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{{DISPLAYTITLE:High Intensity Interval Training (HIIT) Tabata and Wingate}}
HIIT can be highly effective training, but involves a risk of injury. HIIT has been shown to improve aerobic capacity in untrained and moderately active individuals more quickly than Continuous Moderate Exercise, as well as having potential benefits for highly trained athletes. HIIT has also been shown to reduce body fat in untrained people more effectively than Continuous Moderate Exercise. However, there is no evidence to suggest that HIIT can replace other forms of training for endurance races. High Intensity Interval Training (HIIT) uses repeated short periods of very intense cardiovascular exercise separated by lower intensity recoveries. (I've found the [[Stryd]] estimate of power output is the best approach to gauging effort during HIIT, though [[Moxy]] can provide some interesting insight from [[Muscle Oxygen Saturation]].)
If you'd like to know more about the science behind HIIT, see [[The Science of High Intensity Interval Training]].
=What is HIIT?=
High Intensity Interval Training is a form of [[Introduction to Interval Training| Interval Training]] using short intervals of 10 seconds to 5 minutes at an intensity at or above 90% [[VO2max|V̇O<sub>2</sub>max]]<ref name="Boutcher2011"/>. High Intensity Interval Training, abbreviated to HIIT or HIT, is sometimes called High-Intensity Intermittent Exercise<ref name="Trapp-2008"/> or Sprint Training<ref name="Gibala-2006"/>.
The [[Tabata]] workout is one of the best-known protocols for HIIT and consists of 7-8 repeats of 20 seconds at 170% of [[VO2max|V̇O<sub>2</sub>max]] with 10 seconds rest. The number of repetitions is defined by how long the required intensity can be maintained. An athlete should be able to complete 7-8 intervals; if 9 can be performed, the intensity is increased. However, few people actually follow the [[Tabata]] protocol because it requires specialist equipment to measure [[VO2max|V̇O<sub>2</sub>max]], then calculate 1.7x the [[VO2max|V̇O<sub>2</sub>max]] workload that should be used. In practice, most people do what I call the WinTab workout (see below).
==4 x 4 (The Norwegian Method)==
''Main article: [[Medium Intensity High Volume Intervals]]''
The original Norwegian Method is to perform four intervals, each of four minutes at 90-95% of maximum heart rate, with 3-minute recoveries, often called "4x4". At first glance this appears to be an odd specification, as it's impossible to immediately increase your heart rate to 90% of maximum, and the original definition<ref name="Helgerud-2007"/> talks about trying to get your heart rate to 90% or above in 60-90 seconds, then adjust the effort to keep your heart rate in range. This approach was refined by a more detailed study<ref name="Acala Roche-Willis Astorino 2020"/> that used a range of 85-95% of max heart rate. In that study, the subjects increased their effort rapidly to 85-100% of the effort for their [[VO2max|VO<sub>2</sub>max]]. After their heart rate reached 95% of max, the effort was reduced to keep it in the 85-95% range. What's that mean in practice? Given the details below, you need to estimate your [[VO2max|VO<sub>2</sub>max]], then either work out your pace or power.
* '''Power'''. Use the formula "weight in Kg * [[VO2max|VO<sub>2</sub>max]] * 0.097". You then start the 4-minute interval at 85-100% of that power.
* '''Pace'''. Luckily, it happens that pace in meters/second is roughly the same as power in watts/Kg. So you can use the formula to "[[VO2max|VO<sub>2</sub>max]] * 0.097" to estimate your target pace in meters/second, then use an online converter to change that to min/mile or min/Km.
Dropping your effort as the interval progresses may result in a surprisingly large reduction, with the study showing that that most intervals ended at about 60% of the initial power. The study also showed that the second through fourth interval had a lower initial power requirement, roughly 10-15% lower than the first interval.
Remember, you can estimate your [[VO2max|VO<sub>2</sub>max]] from a race performance using a [[Running Calculator]].
(Note that the more recent versions of the Norwegian Method use [[Medium Intensity High Volume Intervals]].)
===4x4 Conversion Details===
The study had athletes with average [[VO2max|VO<sub>2</sub>max]] of 37, average weight of 72 Kg, and average peak power output of 260w, which is 3.6 w/Kg. A [[Stryd]] based study<ref name="stryd"/> showed that there's a linear relationship between [[VO2max|VO<sub>2</sub>max]] and peak power. (Peak power at [[VO2max|VO<sub>2</sub>max]] varies with protocol). For this study, the peak power in w/Kg is [[VO2max|VO<sub>2</sub>max]] * 0.097.
===4x4 Effort Worked Example===
Assume your [[VO2max|VO<sub>2</sub>max]] is 53 and your weight is 60, then the initial target power is 53 * 0.097 * 60 = 309 watts. So the target range would be 260-309w at the start of the interval. Alternatively, the required pace is 0.097 * 60 = 5.14 meters/second, so the range is 4.37 to 5.14 m/s. That converts to 3:49-3:14 min/Km or 6:08-5:13 min/mile. The power or pace is then dropped to keep your heart rate below 95% max.
==Wingate==
This style of HIIT is based around the Wingate test, which is used to measure peak anaerobic power and anaerobic capacity<ref name="Vandewalle-1987"/>.
<ref name="JD"> Jack Daniels, Daniels' running formula, date 2005, publisher Human Kinetics, location Champaign, IL, isbn 0-7360-5492-8</ref>
<ref name="JD-P132"> Jack Daniels, Daniels' running formula, date 2005, publisher Human Kinetics, location Champaign, IL, isbn 0-7360-5492-8, pages 132</ref>
<ref name="Helgerud-2007"> J. Helgerud, K. Høydal, E. Wang, T. Karlsen, P. Berg, M. Bjerkaas, T. Simonsen, C. Helgesen, N. Hjorth, Aerobic high-intensity intervals improve VO2max more than moderate training., Med Sci Sports Exerc, 39 !!V̇olume!!, issue 4, pages 665-71, Apr 2007, doi [http://dx.doi.org/10.1249/mss.0b013e3180304570 10.1249/mss.0b013e3180304570], PMID [http://www.ncbi.nlm.nih.gov/pubmed/17414804 17414804]</ref>
<ref name="Acala Roche-Willis Astorino 2020">Justin J. Acala, Devyn Roche-Willis, Todd A. Astorino, Characterizing the Heart Rate Response to the 4 × 4 Interval Exercise Protocol, International Journal of Environmental Research and Public Health, publisher MDPI AG, volume 17, issue 14, date 2020-07-15, ISSN [http://www.worldcat.org/issn/1660-4601 1660-4601], doi [http://dx.doi.org/10.3390/ijerph17145103 10.3390/ijerph17145103], page 5103</ref>
<ref name="stryd">https://blog.stryd.com/2019/12/06/how-to-use-stryd-power-to-calculate-your-vo2/, How to use Stryd power to calculate your VO2, Accessed on 2023-08-21</ref>
</references>
