This mode of training has existed since the latter part of the 20th century but has grown in popularity from brands such as CrossFit. Functional fitness training ranked 14th on the ACSM’s top 20 worldwide fitness trends for 2021 (1). HIFT combines aspects of high-intensity interval training with functional multi-joint movements that challenges aerobic fitness and maximal strength (2). An example workout would be ‘Nancy’ from the CrossFit community. This includes 5 rounds of a 400-m run and 15 barbell snatches. It’s completed without rests between rounds and it’s typically timed (3). Today, I’ll give you an insight into whether if HIFT is suitable for your goals, its risks, and potential rewards.
Through a combination of various types of training on a range of energy systems, HIFT can improve many aspects of health and fitness. Using the previous example workout ‘Nancy’, the 400-m run targeted the anaerobic/aerobic system whilst the 15 barbell snatches were focused on power and power-endurance. It’s no surprise that this mode of training is difficult and comparable to military-styled conditioning. In fact, when fully embraced, HIFT improves strength, cardiovascular endurance, body composition, and promotes general physical preparedness for unpredictable demands (4). Additionally, compared to a traditional training model of using sets and reps, it has been suggested that HIFT substantially improves upper-body muscular endurance and aerobic power (5).
Contrastingly, some authors compared HIFT with traditional circuit training and have observed little significant improvements between the methods (6). However, a common theme across most studies indicated that HIFT is extremely effective at improving body composition. This could result from the higher adherence of HIFT programmes due to shorter workout times, more variations, and enjoyment (7). A key concept of staying consistent with a programme depends on intrinsic (e.g. for enjoyment) and extrinsic (e.g. for rewards) motivations. Recent literature regarding the motivational factors of different modes of training has found that CrossFit ranked the highest in enjoyment compared to training alone, with a group, and with a personal trainer (8).
One of the biggest disadvantages of HIFT is the injury rates and movement dysfunctions. For instance, CrossFit has received much criticism over its methodology. Of most partakers in this method, 73.5% sustained some form of injury with 7% requiring surgery (9). In a more general context, a survey of 213 HIFT practitioners showed that 7.1 injuries occur every 1000 hours of participation. Moreover, competitive athletes and people with more experience with this type of training are 5.69 and 3.77 times more likely to sustain an injury — respectively (10).
In short, if you are thinking about CrossFit or adding HIFT to your training, you should have an injury prevention plan as part of the overall programme. This could include exercises that target movement dysfunctions, such as addressing a lack of ankle mobility to improve squat depth and weight distribution — which could reduce the stress placed on the knees. Nevertheless, the benefits of HIFT are substantial when utilised effectively.