So much attention is given to “Tabata”, it has become synonymous with high intensity interval training (HIIT). There are many HIIT protocols that have more exciting results than Tabata training. This article will focus on HIIT protocols that showed to be effective in fat loss.
- Describe how HIIT research protocols measure reductions in fat.
- Relate the research training protocols for use with clients on the gym floor.
High intensity interval training can be described as exercise that has incomplete recovery, different work and rest ratios, and is physically & mentally demanding. It is fun, moves quickly, is creative, and can be applied in any situation.
Interval training has been used since 1912 when Finnish runner, Hannes Kolehmainen, used intervals at race pace to train for the 10,000-meter Olympic race (Billat, 2001). According to Billat (2001), interval training was first described in scientific journals by Reindell and Roskamm (1959) and Reindell et al., (1962).
Tabata et al., (1996) conducted a study to investigate if it was possible to decrease training volume and increase intensity. Dr. Tabata was asked to do the study by the coach of the Japanese speed skating team who wanted to use the results of the study to train his skaters. Tabata’s 20-seconds work/10-second rest for 4 minutes showed that V02max improved by 7 ml/kg/min and anaerobic capacity by 28%.
10 HIIT Protocols for Fat Loss
- Tremblay, Simoneau, and Bouchard (1994) compared medium intensity continuous training (MICT) to HIIT for fat loss and muscle metabolism. The MICT group did 20-weeks of endurance cycling 4 or 5 times per week for 30 to 45-minutes at an intensity of 60% - 85% of heart rate reserve. The HIIT group started by doing 25, 30-minute MICT sessions at 70% of heart rate reserve. Then they did 16-short and 19-long interval sessions over 15 weeks. The short intervals were 10 – 15/15 – 30 (work/rest) seconds and the long intervals were 4 - 5/60 - 90 (work/rest) seconds, both at an intensity of 60% - 70% of maximal work output. Recovery was a heart rate of 120-130.
The total energy expenditure for the MICT group was 28,757.04 kcals compared to the HIIT group at 13,829.17 kcals. The decrease in the sum of 6 skinfolds in the HIIT program was nine-fold greater than MICT group (MICT decrease, 79.2 – 74.7 mm [4.5 mm] and HIIT decrease 94.2 – 80.3 mm [13.9 mm]). There was a significant increase in enzymes promoting fat being used as energy for muscle contraction.
- Shepard, et al., (2015) investigated if the results of HIIT are the same in a real-world environment compared to a research setting. They used an instructor-led, group-based, gym setting HIIT compared to MICT. The HIIT protocol consisted of repeat sprints (15–60 seconds, >90% HR max with 45 – 120 seconds of active recovery) cycling 18 - 25 minutes/session, 3 sessions/week. The MICT cycling was 70% of HRmax 30–45 minutes/session, 5 sessions/week. The study lasted 10 weeks. Average weekly training time was HIIT = 55 mins and MICT = 128 mins.
The results indicate both groups improved or reduced: V02max, insulin sensitivity, feelings of energy, feelings of health perception, and reduced fat mass. High intensity interval training had the same results as MICT with 73 minutes less training time.
- Heydari, Freund, and Boutcher (2012) conducted a 12-week high intensity intermittent (HIIE) exercise program with young overweight males. There was an exercise and control group. The HIIE training was cycle sprinting for 8-seconds and 12-seconds active recovery for 20-minutes at 80–90% of peak heart rate.
Measurements included: aerobic power, total body fat, abdominal fat, trunk fat, visceral fat mass, and fat free mass. Results for HIIE included: aerobic power improved 15%, weight loss reduced 3.3 lbs, total fat mass reduced 4.4 lbs, abdominal fat reduced .22 lbs, trunk fat reduced 3.3 lbs, visceral fat reduced 17%, waist circumference decreased 3.5 cm by week six , fat free mass increased .88 lbs for the legs, and fat free mass increased 1.5 lbs for the trunk.
- Islam, Townsend, and Hazell (2017) had nine active men perform three different “all out” sprint interval training sessions: 1) 4 × 30-second intervals - 4-minute recovery, 2) 8 × 15-sec intervals - 120-second recovery, and 3) 24 × 5-second intervals - 40-second recovery. Each protocol was performed once. The researchers found the following results: exercise energy expenditure was greater with 24 × 5-second bouts - 40-second recovery, post-exercise energy expenditure was greater with 8 × 15-second - 120-seconds recovery, and post-exercise fat oxidation was similar with 8 × 15-sec bouts - 120-seconds recovery and 4 × 30-sec bouts - 4 min recovery. The researchers conclude shorter intervals increase exercise energy expenditure and longer intervals promote greater post-exercise fat use.
- Whyte, Gill, & Cathcart (2010) had 10 overweight/obese sedentary men as subjects. The subjects performed 2 weeks of HIIT, doing 6 sessions. The workout was 4 to 6, 30-second Wingate sprints with 4.5-minute recovery. The results show VO2max and Wingate power increased, insulin sensitivity and resting fat oxidation rate higher (24 hours post-workout), and systolic blood pressure, resting carbohydrate oxidation were lower (24 hours post-workout), and waist (-2.4 cm) and hip (-1.1 cm) circumferences decreased. The researchers conclude the results highlight the potential for HIIT to provide an alternative exercise option to MICT for improving vascular and metabolic health in an overweight/obese population.
- Little, et al. (2009) investigated the effects of a protocol of low-volume, high-intensity interval training on muscle mitochondrial capacity in muscle. They had seven men perform six training sessions consisting of 8-12, 60-second intervals at an intensity of 100% of peak power, with 75-seconds of active recovery between intervals. The results indicate HIIT increased exercise capacity on cycling time trials and increased muscle mitochondrial capacity. If a client increases mitochondria capacity, he or she will be able to exercise harder and longer and use more energy to burn more calories.
- Perry, et al, (2008) conducted a study by using untrained men and woman performing HIIT for 6-weeks, 3 days/week. The subjects did 10, 4 min intervals at 90% VO2 peak, with 2 min rest. The major adaptations during exercise included: reduced break down of glycogen (more fat being used), reduced lactate accumulation, increased fat oxidation at 60% of pre-training VO2 peak, training power output increased by 21 watts, and VO2 peak increased by 9%.
- Trapp, et al. (2008) investigated the effects of high-intensity intermittent exercise (HIIE) training on fat loss in young women. There were three groups: 1) HIIE, 2) steady-state exercise, or 3) control. The HIIE protocol consisted of 8-seconds of all out sprinting and 12-seconds of pedaling slowly for a maximum of 60 repeats a session equaling 20-minutes. Steady state exercise started with subjects exercising for 10-20 minutes at 60% V02peak, and the duration of the exercise was gradually increased to a maximum of 40-minutes per session. The results show both groups significant improved cardiovascular fitness. Only the HIIE group had a significant reduction in: total body mass, fat mass, trunk fat, and fasting plasma insulin levels.
- Zhang, et al., (2017), investigated the effect of HIIT and prolonged continuous exercise training on abdominal visceral fat in obese young women. The subjects were put into one of three groups: 1) HIIT, 2) MICT, or 3) no training control. The HIIT protocol was 4-minutes of cycling at 90% V̇O2max with 3-minutes of passive recovery, until 300 kilojoules of work were done. The MICT protocol was cycling at an intensity of 60% V̇O2max until 300 kilojoules of work was achieved. Results indicate that both groups had significant reductions in visceral fat evaluated in eight anatomical locations. The researchers point out the average weekly training time for the HIIT group was 33.87-minutes compared to 62.73-minutes for MICT, a difference of 28.87-minutes. The researchers conclude that due to it’s time efficiency, HIIT appears to be a predominant strategy for controlling or reversing obesity.
- Maillard, Pereira, and Boisseau (2018) conducted a meta-analysis to evaluate the effectiveness of HIIT in reducing total, abdominal, and visceral fat mass in normal-weight and overweight/obese adults. There is evidence showing running was more effective than cycling in reducing total and visceral fat mass. High-intensity (above 90% peak heart rate) training was more successful in reducing whole body adiposity, while lower intensities had a better effect on changes in abdominal and visceral fat mass.
As the research has shown, HIIT training has been an effective, time efficient approach in reducing body fat. Due to the nature of the different HIIT training protocols, it’s important for fitness professionals to qualify their client’s physical capabilities before implementing HIIT training into their training program to ensure the safety and effectiveness of the routine.
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