Although you may have heard it called something different, high intensity interval training or HIIT is the number one fitness trend, according to the American College of Sports Medicine. Programs such as CrossFit, P90X, Insanity, and many others base their workouts on this style of training. It involves intense bursts of energy followed by short periods of rest. CrossFit, in particular, also involves Olympic style weightlifting.
As popularity has increased, with more people participating, so too have injury rates. So the question is… is it safe? Well that is a difficult question to answer because of two reasons. The first is there are many factors of any exercise program or participant which can create a risk of injury. Secondly, few studies have been completed to evaluate these programs from an injury risk standpoint.
One study from the Journal of Strength and Conditioning Research published in 2013 specifically tried to address this issue with CrossFit training. The findings reported were based on a survey of 132 CrossFit athletes. Researchers found that 73.5% of participants had sustained an injury that had prevented them from working, training, or competing. Of these injuries, 9 required surgery.
The injury rate reported is similar to sports like Olympic weightlifting, power lifting, and gymnastics but less than contact sports like rugby. Surprisingly, however, this is the same rate of injury for general fitness workouts. They also found that shoulder injuries accounted for 25% of injuries reported.
Also of note, in 2012 the Canadian military released a general order asking personnel not to participate in HIIT.
This was because a few personnel developed a rare but potentially life-threatening condition called exertional rhabdomyolysis. They required hospitalization, and most of them had been taking part in a CrossFit workout. Exertional rhabdomyolysis is the breakdown of muscle fibers, leading to a large release of the protein myoglobin into the bloodstream. This can result in serious kidney damage and even death.
So to answer the question, “Is it safe”? My answer to that question is a qualified, “Yes!” However, a few points should be made and you can judge and decide if it right for you. HIIT is not for everyone. Evaluate your goals and be realistic with your current level of fitness before deciding whether to try it.
Modify the intensity of the work intervals to a challenging level for YOU! Focus on finding your own optimal intensity as opposed to keeping up with other participants. HIIT workouts are more exhaustive than steady state workouts. Therefore a longer recovery period is often needed.
Not all HIIT programs are the same. Some incorporate lots of weightlifting or body weight exercises, while others focus on running, core, and calisthenics. Find the one which is right for you.
In conclusion, I would emphasize that there are many benefits to HIIT and they have become popular for many reasons. But as in any sport or fitness program injuries will and do occur. So be smart and listen to your body and seek advice from a trained orthopedic, like myself, before starting. Create realistic goals, start slowly, and gradually advance yourself. Longer recovery periods are a must and proper diet and hydration are equally important. So have fun and give HIIT a try!