Redefining Exercise Intensity

The Problem

Many use the concept of exercise intensity to govern their fitness programs. The most commonly used method of calculating exercise intensity is a formula involving your Maximum Heart Rate (MHR = 220 – individual’s age). This allows an individual to exercise at any percentage of their MHR to vary exercise intensity.

However, there are some fundamental issues with defining exercise intensity this way. The problem with using a percentage of MHR is that it measures the individual, not the activity. Knowing your MHR is important for only one reason -- it can only tell you how hard you are working. However, when using PROTOGYM’s high intensity philosophy of training, it is assumed that the individual is always working as hard as possible. Therefore, exercise intensity needs to be redefined as something other than your body’s response (heart rate) to an exercise.

There are a few issues in measuring the body’s response to an activity.

#1 - The same task is not the same for everyone. For example, consider how an exercise such as the push-up has two key issues:

People vary in height and weight and therefore the difficulty changes. A shorter/lighter person has less weight and better leverage to do a push-up. The taller/heavier person will have a higher difficulty level.
A better conditioned person will not be as affected by a given activity. If two physically identical people (same height and weight) of different conditioning levels (one ‘out of shape’ and one ‘in shape’) complete the same task (10 push-ups), the lesser conditioned individual will usually have a greater increase of heart rate when the task is completed. This means that the ‘out of shape’ person’s body has to work harder physiologically, not physically, to complete the given task.

#2 - When you measure the person, you cannot know what the activity is.

I.E. – Two individuals can be performing two different activities and have the same heart rate. In this example, say one is performing push-ups and the other is running. If they both have the same heart rate then you cannot know which individual is performing which activity. Therefore, heart rate is an indicator of the body and not the activity.

#3 - The fundamental issue at hand is we want to measure the physical activity and not its physiological output.

If people want to measure exercise intensity, why would they measure your resulting heart rate? This is just a physiological output of the body. Instead, why not measure the actual push-up when it is happening?

The Solution

In light of these discrepancies, PROTOGYM chooses to measure exercise intensity by determining the intensity level of the exercise, not the individual. This method ensures a true measurement system that applies to any individual. It also changes the purpose of the system as now it conducts physical measurements of a given activity instead of various physiological outputs of the body. Based on this technique, there are two primary factors that affect exercise intensity.

The first is proprioception. Proprioception is an individual’s ability to process and exist in 3D space. Using vision, the inner ear (Vestibular system), and the various sensors throughout the body (Somatory system), the brain (cerebellum and spinal cord) decodes the data from all three of these systems and tells the skeletal muscles how to behave. This allows us to stand upright, walk, and balance in any situation or environment.

Therefore, an environment possessing greater instability increases the proprioceptive difficulty for the individual. For example, standing on one leg or an instable surface is “harder” than standing on a solid floor. The increased instability of the surface requires a higher level of proprioceptive ability to balance and maintain one’s center of gravity (COG). PROTOGYM uses a proprietary system to calculate the proprioceptive score of every body part regardless of how it is engaged or (de)stabilized.

The second factor is force. The body creates force to move loads (mass) through space. This could be a barbell during a bench press or the body itself during a push-up. The higher the weight, the more force is needed, which increases the difficulty of the movement.

Proprioception and force are inversely related which brings us to the conceptual formula for intensity:

For example, an individual is given a 50lb barbell and told to do bicep curls. Let’s say the individual performed 20 repetitions before exhaustion. Now how many repetitions would you think they could do if they were told to do them while standing on one leg assuming they started fresh? Surely your answer was ‘less than 20’ and you would be right.

The person would not do 20 because standing on one leg increases proprioception, which in turn increased the intensity of the exercise. Since the intensity is higher, they will not be able to output as much work (in this case 20 reps). If we lowered the load, say 30lbs, and then maybe they could do the 20 reps.

This is the basic fundamental concept of exercise intensity. PROTOGYM will use this system to measure all exercise activity. This measurement technique can be applied to all types of exercise (resistance, plyometrics, core, balance, SAQ, isometrics). This allows PROTOGYM to efficiently progress an individual to the highest levels of fitness performance.