What is Fitness?

When I teach a course on health and fitness assessment, I always ask students to start by defining those two words. In particular, what is fitness? Sometimes I’ll show students a picture of a fitness model from some magazine cover and ask them if the individual is fit. Typically my students want to say yes, but they sense a trap and hold themselves back. We are all conditioned, day by day, month by month of checking through the grocery store cashier line, to think that the gods of fitness are the bronzed airbrushed models that adorn magazines such as Oxygen or Men’s Fitness. But, the immediate qualifier that must follow any question about your fitness is: “Fit for what?” Marathon runners are very fit for endurance running. Gymnasts typically have great flexibility, balance, and coordination. Football players might be very fast, strong, or powerful, depending on their position. But try interchanging these athletes into each other’s sports and you suddenly have the comical scenario of watching someone with no fitness trying to compete. Fitness is very specific. You cannot simply get “in shape”. The fundamental problem with exercise training is that you must choose what system(s) you want to train. To be sure, it is possible to increase in strength, flexibility, endurance, and coordination all at the same time. But it is not possible to maximize all of these components of fitness simultaneously. Choose your goals, and progress appropriately. There are a number of components of fitness, typically categorized into those associated with health (aerobic fitness, muscular endurance, strength, flexibility, body composition) and those associated with skillful performance (speed, balance, coordination, reaction time). An athlete might have to train in both health-related and skill-related components of fitness while an individual interested only in exercise for health would typically focus only on the health-related components of fitness. Yet, even within the health related components there is a wide range of outcomes. Many individuals who primarily train with weights in a gym are only interested in increasing strength, increasing muscle mass and reducing fat. This addresses only two components of fitness (strength and body composition) while ignoring many others. Again, one must think about one’s goals before setting up a training programme.

A critical part of increasing fitness is knowing your fitness level to begin with. Setting goals, progressing through increased levels of fitness, and eventually achieving your goals all starts with assessing where you are to begin with.

Principles of Training

There are a number of basic principles of exercise training. A principle is a fundamental law, doctrine or assumption, and training is repetitive bouts of exercise designed to apply a particular type of physiological stress. So, principles of training are laws or doctrines used to apply exercise bouts appropriately with the goal of increased fitness. In my mind, there are seven principles of training:

Overload. This principle states that regular application of a specific exercise overload enhances physiologic function to induce a training response. In other words, your body only adapts to that which it is unused to doing. If you walk half a mile every evening after dinner and have done so for the past 10 years, you are not experiencing overload. Each day, your walk is exactly the same as the previous day and your body is not stressed beyond what it is accustomed to.

Progression. There is a need for continual overload: the body adapts to the initial overload. Your body adapts remarkably well to exercise overload, and in order to keep increasing fitness there is a need to keep increasing the overload. If you increase your nightly walk from half a mile to one mile you have experienced an increase in overload. But, relatively quickly your body adjusts to that new overload and your nightly walk of one mile becomes mundane and easy. Your body is no longer experiencing overload and therefore there is no continued increase in fitness. A general rule of thumb is that a 10% progression per week is an appropriate progression (though this varies dramatically from specific case to case, and depends on the system being trained). Someone interested in increasing fitness must be in a constant state of progression, whereas using physical activity for health and general fitness does not require constant progression since a plateau in fitness might be acceptable.

Specificity. Training adaptations are specific to the activity performed, to the muscles used and to the particular type of overload applied (intensity, duration, etc). Flexibility training will result in increased flexibility, strength training will result in increased strength, endurance training will result in increased endurance. This may seem obvious and intuitive, but it is surprising how often athletes forget this basic principle in their training (in particular see future posts on the emergence of non-specific body building training for many sports).

Individual Differences. Individuals adapt differently to the same training program due to a number of factors (genetics, pre-training status, gender, age, lifestyle (nutrition, sleep habits, etc), psychological factors.

Reversibility. Health or fitness benefits only last as long as they are being trained. This is the “use it or lose it” principle and is pretty self-explanatory. However, the nature of reversibility (de-training) and the variability of rates of detraining between individuals and organ systems is quite complex.

Diminishing Returns. The fitter you become, the harder you have to work to achieve the same gains in fitness. Eventually, a plateau in training adaptations is reached. Hopefully this does not happen until the individual has achieved their fitness goals. Finding new ways to break through plateaus is challenging, and there are specific ways to determine whether an individual has reached their true potential or not.

Recovery & Recuperation. Adequate rest is needed between workouts for tissue repair and injury avoidance. Though an active lifestyle is healthy, the actual act of exercise is actually very damaging to tissues. Muscle cells are damaged and inflammatory responses to exercise wreak havoc on various body tissues. It is during the rest following exercise that growth and increases in fitness actually occur. Without adequate planned rest, overtraining and breakdown can occur.

Some of these principles are more basic than others. Some are not pertinent to some individuals, depending on their training goals and dedication to training. For an individual interested in activity for health who is active three times per week, for example, the principle of recovery and recuperation is more or less irrelevant. But, the two principles that are absolutely critical to designing a programme to increase fitness and performance are overload and progression. At any given time point in an exercise training programme, an individual should know where they are in terms of progression. How far have you come in the past 6 months? How far away are your goals? How much time will it take to achieve those goals? How much progression do you need to reach your goals by your target date? Is this a realistic progression? These are all questions that any individual in a training programme must regularly ask themselves.

If you are just beginning a training programme, no matter what level of fitness you are at or what your goals are, familiarize yourself with the principles of overload and progression and put some thought into where you want to go with your exercise training. What are your goals? When do you plan on achieving them? That brings us to the next point: where are you right now in terms of fitness? There are numerous fitness tests, some designed for high performance athletes and others designed for sedentary individuals. Establishing your current fitness level is an important first step on the road to increased fitness.