet those needs.
But since then there has been new research looking at injury rates, and a high-profile lawsuit.
So today we look at how frequent these injuries are, and how and why they may happen.
What are CrossFit workouts?
CrossFit uses traditional equipment and movements in sometimes untraditional ways. Bars and weights feature heavily, as do body weight exercises, and some cardio.
They take a variety of these movements, a little cardio, and put them together a workout. You then try to complete the workout as fast as you can, or complete as much as you can in a set time. The faster you finish, or the more repetitions, the more intense the workout. This “intensity” is a key component of CrossFit.
As speed is important, sometimes our technique suffers, or changes to let us to get more repetitions done (like kipping pull ups).
What benefit will I get from CrossFit?
Some people puff their chest out about their favoured exercise and want to promote it above all others. But they often present this as a false dichotomy, where one is argued to be better than another.
We don’t care about that. There’s no “good” or “bad” exercise *. Any exercise is fine by us if it’s safe, and effective, for the person doing it. So how effective is CrossFit?
From the research we’ve read to far, it compares well to other exercise.
A 2012 master’s thesis compared CrossFit exercise to a combination of traditional resistance and cardio training. Clearly the intensity of exercise in the CrossFit group was greater, and the sessions were shorter.
But there was no real difference in outcomes. Both groups had improvements in muscular endurance. And neither group had a change in blood sugar levels (the main point of the study) or body composition.
A 2013 study (well-known for reasons we’ll discuss later) did show changes in body composition, as well as improved aerobic fitness, after 10 weeks of CrossFit training in a group of men and women who were already CrossFitters. In this case, the exercise program probably explains some of the difference – these guys and girls did 5 sessions a week!
But this research had no comparison group. We don’t know how this would have compared to different exercise, but we can see a clear benefit as a mode of exercise.
More recent research has confirmed we get a similar benefit to other, less intense modes of exercise. We just get a faster benefit. If that suits you, that’s great news!
So CrossFit is safe and effective, and injuries are not an issue?
Not yet. So far, we’ve only found there are some benefits from the CrossFit style of training. But who doesn’t want quicker results?
We’ve also identified that the workouts are programmed in a way that is less flexible than more traditional exercise programs. Everyone does the same workout in theory, just a bit slower, or with a lighter weight, if needed. From the CrossFit website:
We scale load and intensity; we don’t change the program. The needs of Olympic athletes and our grandparents differ by degree, not kind.
An experienced fitness professional would find this hard to justify. My grandparents don’t need to be able to clean or snatch from the floor. Lift from the floor, absolutely. Lift from the floor with speed? Not a chance.
Could the education of CrossFit instructors influence injury risk?
Given the intensity of sessions is higher, and speed of lifts faster, it makes sense that some risks may be greater.
So we want our instructors to be well qualified. But you can gain a CrossFit qualification very easily – that’s part of the controversy. The entry level certificate can be completed in just two days.
You don’t need a CrossFit certificate to work in a CrossFit gym. If you have a regular fitness or exercise science qualification you can do the job. And these are longer, more rigorous qualifications.
And when you are a more qualified trainer, a funny thing happens. You tend to program CrossFit workouts differently…
Education & CrossFit programming
Most CrossFit instructors hold a CrossFit certification – 87%, according to one study. Half of instructors hold a personal training qualification as well, while about a quarter have a Bachelor’s degree, or higher.
Most instructors (92%) reported teaching the Olympic lifts in their role. But those with higher qualifications were less likely to use these lifts.
One of the key fundamentals of CrossFit programming is that everyone should be able to do these lifts. But more qualified instructors tend to teach these lifts less to their clients! Why is that?
We can’t tell for sure based on this study. But my theory is those with higher qualifications have more tools in their coaching toolbox.
What I mean by that is, they are trying to get a training adaptation for their clients. That could be improving strength, speed, reducing body fat, etc. The specifics don’t matter.
There are many ways we can get that adaptation. If one method does not suit, we can try another. If a client struggles with one exercise, we can modify it, or find a different one. A good trainer is flexible.
But the focus on speed, group exercise, and uniform workouts in CrossFit does not encourage this flexibility.
What are the injury risks of CrossFit?
As with any new mode of exercise, the evidence has evolved over time. This research was collated into a few systematic reviews in 2018 (we explain the steps and benefits of systematic reviews in a previous article), so these are where we’ll focus our attention.
The first systematic review we found identified that CrossFit participants reported more muscle soreness, restricted movement, and fatigue post-exercise than other modes of exercise. They train at high intensity, so that makes sense. But this may discourage some people.
Injury occurred in about 20% of those surveyed (from a 2014 American study by Ben Weisenthal and colleagues) in the previous six months. But when a trainer was involved in the session, injuries were less likely.
There were no studies that directly compared CrossFit injuries to other exercise included in this review though, so we are limited in what we can conclude from this study.
In fact, by 2018 there had only been three studies which used a comparison group, or compared findings to other modes of exercise. These were discussed in a different review, and identified that injury rates were similar to other recreational exercise.
So all this talk of injury is just hater propaganda?
As usual, it’s more complex than that. The study above reporting 20% of participants having an injury in the last 6 months was quite low – other studies reported up to 70%. The definitions of injury vary however, so direct comparisons are hard.
We can also look at injuries occurring over time, as the amount someone participates could influence injury rates.
In good news for CrossFit, injuries occur about 2-3 times per 1000 training hours according to the studies looked at so far. This is similar to what we see in Olympic weightlifting and powerlifting, though more than recreational resistance training.
We can see a pattern to these injuries. Men are more likely to get injured than women. The shoulder and lower back are the common injury sites. The most common movements to cause injuries are overhead movements, gymnastics movements, and Olympic lifts.
Injuries are more likely to occur in those with a higher BMI, and those with a prior injury. And those doing other exercise outside of CrossFit were more likely to be injured.
I highlight these because all are examples of people with a different tolerance to exercise. Someone with a higher BMI may have a limited, exercise history. Someone injured, or previously injured, may need changes to their training to prevent reinjury. And someone doing extra exercise has a higher training load, which will contribute to injury risk if not accounted for.
If instructors have a range of tools in their toolkit, they can consider these issues. If they are flexible in their programming, they can lower risk. Instructor involvement is associated with less injury, so we want active, involved instructors, not cookie-cutter programs.
Newer research on CrossFit and injury
Research continues, and our opinions may change over time. So lets look at what has been published since these reviews.
A recent study comparing CrossFit to traditional resistance training found that CrossFit participants were 30% more likely to have suffered an injury in the two years prior. And they were about 85% more likely to have sought treatment for an injury (a possible indication of how bad it was).
And an even more recent study of novice lifters found that while only 15% of participants were injured, the incidence per 1000 hours was much higher than other research (9.5). This was a short study (only eight weeks), so this number may have gone down with more training, as we expect to see more injuries at the beginning of a program like this.
So what do I think now, after reading this new research? My opinion hasn’t changed much yet. If you are durable, injury-free, and not doing a lot of extra exercise, you’ll be fine with the cookie-cutter programs. But it’s not my exercise of choice for anyone with specific sporting needs, injury concerns, limited exercise histories, or cardiac risk factors.
When looking at individuals, we individual risk and needs. With more specific needs, you need more specific programs. And the more specific our programming, and the more qualified our instructors, the less the exercise looks like CrossFit.
The elephant in the room!
We need to discuss the lawsuit. If you don’t know what I’m talking about, the National Strength and Conditioning Association (NSCA) publishes an academic journal, The Journal of Strength & Conditioning Research.
This journal published an article in 2013 that we mentioned earlier. It showed a significant benefit from CrossFit training. So reading the paper, it’s hard to see what the lawsuit was about.
The participants (43 men and women) trained five days a week, each session consisting of some heavy strength work, followed by circuits of CrossFit favourites like handstand push ups, clean and jerk, box jumps, kettlebell swings, etc. These were either completed as quickly as possible, or doing as many as possible in the time allowed.
The study started with 54 taking part, but 11 dropped out. It is normal to exclude dropouts from your results, but this comment was part of the Subjects section which described the group:
Of the 11 subjects who dropped out of the training program, 2 cited time concerns with the remaining 9 subjects (16% of total recruited subjects) citing overuse or injury for failing to complete the program and finish follow-up testing.
This was then expanded on in the Discussion section:
A unique concern with any high-intensity training program such as HIPT or other similar programs is the risk of overuse injury. Despite a deliberate periodization and supervision of our Crossfit-based training program by certified fitness professionals, a notable percentage of our subjects (16%) did not complete the training… there are emerging reports of increased rates of musculoskeletal and metabolic injury in these programs. This may call into question the risk-benefit ratio for such extreme training programs.
So what’s the problem with these injury rate statements?
It appears the reasons for dropping out were made up. Or at least, the authors didn’t have clear evidence of this they could produce.
The thing is, compared to later research this figure is low! If this was the injury rate, it compares well to the other research. And these other articles haven’t been the subject of lawsuits.
But the NSCA offers personal training and strength and conditioning certifications, which were claimed by CrossFit to be competing with their certifications. So CrossFit may have thought they were on stronger legal ground here, compared to other publishers.
In December 2019 a Californian court found in favour of CrossFit in their lawsuit, awarding nearly $4 million in damages.
But it didn’t need to be this bad. The paper should have been retracted (and later it was). There may have been a settlement and public apology. But the NSCA destroyed evidence, and withheld devices such as computers and phones they were told to produce, acting in bad faith.
I’ve read some breakdowns of the result on legal websites, and their advice is simple – be honest in court, and do what the judge tells you to! The NSCA really messed up.
Does this mean the research is wrong?
No. It just means this single piece of research had one error in it, that wasn’t immediately admitted to when found. You can trust the main findings of the study – which as we said, were positive.
But some people will use this case to discredit research they don’t like. That’s an example of their own bias. And there’s a fair chance they don’t know how to read research well.
This doesn’t mean science is broken, or there’s a conspiracy against CrossFit.
It just means one person took a shortcut. And it wasn’t picked up by their co-authors, or in peer review. Personally, this type of thing makes me live in constant fear I’ve made a mistake in my own research, and I’ll eventually be exposed for the impostor I am!
The sort of conjecture seen in this paper is perfectly acceptable in normal conversation. But academics are held to a higher standard. Any statement of fact needs supporting evidence.
Summing up CrossFit and injury
Depending on your personal preferences, you may want to accuse us of being bias either for or against CrossFit. In fact, after the last article I wrote on this topic I’ve been accused of both.
But from my reading of the research, being a zealot one way or the other isn’t justified. There may be more risk than other types of exercise, but we’ve also found that individual factors are key.
If we control the load we expose someone to, and avoid aggravating old injuries, this can be a safe mode of exercise. But that’s a big if. Part of the art of personal training is managing this, while getting the best training effect we can.
And depending on the risk factors a pre-exercise screening identifies, high intensities may not be a safe way to train. Group exercise, with low levels of supervision, even less so.
So we also need to recognise that qualified, skilful instructors have a huge impact.
And there are some positives we don’t find with other exercise. CrossFit appeals to those who enjoy the social and community aspects of group exercise, something we usually associate with team sport.
And others get satisfaction out of mastering skills, and competing against themselves or others. If you want to learn new exercise techniques, or compete as a CrossFit athlete, this could be the place for you.
I’ve published an article in Personal Training Quarterly, another NSCA publication. I’m also a member of the Australian Strength and Conditioning Association, which was previously affiliated with the NSCA. The two bodies maintain a close relationship.
* I’m sure you could find an objectively “bad” exercise if you tried hard enough, so don’t email me to let me know I’m wrong. You get the idea.