Despite its popularity, High intensity interval training or HIIT certainly isn’t new. In fact, HIIT dates back to the 1920’s when pioneer track and field coaches were utilising this form of training with their 200 and 400 meter runners. Later, in the 1960’s a series of seminal experiments by legendary physiology researchers by the likes of “Hill” and “Astrand” helped us understand how the body reacts to this form of training. The growing list of or HIIT programs continue to emerge, many of us may start to feel confused as to which type of HIIT program should I choose for my client. Originally, HIIT programs were used to improve maximal aerobic performance or V02 Maximum in endurance trained athletes. Training at or near maximal intensities is thought to stress both central and peripheral (heart and muscle) responses necessary for maxima aerobic performance improvements. The reason HIIT evolved was to allow athletes to train at these maximal intensities for short periods of time, and with sufficient rest repeat this process to accumulate sufficient exposure to improve maximal aerobic performance. More recently, HIIT have also been used to improve:
- Fat loss
- Metabolic conditioning
- Muscular endurance and general physical conditioning
- Insulin sensitivity
- Vascular health
For functional training instructors, HIIT offers a time efficient way to improve multiple health and performance outcomes in a compatible format. To date, most research suggests both cycling and running forms of HITT are most effective, however that is not to say other forms of HITT, such as HIIT performed as part of a functional training circuit cannot be equally effective. For example, in a recent study, researchers from the Kennesaw State University, reported a significant improvement in several health and performance measures including strength, metabolic conditioning and body composition following 16-weeks of “High Intensity Functional Training” two-times per week. If we compare the results obtained in this study, with the current recommendations for resistance training which states, individuals should train the entire body 2-3 days per week, in conjunction with 150 mins per week of moderate intensity aerobic exercise, its clear HIIT offers a time-efficient benefit for general health improvement, particularly when integrated with a functional exercise training program.
Importantly, the way you prescribe a HIIT session can have a widely different effect on both health and performance outcomes. Therefore, careful attention must be paid to the acute training variables (interval ratio, total length of the session etc) to maximise the benefits of this type of training. Over the next few weeks, we will look at the different types of HIIT, sprint interval training and metabolic conditioning programs and how they can be integrated with a functional training program to maximise your clients’ health and physical performance.