If you are constantly asking yourself, “What exercises should I do today?”, you might want to reconsider your exercise plan. (Better: consider your lack of exercise plan.) After all, progress comes from planned, progressive overload of the body system. Exercise needs to be systematic and specific to be most effective. The good news is that it doesn’t have to be complicated.
I am not a fan of the “workout of the day”—best known as the “WOD”. My reasoning is that is rarely individualized. It is usually some random mix of exercises scrawled on a whiteboard by a trainer who may or may not have given careful consideration to what is included. Now, of course, strength and conditioning coaches will design daily workouts around team/position goals—but there is always a bit of flexibility for individual needs. Personally, as well, we will have our own planned WOD, but, again, this is individualized.
No doubt, the WOD approach has been beneficial for the countless exercisers who are clueless (no criticism intended) about what exercise they should be doing and/or those who simple don’t want to have to think about what to do when they go to the gym. This is fine, if the goals are limited (and there are no physical limitations to exercise), but, for those who wish to see specific progress, non-specific or random exercise will have less than effective results.
Exercise goals will fall into several broad categories within which one’s emphasis will be dependent upon interest, need, and opportunity. These are: cardiorespiratory endurance, muscle strength, muscle endurance, flexibility, body composition, and motor skill-related performance (e.g., speed, power, balance, coordination, agility, and reaction time). With these in mind, the exercise program (there is a reason I use “program” as opposed to “session”, which I will come to shortly) will generally consist of some mix of aerobic (“cardio”) exercise, weight/resistance training, flexibility exercise, and performance or skill-based training. Each is addressed as a separate component to the exercise.
High-intensity interval training (HIIT), high-intensity interval resistance training (HIIRT), and high-intensity resistance training (HIRT) are labels that are applied to a variety of exercise approaches (correctly and, often, incorrectly). I’d like to spend a few moments today differentiating between these and discuss some of the “whys” and “hows”. While these may seem to be different labels for the same basic thing, they are really not the same and have very different places in your exercise program.
HIIT. High-intensity interval training is an effective means of improving one’s maximal oxygen consumption (VO2max; i.e., cardiorespiratory endurance). There are also advantages in improving anaerobic endurance (e.g., lactate tolerance) in certain applications.
HIIT is a type of aerobic exercise. Thus, it is performed using the more traditional modalities of aerobic exercise, e.g., treadmill or outdoor running (for some, walking), cycling, stairstepper, elliptical, rowing, etc. The modality is less important than the intensities. Some protocols are best accomplished on specific equipment (the true Tabata IE1 protocol, for example, can best be performed on a stationary leg ergometer—stationary cycle—because the required intensities and sequencing of intervals is nearly impossible on a treadmill or stairstepper and has a high risk of injury on a rower), but overall the modality is mostly a matter of preference and/or availability.
There is no specific HIIT protocol. What makes it “interval training” is the systematic variation of intensities. Following a warm-up, the interval period is a defined set of cycles of high-intensity (usually greater than 85% VO2max or maximum heart rate) followed by a recovery at a low intensity (usually less than 60% maximum). These cycles are usually uniform, e.g., 5 cycles of 1-minute high intensity followed by 1-minute recovery. Ideally, they are 20- to 60-sec cycles of high-intensity, but there are no rules, per se. The cycles can be less uniform, as I will discuss in a subsequent post. When more random, it is referred to as “Tempo” or “Fartlek” training. Uniform or random, the intervals must be of sufficient intensity to stimulate cardiorespiratory adaptations.
HIIRT. I differentiate between HIIRT and HIRT. Some do not, which somewhat muddies the waters. In my opinion, there is a distinction. That distinction lies in the intent and the nature of the activities included. There is also a distinction in how the exercise can be progressed.
I define HIIRT to include predominately body-weight exercises or similar exercises performed with kettlebells, sandbags, medicine balls, Bulgarian bags, and the like. Because these are done for time and/or high-repetitions (i.e., greater than 12 repetitions per exercise) these workouts are ideal for burning excess calories for fat loss. The benefits for cardiorespiratory fitness and strength are on the low end (despite the claims). Because these are performed with minimal overload (and regular progression) and for such high reps, HIIRT will not produce large amounts of hypertrophy (muscle size). HIIRT might give the appearance of hypertrophy, as the body becomes leaner and musculature is more defined, but, as I will discuss in a subsequent post, the resistance is not sufficient to stimulate significant strength and hypertrophy gains. With regards to cardiorespiratory endurance, HIIRT is not performed to the intensities, similar to HIIT, that are sufficient for significant increases in VO2max. Most exercises included in HIIRT workouts cannot be performed with proper technique at the necessary intensities to improve cardiac function—the risk of injury is increased as fatigue sets in. Indeed, HIIRT is best for fat loss because it promotes a much elevated post-exercise oxygen consumption (and subsequent calorie burn) for as much as 24-48 hours post-exercise.
HIRT. HIRT is what I would have called “circuit training” in the past. Arthur Jones, founder of Nautilus, promoted this type of HIRT in the 1970s. Now, technically, strength training (i.e., training for strength; low reps and heavy weight) is “high-intensity resistance training”, since resistance training intensity is defined as a percentage of the maximal lift (i.e., 1-repetition maximum, 1-RM). Specifically, though, HIRT involves either super-setting (i.e., mini-circuit sets) or sets to volitional fatigue (momentary muscular failure), including breakdown sets. Despite the “intensity” moniker, the actual intensity (defined by %1-RM) is rather low. HIRT is typically performed for 6-15 repetitions. With the exception of a “one-set to failure” approach (e.g., the old school Nautilus workouts), the focus is more on volume (= weight x repetitions x sets) than intensity. Thus, HIRT serves best for time-efficiency (one can accomplish a lot of volume in a short period) and overall muscle hypertrophy (specifically, sarcoplasmic hypertrophy or muscle volume). It is also great for those who want or need to get out of the gym quickly. Like HIIRT, it also has the added benefit of prolonged calorie burns.
One of the biggest distinctions between HIIRT and HIRT is the nature of the exercises performed. HIRT is not unlike more traditional weight training. That is, it involves the principles of overload and progress utilized in all weight training. Form and tempo are maintained. The weight is increased from workout to workout. The key difference is that exercises are performed as super-sets. Unless strength/power is the primary goal for lifting weights, HIRT can benefit muscle strength, muscle endurance, and body composition.
While HIIT, HIIRT, and HIRT may seem the same, they are different and have a different role to play in one’s overall exercise program. In summary:
HIIT = cardiorespiratory endurance and anaerobic endurance
HIIRT = body composition (specifically, fat loss)
HIRT = muscle strength/endurance, muscle hypertrophy, body composition