Can We Draw General Conclusions from Interval Training Studies?

Abstract

Interval training (IT) has been used for many decades with the purpose of increasing performance and promoting health benefits while demanding a relatively small amount of time. IT can be defined as intermittent periods of intense exercise separated by periods of recovery and has been divided into high-intensity interval training (HIIT), sprint interval training (SIT), and repeated sprint training (RST). IT use has resulted in the publication of many studies and many of them with conflicting results and positions. The aim of this article was to move forward and understand the studies' protocols in order to draw accurate conclusions, as well as to avoid previous mistakes and effectively reproduce previous protocols. When analyzing the literature, we found many inconsistencies, such as the controversial concept of 'supramaximal' effort, a misunderstanding with regard to the term 'high intensity,' and the use of different strategies to control intensity. The adequate definition and interpretation of training intensity seems to be vital, since the results of IT are largely dependent on it. These observations are only a few examples of the complexity involved in IT prescription, and are discussed to illustrate some problems with the current literature regarding IT. Therefore, it is our opinion that it is not possible to draw general conclusions about IT without considering all variables used in IT prescription, such as exercise modality, intensity, effort and rest times, and participants' characteristics. In order to help guide researchers and health professionals in their practices it is important that experimental studies report their methods in as much detail as possible and future reviews and meta-analyses should critically discuss the articles included in the light of their methods to avoid inappropriate generalizations.

Is interval training the magic bullet for fat loss? A systematic review and meta-analysis comparing moderate-intensity continuous training with high-intensity interval training (HIIT)

“…This may be due to greater resting energy expenditure and fat utilisation immediately following interval training exercise 25 26. However, there are currently many different approaches to performing interval training,27 and there is still no consensus as to which training method (HIIT/SIT vs MOD) is best to reduce body fat. The considerable variability among interval training protocols,27 compared with fairly homogeneous MOD protocols, introduce ‘noise’ in the literature.…”

“…However, there are currently many different approaches to performing interval training,27 and there is still no consensus as to which training method (HIIT/SIT vs MOD) is best to reduce body fat. The considerable variability among interval training protocols,27 compared with fairly homogeneous MOD protocols, introduce ‘noise’ in the literature. No study has yet addressed the simple question: Which type of exercise is better for weight loss?…”

Mechanistic and methodological perspectives on the impact of intense interval training on post‐exercise metabolism

“…A significant source of inconsistency is the heterogeneity between exercise protocols used to examine characteristics of the EPOC response. Unlike MICT, which involves a submaximal bout of exercise at an easily verified intensity that can be standardized across individuals, HIIT and SIT are infinitely variable in terms of the number, intensity, and duration of the work bouts, as well as the work‐to‐rest ratio . Large variability exists within the thirteen studies examining EPOC following HIIT (Tables and ), as three studies utilized the ten‐by‐one protocol (10 × 1 minute at ~90% HR max with 1 minutes rest or recovery periods), and the remaining ten involved other variations of near‐maximal exercise bouts separated with varying amounts of rest or recovery, though notably at similar intensities.…”

“…Unlike MICT, which involves a submaximal bout of exercise at an easily verified intensity that can be standardized across individuals, HIIT and SIT are infinitely variable in terms of the number, intensity, and duration of the work bouts, as well as the work-to-rest ratio. 85 Large variability exists within the thirteen studies examining EPOC following HIIT (Tables 1 and 2), as three studies utilized the ten-by-one protocol (10 × 1 minute at ~90% HR max with 1 minutes rest or recovery periods), and the remaining ten involved other variations of near-maximal exercise bouts separated with varying amounts of rest or recovery, though notably at similar intensities. With respect to SIT, the most consistently used protocol in the literature is the traditional Wingate protocol (30-second bouts of "all-out" exercise separated with 4 minutes of rest); however, comparison across even these studies is challenging, as the number of work bouts varies between two and six.…”

O papel da intensidade e do volume na prescrição do exercício e os impactos na prescrição nutricional

“…www.vponline.com.br O papel da intensidade e do volume na prescrição do exercício e os impactos na prescrição nutricional A Introdução A discussão que relaciona as variáveis agudas do treinamento intensidade e volume vem, desde muito tempo, chamando a atenção da literatura científica e dos entusiastas envolvidos na rotina da ciência do treinamento físico 1,2 . Mais recentemente, em especial na última década, essa discussão tem se avolumado substancialmente, tendo em vista os interesses pessoais e as possibilidades de mercado, passando por questões fundamentais como as preferências pessoais, as necessidades particulares, a eficiência/eficácia dos métodos, as especificidades em questão, a taxa de adesão aos programas e as individualidades envolvidas [3][4][5][6][7][8][9][10][11] .…”