Measures of intensity for cardiovascular exercise
Continuing from last week, we are covering two more methods of assessing the intensity of your exercise level.
The Rate of Perceived Exertion method (RPE)
RPE (also referred to as the Borg scale of exertion) is a straightforward way to assess the intensity of a workout using either of two scales developed.
The first (and the original) scale is from 6 to 20, with 6 being not moving but awake (also rated as 1 metabolic equivalent task – MET) and 20 being at maximal exertion. Aligning this scale with the heart rate method, 11 would equate to 60% of maximum heart rate and 15 to 17 would equate to 80 – 90% of your maximum heart rate.
The second is the modified RPE or Borg scale of exertion, which utilises 1 to 10. 1 represents awake but no activity (also rated as 1 metabolic equivalent task – MET) and 10 being maximum exertion. Aligning this to your heart rate is easier, with each number equating to the equivalent percentage. I.e. 1 = 10% heart rate max or 8 = 80% heart rate max.
These methods are used regularly due to the ease and non-invasiveness of the test, however the pitfall is the over estimation of the intensity by participants.
Measures of distance over time
Measures of distance over set time period can be a simple (once calculated) and effective tool to use, particularly if you are training for high intensity events. To calculate your intensity, you need a mode to test (for example running). Have a set distance (in this instance we will use 1km) however you may want different distances for different training reasons.
In this example, we will time the run and then calculate the time travelled each second. If the person ran the 1km in 5 minutes, the calculations would be:
1000 (meters in a km)/ (5 x 60)
=3.33mtr/sec (which is your 100% for 1000mtrs)
Using this formula, if you wanted to improve speed, training at a higher percentage (at times) may be necessary. If you wanted to calculate a specific goal (in this case 120% of your mtr/sec), the calculations would be:
(3.33/100) x 120
=3.99mtr/sec (let us say 4mtr/sec rounded)
If you were aiming for a distance goal (say 400mtrs) then using the 120% rate the calculation would be:
400/4 = 100 seconds to run the distance
If you were running a time (lest say 15 second sprints) at 120%, the calculation would be:
15 (seconds) x 4 (mtr/sec)
= 60 meters
The distance per second method can be used in any cardiovascular activity, however it can be used in any method. The downfall is that some people may not test to their full potential, giving an incorrect measure of mtr/sec.
Both these methods have good points and not so strong points; however, they are still a good tool if used accurately. Next week I will explain two methods used to gauge the intensity of your resistance training.