Interval training alternates periods of moderate-to high-intensity effort (such as sprinting) with periods of low- to moderate-intensity effort (like walking or jogging). It is often contrasted with long duration, “steady state” exercise (like jogging).
High Intensity Interval Training (HIIT) is a popular form of interval training that involves (surprise!) intervals of high intensity. HIIT has been found to boost the metabolism, build lean muscle, and keep the body burning calories up to 48 hours after the workoutPhysiological adaptations to low-volume, high-intensity interval training in health and disease. Gibala M.J., little, J.P., MacDonald M.J et al, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada. Journal of Physiology 2013, March;(590):1077-1084.. HIIT has been shown to be more effective at improving athletic performance and releasing beneficial hormones than steady state exerciseEffects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Tabata I, Nishimura K, Kouzai M, et.al. Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kagoshima Prefecture, Japan. Medicine and Science in Sports and Exercise 1996, Oct;28 (10):1327-30.Hormonal and inflammatory responses to different types of sprint interval training. Meckel Y, Nemet D, et al. Journal of Strength and Conditioning Research, 2011 Aug;25(8):2161-9.. While it’s often used in the context of cardiovascular exercise, interval training can be employed with weights, kettlebells, or any form of exercise. Tabata Training and the Little Method are also popular forms of HIIT.
The Complete Guide to Interval Training (Infographic)
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