High intensity interval training, often abbreviated as HIT or HIIT, has become quite the rage in a world where time is precious and the last thing most people want to do these days is “slave away” on a treadmill or elliptical for an hour. I wrote a blog post about three tips to maximize your interval sessions here. While the easiest and most common way to perform an interval is through traditional cardiovascular exercises (jog/run, elliptical, stair climber, rowing, etc.), there are other ways.
Brett Klika and Chris Jordan recently published a paper in a sports and exercise journal describing the effects, benefits and precautions of a specific type of interval training: high-intensity circuit training (HICT). The appeal of HICT is that it can be done anytime, anywhere with one main piece of equipment: you. It focuses on rotating through a series of 9 to 12 bodyweight exercises that challenge different areas of the body (upper body, lower body, core, etc.) in rapid succession. The authors recommend performing 30 seconds of an exercise – for a target of 15 to 20 repetitions – and then moving onto the next one within 30 seconds (they prefer less).
Their example workout was well-described in a Fitness info-graphic in the NY Times. If you perform all 12 exercises for 30 seconds and only take 5 seconds off between, then you have a seven minute workout. Interestingly, my colleague at Hospital for Special Surgery measured how many calories someone burns doing this workout using a Parvo metabolic cart (it’s expensive, and accurate) – 52 calories. That translates to nearly 450 calories an hour – pretty good.
And now some insights from the research article and my own thoughts:
Insights from the Research Article
Exercise selection should be focused on a balanced (i.e. pushing, pulling, squatting, core) rotation through all large, major muscle groups that can be modified for safety and appropriateness based on the location and client’s ability level.
Form and technique are paramount before moving with increased intensity. Don’t perform intervals with exercises that you can’t do properly and perfectly for 15 repetitions – because you’ll probably be doing them tired now (imagine your last exercise in the circuit).
Caution for: Overweight/obese (stress on joints), detrained, previously injured, elderly, or for individuals with comorbidities. For example, individuals with hypertension should be mindful to breathe during isometric exercises (wall sit, plank, and side plank) to avoid a potential spike in blood pressure. It's not to say that these populations can't do HIIT training, but it's important to listen to your body when starting to prevent unnecessary injuries.
Specificity of Training: Although HICT can be an efficient means by which to improve health and decrease body fat, it may be inferior to creating absolute strength and power, specific endurance, and other specific performance variables. What’s your goal?
Building in Recovery: The authors recommend minimizing total rest, stating that recovery can be improved by placing an “easier” exercise after a harder one. Their example is a plank after jump squats.
Repeats: The authors mention you can perform the circuit multiple times for a longer workout. If you perform the 7 minute version, and you take 2 minutes off after each full circuit to recover, you can do 3 circuits in 25 minutes or so.
Jason’s Thoughts
Usefulness
These workouts alone will not help you run a marathon, lift really heavy things or be the best at a sport. However, they provide a great calorie burn and good general conditioning in a short period of time – which is what most of the population needs.
It also allows people to get away from the traditional 45 minute slog on a treadmill, elliptical or other piece of cardio equipment. If you enjoy your workout more, you’re more likely to do it! You can do this on the road, at home, anywhere. You can also add a few pieces of equipment in (kettlebells, battle ropes, jump ropes, resistance bands, mini bands, stability ball, etc.) and have endless variations.
These workouts are NOT one-size-fits-all. You need to make sure you are giving the right exercises (see first insight at the beginning), at the right intensity (too little = no effect, too much = injury) to the right person (age, weight, current activity level, ability to move properly, etc.) at the right time (injury history? Training goal?). This is why a good trainer with knowledge of movement and exercise science can go a long way in getting you results and keeping you safe.
Rest Time
5 and even 15 seconds between exercises is a really, really short time, so be careful if you’re just getting off the couch. The traditional recommendation is for beginners to start with a rest period equal to twice the interval length, if that interval is an all-out effort. Some of these exercises may not be an all-out effort, but if this is all new to you, give yourself at least that 30 second rest time between exercises, particularly the ones that leave you breathless afterward. You can always make it harder in the future – as long as you’re not injured from working unrealistically hard in the recent past.
Exercise Selection (from the Seven Minute Workout exercise examples, see the NY Times link):
2. Wall sit – can add an upper body movement like wall slides (raising arms up and down while keeping the shoulders down in its sockets to mobilize the shoulders) or external rotations (starting with elbows at a 90 degree angle against the wall, arm and palms down, then slowly rotate your arms and palms up without moving your upper arm). Here’s an example, no need to use the bar:
4. Abdominal crunches – Most people are seated in trunk flexion all day at a desk, so there’s little need to train trunk flexion further. It’s very easy to go too far on a crunch and create discomfort on the neck, shoulders or lower back. I’d rather see someone do heel taps, leg cycling (move one leg at a time), dead bugs or partial trunk curl ups learned correctly. Here’s an example:
5. Step Up onto Chair – Chairs are high. If stepping up that far creates sloppy form (either on the way up, OR down), then start lower – like on a stair.
7. Dips – Most people go too low and place excessive anterior (forward) stress on the shoulders, which can lead to shoulder injury. Don’t go too deep by controlling your descent. Or to get a similar effect, consider close grip pushups with your body raised up to reduce that anterior strain (start against a stable window sill or countertop)
3. & 11. Pushups & Pushups w/ Rotation – Learning to stabilize rotation is good, but first be sure you can do a proper pushup. To make this more manageable, you may need to elevate your upper body, or preform modified pushups from your knees. I wrote a blog post about performing a proper pushup here. Once your pushups are solid, then focus on adding movements like rotation. A great beginner anti-rotation movement, which you could do in place of the pushups with rotation is shoulder taps:
13. The missing exercise: pulling. It’s really hard to do a “pull” exercise like rows, lat pulldown or pullups without equipment, but to stay totally balanced, there should be a pull in this list. A small investment in a light, portable $5 to $10 resistance band can do the trick. I’d say put it in place of one of the sets of pushups or the dips.
Tell Me: What has your experience been like with interval workouts? How would you modify the seven minute workout to meet your needs?
Photo Courtesy of Microsoft Images