HIIT

What is HIIT?

The name describes the structure. Work hard, back off, repeat. A session might be six 60-second rowing efforts with a minute of easy paddling between each, or a handful of 20-second sprints separated by several minutes of walking.

Two features define it. The work intervals sit near the ceiling of what a person can sustain, and they are broken up by recovery rather than run together. Harvard’s Nutrition Source puts the target during the hard portions at roughly 80 to 90 percent of maximum heart rate. Recovery is what makes those intensities reachable at all. Nobody holds 90 percent of maximum heart rate for forty minutes straight, but a trained person can accumulate fifteen or twenty minutes up there if it arrives in pieces.

That trade is the whole idea. Endurance running builds cardio by holding a moderate pace for a long time, and HIIT chases a similar signal by swapping duration for intensity. For a fighter already juggling sparring and strength sessions, the appeal is time.

How HIIT works in a fight context

MMA is intermittent by nature. A round is a sequence of scrambles and exchanges broken up by resets, and the physiology reflects that shape. Research led by Chris Kirk describes MMA as repeated high-impulse actions lasting up to 15 minutes in a standard professional bout and 25 in a championship fight, with blood lactate measured between 9 and 21 mmol per litre after competition. Amateur data from Petersen and Lindsay found average heart rates above 90 percent of maximum even during the one-minute rest between rounds.

So the sport is intense and also long. Evidence from other combat sports puts the aerobic contribution to competition energy at roughly 60 to 70 percent. A fight is too long to be a sprint and too hard to be a jog.

Interval training appeals to coaches because its shape mirrors that pattern: hard effort, brief recovery, hard effort again. Whether the adaptations transfer as neatly as the resemblance implies is a separate question, and one the research handles with less confidence than most training articles admit.

The four types of HIIT

HIIT covers a family of protocols rather than a single workout, and the differences matter, because each variant stresses the body in its own manner. The framework below comes from Martin Buchheit and Paul Laursen, whose work is widely used in combat sports conditioning.

Type	Work intervals	Intensity	Recovery	Mainly targets
Long HIIT	2 to 8 reps of 2 to 8 minutes	90 to 100% of speed at VO2 max	1 to 3 minutes	Heart size and oxygen delivery
Short HIIT	8 to 10 reps of 10 to 60 seconds	100 to 120% of speed at VO2 max	10 to 60 seconds	Both heart and muscle
Repeat sprint training (RST)	Blocks of 3 to 10 second sprints	All out	15 to 60 seconds between sprints	Muscle acid tolerance
Sprint interval training (SIT)	4 to 6 reps of 20 to 30 seconds	All out	1 to 4 minutes	Muscle acid tolerance

Tabata is the best-known named protocol in the short HIIT family, built on 20 seconds of work against 10 seconds of rest. Harvard’s Nutrition Source credits its development to Izumi Tabata in 1996, during research on Olympic speed skaters.

HIIT vs. steady-state cardio

Readers usually want this comparison against roadwork, the long morning run that has been part of fight preparation for a century. The two methods are not interchangeable.

	HIIT	Steady-state cardio (MICT)
Intensity	Roughly 80 to 95% of maximum heart rate during work intervals	Roughly 50 to 80% of maximum heart rate
Typical session	10 to 30 minutes of work	30 to 90 minutes
Structure	Alternating effort and recovery	One continuous pace
Main draw	Time efficiency	Lower fatigue cost, easier recovery
Where fighters use it	Nearer competition, as intensity climbs	Base building and between camps

Cleveland Clinic notes that a worthwhile interval session can run as little as 10 minutes and rarely stretches past an hour. Coaches lean on running to build an aerobic base between camps, then introduce intervals as a bout approaches. Neither method has been shown to dominate the other for combat athletes.

What the research actually says

Most articles on this topic assume the benefit and move straight to the workouts. The evidence is thinner than that.

A 2020 meta-analysis by Vasconcelos and colleagues pooled interval training studies across combat sports. It found gains in VO2 max relative to body mass of about 2.8 ml/kg/min in striking sports and 2.4 in grappling sports, with anaerobic capacity improving in the grappling group alone. Emerson Franchini’s review of Olympic combat athletes reported gains relative to body mass but none in absolute terms, so the verdict can shift with the measure reported.

For MMA specifically, the evidence narrows to almost nothing. Kirk’s review of the field identified one study reporting interval outcomes in MMA athletes: Kostikiadis and colleagues gave national-level fighters rowing intervals twice a week and sprint intervals once a week across four weeks, and Kirk’s review puts the resulting rise in estimated VO2 max at about 13 percent. The spread between individuals was about as wide as the average gain, which is the honest headline. Some fighters improved a great deal. Others hardly moved.

Kirk’s group also examined training load in MMA athletes and found that few completed any structured supplementary conditioning, and that where it appeared inside technical sessions it was organised ad hoc, with no measurement of intensity.

Common misconceptions

Any hard circuit counts as HIIT. Intensity has to be measured against something. Harvard’s Nutrition Source draws the line directly: circuit training varies its intensity by design, whereas HIIT specifies near-maximal effort. An exhausting class is not automatically an interval session.

HIIT is purely anaerobic. The work periods lean heavily on anaerobic pathways, yet the reason coaches program longer intervals is aerobic, targeting a bigger stroke volume and better oxygen delivery.

Fitter fighters get more from it. The reverse may hold. Analyses summarised in Kirk’s review suggest athletes already above roughly 50 ml/kg/min of VO2 max can respond weakly to short intervals, because their movement efficiency lessens the physiological disturbance a session creates.

Frequently Asked Questions

Is HIIT the same as circuit training?

No. Circuit training moves through stations at variable intensity, while HIIT is defined by near-maximal work intervals paired with recovery.

Do professional MMA fighters actually do HIIT?

Some do. Kirk notes that the UFC Performance Institute has pushed targeted interval protocols, yet his own training-load research found structured conditioning rare among the fighters sampled.

What does SIT stand for?

Sprint interval training, an all-out variant using roughly 20 to 30 second efforts with long recoveries. It targets the muscles more than the heart.

Is HIIT better than running for fight cardio?

Nobody has compared them directly in MMA athletes. The two produce different adaptations, and coaches typically use both at different stages of a camp.

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Sources

1. Kirk, C., Clark, D., Langan-Evans, C., Morton, J. “The physical demands of mixed martial arts: A narrative review using the ARMSS model.” Journal of Sports Sciences, 2020.
   https://www.tandfonline.com/doi/abs/10.1080/02640414.2020.1802093
2. Kirk, C., Langan-Evans, C., Clark, D., Morton, J. “Quantification of training load distribution in mixed martial arts athletes: A lack of periodisation and load management.” PLOS ONE, 2021.
   https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251266
3. Kostikiadis, I.N., Methenitis, S., Tsoukos, A., Veligekas, P., Terzis, G., Bogdanis, G.C. “The effect of short-term sport-specific strength and conditioning training on physical fitness of well-trained mixed martial arts athletes.” Journal of Sports Science and Medicine, 2018.
   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6090403/
4. Vasconcelos, B., Protzen, G., Galliano, L., Kirk, C., Del Vecchio, F. “Effects of high-intensity interval training in combat sports: A systematic review with meta-analysis.” Journal of Strength and Conditioning Research, 2020.
   https://journals.lww.com/nsca-jscr/FullText/2020/03000/Effects_of_High_Intensity_Interval_Training_in.32.aspx
5. Franchini, E., Cormack, S., Takito, M.Y. “Effects of high-intensity interval training on Olympic combat sports athletes’ performance and physiological adaptation: A systematic review.” Journal of Strength and Conditioning Research, 2019.
   https://journals.lww.com/nsca-jscr/fulltext/2019/01000/effects_of_high_intensity_interval_training_on.29.aspx
6. Petersen, C., Lindsay, A. “Movement and physiological demands of amateur mixed martial art fighting.” Journal of Sport and Exercise Science, 2020.
   https://ir.canterbury.ac.nz/handle/10092/100773
7. Buchheit, M., Laursen, P. “Using HIIT Weapons.” In Science and Application of High-Intensity Interval Training. Human Kinetics, 2019.
   https://www.researchgate.net/publication/340406664_Using_HIIT_Weapons
8. Harvard T.H. Chan School of Public Health, The Nutrition Source. “High-Intensity Interval Training.” Accessed 28 July 2026.
   https://nutritionsource.hsph.harvard.edu/high-intensity-interval-training/
9. Cleveland Clinic. “High-Intensity Interval Training: It’s for Everyone!” Accessed 28 July 2026.
   https://health.clevelandclinic.org/think-you-cant-do-high-intensity-interval-training-think-again

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