There’s not much difference when you read between the letters, but when it comes to HIIT (high-intensity interval training) vs. HIFT (high-intensity functional training), these two types of training modalities are distinctly different. HIIT is often characterized by short bouts of vigorous activity, intersected with rest or low-intensity active recovery periods. HIFT is defined as utilizing constantly varied movements, incorporating different types of workouts at assorted durations, with or without active rest periods. Both training modes are great for shredding body fat, maintaining an active lifestyle and improving overall health. But, to understand which training modality is right for you, you must first identify what your goals are and what you’re training for.  

What Is High-Intensity Functional Training?

High-intensity functional training (HIFT) is a type of training modality that has exploded onto the fitness scene gaining immense popularity. Incorporating high-intensity training with functional fitness, strength training and Olympic lifting, HIFT emphasizes multi-joint movements that can be modified to any fitness level.

High-Intensity Functional Training (HIFT) workouts usually take place in a one-hour class in a group-training aspect, comprised of three components; a dynamic warm-up such as a running or biking followed with a stretching and movement warm-up for mobility, a strength portion, and workout of the day (WOD). If your coach does not include a cool-down component in your class, then its suggested to conduct some light movement and stretching until your body temperature and heart rate, cool down to a normal resting rate.

HIFT incorporates both aerobic and anaerobic movements or muscle strengthening exercises, eliciting greater muscle recruitment than repetitive aerobic exercises such as HIIT improving endurance, strength, and mobility [R,R,R]. 

What is a WOD (Workout of the day)? A WOD is just that, the workout of the day. However, a WOD typically consists of a few intersected multi-joint movements, that are conducted for time, meaning how fast you can complete a set, total weight lifted, or conducted for as many reps as possible (AMRAP). HIFT has several other acronyms and you can learn them all here.

What Is High-Intensity Interval Training?

HIIT is a very different type of training modality than HIFT. As compared to HIFT, HIIT is unimodal, meaning that it has it incorporates one type of movement such as running, cycling, or functional movements such as burpees or jumping jacks [R]. However, many people have misconceptions of what HIIT really is. HIIT is a specific type of training, that incorporates both high-intensity training and interval training to form HIIT. HIIT is essentially aerobic exercise or cardiovascular training for short burst of time. The main objective of HIIT is to increase the intensity of cardio training, with each workout typically lasting for only 30-90 seconds as opposed to prolonged endurance training such as jogging and cycling.

Numerous studies have proven that HIIT improves cardiovascular endurance through peripheral adaptations such as changes in carbohydrate metabolism in addition to burning more calories and body fat [R]. Interestingly however, HIIT does not elicit changes in VO2, but still enhances aerobic endurance [R]. Conventional forms of cardio are monotonous and boring to those that just want to work out to stay in shape. That’s one of the reasons why HIIT has become increasingly popular in recent years, primarily because of its ability to burn more fat through shorter bouts of high-intensity work.

HIIT Vs HIFT

HIIT and HIFT are often times mistaken as being synonymous. Although, they do share conceptual commonalities, in regard to their high-intensity nature, and aerobic response both training modalities elicit distinctly different performance outcomes and physiological responses. The biggest differences between HIIT vs HIFT, are the uses of rest intervals, resistance training, and constantly varied movements. 

Uni-Modal Vs Multi-Modal

HIIT is unimodal, meaning that it sticks to one type of aerobic exercise (running, biking, rowing) for several sets. HIFT is multi-modal meaning it uses multiple functional movements, with no defined rest intervals. Functional movements also known as compound movements are exercises that use the entire body, such as squats, deadlifts, thrusters, and snatches, cleans, and pull-ups. These types of weightlifting, powerlifting, or Olympic lifting movements, are generally prescribed in a certain number of sets and reps, to elicit strength and hypertrophy response, without cardiovascular capacity or endurance.  HIFT takes these movements and prescribes them in a continuous circuit or interval format at a high-intensity with greater volume. HIFT training will help develop and improve muscle strength and power, gain lean muscle mass, and improve aerobic endurance capacity [R].

Although limited research exists comparing HIIT vs HIFT, studies using HIFT methods have shown significant changes in body composition, muscle strength and power, as well as improved peak performance and aerobic capacity [R]. A recent study compared the differences in physiological response and training adaptations between HIIT (unimodal) and HIFT (multi-modal) training methodologies. A group of 28 women was assigned to six weeks of either HIIT or HIFT training. The study showed that the while both the HIFT and HIIT groups significantly improved aerobic capacity (7% vs. 5%, respectively), and anaerobic power (15% vs. 12%, respectively), after six weeks of training, only the HIFT group improved muscle strength, power, and muscular endurance [R].

No Defined Rest Interval 

The second major difference between HIIT vs HIFT, is that there is no defined rest interval. Dependent upon the WOD, HIFT workouts are based around completing repetitions in the fastest time possible (for time), lifting a max effort amount of weight, or completing as many rounds as possible (AMRAP) in a given time period to increase workout load and volume. Based on your fitness level and experience, rest intervals vary and often are not prescribed, but taken as needed. HIIT revolves around completing ‘all-out’ sprint like intervals repeated for multiple rounds. This type of training can be included in HIFT since it is multi-modal, but they are not the same.

HIIT Vs HIFT: Which One Is Right For You?

When choosing a training program, it really is dependent upon your goals. HIFT is proven to induce greater muscle adaptations, meaning you’ll gain more lean muscle mass than HIIT, while they both improve body composition and aerobic capacity. Both training programs are great for overall health and fitness and one really isn’t better than the other. It’s really dependent on what you want, how you want to look, your schedule, your budget, and your goals. The most important part is to just get out there and get moving.

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