HIIT - High Intensity Interval Training

HIIT - A Smarter Way to Train

Alex Rabindranath

October, 2013

High Intensity Interval Training (HIIT) has been a hot topic of interest in fitness and physical activity in the last decade, being used and examined by professional athletes, recreational exercisers, and in clinical research. HIIT workouts consist of high intensity workloads (> 85% VO2Max – the maximal rate at which one’s aerobic systems can uptake and utilize oxygen effectively during exercise), done for a short duration (30 sec – 4mins), interspersed with recovery times in-between sets (Work:Rest ratios usually 1:1, 1:2 or 2:1). HIIT has been consistently shown to have similar, if not better, physical health benefits and improvements in performance when compared to traditional continuous endurance exercise (long runs, jogs, bike rides etc.) with a lower total volume of work done. In other words, HIIT programs allow for a shorter total workout time and volume, while producing similar or superior results to moderate intensity, long duration exercises (See charts below for HIIT benefits and a comparison to continuous endurance exercise – Zuhl & Kravitz, 2012).

Lack of time is a major barrier for most of the population when it comes to exercising and being physically active, as we all have many other responsibilities and commitments in our lives (school, work, family, friends, relaxing etc.). HIIT workouts can be a great asset when time constraints are present as athletic performance and many health benefits can all be achieved in a short period of time. Especially if your goals incorporate increasing your cardiorespiratory capacity (VO2Max), improving your body composition, or improving athletic performance, HIIT is definitely the way you’ll get the most ‘bang for your buck’.

In addition to these time saving and health related benefits, HIIT has also been shown to induce post-exercise oxygen consumption (EPOC), and to a greater degree than continuous endurance exercise (LaForgia, Winters, & Gore, 2006). Since HIIT consists of high intensity exercise, you will be using your anaerobic systems to provide energy during sets, which brings the body into a state of ‘oxygen debt’. Throughout the day after your workout, you will be burning more calories as your metabolism is increased to pay back this debt and to oxidize other by-products of using the anaerobic systems for energy, like lactic acid. So on top of the calories you will burn during your HIIT workout, you will also continue to burn calories afterwards for as long as 24-48 hours.

Many studies have shown that there is a marked increase in VO2Max, skeletal muscle oxidative capacity, and other athletic performance markers (higher vertical jump, faster 10m sprints etc.) from engaging in HIIT programs that last as little as 2-3 weeks (Acton-Jacobs et al., 2013; Bogdanis et al., 2013; Buchan et al., 2013; Tjonna et al., 2013). A recent study by Tjonna et al. (2013) found that an experimental group who participated in only one set of HIIT (one 4 minute set at 90% VO2Max, three sets/week for 10 weeks) showed similar improvements in weight loss and increased VO2Max to those who participated in more sets of the same HIIT protocol. This suggests that even engaging in minimal amounts of HIIT can be effective in improving cardiorespiratory fitness and overall health. Additionally, single sessions of HIIT have also been shown to increase transcription and biogenesis of mitochondria in skeletal muscle cells, even in highly trained athletes (Acton-Jacobs et al., 2013).

The majority of studies also show that HIIT is an excellent way to increase mitochondrial density and biogenesis in muscles, which also results in increased oxidative capacity (Acton-Jacobs et al., 2013; Boyd et al., 2013). Mitochondria are the ‘power-houses’ of cells and if their numbers are increased, more ATP (energy) can be synthesized and utilized by muscles. Simplified, this means that by increasing your mitochondrial content and oxidative capacity in skeletal muscles, you will be able to utilize oxygen more effectively and be able to work for longer at higher intensities, before having to rely on the anaerobic systems to provide energy. This is also known as increasing your anaerobic or lactic threshold.

As it is agreed upon that HIIT is one of the most effective ways to increase VO2Max, skeletal muscle oxidative capacity, and athletic performance, it is also agreed that performing workloads at higher/highest possible intensities results in the most robust improvements. The best benefits are usually obtained when working at 90% VO2Max or higher. Some sources propose that supramaximal intensities (>100%VO2Max) may be even more effective at improving aerobic and sprinting performance (Cicioni-Kolsky et al., 2013). In a review on HIIT, Buchhat & Laursen (2013) suggest that maximal/close to maximal intensities, as used in HIIT, are most effective at increasing aerobic capacity (VO2Max) because they stress the oxygen transport system the most, activate more and larger motor units of muscle fibers, and are performed at near maximal cardiac output. Moholdt et al. (2013) also report that regardless of frequency, duration, program length, and initial fitness levels, working at 100% VO2Max during HIIT programs increased VO2Max the most compared to other intensities. While there is evidence that there are still benefits seen from HIIT if used at lower intensities (Boyd et al., 2013), the best and most profound benefits are achieved at higher intensities (Acton-Jacobs et al., 2013; Boyd et al., 2013; Buchhat & Laursen, 2013; Cicioni-Kolsky et al., 2013; Moholdt et al., 2013).

Another great feature of HIIT is that it can be utilized by pretty much anyone, and at any fitness level. Both clinical and healthy populations have shown beneficial results from engaging in HIIT programs, aiding individuals with cardiovascular disease, obese and overweight individuals, and even seniors 75+ years old (Boyd et al., 2013, Moholdt et al., 2013). The feasibility of implementing HIIT in these clinical populations, healthy individuals, and high performance athletes, shows how diverse and beneficial this type of exercise can be. So if you’re lacking time to get a ‘full’ workout in, or are tired of running on the treadmill for hours and hours, give HIIT a try, and you should see the same, if not better results from a much shorter workout.

If you want to try a HIIT class out for FREE with me, I run them at Tait Mckenzie, York University. Click here for more details. The group cycling classes I teach also incorporate HIIT throughout and are an excellent high-energy workout. If you want to sign up for these classes or want more information, click here.




Acton-Jacobs, R., Fluck, D., Bonne, T.C., Burgi, S., Christensen, P.M., Toigo, M., Lundby, C. (2013). Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function. Journal of Applied Physiology, doi:10.1152/japplphysiol.00445.2013

Bogdinas, G.C., Stavrinou, P., Fatouros, I.G., Philippou, A., Chatzinikolaou, A., Draganidis, D., Ermidis, G., & Maridaki, M. (2013). Short-term high-intensity interval exercise training attenuates oxidative stress responses and improves antioxidant status in health humans. Food and Chemical Toxicology, doi.org/10.1016/j.fct.2013.05.046.

Buchan, D.S., Ollis, S., Young, J.D., Cooper, S.M., Shield, J.P.H., & Baker, J.S. (2013). High intensity interval running enhances measures of physical fitness but not metabolic measures of cardiovascular disease risk in health adolescents. BMC Public Health, 13, 498-510.

Buchheit, M., & Laursen, P.B. (2013). High-intensity interval training, solutions to the programming puzzle. Part 1: Cardiopulmonary Emphasis. Sports Medicine, 43, 313-338.

Buchheit, M., & Laursen, P.B. (2013). High-intensity interval training, solutions to the programming puzzle. Part 2: Anaerobic energy, neuromuscluar load, and practical applications. Sports Medicine, doi 10.1007/s40279-013-0066-5. 

Burgomaster, K.A., et al. (2008). Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. Journal of Physiology, 586 (1), 151-160.

Boyd, C.J., Simpson, C.A., Jung, M.E., & Gurd, B.J. (2013). Reducing the intensity of interval training diminishes cardiovascular adaptation bot not mitochondrial biogenesis in overweight/obese men. PloS ONE, 8(7), e68091. doi:10.1371/journal.pone.0068091

Cicioni-Kolsky, D., Lorenzen, C., Williams, M.D., & Kemp, J.G. (2013). Endurance and sprint benefits of high-intensity and supramaximal interval training. European Journal of Sport Science, 13(3), 304-311. 

Daussin, F.N., et al. (2008). Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 295, 264-272.

Faud, O., Schnettker, R., Schulte-Zurhausen, R., Muller, F., & Meyer, T. (2013). High intensity interval training vs. high-volume running training during pre-season conditioning in high-level youth football: A cross-over trial. Journal of Sports Sciences, doi: 10.1080/02640414.2013.792953.

Helgerud, J., et al. (2007). Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine and Science in Sports and Exercise, 39(4), 665-671.

Horowitz, J.F., & Klein, S. (2000). Lipid metabolism during endurance exercise. American Journal of Clinical Nutrition, 72, 558-563.

LaForgia, J., Withers, R.T., & Gore, C.J. (2006). Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. Journal of Sports Science, 24(12), 1247-1264.

MacDougall, J.D., et al. (1998). Muscle performance and enzymatic adaptations to sprint interval training. Journal of Applied Physiology, 84(6), 2138-2142.

Moholdt, T., Madssen, E., Rognmo, O., & Aamot, I.L. (2013). The higher the better? Interval training intensity in coronary heart disease. Journal of Science and Medicine in Sport, doi.org/10.1016/j.jsams.2013.07.007

Perry, C.G., et al. (2008). High-intensity aerobic interval training increases fat and carbohydrate metabolic capacities in human skeletal muscle. Applied Physiology, Nutrition, and Metabolism, 33(6), 1112-1123.

Talanian, J.L., et al. (2007). Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. Journal of Applied Physiology, 102(4), 1439-1447.

Tjonna, A.E., Leinan, I.M., Bartnes, A.T., Jennsen, B.M., Bibala, M.J., Winett, R.A., & Wisloff, U. (2013). Low- and high-volume of intensive endurance training significantly improves maximal oxygen uptake after 10-weeks of training in healthy men. PloS ONE, 8(5): e65382. doi:10.1371/journal.pone.0065382.

Slørdahl, S.A., et al. (2004). Atrioventricular plane displacement in untrained and trained females. Medicine & Science in Sports & Exercise, 36(11), 1871-1875.

Sloth, M., Sloth, D., Overgaard, K., & Dalgas, U. (2013). Effects of sprint interval training on VO2max and aerobic exercise performance: A systematic review and meta-analysis. Scandinavian Journal of Medicine & Science in Sports, doi: 10.1111/sms.12092.

Zuhl, M. & Kravitz, L. (2012). HITT vs. continuous endurance training: Battle of the aerobic titans, IDEA Fitness Journal, 9(2).

Exercise 2 - 3 Point Hip Abduction With a Theraband

Alex Rabindranath

April, 2013

3-Point Hip Abduction With a Thera-band

Mobility and strength at the hip joint is essential for almost all sports, and in any activity that involves running, jumping, and quick accelerations. The specific motion of hip abduction; extending the upper and lower leg out laterally from the midline of the body, is especially important in sports. Hockey, which uses hip abduction and extension to push into and off from the ice, and soccer, which requires significant hip strength and coordination to kick, change directions, and control the ball successfully, are great examples of this (Thorborg et al., 2011).

In addition to the requirements of hip abductor strength for sport specific movements, they are also crucial in injury prevention. Individuals with chronic ankle instability (CAI) have been shown to have weaker gluteus maximus and gluteus medius musculature in the effected limb (Webster & Gribble, 2013). This imbalance in gluteal strength is hypothesized to lead to improper foot and ankle positioning, predisposing the individual to greater risk of future or repeated ankle injury (Webster & Gribble, 2013). Strengthening the hip abductors and external rotator muscles has been shown to alter the lower leg joint loading, which can reduce the risk of injury and shows the value of hip strengthening exercises in both rehabilitation and prevention of lower extremity injuries (Snyder et al., 2009).

Bilateral discrepancies in hip strength in soccer players have often been noted to be a hypothesized causal factor in groin injuries (Thorborg et al., 2011). Dominant-leg hip adductor strength has been shown to be higher than non-dominant leg adductor strength in soccer players, which can lead to imbalances that predispose them to injury (Thorborg et al., 2011). If one thinks to the primary motions involved in ball control and ball striking, it is clearly evident that hip musculature plays a crucial role in game play and success. Exercises like the 3-point hip abduction with a thera-band can be a great addition to training and rehab regiments as it focuses on improving hip abduction strength in multiple ranges of motion and can also increases stability in hip, knee and ankle of the planted leg. 

Evidence linking reduced hip abduction and external rotation to sacroiliac joint pain is another concern which makes exercises that increase hip mobility and strength a must have in any rehabilitation program (Bussey, Bell & Milosavljevic, 2009).  Exercises like the 3-point hip abduction may also have great potential for use in Eastern cultures, where kneeling and cross-legged sitting are required in everyday activities (Kapoor et al., 2008). Also, knee and hip arthroplasty patients are of great concern when considering daily activities and adequate hip and knee movement capabilities, and exercises that strengthen these muscles and joints are crucial for successful rehabilitation (Kapoor et al., 2009).

Whether looking for improvements in performance, aiding in rehab, or trying to prevent common injuries, hip strengthening exercises like the 3-point hip abduction are a great supplement to any program. Combing this exercise with other great hip and gluteal exercises like hip thrusts and glute bridges can be a great way to get an edge on your competition. In addition this exercises can be tailored specifically to specific sports; for example focusing primarily on the ‘out and back’ abduction position seen in Figure 1.2 and Figure 2, is a great way to improve hockey stride strength. The exercises can even be combined with sport specific drills, such as controlling a soccer ball in the same planes of motion as seen in the exercise (Figures 1.2 - 1.4).


Proper Form

The 3-point hip abduction exercise is done with a thera-band wrapped around both feet in line with your baby toes. Starting in a ready position (Figure 1.1) the next steps are to abduct one leg to 3 different points; out and back (Figure 1.2), out to the side (Figure 1.3), and out and forward (Figure 1.4). In the ready position you want to have your butt sticking out slightly in an anterior pelvic tilt, and have a slight bend in the knees. Try to keep you waist as flat as possible when abducting to the 3 different positions. Bring your leg out as far as possible to these positions and make sure the abduction is coming from the hip.

You also want to make sure that the planted leg stays balanced and stable while the active leg is abducting. Keep the slight bend in the knee in the planted leg and try to maintain its position over your baby toe. This will help to increase stability and balance in the non-active leg while making sure that your glutes are activated. Keeping your waist as flat as possible throughout the exercise will also promote this.

Figure 2 - Hockey Stride  (Adapted from www.hockeytutorial.com)

Figure 2 - Hockey Stride (Adapted from www.hockeytutorial.com)



Bussey, M.D., Bell, M.L. & Milosavljevic, S. (2009). The influence of hip abduction and external rotation on sacroiliac motion. Manual Therapy, 14, 520-525.


Kapoor, A., Mishra, S.K., Dewangan, S.K. & Mody, B.S. (2008). Range of movements of lower limb joints in cross-legged sitting posture. The Journal of Arthroplasty, 23(3), 451-453.


Snyder, K.R., Earl, J.E., O’Connor, K.M. & Ebersole, K.T. (2009) Resistance training is accompanied by increases in hip strength and changes in lower extremity biomechanics during running.  Clinical Biomechanics, 24, 26-34.


Thorborg, K., Couppe, C., Petersen, J., Magnuson, S.P. & Holmich, P. (2011). Eccentric hip adduction and abduction strength in elite soccer layers and matched controls: A cross-sectional study. British Journal of Sport Medicine, 45, 10-13.


Thorborg, K., Semer, A., Petersen, J., Madsen, T.M., Magnusson, P. & Holmich, P. (2011). Hip Adduction and Abduction strength profiles in elite soccer players. The American Journal of Sports Medicine, 39(1), 121-126.


Webster, K.A. & Gribble, P.A. (2013). A comparison of electromyopraphy of gluteus medius and maximus with and without chronic ankle instability during two functional exercises. Physical Therapy in Sport, 14, 17-22.

Exercise 1 - Deep Squats

Alex Rabindranath

March, 2013

Deep Squats

     The deep squat is a great exercise that incorporates all of the major leg muscles and is beneficial in both rehab and sport specific exercise regiments. Ankle dorsi flexors and plantar flexors, knee extensors and flexors, and hip extensors and flexors are all engaged at different stages of the deep squat (Robertson et al., 2008). The involvement of all the lower extremity musculature and joints makes the deep squat a perfect exercise to train or restore functional movements in the legs. Deep squats have been shown to increase dynamic speed-strength and dynamic maximal strength (Hartman et al., 2012), as well as improvements in high velocity movements, which are integral to activities that involve running and jumping (Drinkwater, Moore & Bird, 2012).

Deep squats can also be modified to focus on strengthening specific muscles, making it an ideal exercise for many training and rehab programs. Bryanton et al. (2012) have showed that the hip extensor, knee extensor and ankle plantar flexor musculature can all be specifically engaged, and can therefore be specifically trained, by modifying squat load and depth. Knee extensors are activated more by increasing squat depth, the ankle plantar flexors are engaged most at heavier weight loads, and the hip extensors are stimulated most by increasing both squat depth and load (Bryanton et al., 2012). These variations in muscle activity can help practitioners and trainers make rehab or sport specific modifications to the deep squat exercise in order to isolate muscles and maximize efficacy of training.

When compared to partial range of motion squats, the deep squat is much better for general strength training due to its functional aspects (Hartman et al., 2012). Training regiments and recreational weight training programs have often used partial range of motion squats with heavy loads in order to achieve their desired results, but these methods have been proven inferior in many aspects (Hartman et al., 2012, Drinkwater, Moore & Bird, 2012).

 Only at the ranges of motion and joint positions achieved in deep squats are the neural and morphological requirements met to stimulate positive acceleration from hip and knee extensors (Hartman et al., 2012). Sets of partial range of motion squats were deemed to be useless in comparison to full range of motion squats because of their inferiority in maximizing force, velocity, work, and power (Drinkwater, Moore & Bird, 2012). From an injury prevention perspective, deep squats have a lower risk of injury compared to partial range of motion squats, due to the deeper joint positions achieved when performed properly and the lower weights being used (Hartman et al., 2012). The ability to achieve greater velocities and speed-strength performance while using lower weights results in a lower risk of injury because there are less tensile forces created at the knee and less compressive and shearing forces created at the thoracic spine (Hartman et al., 2012).

Clearly deep squats are the superior choice in comparison to partial range of motion squats. The benefits of engaging all the lower extremity musculature, creating sport-specific increases in strength and velocity, increasing functional movements, and being modifiable to isolate certain muscles make deep squats a highly transferable and valuable exercise. Whether being used with high-level athletes, rehab patients, or recreational exercisers, the deep squat is an exercise that can be tailored to meet many training goals.

Deep Squat Proper Form

  Figure 1   

 Figure 1 

The deep squat takes the same form as any squat, but entails the hips dipping below parallel to the knees and even as low as the ground. The inside of your feet should be shoulder width apart throughout and your arms should be above your head, keeping your mid-arm in line with your ears. Holding a dowel, stick or other long straight object (golf club, hockey stick etc) is helpful to keep proper form. Make sure your knees are positioned approximately above your baby toes and that they do not go out in front your toes during the exercise. Ensure that your knees stay out (lateral) above your baby toes and do not let them move inward (medial) during the squatting motion. Maintain a good arch in your feet while having your weight focused on your heels, and specifically the outside of the heels.

  Figure 2

 Figure 2

Start the deep squat in an athletic position and then make a sitting back motion as opposed to a sitting down motion. Squat down until your thighs are just below parallel but continue further down if you can (Figure 1). Keep a neutral lumbar arch when squatting down and keep your hands above your head. When pushing up to stand back up from the deep squat make sure to keep all the proper aspects of form mentioned above and push into the ground through your heels.


Bryanton, M.A., Kennedy, M.D., Carey, J.P. & Chiu, L.Z.F. (2012) Effect of squat depth and barbell load on relative muscular effort in squatting. The Journal of Strength and Conditioning Research, 26(10), 2820–2828.

Drinkwater, E.J., Moore, N.R. & Bird, S.P. (2012). Effects of changing from full range of motion to partial range of motion on squat kinetics. The Journal of Strength and Conditioning Research, 26(4), 890-896.

Hartmann, H., Wirth, K., Klusemann, M., Dalic, J., Matuschek, C., & Schmidtbleicher, D. (2012) Influence of squatting depth on jumping performance. The Journal of Strength and Conditioning Research 26(12), 3243– 3261.

Robertson, D.G.E., Wilson, J.M.J. & St. Peirre, T.A. (2008). Lower extremity muscle function during full squats. Journal of Applied Biomechanics, 24, 333-339.

Saez Saez De Villarreal, E., Izquierdo, M. & Gonzalez-Badillo, J.J. (2011). Enhancing jump power after combined vs. maximal power, heavy-resistance, and plyometric training alone. The Journal of Strength and Conditioning Research, 25(12), 3274-3281.