If You Stretch It, You Need to Strengthen It, Too!

By Joe Ingriselli, DPT, MA, ATC

Stretching and strengthening, two components that define the essence of training.  The peanut butter and jelly of training if you will.  If you are lacking in one area, chances are this iscausing a deficit in the other half of your training sandwich.  How often have we heard “Oh it’s probably just tight so stretch it!”  Simple solution to a chronic problem right?  But we cannot forget the other half, strengthening.  Dusting off our brains, we know that muscle tissue is actually composed of little units called sarcomeres.  These units are made up of actin and myosin filaments that work together to help your muscle contract.  I won’t bore you with the specifics but if you would like more in-depth information on muscle physiology I recommend reading “Skeletal Muscle Physiology: Plstretchasticity and Responses to Exercise” by W. Kraemer and B. Spiering (2007). 

Sorry for the physiology side track but we must learn to walk before we can run.  So where were we…oh yea stretching and strengthening.  What is truly amazing about the human body is its ability to adapt and change so that we remain as balanced as possible.  Our bodies are constantly trying to maintain homeostasis.  Our muscles, being part of our body, are no different.  We apply a stress and our muscles react to that stress in order to return to what they consider normal.  In particular muscles always want to be at an optimal length for producing the right amount of force and the strongest contraction.  If a muscle is stretched too much you will not get that muscle to produce the optimal amount of force output.  If a muscle is too short (imagine your leg with your knee straight, tightening your quad as tight as possible creating maximal shortening of your quad muscle) you also will not achieve optimal force output.

So let me take this concept a step further and discuss what current literature is telling us about stretching.  Recently there has been increasing research in the area of sarcomerogenesis.1 Sarcomerogenesis is simply the laying down of new sarcomere units within skeletal muscle when it is stretched beyond its normal limit.  Another analogy for you, imagine your muscles as a railroad system used to power and move around any weight you are exposed to, wether its a bag of groceries or a deadlift PR.  If we stretch a muscle beyond its normal limit we have to add more pieces of railroad track for it to function properly.  This new track not only lengthens the existing track but returns the railway system to its optimal operating distance (Recall if a muscle is too short or long it will not function efficiently).  So this new railroad track is essentially sarcomerogenesis in a nut shell.

So great, we have our brand new railroad set up to run and we can continue to ship our supplies to the rest of the team on the Oregon Trail right?  Unfortunately no.  See what we have essentially just done is laid down the new track but have not bolted in the pieces or added secondary support structures to give STRENGTH to the new railway.  Essentially all we have done is create what is referred to as a “plastic” change in muscle.  Unfortunately for us plastic changes do not allow us to generate force (ie lift that bag of groceries or set that deadlift PR).  So what the hell are we supposed to do?!?  Easy my friends! WE STRENGTHEN!  Once a new range of motion and increase in flexibility has been achieved we should always train our strength within this new range of motion.  This allows us to train and recruit these new sarcomere units we have laid down.  Now and only now do we have a functioning railroad system.

Current research also points towards multiple sessions of stretching as opposed to a single long duration stretch to improve flexibility and sarcomere addition.  Also eccentric strength training is a great way to challenge a muscles strength while lengthening the muscle unit.  To improve your flexibility and strength within this new range, try stretching a tight area multiple times a day instead of just once following a workout.  Also pepper in some eccentric exercises if the area that is tight and see how this helps your overall flexibility!  So for those who argue “Just stretch it out” you may be missing the train.  We are only as strong as our muscles allow us to be within a certain range of motion.  So the next time you stretch remember your peanut butter to jelly ratio and make sure you strengthen within your new range!

Stick around for some upcoming articles on exercises you can implement in your training to strengthen what you stretch!


  1. Zöllner AM, Abilez OJ, Böl M, Kuhl E. Stretching skeletal muscle: chronic muscle lengthening through sarcomerogenesis.PLoS One. 2012;7(10):e45661. doi: 10.1371/journal.pone.0045661. Epub 2012 Oct 1. PubMed PMID: 23049683; PubMed Central PMCID: PMC3462200.