Understanding some of the science behind strength training

We've all heard about it or have done it personally.  Strength training is one of the main reasons people go to a gym or exercise regularly.  From adolescence to senesence (when you're old)people want to get stronger.  Some want bulging biceps or a wash board stomach, while others just want to be able to do their daily routines a little easier.  Strength training can offer all of these things and more.

Despite its popularity, most people don't really understand what is happening to the muscle when we are strength training.  Here's a few imprortant concepts you should know when it comes to gaining strength. 

Hypertrophy - this is muscle growth.  This is why many people strength train, to get physically bigger muscles.  Are bigger muscles stronger muscles??  Yes!  Muscle strength is directly related to the surface area of a muscle.

Neural drive - The amount of nerves that are actively firing in that muslce during a muscle's contraction.  There are many nerves within a muscle, each having the responsibility of making a small part of the muscle contract.  The more nerves fire, the stronger the contraction, the more force a muscle can generate. 

If we put both of these concepts together you can see how we get stronger as we strength train.  Here's a scenario for you:

You go to the gym for the first time and lift a weight you feel is heavy five times in a row and are unable to lift it for a sixth time.  You go home and decide that you are going to do the same thing every other day for eight weeks to see what happens. On your second visit to the gym you lift the same weight five times in a row and then you are able to lift it for a sixth and seventh time before you fail at the eighth repetition.  After smiling at your new found herculean strength you think to yourself:  "Did I get stronger after just one time at the gym?"  You quickly go home and rip your shirt off to examine your muscles, thinking that maybe they actually did get a little bigger as you flex in the mirror.

Did you get stronger?  Yes you did!  Did your muscles get bigger - they definitely did not!  You got stronger due to increased neural drive.  After the first day of training your nerves picked up on the idea that you were going to do this strenuous activity so they responded by increasing the number of nerves that participated in the contraction.  Viola!  Instant strength gain.  This is absolutely true and supported within the research as well as from first-hand accounts from people who strength train.

Now you continue your training and you make steady progress. Perhaps one extra rep, perhaps you added a few extra pounds to the weight.  It's been three weeks now and you feel great...but you don"t look any different.  Every time you look in the mirror after working out you seem bigger (which is because increased blood flow to the specific muscles that are working) but it's only temporary.  The next morning you are back to square one. 

When do the muscle start getting bigger?  Generally speaking, hypertrophy takes about four weeks to occur.  That's four weeks of consistant training, so please don't go to the gym and work out one day and then sit on the couch staring at a calandar with a day circled four weeks from now.  Doesn"t work that way.

The bottome line is that we gain strength from both muscle hypertrophy as well as increased neural drive, and both of these adaptive mechanisms are at work while we are strength training in order to give us what we want....more strength.

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Yours in health

Chris Ostling PT, DPT