Table 2.

Definitions of high-intensity functional training.

References	Definition of high-intensity functional training
Feito et al. (2018)	A training style [or program] that incorporates a variety of functional movements, performed at high intensity [relative to an individual's ability], and designed to improve parameters of general physical fitness (e.g., cardiovascular endurance, strength, body composition, flexibility, etc.) and performance (e.g., agility, speed, power, strength, etc.).
Teixeira et al. (2020)	HIFT is a modality characterized by presenting high volumes and training intensities with constantly varied exercises with or without any recovery interval between the series. HIFT training sessions consist of Olympic weightlifting exercises (e.g., clean and jerk, snatch), gymnastics (e.g., lunges and pull-ups) and metabolic conditioning (e.g., running and rowing). In addition to the diversity of functional movements performed in high intensity, HIFT aims to improve physical conditioning variables (i.e., strength, body composition, among others) and performance (i.e., speed, power, among others).
Gomes et al. (2020)	Exercise regimen characterized by high intensity, constant variation, and functional movement is often performed in rapid, successive repetition with limited or no recovery time. HIFT is based on the concept of increased work capacity over time while using a variety of exercise modalities, including mono-structural (e.g., running, rowing, etc.), as well as body weight movements (e.g., squats, push-ups, etc.) and weightlifting derivatives (e.g., snatch, shoulder press, deadlift, etc.).
Browne et al. (2020)	HIFT incorporates many of the same principles as HIIT, including the relatively high work-to-rest intervals. However, HIFT training goes further and weaves multimodal resistance training with cardiovascular exercises. HIFT consists of a variable series of these functional whole-body exercises with little rest, while HIIT consists of unimodal, single-plane movements with distinct periods of low-intensity activity or rest.
Ben-Zeev et al. (2020)	HIFT is a form of physical activity that can be modified to any fitness level and elicits greater muscle recruitment than repetitive aerobic exercises, thereby improving cardiovascular endurance, strength, and flexibility. HIFT emphasizes functional, multi-joint movements via HIIT and muscle-strengthening exercises.

ADLs, activities of daily living; HIFT, high-intensity functional training; HIIT, high-intensity interval training.