sports Review High-Intensity Functional Training (HIFT): Definition and Research Implications for Improved Fitness Yuri Feito 1,* ID , Katie M. Heinrich 2,† ID , Scotty J. Butcher 3,† and Walker S. Carlos Poston 4,† 1 Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA 30144, USA 2 Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA;
[email protected] 3 School of Rehabilitation Science, University of Saskatchewan, Saskatoon, SK S7N 2Z4, Canada;
[email protected] 4 Institute of Biobehavioral Health Research, National Development and Research Institute, Leawood, KS 66211, USA;
[email protected] * Correspondence:
[email protected]; Tel.: +1-404-578-7764 † These authors contributed equally to this work. Received: 16 June 2018; Accepted: 3 August 2018; Published: 7 August 2018 Abstract: High-intensity functional training (HIFT) is an exercise modality that emphasizes functional, multi-joint movements that can be modified to any fitness level and elicit greater muscle recruitment than more traditional exercise. As a relatively new training modality, HIFT is often compared to high-intensity interval training (HIIT), yet the two are distinct. HIIT exercise is characterized by relatively short bursts of repeated vigorous activity, interspersed by periods of rest or low-intensity exercise for recovery, while HIFT utilizes constantly varied functional exercises and various activity durations that may or may not incorporate rest. Over the last decade, studies evaluating the effectiveness of HIIT programs have documented improvements in metabolic and cardiorespiratory adaptations; however, less is known about the effects of HIFT. The purpose of this manuscript is to provide a working definition of HIFT and review the available literature regarding its use to improve metabolic and cardiorespiratory adaptations in strength and conditioning programs among various populations.