I often like to bring in tidbits of Health Science to my HIIT class.  Well, that and a healthy dose of music trivia.  But I do think the education about fitness is likely more appreciated.  One topic I bring up often is our Central Nervous System (CNS).  Specifically, what role it plays in the remarkable way in which our body autonomously does things.  By “things” I mean everything from breathing to maintaining posture to muscle selection. 

Muscle selection is really, cool.  Think about it.  When you go to perform an everyday task, like lifting a box and putting it on a shelf, do you consciously think to yourself “OK, first I’m going to bend over which will involve contraction of several muscles in my lower body in preparation for both the load and to maintain balance.  Then I will grasp the box which I think might weight about 40 pounds so I will prepare my core, my back, and my arms for about that amount of weight while simultaneously adjusting the muscles in my lower body both for the load and to continue to maintain balance.  Once I start to lift, I will adjust the amount of force I prepared for based on the actual weight of the box, which I’m determining at the same time as all these other activities, then I proceed to lift it high enough for the shelf using just enough force as to not waste energy.  Then I will put it down and relax the muscles that I just used in an order that minimizes the chances of injury.” I suspect nobody walks through any of this in their head, they just grab the box and put it on the shelf, end of task.

There are two incredibly interesting CNS topics that I bring up quite often because whether you are training on your own at the gym or participating in a fitness class these are cool ways to improve your workout. 

These are proven fact, not just opinion and conjecture. Rather than make this post even longer than it already is, I’m going to briefly describe each of these as I do in my HIIT classes and put links for each where you can read more detail along with references.

1. Reciprocal Inhibition.  This is a CNS “feature” that basically says if you flex one muscle, your CNS will forcibly relax the opposite.  Why is this important? It’s good for stretching for one thing but more to my point, it’s great for programming workouts for efficiency.  If you’d like to prove it to yourself, try flexing your biceps as hard as you can then simultaneously flex the triceps on the same arm. You might be able to get a little blood in the triceps, but you’ll see quickly that your CNS has effectively shut down the triceps.  Try the opposite too, flex your triceps then try to fire your biceps.  Not gonna happen! I think it’s clear why our CNS evolved this way, if you could put 100% effort into opposite muscle groups your body would be doing something incredibly unsafe.  Kinda like putting your car in drive and reverse at the same time (sort of).  So besides stretching, think about super-sets. Realizing this concept, try supersetting curls and triceps extensions with no rest in between.  Or bench press and machine row, no rest between sets.  Why no rest?  Because while you are working one muscle group the opposite is being forced to rest.  It really does work.  Read more here: Supersets: Use this exercise strategy to get more done in less time.
2. Think about the muscle you are working on, focus on it exclusively in your mind.  This is a trick my old training partner told me about.  Sounded plausible to be so I didn’t question it, plus she was a genius at this stuff, so I went with it.  Well turns out there a lot of science behind this than I imagined! For more information check out The Mind Muscle Connection.