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A new study from Rutgers published today found that people who participate in high intensity interval training (HIIT) workouts are at a greater risk of injury than some other styles of exercise—but that didn’t exactly come as a shock to me.
I don’t say that because I hate HIIT, or believe that it’s particularly dangerous on its own. The protocol can be useful to make the most of your workout when you’re low on time, or if you really want to crank up your heart rate and get sweaty (intensity is in the name, after all).
My problem is more with how the term is thrown around by irresponsible trainers and gyms looking to cash in on the latest workout trends without taking their clients’ health and safety into account, particularly in group fitness classes. I’ve had a few particularly egregious experiences in boutique fitness classes around New York City that left me both outraged and concerned for the safety of anyone with less training experience than me who might walk into the gym.
To be clear, the Rutgers researchers behind the study didn’t draw a link between fitness classes and the increase in HIIT-related injuries. “When we queried Google trends, we did not utilize ‘group fitness classes’ as a search term,” study co-author Nicole Rynecki told Men’s Health in an emailed statement. “Therefore, we cannot comment on any causality between group fitness classes and increased HIIT-related injuries.”
That said, my own experiences—and those of my colleagues and friends—lead me to believe that you might be better off staying away from HIIT workout classes at flashy gyms as a matter of policy.
What Is HIIT, Anyway?
The first issue is how gyms are jumping on the trend to characterize any type of workout with interval periods as HIIT. There are many different protocols within the genre, which are characterized by specific work to rest periods—so, if you try out a 1:1 series, you’ll work for 30 seconds, then rest for 30 seconds, while a 1:5 setup would call for 15 seconds of intense work with 75 seconds of rest to recover. The structure can be even more strict, too; Tabata, a popular quick-hitting variant, uses 8 rounds of 20 seconds on, 10 seconds off (2:1) to pack a ton of action into just 4 minutes, while others demand that your rest periods are spent actively moving, i.e. walking for rest after sprinting for work.
One protocol that will never be considered HIIT is 30 seconds of one dumbbell exercise followed immediately by 30 seconds of another similar dumbbell exercise, as I was instructed to do in one of the fitness classes I attended. That’s a superset, and that structure can also be useful when used correctly—but not when multiple pairs are strung together and you aren’t given the appropriate opportunity to rest and recover between exercises.
That the instructor gallivanting at the front of the room for the period had written out “HIT” on the exercise board rather than the correct acronym might have been an accidental slip, but it illustrated how little he likely knew of the principles behind the workout.
What’s Wrong With HIIT At Designer Gyms
My concern with HIIT-based boutique fitness classes comes down to a simple principle: If you don’t know what you’re doing, you shouldn’t do it until you learn how.
You can’t BS a burpee—you either know how to do it or you don’t. If you’re performing one rep in front of a trainer who is paying attention and ready to help you fix your form, that’s okay. If you’re tossed into the back of a room filled with 25 other people, pulsing music, strobe lights, and just one instructor (who’s more interested in preening for their Instagram feed than your form), you’re going to have some problems when you’re expected to knock out reps for 30 seconds with no rest. That latter scenario is more common than the former, in my experience.
You’re setting yourself up for failure, according to Men’s Health fitness director Ebenezer Samuel, C.S.C.S. “The scary part is that most people aren’t getting much benefit from their HIIT training anyway, because the can’t really activate the muscles they should because they don’t understand the exercises as they should,” he says. You wind up half repping through the whole session, desperately working to keep up with everyone else.
Even worse, beginners are thrown right in with seasoned workout vets without any warning. “These workouts are marketed as ‘one size fits all.’ However, many athletes, especially amateurs, do not have the flexibility, mobility, core strength and muscles to perform these exercises,” co-author Joseph Ippolito wrote in the Rutgers study. That’s especially true of gyms that allow you to sign up for a class without any type of background check or introduction—once you sign the waiver, you’re in.
The Rutgers team didn’t account for HIIT-based classes specifically in the study, but they did acknowledge how important good coaching can be—and how the rise of injuries could be stemmed going forward.
“A previous study published by Summitt and colleagues in 2016 indicated that a third of shoulder injuries in CrossFit athletes may be attributable to improper form,” Rynecki wrote. “Since shoulder injuries accounted for the largest proportion of upper extremity injuries in our dataset, we emphasize the critical role of trainers in providing proper guidance and teaching novice athletes proper form.”
How You Can Avoid Getting Hurt Doing HIIT
Don’t set yourself up to fail. Make sure that you interact with the instructor as much as possible, and don’t be afraid to ask questions about any moves that you’re unfamiliar with beforehand. This advice doesn’t just apply to HIIT classes—the same should be true for CrossFit, spinning, or any type of group fitness setting.
Most importantly, feel confident to speak up. No matter how convincing (or obnoxious) the trainer is, if they haven’t respected you enough to provide proper instruction, you shouldn’t respect them enough to follow their workout. “Too often people think they have to ‘stick it out’,” Samuel says. “You don’t—and shouldn’t—if it doesn’t feel right.”