HIGH INTENSITY INTERVAL TRAINING

High intensity interval training or HIIT is now a very popular way to exercise. Since the early 2000’s we have seen HIIT advertised in pretty much every gym around and sold as various types of fitness activities. However, if we look back at the history and creation of HIIT we see that this type of training method was mainly associated with cycling or running.

HIIT itself involves alternating bouts of both high and low intensity exercise to increase the amount of high intensity work performed. The low intensity, or rest periods, allow for buffering and clearing of lactic acid from the blood which then allows the individual to perform another bout of high intensity work. This type of training method is nothing new. For years, people have ran hills, done sprint training and also done traditional interval training in order to get that extra “oomph” from their training. But HIIT is different. It involves working extremely hard for an astonishingly short period of time, whilst gaining remarkably similar benefits as typical endurance training. We have seen some astonishing results with interval training at HIIT work. Some of this dates back to the early 1900’s. in the 1924 Olympic games Paavo Nurmi, a finish athlete, used interval training in his preparations leading into the games where he won several gold medals. In the 1930’s we saw the creation of fartlek training from Swedish coach Gosta Holmer. Fartlek was a different type of interval training but still had very similar principles in that it allowed individuals to work at higher intensities. In the 1970’s Sevastian Coe used interval training as part of his preparations. He would perform 200m runs with only a 30second rest before repeating. More recently, and probably the most famous protocol which really sold HIIT to the industry was the creation of tabata training in 1996 by professor Izumi Tabata. Originally performed on Olympic speed skaters. Tabata would have athletes working flat out (170% VO2 max) for 20seconds, followed by 10seconds rest. This was repeated for 4 minutes (8 rounds).

Some other common HIIT protocols include the following:

Gibala intervals

Developed in 2009 by Professor Martin Gibala and his team. 60 seconds of work (95% VO2max) followed by 75 seconds of rest, repeated 8-12 cycles

Burgomaster intervals

Developed in 2005 by Kirsten Burgomaster and a group of scientists. 30 seconds all out with 4 minutes of very easy recovery, repeated 4-7 times.

We know that HIIT has some fantastic benefits on both health and performance. Generally we see HIIT used for 1 or more of the following 3 reasons:

• Improved performance
• Improvements in body composition
• Health benefits

The fitness industry itself seems to be overwhelmingly based on body composition. For this reason, we will spend a little bit of time looking at how HIIT can help improve your body composition. HIIT has repeatedly shown results to have a greater impact on fat loss than traditional steady state exercise has. Some of the reasons for this are as follows:

• When using HIIT as an exercise protocol there is a greater use of lipids as a fuel source.
• Due to the huge amounts of lactic acid produced when performing HIIT we also see an increase in growth hormone output. This hormone will have huge impacts on changing body composition such as helping to remove excess body fat and build or maintain lean muscle tissue.
• HIIT has been shown to improve insulin sensitivity and glucose metabolism. A great factor for those who suffer with poor blood glucose profiles, such as diabetics or overweight individuals.
• HIIT also produces an extended EPOC (excess post oxygen consumption) profile, or more commonly known as the after burn. As an example lets look at the benefits of Tabata training on EPOC.
• Tabata takes you into EPOC (Excess Post Oxygen Consumption) which basically means after the 4 minutes is over your body will require additional oxygen to help you recover. This in turn will elevate the consumption of fuel and in particular the body’s fat stores. Tabata has been shown to elevate EPOC for upto 48 hours following a session. Who wouldn’t want to be burning additional fat for 48 hours from just a 4 minute workout?

HIIT has also demonstrated some fantastic health benefits. Recent studies have shown that when using HIIT protocols there have been improvements in lipid pofiles, reduced blood pressure and an improvement in overall myocardial function in patients suffering with cardiovascular disease. Type 2 diabetic patients and showed reductions in blood glucose along with increased mitochondrial activity and GLUT4 expression following 2 weeks of 3 x 20 min HIIT sessions per week. Using HIIT to help improve health has not only shown to be effective, but also safe. HIIT has been used effectively with no adverse reactions on some of the following patients.

• Type 2 diabetics
• Patients suffering from angina
• Patients suffering from heart failure
• Patients following myocardial infractions
• Post cardial stenting and coronary artery grafting

When creating HIIT sessions to include in either your own workouts or for clients, there are certain things e need to take into account to ensure the session is effective.

Pick a goal

Firstly, we must understand the goal of the session. Spend some time working out exactly what you want to achieve from the high intensity work.

Energy system demands

Once you have the goal you must decide which energy system you want to task. The relationship between duration, intensity and rest is very important to ensure you are sticking to the goal you set out to achieve.

Exercise selection.

When designing HIIT workouts avoid complex exercises. The idea is to get clients working at extremely high intensities. This will be difficult to achieve if you are asking them to perform exercises which require a high skill level. Stick with the simple exercises which involve multiple joints and large muscle groups to see the best results.

Frequency of training

ACSM recommend starting with 1 HIIT session per week for those that are new to this method. Following this aim to build up to 3-4 sessions per week to see maximal results in your training.