Relative Intensity: A better way to regulate training intensity. Here’s how to calculate it

Intensity in weight training is usually defined as the percentage of weight compared to your repetition maximum (RM).  The equation for it looks like this (amount of weight being used/1 repetition maximum).  If you are performing the bench press with 80 pounds and your maximum bench press is 100 pounds, the training intensity would be 80% repetition maximum.  This is defined as the absolute intensity. BUT, a funny thing happens after the first repetition, the second repetition is a little harder, and then shockingly, the third repetition is harder than the second and so forth.  As the set continues, your strength continues to drop.  That 100 pound maximum bench is now less, so each repetition becomes a greater percentage of your repetition maximum.  This is where relative intensity comes in.

Relative intensity does a better job of accounting for fatigue throughout a training set.  This method has been used in a lot of the prominent training programs coming from Dr. Bazyler and Dr. Stone’s lab down at East Tennessee State Univ.    For an overview of the type of periodization/training program read this: (study)

Relative intensity accounts for the percentage rep max compared to your relative repetition max.  In the example below, the athletes relative 1 RM is 200 kg and his 5 RM is 170 KG.  If the athlete performed a set of 5 with 170 kg, this would be 100% relative intensity (he can’t performed a 6th rep).  Now if the athlete want was training in an intensity zone of 85-90% (moderately heavy), you simply take the 170 kg and multiply it by .85 to get the lower range and .90 to get the higher range.  Therefore, the athlete would train with a weight somewhere between 145 kg and 153 kg that session, depending on how they feel. Overall, this provides a better strategy to manage fatigue, especially in athletes whom require multiple training sessions, manage class, and have boat loads of stress.  It avoids the issue of training to failure all the time, which is an  issue when using absolute intensity/repetition maximums.

1RM back squat=200kg

3×5 RM (100%)=170kg

Relative Intensity= (low range: 170kg x . 85) (high range: 170 kg x 0.90)= 145 kg- 153 kg