Every day people use the term “fitness” when they talk about health, exercise, and sport.  But what is the actual definition of fitness? There are many different terms used to describe fitness; “physical fitness”, “health-related fitness”, “muscular fitness” and many more. Fitness had gone from being described as an “ability” to a “set of attributes”, whereby the skill related components of physical fitness include agility, balance, coordination, speed, power, and reaction time. In addition to this health factors such as cardiovascular endurance, muscular strength and endurance, flexibility, and body composition are also considered major factors of fitness today.

There has recently been a fitness revolution and expansion of newly developed High Intensity Interval Training programmes, designed to maximise fitness and fat loss. These HIIT programmes Include workout’s such as CrossFit, Insanity and MetaFit and currently used as a brand which represents ultimate fitness. The aim of HIIT is to forge a broad, general and inclusive fitness, whereby companies such as CrossFit have sought to build a program that will best prepare “trainees for any physical contingency”.

But do this HIIT programmes actually work? Or are they just another cult like trend used to exploit the growing interest of fitness in today’s society?


What is CrossFit?

CrossFit was founded by Greg Glassman is 2000 and is now considered along with recent workouts such as Insanity and MetaFit, to be part of a new fitness revolution. CrossFit is defined as a fitness programme that forces elite fitness. It optimizes fitness through a series of functional movements that are performed at high intensity, resulting in physical endurance and the reaching of anaerobic thresholds.

What does it involve?


The CrossFit programme itself involves a series of aerobic exercises, body weight exercises and weight lifting exercises that are not for the faint hearted. CrossFit is not easy and it’s not simple but by offering a constantly-varied approach to training, the functional movements at maximum intensity and maximum physical and psychological tolerances can lead to dramatic gains in fitness.

The main aspect of CrossFit, Insanity and Metafit is the level of intensity. Intensity is essential for results, the more work you do in less time, the more intense the effort and the greater the gains. The magic of these workouts lies within the series of precise movements that are considered the core movements of life. They combine movements such as sprintingrowingjumping rope, climbing rope, flipping tires, weightlifting, carrying heavy objects, and many bodyweight exercises such as push ups, pull ups, burpees, squat jumps, etc. Some moves require equipment including barbellsdumbbellsgymnastics ringspull-up barskettlebellsmedicine balls, and boxes for box jumps. These exercises are compound movements that are constantly varied, at high intensity and are performed in a wave of contraction from core to extremity.

The workouts are usually around 45 minutes to an hour long involving a warm-up, a skill development segment, the high-intensity WOD, and a period of individual or group stretching. The programmes themselves have been developed to provide ultimate fitness that can be used in all walks of life. Not only do they involve animal training and precise movements but they also involve the importance of nutrition. By containing diet plans, this new fitness revolution teaches that being fit isn’t solely about exercise; it is also highly about the health and nutrition that is required to support exercise.

Why Chose CrossFit?

Programs such as 10 Minute Abs and Butts and Guts are designed, marketed and fuelled by the desire to look good naked, but do they produce results? Spot reduction doesn’t work, and there are no shortcuts. Not only this but fitness products have little worth without a complementary diet, and a lack of effort and commitment can derail even the best program. With programmes such as CrossFit the primary goal is not to improve physiques, it is to force elite fitness. However, we would be fooling ourselves if we didn’t acknowledge the beauty of CrossFit results and the glorifying figures of these athletes.

CrossFit is noteworthy for its use of a virtual community Internet model. By joining this virtual community, the gains are not only recognised through changes in physique but also through the three important factors of fitness that could totally change your life. These factors are strength, mobility and endurance. Strength is the ability to move the body under load, by gaining strength through our own bodyweight; we can conquer the effects of gravity, increasing our quality of life and ability to survive as we age. Mobility involves the ability to move in a variety of directions and carry out both simple and complex tasks. Mobility is crucial and involves stable, controlled, and coordinated movements within unstable and unpredictable environments. Endurance is the ability to sustain a task over time and is significant as many aspects of life require repetitive or sustained activity.

The Science behind High Intensity


Recently, high-intensity interval training with minimal time commitments have been marketed in an attempt to overcome the barrier of “lack of time” to exercise and too eventually increase the physical activity level and health status of the general population. CrossFit and other competitor HIIT programmes may offer a sense of community and a change in lifestyle and nutrition, but can you get the same results from low intensity training?

There have been many scientific studies used to show that low-volume interval training, usually performed at maximum physical tolerances, can induce metabolic adaptations and enhance endurance exercise capacity within a short period. Tong et al carried out a study, whereby he investigated the effects of high intensity interval training on cardio respiratory fitness and aerobic based exercise capacity. His study involved twelve women and four men, who were mildly obese but otherwise healthy. Candidates were assigned randomly into either of the two groups: interval training (IT) and IT plus proportional-assist ventilation (IT+PAV). Both groups performed interval training three times a week for 6 weeks. They found that after the 6-week intervention, a small but significant improvement of ∼7%in V.O2peak was noted in both groups, these results suggest that intense interval training can be used as an effective way to enhance central and peripheral adaptations in O2 transport and utilization. This highlights that interval training enhances cardio respiratory fitness and aerobic-based exercise capacity in sedentary and mild obese subjects. Moreover, minor %BF reduction was observed in the IT group after the interval training and candidates also showed an increased muscular work capacity.

Therefore, to answer your question more direct- YES high intensity interval training does work to enhance fitness, and does so in short periods of time. There are many more studies available providing heaps of evidence to support that high intensity interval training is a beneficial approach to weight control or weight loss and tends to enhance exercise adherence and reduce attrition compared with single bout continuous exercise. However, like I stated previously, these programmes are NOT for the faint hearted, whereby the recommended intense interval training protocol, is often considered unsafe, impractical and intolerable for general populations, especially sedentary and obese ones.

In my Opinion…

At the end of the day, the new HIIT revolution is another emerging market within the fitness paradigm, with various forms of marketing, becoming a new way for companies to make more money. However, these programmes do work and can get those short term results that meet the public demands. I don’t know about you but my major problem with my workouts is that the results are long term, and so after a week of working especially hard and not seeing those instant results, I get disheartened. Most people in this case give up, and that’s why, in my opinion, exercise and workouts have become a “trend” to the general public rather than a lifestyle change. Therefore programmes such as CrossFit are ideal for those who aim for instant results, and have stacks of scientific evidence to back them up. However, because of the intensity and heavy work load, these programmes are often considered unsafe, especially if performed in a short period of time with bad form, therefore perhaps they are not ideal for overweight members of the public, and more for those who are already fit, but want to maximize their fitness levels and optimise their physiques. I’ve tried insanity… My …Oh My… the first time I tried insanity about a year and a half ago, it ended with me collapsed on the floor in a bucket of sweat.  Before this I considered myself fit, whereby I ran everyday for 7 mile… but I was wrong! But through following the insanity regime, my fitness today has drastically improved. Eventually I was able to keep up with the pros on the video, and as a result of maximizing my exercise capacity and cardio respiratory fitness I can now run with a fast pace over larger distances, also highlighting an increase in my endurance. However, having a bit of a sweet tooth and thinking I’m always right, meant I did not follow the nutrtitional plan, therefore the visual results did show improvements but were not maximised. So if you’re ready for the HIIT revolution and have the dedication and commitment needed for the extremely hard workload, then join the community today the results will be fantastic and endless… But don’t say I didn’t warn you!



Greg Glassman. (2007). Understanding CrossFit. The CrossFit Journal Articles. 1 (56), p1-2.

Redefining Fitness for Health and Fitness Professionals, Lon Kilgore, Ph.D. Midwestern State University, College of Health Sciences and Human Services , Department of Kinesiology.

Berger, Russell. “Form follows function.” (2010).