HIIT training is an interval training that consists of 20 minutes or less of High Intensity Interval training. HIIT training consists of exercises using major muscle groups, compound movement and high Intensity training.
This work out will be high energy, fast moving and will work you towards achieving greater cardiovascular endurance, agility, and flexibility. The work out regiment can be modified for those unable to preform certain movements.
The main focus with HIIT training is that you are working at near level of intensity in short bursts of 20 seconds intervals preformed to failure and resting for 10 seconds in between. There are many different exercises that will be utilized, although many of the exercises are as simple as jumping rope, mountain climbers, push ups, and plyometric jumping exercises.
There are a few main points as to why HIIT training is superior in many ways to regular cardiovascular training:
EPOC- Excess Post Oxygen Consumption- amount of oxygen consumed by the body after exercise is completed. Research has shown this accelerates weight loss. EPOC consumes oxygen at an elevated rate, as well as expends energy at an elevated rate, by the following methods:
- Replenishment for the immediate source of energy known as the phosphate system. The body is also restoring the muscle glycogen that was consumed during the exercise
- The body continues to expend energy post-exercise to re-oxygenate the blood. Also during post exercise, the body restores levels of circulatory hormones to normal.
- During EPOC, the body expends energy to cool off after exercise.
- Energy is consumed at an elevated rate to return the body to a normal breathing & heart Rate.
Evidence Suggests that high intensity interval resistence training has a more prounounced effect on EPOC levels than simliar types of aerobic training. Additionally, current research indicates that as resistence intensity increases, the EPOC duration also increases. In a 2011 study, one 6- minute workout bout produced 5 times the calorie burn after the workout was over. The calories burned during the 6 minute workout were 50 calories and the metabolism remained elevated for 24 hours burning and additional 250 calories. This total of 300 calories is comparable to what people typically burn during 30 minutes of steady state exercise.
High-intensity interval training can describe an exercise session composed entirely of HIIT techniques, or as a component of an exercise plan. HIIT exercise sessions generally consist of a warm up period, then several repetitions of high intensity exercise separated by medium intensity exercise for recovery, then a cool down period. The high intensity exercise should be done at near maximum intensity. The medium exercise should be about 50% intensity. The number of repetitions and length of each depends on the exercise, but may be as little as three repetitions with just 20 seconds of intense exercise. The specific exercises performed during the high-intensity portions vary.
There is no specific formula to HIIT. Depending on one's level of cardiovascular development, the moderate-level intensity can be as slow as walking. A common formula involves a 2:1 ratio of work to recovery periods, for example, 30–40 seconds of hard sprinting alternated with 15–20 seconds of jogging or walking.
The entire HIIT session may last between four and thirty minutes, meaning that it is considered to be an excellent way to maximize a workout that is limited on time. Use of a clock or timer is recommended to keep accurate times, number of rounds and intensity.
Peter Coe regimenA type of high-intensity interval training with short recovery periods was used in the 1970s by the athletics coach Peter Coe when setting sessions for his son Sebastian Coe. Inspired by the principles propounded by the German coach and university professor Woldemar Gerschler and the Swedish physiologist Per-Olof Åstrand, Coe set sessions involving repeated fast 200 metre runs with only 30 seconds recovery between each fast run.
Tabata regimenA version of HIIT was based on a 1996 study by Professor Izumi Tabata (田畑泉) et al. initially involving Olympic speedskaters. The study used 20 seconds of ultra-intense exercise (at an intensity of about 170% of VO2max) followed by 10 seconds of rest, repeated continuously for 4 minutes (8 cycles). The exercise was performed on a mechanically braked cycle ergometer. Tabata called this the IE1 protocol. In the original study, athletes using this method trained 4 times per week, plus another day of steady-state training, and obtained gains similar to a group of athletes who did steady state training (70% VO2max) 5 times per week. The steady state group had a higher VO2max at the end (from 52 to 57 mL/(kg•min)), but the Tabata group had started lower and gained more overall (from 48 to 55 mL/(kg•min)). Also, only the Tabata group had gained anaerobic capacity benefits. It is important to note that in the original study from 1996, participants were disqualified if they could not keep a steady cycling pace of 85RPM for the full 20 seconds of work. Implications for popular exercise regimes that advertise as Tabata training should include overall analysis of the original study.
Gibala regimenProfessor Martin Gibala and his team at McMaster University in Canada have been researching high-intensity exercise for several years. Their 2009 study on students uses 3 minutes for warming up, then 60 seconds of intense exercise (at 95% of VO2max) followed by 75 seconds of rest, repeated for 8–12 cycles (sometimes referred to as "The Little Method"). Subjects using this method trained 3 times per week obtained gains similar to what would be expected from subjects who did steady state (50–70% VO2max) training five times per week. While still a demanding form of training, this exercise protocol could be used by the general public with nothing more than an average exercise bike.
Gibala's group published a less intense version of their regimen in a 2011 paper in Medicine & Science in Sports & Exercise. This was intended as a gentler option for sedentary people who had done no exercise for over a year. It included 3 minutes of warm-up, 10 repetitions of 60-second bursts at 60% peak power (80- 95% of heart rate reserve) each followed by 60 seconds of recovery, and then a 5-minute cool-down.
Timmons regimenJamie Timmons, professor of systems biology at the University of Loughborough, is a proponent of a few short bursts of flat-out intensity. In a BBC Horizon programme in February 2012, he put Michael Mosley on an exercise bike regimen consisting of three sets of about 2 minutes of gentle pedalling followed by 20 second bursts of cycling at maximum effort. This was done three times a week for a total of 21 minutes of exercise per week (3 minutes of intense exercise), plus warm-up and recovery time. Measurable health benefits were reported, including significantly improved insulin sensitivity.
Aerobic benefitsStudies by Tabata, Tremblay and others have explored the effectiveness of this method compared to traditional endurance training methods. A 2008 study by Gibala et al.demonstrated 2.5 hours of sprint interval training produced similar biochemical muscle changes to 10.5 hours of endurance training and similar endurance performance benefits. According to a study by King, HIIT increases the resting metabolic rate (RMR) for the following 24 hours due to excess post-exercise oxygen consumption, and may improve maximal oxygen consumption (VO2 max) more effectively than doing only traditional, long aerobic workouts. Tabata's 1997 study concluded that "intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally." Around 20% of participants in Timmons' 2010 study showed less than 5% improvement in aerobic capacity. Conversely, about 20% of participants were described as "high-responders". A complex mixture of genes are involved, but differences in 11 single-nucleotide polymorphisms alone could predict 23% of the total variance in VO2max. Timmons was able to demonstrate that about half of the responsiveness of aerobic capacity to HIIT was genetically determined.
High-intensity interval training has also been shown to improve athletic performance. For already well-trained athletes, improvements in performance become difficult to attain; increases in training volume may yield no improvements. Previous research would suggest that, for athletes who are already well-trained, improvements in endurance performance can be achieved through high-intensity interval training. A 2009 study by Driller and co-workers showed an 8.2 second improvement in 2000m rowing time following 4 weeks of HIIT in well-trained rowers. This equates to a significant 2% improvement after just 7 interval-training sessions. The interval-training used by Driller and colleagues involved eight 2.5 minute work bouts at 90% of vVO2max, separated by individualized recovery intervals.
Metabolic benefitsLong aerobic workouts have been promoted as the best method to reduce fat, as it is popularly believed that fatty acid utilization usually occurs after at least 30 minutes of training. HIIT is somewhatcounterintuitive in this regard, but has nonetheless been shown to burn fat more effectively. There may be a number of factors that contribute to this, including an increase in resting metabolic rate. HIIT also significantly lowers insulin resistance and causes skeletal muscle adaptations that result in enhanced skeletal muscle fat oxidation and improved glucose tolerance.
Timmons' group showed that two weeks of HIIT can substantially improve insulin action in young healthy men.  Gibala's group reported a 35% increase in both insulin sensitivity and muscle oxidative capacity among seven sedentary people after two weeks on the lower-intensity regimen outlined above. Timmons believes that this response is because HIIT uses 80% of muscles in the body, compared to 40% for gentle jogging and cycling. In young women, HIIT three times per week for 15 weeks compared to the same frequency of steady state exercise (SSE) was associated with significant reductions in total body fat, subcutaneous leg and trunk fat and insulin resistance.
Cardiovascular diseaseA 2011 study by Buchan et al. assessing the effect of HIIT on cardiovascular disease markers in adolescents reported that "brief, intense exercise is a time efficient means for improving CVD risk factors in adolescents". A meta-analysis by Weston et al. (2013) has identified that HIIT has more physiological benefits than moderate intensity continuous training (MICT) in patients with lifestyle-induced chronic disease. Indeed, the improvements in cardiorespiratory fitness after HIIT are almost double that of MICT.