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How to keep your injuries from adding up

***Editors note, there will be algebra-like mathematics involved in this post Talking about injuries is boring.  Talking about math is more boring.  Using math to talk about injuries has the potential to be an all-time boring blog post.  Luckily I readily accept the challenge to take two incredibly boring topics and create the most interesting, informative, and entertaining reading you will do all day.  I promise it will someday save you from nagging pain, discomfort, and exercise-induced injury.* *Promise not available in all states.  Some restrictions apply.  Limit one offer per household E=MC2.  F=MA. U + ME = US.  Equations are the rules that govern the physical world.  The fitness world is no different (except for 220-AGE=Max Heart Rate, that’s about as accurate as the clock on my microwave).  When talking about injuries, one equation best dictates the potential for a non-traumatic issue to occur:


I=Injury N=Number of Repetitions F=Force (relative to the maximum potential of the individual) A= Amplitude (essentially the range of motion) R = Rest Still there? I promise before the end of this you’ll come to love that formula despite its mathematical connotation.  Let’s break down the formula and use some examples.  We will make it really simple and say that a high “I” means a higher probability of injury, so any way that we can make “I” smaller is good.  Here’s several ways an injury can happen:
  1. A high number of repetitions (N) combined with a moderate force (F) divided by a short range of motion (A) and little rest (R).  This is your classic overuse injury.  Think carpal tunnel syndrome.  You type all day.  It’s a moderate force based on the potential output of your fingers.  It’s a relatively short range of motion, and you hardly rest.
  2. One repetition (N) a force greater than your potential (F) divided by a decent (though not good enough) range of motion and no rest.  This is the heroic attempt to carry the refrigerator downstairs all by yourself.   You exceed the force potential of your body (in this case, your lower back) and you’re on the couch for a few weeks.
  3. High repetitions (N), high force (F), increasingly reduced range of motion (A), and limited rest.  This is a sport-induced injury much like what a baseball pitcher would experience over the length of a season.  Failure to maintain mobility during the season greatly increases the likelihood of breakdown, just like failing to maintain your car during a lot of driving.
Ok, those are just a few scenarios exhibiting how and why the injury formula works.  So how do we use the injury formula to reduce our chances of getting hurt?  Lets break it down scenario by scenario:
  1. Ok, so carpal tunnel isn’t the best example to provide a solution for; I don’t know if your boss would be happy about me telling you to cut down on your productivity.  Let’s change it to a more fitness-related problem, jogging.  Lots of injuries here, high reps, short range of motion (jogging does not take one joint through a full range of motion), and rarely enough rest for those piling on the miles.  Also, there is a surprisingly high amount of ground force involved in jogging, packing on the wear and tear on the muscles.

That's a lot of F

Rather do what I usually do which is tell you to toss running out the window completely, I’m going to suggest a more reasonable solution for those capable, and for the sake of this discussion.  Sprinting or near-sprinting solves a lot of our problems.  We cut down on reps (N), increase the force (F) although only minimally because our angle relative to the ground is more favorable.  The range of motion is greatly increased (A), and we can get a lot more rest (r), while still getting a much more effective workout.
  1. From our failed moving man example, we can form yet another argument for my favorite thing in the world, getting stronger!!!  Remember, F is relative to the maximum potential of the individual.  Much like a machine, our bodies are far more efficient and less likely to be injured at 50% capacity rather than nearing 100%.  So if we are lifting a 250 lb fridge and my body is capable of producing 500 lbs of force while yours is only capable of 300, you are at a far greater risk of being hurt.  Getting stronger enables us to handle any task with greater safety over time, regardless of the rest of the formula.
  1. Now to our athletes.  A well-trained athlete is going to have a tough time altering too much of the top of the formula.  We will assume they are going to be requiring about the same (N) as dictated by their sport.  So let’s dominate the denominator!  If we improve the range of motion (A) or at the least maintain it, we’re mitigating the injury risk.  And if we improve either the quality or quantity of rest (or both!) we’re going to see less injuries as an end result.  For baseball pitchers, that means measuring range-of-motion preseason and throughout the year and focusing on maintaining the initial numbers.
So there you go, I promised it wouldn’t be as painful as Mrs. Smith’s high school pre-calculus class, and hopefully a lot more useful.  Next time you start to feel some aches and pains, maybe it’s time to break out the calculator!