What is the basic principle of fitness training in which the body is stressed and adapts to that stress?

This activity contains 28 questions.

Some questions in this exercise may have more than one correct answer. To answer such questions correctly, you must select all the correct answers. Also note that answer choices in this exercise appear in a different order each time the page is loaded.

The human body adapts well when exposed to stress. The term stress, within the context of exercise, is defined as an exertion above the normal, everyday functioning. The specific activities that result in stress vary for each individual and depend on a person’s level of fitness. For example, a secretary who sits at a desk all day may push their cardiorespiratory system to its limits simply by walking up several flights of stairs. For an avid runner, resistance training may expose the runner’s muscles to muscular contractions the athlete is not accustomed to feeling. Although stress is relative to each individual, there are guiding principles in exercise that can help individuals manage how much stress they experience to avoid injury and optimize their body’s capacity to adapt. Knowing a little about these principles provides valuable insights needed for organizing an effective fitness plan.

Progressive Overload

Consider the old saying, “No pain, no gain.” Does exercise really have to be painful, as this adage implies, to be beneficial? Absolutely not. If that were true, exercise would be a lot less enjoyable. Perhaps a better way to relay the same message would be to say that improvements are driven by stress. Physical stress, such as walking at a brisk pace or jogging, places increased stress on the regulatory systems that manage increased heart rate and blood pressure, increased energy production, increased breathing, and even increased sweating for temperature regulation. As these subsequent adaptations occur, the stress previously experienced during the same activity, feels less stressful in future sessions. As a result of the adaptation, more stress must be applied to the system in order to stimulate improvements, a principle known as the progressive overload principle.

For example, a beginning weightlifter performs squats with 10 repetitions at 50 pounds. After 2 weeks of lifting this weight, the lifter notices the 50 pounds feels easier during the lift and afterwards causes less fatigue. The lifter adds 10 pounds and continues with the newly established stress of 60 pounds. The lifter will continue to get stronger until his/her maximum capacity has been reached, or the stress stays the same, at which point the lifter’s strength will simply plateau. This same principle can be applied, not only to gain muscular strength, but also to gain flexibility, muscular endurance, and cardiorespiratory endurance.

Principle of Specificity

The more specific the exercise to individual training goals, the better. While vigorous ballroom dancing will certainly help develop the cardiorespiratory system, it will unlikely improve a person’s 10k time. To improve performance in a 10k, athletes spend the majority of their time training by running, as they will have to do in the actual 10k. Cyclists training for the Tour de France, spend up to six hours a day in the saddle, peddling feverishly. These athletes know the importance of training the way they want their body to adapt. This concept, called the principle of specificity, should be taken into consideration when creating a training plan.

This can be applied to our previously discussed components of fitness. If you are looking to improve your cardiorespiratory fitness so that you can play a full 90-minute soccer game, you need to focus your training program accordingly. Of course when we look at sport-specific types of training, cardiorespiratory fitness will not be the only programming needs of this type of athlete. For something like a soccer player, they will also need to have agility, speed, strength, power, and good reaction time in order to be able to sprint to defend a breakaway forward, react to a ball being shot on goal, or dribble past a defender. Being able to manage overall workload (and the stress associated with that workload) will also be essential in creating a safe and effective program.

Stress, as it relates to exercise, is very specific. There are multiple types of stress. The three main stressors are metabolic stress, force stress, and environmental stress. Keep in mind, the body will adapt based on the type of stress being placed on it.

Metabolic stress results from exercise sessions when the energy systems of the body are taxed. For example, sprinting short distances requires near maximum intensity and requires energy (ATP) to be produced primarily through anaerobic pathways, that is, pathways not requiring oxygen to produce ATP. Anaerobic energy production can only be supported for a very limited time (10 seconds to 2 minutes). However, distance running at steady paces requires aerobic energy production, which can last for hours. As a result, the training strategy for the distance runner must be different than the training plan of a sprinter, so the energy systems will adequately adapt.

Likewise, force stress accounts for the amount of force required during an activity. In weightlifting, significant force production is required to lift heavy loads. The type of muscles being developed, fast-twitch muscle fibers, must be recruited to support the activity. In walking and jogging, the forces being absorbed come from the body weight combined with forward momentum. Slow twitch fibers, which are unable to generate as much force as the fast twitch fibers, are the type of muscle fibers primarily recruited in this activity. Because the force requirements differ, the training strategies must also vary to develop the right kind of musculature.

Environmental stress, such as exercising in the heat, places a tremendous amount of stress on the thermoregulatory systems. As an adaptation to the heat, the amount of sweating increases as does plasma volume, making it much easier to keep the body at a normal temperature during exercise. The only way to adapt is through heat exposure, which can take days to weeks to properly adapt.

In summary, to improve performance, being specific in your training, or training the way you want to adapt, is paramount.

Dawn Markell & Diane Peterson, Health and Fitness for Life. MHCC Library Press. Sept 4, 2019. https://mhcc.pressbooks.pub/hpe295

The best way to achieve optimum results in exercise and fitness is to follow a plan. But not just any plan, such as “I’m going to run 5 miles every day” or “I’ll lift the heaviest weight I can every time I work out.” Your body is an amazing machine that responds to specific stimuli in distinct ways, and your brain is constantly working to protect the body from threats – like way too much stress on the muscles and tendons from continuous all-out hard exercise.

Principle (noun): 1. a basic truth or theory;  2. an idea that forms the basis of something;  3. a law or fact of nature that explains how something works or why something happens.

Fortunately, exercise science gives us five basic principles we can incorporate into a fitness program that will develop the changes, or “adaptations” we desire, in a safe and lasting way. These five principles are:

• The Overload Principle
• The F.I.T.T. Principle
• The Specificity Principle
• The Rest and Recovery Principle
• The Use It or Lose It Principle

The Overload Principle and the F.I.T.T. Principle work together, so let’s review these first.

The Overload Principle is considered the most important concept in exercise. In simple terms, it means that your body will adapt to the demand you impose on it. For example, when you lift a heavy weight you haven’t lifted before, or you complete a hard cardio workout that puts new demands on your heart and lungs, physiological changes will take place that will allow you to do this more easily next time.

Because the body is so adaptable, the demands we put on it must gradually and progressively increase over time in order to achieve long-term fitness gains. These demands must be applied slowly, because too much too fast causes the body to react negatively to excessive stress. (For more about this concept, read The Body’s Response to Stress – Understanding the General Adaptation Syndrome.)

So it’s important to strategically vary your mode of exercise, intensity and duration of training in order to get better, stronger or faster. This is where the F.I.T.T. Principle comes in.

F.I.T.T. stands for Frequency, Intensity, Time and Type. These are the four areas where increases in workload or demand can be made in order to progressively overload the body so it adapts in the desired way.

Frequency means how often an exercise is performed. After any kind of exercise, your body begins a process of repairing and rebuilding stressed tissues. It’s important to find the right balance of work and recovery that provides just enough stress for the body to adapt as well as recover for the next session.

Intensity is the amount of effort or work completed in a specific exercise. For example, walking at a conversational pace is low intensity, whereas sprinting for 400 yards is high intensity. In strength training, factors that influence intensity are the weight itself (load), the number of sets and repetitions, the tempo of the repetitions, and whether a level of instability has been added (such as standing on one leg while doing shoulder presses.) Once again, just enough intensity to overload without overtraining, injury or burnout is what’s important here.

Time is simply the duration of the exercise session. It’s a function of intensity and type.

Type means the type of exercise performed – strength training, cardio, or a combination of both. The type of exercise is tied to the Specificity Principle, discussed next.

This table illustrates how to combine the Overload Principle and the F.I.T.T. Principle for strength training or cardiovascular training:

The Specificity Principle is, quite simply, that the exercise you do should be specific to your goals. For example, if your goal is simply health and weight management, focus on total body strength, cardio and a healthy diet. If you are a runner wanting to improve your race times, include speed workouts in your training. If you’re a cyclist training for a 100-mile ride, focus on building up longer distance training rides at an endurance pace.

The Rest and Recovery Principle is critical to achieving gains in fitness. The body simply cannot tolerate too much stress, and over time will instead “shut down” in order to protect itself. This results in overtraining syndrome, burnout, excess fatigue, and a weakened immune system. (Read The Body’s Response to Stress – Understanding the General Adaptation Syndrome.) Exercising every day is perfectly fine – just not the same exercise at the same intensity. Especially with strength training, it’s important to allow at least a day between sessions to allow muscles to repair and rebuild. However, working different muscle groups on different days (what’s called a “split routine”) will allow for this recovery period for one muscle group while working another. Low intensity cardio can be done every day, but rest between intense sessions. Rest and recovery are important for your mental state too!

The fifth principle, while not specifically targeted to fitness adaptations, is still important to be aware of – Use It or Lose It. Most everyone is aware of this concept at some level, as it applies to many things in life. With respect to the body, muscles build strength (called “hypertrophy”) with use, and lose strength (“atrophy”) with lack of use. This includes not only the skeletal muscles, but also the heart and even the brain (although it’s not technically a muscle.) How quickly atrophy occurs is dependent on many factors, and will be the subject of a future blog post.

Incorporating these principles into your fitness routine will ensure you get the best results in the most efficient way, while preventing injury and overtraining.  But it can be complicated. As a virtual fitness coach and personal trainer certified through the National Academy of Sports Medicine (NASM), I have the knowledge and experience to develop a progressive program specifically designed for you and your fitness goal. We’ll work together, on your schedule, to get you where you want to be, safely and effectively. Contact me today for a free consultation!