ECCENTRICITY

When I began weightlifting in high school, I had no idea what I was doing.  I would walk into the gym with neither a plan nor a workout written down to follow.  It was so bad…..I didn’t even know what part of the body I was going to work on…..and this as I was walking in to do my workout!  Often times, I would just decide on the spot, “I guess I’ll do arms today.”  I would walk over to some dumbbells and pick a pair and curl them up and down, up and down, up and down.  Oh was I clueless!  I wish I had known then what I know now about a thing called muscle contractions and how they work in weight training.  It is something you can definitely use to your advantage if you want your muscles to grow at a faster rate.  I will go over the types of muscle contractions and bring the application at the end that will tie everything together.

A muscle contraction is when the muscle is shortening or tightening.  It can also refer to the development of tension within a muscle.  When you’re weightlifting/weight training, you’re adding tension and resistance to the muscles which will create different types of contractions.  There are two main types of muscle contractions: ISOTONIC contractions and ISOMETRIC contractions.  An isotonic contraction is a contraction where the muscle shortens and lengthens but retains constant tension.  There is movement from limbs that are involved. An isometric contraction is a contraction in which the muscle develops tension but does NOT shorten or lengthen. There is no limb movement involved.  You might be thinking “how does a muscle develop tension without shortening? Let alone without even moving?”  Well, the world of weight training can be a wonderful thing because of things called tension and resistance.

The isotonic contraction is broken down into two types: the concentric contraction and the eccentric contraction.  Each contraction is unique in its own way. I’m going to use the simple exercise of the barbell bicep curl to explain these contractions.

  1. THE CONCENTRIC CONTRACTION (isotonic) – In a concentric contraction, the muscles shorten to produce movement.  When you pick up a barbell, add some weight to it, and bend your arms at the elbow to bring that bar up near your chest, that is the concentric contraction.  The biceps are shortening and tightening to get that heavy bar moving.  Go ahead….take a look at your bicep.  Make a fist and turn it upside down.  Now bend your arm and bring your fist toward your shoulder.  Watch your bicep shorten.  Try it…..I’ll wait.
  2. THE ECCENTRIC CONTRACTION (isotonic) – In an eccentric contraction, the muscle lengthens or stretches.  How is this possible?  A muscle contracts as it is shortening, right?  How is it contracting while lengthening or stretching out?  This is where resistance and tension comes in to play.  With the barbell bicep curl, after bringing the bar up near your chest, you are now going to lower the bar back down to the starting position near your waist.  While you’re doing this, the weight on the bar is a force of resistance that is causing tension on your biceps as they are extending to lower it.  The muscles are fighting the resistance that the bar brings to keep it up, all while stretching out.  The key to an eccentric contraction is the resistance and the tension that’s put on the muscle(s) you’re working.  Again, make a fist, turn it upside down, bring the fist to your shoulder by bending at the elbow.  Now straighten your arm out and bring that fist back down to your waist.  Watch the bicep muscle lengthen (stretch).  That’s what an eccentric contraction looks like.
  3. THE ISOMETRIC CONTRACTION – In an isometric contraction, the muscle develops tension and there is some shortening or maybe some lengthening of the muscles, but there is no limb or body movement.  Again with the bicep curl example.  You curl the bar up near your chest, and you start to lower the bar back down to your waist, but instead you stop the bar halfway between your chest and your waist.  Your arms are now bent at a 90 degree angle and you are now holding the bar in place and fighting to keep the bar from moving.  You are squeezing your biceps to keep that bar stable and your arms at 90 degrees.  That is an isometric contraction.  There is tension on your biceps but your arms are not moving.  You hold that bar in place as long as you can before your biceps just can’t anymore….’til failure.

So what does all this mean?  How can we use this to our advantage?  Like me when I started weight lifting, if you are just grabbing the bar or the dumbbells and curling up and going back down, up and down and up and down up and down, you are missing a great opportunity with the eccentric and the isometric contractions.  The eccentric contraction takes 50% more strength than the concentric contraction.  So, in the bicep curl example, you can work your muscle so much more if you slow down the eccentric curl and take 2 or 3 seconds to bring the bar back down to your waist as opposed to bringing it down to you waist in under a second.  Also, on the last rep of your set,  throw in an isometric hold with your arms at 90 degrees for 10 seconds.  An isometric contraction takes 20% more strength than a concentric contraction.  Not only can you do this with a bicep curl, but you can do this for any exercise.  Take the opportunity to slow down that eccentric curl and make it count.  Throw in some isometric contractions as well.  Another exercise I utilize this for at times is the squat exercise.  I’ll do what is called a “pause squat” where I will squat down to my deepest depth and hold that position for 3 seconds and then come up.  The point is, use these isotonic and the isometric contractions to your advantage and your muscles will grow faster because you are working them in a more efficient and effective way.

If this blooooog helps, please “like” and “share” it so it can help others as well.  It’s funny because I had this subject on my mind since I started back in January….it’s the end of July and I am finally getting to it.  Funny how thing work like that.  In the meantime,

STAY TUNED

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