High Intensty Interval Training (HIIT) or high intensity interval training is marked by repeated relatively short session, intermittent exercise, often done with "all out" effort or at an intensity close to what gave rise to the peak oxygen uptake (ie, ≥ 90% of VO2max). In the research journal expressed high intensity exercise has been suggested for aerobic and cardiovascular adaptation gain is greater than the low and medium levels of exercise (Gibala, 2007). High intensty interval training, especially running intervals training, which usually consists of a reduction of running an "all out", resulting in an increase in muscle oxidative enzymes. ie, the maximum increase in citrate synthase activity and pyruvate dehydrogenase (PDH) activity. In a relatively short time (ie, 1-2 weeks) (6-8, 18) (Gibala, 2006).
Although there is not any universal definition, HIIT generally refers to repeated intermittent exercise sessions are relatively short, often done with 'all-out' effort or at an intensity close to what gave rise to VO2max (ie, 90% of VO2peak). Depending on the intensity of training, a single effort may last from a few seconds to several minutes, with some effort separated by a few minutes of rest or low intensity exercise. In contrast to strength training short intense efforts are usually made to the resistance weight to increase skeletal muscle mass, HIIT is usually associated with activities such as cycling or walking and do not cause hypertrophy (Gibala, 2007).
High intensity interval training (HIIT) has been shown to improve performance in a relatively short training period (Sperlich, 2010). Ancient (2012), showed that high-intensity training and endurance exercise continuously bring significant improvements in body composition, aerobic power and heart rate to less than 2 hours 30 min training weekly. In addition, high intensity training proved to be more effective in improving oxygen maximal capacity.
The physiological benefits can be achieved in a short time and with little total energy expenditure during exercise (ie training volume) of training endurance training, however, some evidence suggests it is more pleasant than ET, HIIT is usually closely related to the maximum intensity or supramaximal intensity.
This intensity is a potential threat to the adoption by the general public as HIIT high intensity training is usually associated with individuals who have overweight there is a feeling of fear and just do light exercise activity or low volume. Security protocols for training with higher intensity (ie, supramaximal intervals) for populations with risk of cardiovascular disease (Boy, et.al. 2013).