What is exercise intensity and why is it important?
In simplest terms it is how hard an exercise is at a point in time. It is the level of momentary exertion during exercise. This can be quantified by measures such as a person's heart rate expressed as percentage of one's maximum heart rate or pounds of weight lifted expressed as a perecentage of one's one-rep maximum lift. Exercise of sufficient intensity is necessary to stimulate the body to make a change. When the body is worked beyond what it is equipped to handle the body adapts as a form of self-protection. The body will make a positive adaptation only if given enough time to recover from the exercise.
How high should the level of exercise intensity be?
That depends on what you want to accomplish. The body will adapt to the nature of the demands placed on it. If one engages in lower intensity activities such as running the body adapts by increasing endurance for that activity with little or no increase in muscle strength. If one engages in higher intensity exercise such as weight lifting the body adapts by getting stronger but with less improvement in the way of endurance.
If one’s goal is to get stronger how much high intensity exercise is necessary?
The higher the intensity the less exercise you will be able to withstand, but this high intensity exercise produces a bigger stimulus for strength gains. The larger stimulus for strength gains requires a longer recovery period. For the elite athlete the required intensity level will be quite high, but for those who do little physical activity that intensity level will be lower and manageable. Whether you are 18 or 80 there will be a level that you can manage.
There is a wide range of individual differences in response to high intensity exercise and how much each person can withstand. Some will show great results and some people will be low responders. An experienced trainer will see the difference and change the workout accordingly.
Try performing squats with adequate weight such that you cannot possibly continue with good form after ninety seconds. Try doing it again the next week with more weight or for more reps. You will find that most everybody will improve, and in fact, the improvement at first will come easily as your body will be well rested. If you improve doing just one set an additional set is unnecessary and only serves to dilute intensity. By doing fewer leg exercises you will be able to devote more energy and effort for rest of the muscles of your body. If you work sufficiently hard on every exercise your workout will be less that half an hour. For those who have been inactive and not accustomed to this method one can slowly build up the intensity at their own pace.
How much time is needed to recover from high intensity exercise?
If you start from the premise of how much exercise can you withstand this will lead to drudgery, insufficient recovery, lower intensity, less results, and eventually quitting and injury. Some spend several hours a week in the gym just to maintain their present level of fitness or they claim they have hit a plateau. It does not have to be that way. If they worked out a little less often the quality of their workouts would improve and they might begin to see improvement again.
If you start from the premise of how little the amount of intense exercise you can get away with and still achieve positive results you will find you are willing to workout at a much higher level of intensity, have more time to recovery, and have better results. How often you need to workout will depend on a number of factors; most important are level of intensity, duration of exercise, and frequency of certain exercises. You can discover the right formula through trial and error. If you can find a trainer who knows how to manipulate these variables, and most importantly, knows how to do this safely you will find your continued improvement will be measured in years instead of months. With the right supervision this is a strength training program that people of any age or fitness level can stick to - a 30 minute workout, usually once or twice a week with continuing positive results.