Quantifying Body Weight to Strength Ratios

Training is a continual process of biological growth and change which is balanced and checked by accumulated wear-and-tear. You’re always walking on a knife’s blade, at “the edge of chaos” so to speak, but as your fitness level grows, so does your ability to tolerate a thrashing. You can handle more intensity as weights get heavier, and more volume and more workouts as work capacity improves. The result is a system which grows to match what it’s been trained to do.
– Matt Perryman – Squat Every Day

A common theme you may have seen here so far is a fascination with the role lifestyle habits (specifically exercise and nutrition) have on functional longevity. Weighed heavily on this idea is the significance of muscle mass, strength, bone density, and body composition have on increasing the likelihood of having a relatively high functioning body in your traditional retirement years. This basically comes down to strength development with marginal fat accumulation in comparison.

A simple 10,000 foot view to quantify this is with the following equation:

\frac{strength}{total\,body\,mass} = Body\,Weight\,to\,Strength\,Ratio

As much as I like the clarity and ease of this equation it is far too elementary for our purposes since there are so many ways to quantify strength.

The numerator could be your Olympic total, powerlifting total, or any combination of methods and exercises aimed to rank and quantify strength. For the purposes of functional longevity, the next task is to find a way to quantify strength that optimizes muscle mass, strength, and bone density.

For this, I use the following equation to track overall progress for myself and my clients. Month to month the goal should be to increase the numerator (strength) and depending on the clients’ current goals decrease or increase the denominator (bodyweight). The result should be number in the 0-15 range which, if training is going well, will climb over time. As you become seasoned your goal will be to stave off sarcopenia (loss of muscle with aging) by maintaining the highest ratio you can.

Over many months/years this is a fantastic snapshot to gauge some of the primary indicators of functional longevity. Even though I use this for the most part as an indicator of longevity there is generally a high correlation with aesthetics.

\frac{5RM Squat + 5RM deadlift + 5RM Bench Press + 5RM Standing Press + 5RM Chinup}{total body mass}

A few notes about this:

  • For barbell movements, if you do not have a current 5RM you can estimate by using this chart.
  • For weighted chin-ups, the number is your current body weight + weight added. If you are using an assisted chin-up machine the number is bodyweight – assistance.