High intensity interval training (HIIT) has been popular for many years. However, many trainers do not realize HIIT has been used by coaches and athletes for 104 years (and counting). Hannes Kolehmainen is the first documented athlete to use HIIT. He won a Gold Medal at the 1912 Stockholm Olympics in the 10,000 meters (Tschakert & Hofmann, 2013). He used interval training to run at velocities close to competition velocity, with jogging recovery. Perhaps the most popular HIIT program is Tabata. The “Tabata” program was developed by Izumi Tabata in 1996 to investigate if very low volume and very high intensity could improve aerobic and anaerobic capacity. Since Tabata published his results, there are many other HIIT and medium intensity interval training (MIIT) protocols that have shown to be successful at improving fitness and health of participants. This article will review the most significant and intriguing HIIT and MIIT studies so fitness professionals can be confident implementing them with their clients.
- Summarize the history of HIIT programs.
- Categorize the many different HIIT and MIIT programs for use with a diverse client base.
- Measure the benefits of each program for the numerous health issues our clients have.
- Implement as many of the HIIT and MIIT programs as possible for clients.
Pavoo Nurmi, another Finnish middle-distance runner, used sprint intervals at race pace and won numerous medals at the 1920, 1924, and 1928 Olympics. In 1937, Swedish running coach, Gosta Holmer, introduced Fartlek training to his runners. The word Fartlek means “speed play,” and had athletes doing continuous running using sprints of 50 to 3000 meters. Arguably, Emil Zatopek was the athlete who made interval training most popular. He used 400-meter interval sprints with jog recoveries and was a gold medalist and Olympic record holder in 5,000 meters & 10,000 meters at the 1952 Helsinki Olympics (Tschakert & Hofmann, 2013).
Most trainers have heard a lot about Tabata. When asked what “Tabata” is, many trainers indicate it is high intensity interval training. It seems Tabata has become synonymous with HIIT. There is way more to HIIT than Tabata, and there are many other studies with exciting results.
High intensity interval training is a very popular form of exercise. When “high intensity interval training” is typed into a Google search, there are 2,470,000 results as of 2016. The American College of Sports Medicine survey of fitness trends for 2017 has HIIT listed at number three (ACSM, 2016).
Research investigations of HIIT are not slowing down. Researchers have a never-ending quest to understand the multitude of training protocols for work:rest intervals. When “HIIT Research” is typed into a Google search, there are 1,210,000 results in 2016.
The Tabata (1996) study was remarkable for the fitness results the subjects received from a 4-minute workout. Tabata compared two groups of physical education students:
- moderate-intensity continuous aerobic cycling, five days/week for six weeks at an intensity of 70% of V02max, 60 minutes/session and
- a HIIT group who completed four minutes of a protocol using a continuous 20 second work interval cycling at 170% of V02max with a 10 second rest, 5 days/week for 6 weeks.
The study assessed the effect on V02max and anaerobic capacity. The results show that the moderate-intensity continuous training group increased their V02max by 5 ml/kg/min, with no effect on anaerobic capacity. The HIIT group improved their V02max by 7 ml/kg/min and anaerobic capacity by 28%.
A study that may be even more remarkable than Tabata as the results relate to our clients was done in 1994. Tremblay, Simoneau, and Bouchard (1994) compared two training programs for fat loss & muscle metabolism:
- 20-week continuous endurance cycle training, performed four or five times per week for 30 to 45 minutes at an intensity of 60% - 85% of heart rate reserve and
- 15-week medium intensity interval training (MIIT) performing either 10 – 15/15 – 30 second intervals or 4 - 5/60 - 90 second intervals at an intensity of 60% - 70% of heart rate reserve with recovery of a heart rate down to 120-130 beats per minute.
Subjects were all previous sedentary.
At the end of the study, the researchers calculated the total caloric expenditure for the entire study and found the continuous group used 28,757.04 kcals, and the MIIT group used 13,829.17 kcals. The remarkable part of the results is that when they compared fat loss using the sum of 6 skinfolds, the MIIT group decreased their skinfolds nine times less than the continuous group. The researchers indicate the reason for the dramatic skin fold reduction was the MIIT group had a significant increase in enzymes promoting fat being used as energy for muscle contraction. It could be suggested that the “Tremblay” protocol is a good choice for fitness clients relating to the intensity of exercise and the fat loss.
Shepard “Real World”
A study in which the investigators call “real world” research, Shepard, et al., (2015) deviated from a controlled laboratory environment used by most investigators. Participants performed their training protocols with a group cycling HIIT protocol and researchers compared it to group cycling medium intensity continuous training (MICT) protocol. They used 90 physically inactive volunteers (42 years) who were put into a HIIT or MICT class.
The HIIT group performed repeat cycling sprints, 15–60 seconds, >90% HR MAX with 45 – 120 seconds of active recovery. Each session was 18 - 25 minutes with three sessions per week. The MICT group performed continuous cycling at 70% HR MAX for 30–45 minutes/session with five sessions per week. Both groups trained for ten weeks.
The results of the study show the HIIT group had better attendance at 83% sessions, compared to 61% for the MICT group. The average weekly training time for HIIT was 55 minutes and MICT was 128 minutes. Both groups improved or reduced on the following variables: V02max, insulin sensitivity, feelings of energy (subjective vitality), feelings of health perception, and reduced fat mass. The MICT also reduced systolic blood pressure.
The researchers conclude that when HIIT is performed in a “real-world” group exercise setting there are improvements in cardio-metabolic risk factors and psychological health. Most importantly, the HIIT group had good results, reduced training time, and greater adherence.
In one of the most unique interval training studies by Gunnarsson and Bangsbo (2012) used 18 moderately trained subjects (12 men and 6 women) to train in an endurance running group for 40 minutes/day, three days/week, for seven weeks or a group who performed a “10-20-30” workout, three days/week for seven weeks. The “10-20-30” protocol consisted of a 1.2-kilometer low intensity running warm-up, followed by 3 – 4, five-minute running intervals, with two minutes rest between the interval protocol. Each interval consisted of the following: running for 30 seconds at 30% of maximum intensity, running for 20 seconds at 60% of maximum intensity, and running for 10 seconds at 90–100% of maximum intensity, repeated continuously for 5 minutes.
The researchers indicate the major findings were the “10-20-30” group decreased their 1500 meter running time by 21.00 seconds, five-kilometer running time decreased by 48.00 seconds, V02max improved 4%, total cholesterol and LDL cholesterol were lower, and systolic blood pressure was lower. The endurance group had no improvements.
Gillen Obese Subjects
One of the great things about HIIT research is that investigators use a wide variety of select populations as subjects. Tabata (1996) used physical education students, Tremblay, et al., (1994) used subjects who were sedentary, Shepard, et al., (2015) also used subjects who had not been exercising or physically active, and the last study we will review, Gillen, et al., (2014) used sedentary, overweight and obese males and a female. Gillen and team had seven men and woman in one HIIT group. They performed three, 20-second ‘‘all-out’’ cycle sprints with a two minute recovery between intervals. They exercised three days per week for six weeks and eighteen training sessions. The results show that peak oxygen uptake increased by 12%, resting blood pressure decreased by 7%, and skeletal muscle oxidative capacity increased, but primarily in men.
In conclusion, these five HIIT and MIIT studies are just scratching the service of the exciting research on high intensity interval training. The studies presented here are a cross-section of old, new, and compelling research to whet the appetite of trainers for continued information to improve our client’s fitness. The major understanding of HIIT or MIIT is that they work well for improved fitness, increased fat burning, improving the health parameters of our clients, and enhancing exercise adherence.
Thompson, W. R., (2016). ACSM Worldwide survey of fitness trends for 2017, ACSM'S Health & Fitness Journal 20 (6), 8–17.
Gillen, J. B., Percival, M. E., Skelly, L. E., Martin, B. J., Tan, R. B., Tarnopolsky, M. A., and Gibala, M. J. (2014). Three minutes of all-out intermittent exercise per week increases skeletal muscle oxidative capacity and improves cardiometabolic health, November 3, http://dx.doi.org/10.1371/journal.pone.0111489
Gunnarsson, T. P. and Bangsbo, J. (2012). The 10-20-30 training concept improves performance and health profile in moderately trained runners. J Appl Physiol, 113(1):16-24.
Shepherd, S. O., Wilson, O. J., Taylor, O. S., Thøgersen-Ntoumani, C., Adlan, A. M., Wagenmakers, A. J. M., Shaw, C. S. (2015). Low-volume high-intensity interval training in a gym setting improves cardio-metabolic and psychological health, DOI: 10.1371/journal.pone.0139056
Tabata, I., Nishimura, K., Kouzaki, M., Hirai, Y., Ogita, F., Miyachi, M., and Yamamoto, K. (1996). Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc, 28(10): 1327–30.
Tremblay, A. Simoneau, J. A. and Bouchard, C. (1994). Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism 43(7): 814–818.
Tschakert, G. and Hofmann, P. (2013). High-intensity intermittent exercise: methodological and physiological aspects, Int J Sports Physiol Perform, 8, 600-610.