High-intensity exercise is gaining popularity. The terminology is, however, often confusing and misleading. The acronyms are similar, but there are some differences. This is Part 3 of a three part series,
HIRT. High-intensity resistance training or HIRT is a bit of a misnomer. “Intensity”, with regards to weight training or resistance training, normally refers to the weight lifted—expressed as a percentage of the one-repetition maximimum (1-RM). Thus, “high-intensity” should involve resistances near maximal (e.g., >85% 1-RM). Repetitions for HIRT, however, are typically in the 6-15 rep range (60-85% 1-RM). HIRT has really just become the trendy term for what we used to call “circuit training”. It involves small super-sets of exercise (usually 3-5) performed with no rest. Following a post-super-set recovery period, the super-set is repeated a predetermined number of times. Sound a lot like HIIRT? They are very much alike. Indeed the labels are often used interchangeably (just like HIIT is often used as an umbrella term). Personally, I do see a slight distinction.
The distinction between “HIIRT” and “HIRT” lies mostly in the “interval” specification. Remember, “interval training” involves regular, fixed periods of work and recovery. HIIRT involves a fixed number of reps or performing as many repetitions as possible (AMRAP) in a prescribed time. One is either doing reps faster with the same weight or more reps in the same time period (e.g., performance is often measured as time to complete a WOD or the number of reps performed in the WOD). HIRT, on the other hand, involves greater focus on progressive overload in terms of resistance and, thus, volume. The emphasis of HIIRT is on muscle endurance and fat loss (and to a much lesser extent cardiorespiratory endurance), while HIRT emphasizes muscle strength and hypertrophy, along with fat loss. It is important to note, however, that the hypertrophy gains in HIRT are likely accompanied with smaller strength gains than seen in more traditional strength training programs (where the repetition ranges are lower—e.g., 3-12–and recovery periods are longer to allow for full recovery between sets).
The greatest benefits of a HIRT approach are time and fat loss (while maintaining more muscle mass). Combining exercises into super sets can significantly reduce the time spent in the gym by cutting down on idle time spent resting between sets.
A number of research studies have demonstrated that HIRT (when compared to traditional weight training) can increase resting energy expenditure for 24-48 hours (or longer) and lower the respiratory exchange ratio (RER = VCO2/VO2) which indicates greater fat oxidation. Thus, HIRT is often referred to as “weight lifting for fat loss”.
For some, HIRT might be the ideal approach to weight training long-term. This would include those individuals looking to burn fat and see some increase in muscle mass (e.g., many of us over 50). If strength and more significant gains in muscle hypertrophy are desired, including cycles of HIRT among traditional strength and hypertrophy cycles in the periodization plan might be warranted. It is certainly great for those short-term shape ups where cutting fat is a primary goal.
We have been discussing HIIT, HIIRT, and HIRT over the last few days. Hopefully, I have provided a bit more clarity on the distinctions. They say “a rose by any other name would smell as sweet” (William Shakespeare). The labels, here, are less important than what is being done and for what purpose. Each should have some place in one’s regular exercise program. The degree to which each will find a place will depend on one’s individual goals. Just remember: the body makes specific adaptations to imposed demands.
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Carpe momento!