Defining Different Types of Interval Training: Do we need to use more specific terminology?
Interval training began gaining popularity in modern society throughout the mid 1900’s when track and field athletes started to incorporate them regularly into training programs. Soon after, Christensen, et al. published a study with a sample size of two concluding that “Research on intermittent work may open up a new field in work physiology”1 and in 1968 The Science of Swimming written by James Counsilman strongly advocated the use of sprints in training to optimize performance.2This new found interest had peaked the curiosity of exercise physiologists and as a result a number of studies in the 1970’s utilized higher intensity intervals as training protocols. The consensus was that training intensity was a powerful tool to induce significant positive adaptations.
HIIT programs that have resulted in positive adaptations utilized protocols that included intervals that were 1-4 min in duration, while beneficial SIT protocols have typically included 4-10 intervals lasting 20-30 sec in duration.7Acute responses to these protocols differ and each requires varying levels of aerobic and anaerobic contributions to energy production to complete the exercise. As a result, it is likely that unique levels of physiological stress result in some unique adaptations.
Both can improve aerobic, endurance and sprint capacity as well as markers of muscle metabolism and cardiovascular health in individuals of average fitness. However, training protocols that only last 2-3 weeks in duration have yielded different results. Following two weeks of training both HIIT and SIT appear to improve endurance capacity and markers of metabolism, but only HIIT has been observed to improve aerobic capacity.
Sport Exerc Med Open J. 2015; 1(5): 161- 163. doi: 10.17140/SEMOJ-1-124