Build a better body with HIIT… But be careful when you do it!

High intensity interval training is great. It’s the type of workout that’s over in a few minutes (who doesn’t love a short workout!), you’re likely to be dripping with sweat (the sweat is the proof, right?!), and you generally feel like you’ve had a good and really successful workout (that didn’t take up half a morning!)

The question is: is an HIIT workout all it's cracked up to be when it’s all said and done?

The answer to that is: not always.


Who does and doesn’t benefit from HIIT

A new study, released by Rutgers University confirmed the obvious: HIIT is an effective exercise and it has been proven to be beneficial for improving fitness, boosting energy and promoting not only lean muscle growth, but fat loss1.

The only trouble is, along with all of the benefits, it’s a type of workout we’re seeing a significant amount of people limping away from, having developed injuries as a result, explains study author, Joseph Ippolito, a physician in the department of orthopaedics at Rutgers New Jersey Medical School2.

Why would such a great workout be so harmful? Well, it has to do with your fitness levels when you first start.


How ready are you really for HIIT?

HIIT-type exercises really took off in the early 2000s with workouts including activities that use barbells, kettlebells, boxes, and calisthenics like burpees, push ups and squats and lunges. There are short bursts of intense (and sometimes seemingly crazy) combinations of exercises, followed by short periods of rest, or lower-intensity blocks3.

If you take part in a group fitness HIIT class, you’ll be familiar with the instructor shouting out commands, telling you to go all out because the break is coming in 5… 4… 3… 2… 1… That’s the problem, however. If you’re new to exercise, HIIT might sound amazing. If your body isn’t prepared, it’s going to hurt. Or worse, you’ll be on the bench4.

Put burpees, jumping lunges and box jumps into a 20 second on, 10 second off combo, going all out, there’s plenty that can go wrong when your back, core and legs aren’t strong. Hyperextend your back, tweak your knee or over-rotate your shoulder and it can really do some damage. Even lead to chronic overuse injuries, like osteoarthritis, says Ippolito. Athletes who perform these workouts without supervision are at increased risk for injury from poor form and muscle overuse. There is strong evidence that these types of injuries can have serious implications, which have already seen an increase since HIIT has become so popular, and injuries being seen are specifically from repetitive overload at the knee5.

From the research conducted by the team at Rutgers, it was shocking to see that the average increase in injuries per year was just shy of 51,000; and along with knee injuries, there were injuries relating to nerve damage, internal organ injuries, concussions, puncture wounds, dislocations and strains and sprains. It’s surprising when something that’s supposed to be so inherently good for you, can be so bad.

Of course, the aim of the research is not to discourage people from taking part in these types of exercises.


Take it easy if it’s your first time

Before diving in with both feet, it’s best to start slow and work your way up to being fit and strong enough to do HIIT, and do it well to get the best you can from the workout.

If you’re already at risk of an injury, for example, if you have a chronic illness, if you’ve already suffered an injury, or if you have any other susceptibility, speak to your physician before you take part in HIIT6,7. Once you do decide to join, speak to a fitness trainer to get the basics about form and safety before you try the exercises in a group setting and the adrenalin is already pumping. Then, when you do join the classes, opt for the options with reduced intensity (which there typically are), until you’re familiar with the moves and you’re confident you can perform them safely.

There’s one last tip: if you feel a niggle, stop. It’s that simple. Then start again from the beginning. Getting your sweat on and getting through a short bout of HIIT at the highest level when you’re neither fit nor strong enough to do it yet is not worth the risk of injury. Go slow, and do it right, and before you know it, you’ll be right up there, with the best of them.

If you’re a trained athlete, there’s no harm in checking in with yourself from time to time, either. Respect that your body needs time to recover from strenuous workouts, no matter how fit or strong you are and be sure to take time time to do the necessary stretches you may need to cool down once the HIIT session is over. If you’re going all out, during every training session, make sure you work on your joint range of motion; flexibility in the joints you use most often during HIIT exercises benefit from more focus, as they are then able to cope with the increased demand that is placed on them, and you’re less likely to develop an injury.



  1. Gibala, M., & McGee, S. Metabolic Adaptations to Short-term High-Intensity Interval Training: A Little Pain for a Lot of Gain? Exercise and Sport Sciences Reviews. 2008. 36(2):58-63.
  2. Rynecki, N., et al. Injuries sustained during high intensity interval training: are modern fitness trends contributing to increased injury rates? Journal of Sports Medicine and Physical Fitness, Feb. 12, 2019.
  3. Laursen, P., & Jenkins, D. The Scientific Basis for High-Intensity Interval Training. Sports Medicine. 2002. 32(1):53-73.
  4. Buchheit, M., & Laursen, P. High-Intensity Interval Training, Solutions to the Programming Puzzle. Sports Medicine. 2013. 43(10):927-954.
  5. Roos, L., et al. Musculoskeletal Injuries and Training Patterns in Junior Elite Orienteering Athletes. BioMed Research International. 2015. 259531. .
  6. Summiyy, R., et al. Shoulder Injuries in Individuals Who Participate in CrossFit Training. Sports Health: A Multidisciplinary Approach. 2016. 8(6).
  7. Ross, L., et al. High-intensity interval training (HIIT) for patients with chronic diseases. Journal of Sport and Health Science. 2016. 5(2):139-144.

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