Will Strength Training Make You Less Flexible?

Screen Shot 2014-11-03 at 9.51.50 AM


The other week I received a text from a new client asking if we could include more stretching in our program because they felt as though the strength training was making them tight. I’ve always wondered about this phenomenon myself. I am pretty inflexible (insert character flaw joke here), and it’s pretty tough for me to get into some deep ranges of motion in my upper extremity. Sure, I can still put my hands flat on the floor during a stand and reach test, but putting my arms over my head is greatly impeded by my lat and thoracic extension/rotation or lack thereof. Basically, my upper body is tighter than a car full of clowns and blow up dolls. I’ve always wondered if these was because my strength training program.

I came across some great research that was published ahead of print in the Journal of Strength and Conditioning that answers the aforementioned question: Will strength training make you less flexible? (HERE is a link to the journal article)


The Physiology of Flexibility:

Although one might believe what causes a muscle to actually stretch, there are only hypothesis of why.

  • viscoelastic deformation – elastic materials in the soft tissue are deformed

  • plastic deformation – a threshold of stress is achieved causing deformation at the atomic level

  • increased sarcomeres – sarcomeres are the basic units of muscle, and stretching is thought to create more of these

  • neuromuscular relaxation – Central nervous system “lets go”


But the most logical and research supported explanation as to why muscles “stretch,” or become lengthened, is actually do to changes in the sensation of pain on the onset of stretching. There is pain involved with lengthening the muscle, which will tell our body to stop stretching. Decreasing the pain tolerance will allow the body to lengthen the muscle more.


What Did The Researchers Do?

The researchers wanted to find out the effects strength training had on flexilibity and vice versa. They took 28 recreationally strength trained and flexibility trained females through 12 weeks of either: strength training only, flexiblilty training only, strength training after flexilbity training, OR strength training BEFORE flexibility training.


What Did They Find?

The researchers found that NONE of the groups increased flexibility by measure of the sit and research test. However, none of the groups lost any flexibility, and all groups except the stretching only group went up in strength gains.


In Conclusion:

Strength training does not impede flexibility gains. In fact, it seems as though nothing really creates flexibility gains in 12 weeks.


My Take:

I believe stretching takes place when pain tolerance is built up to the stretch. I remember when I first started doing yoga in college (side note: I quit when someone farted in my face during rolling patterns) and got very flexible. When we got into positions that were very painful, we would work on breathing and meditate in those positions until it felt comfortable, and then go deeper into the stretch. We were basically telling our CNS, “hey it’s ok to be in these stretched out positions.” There was a big mental aspect to this, and now I’m finding it’s research based, which makes complete sense.

I think if strength training was accompanied by this type of stretching noted above, longterm flexibility gains will be made. However, the dynamic and static stretching in which a conscious CNS adaptation isn’t the focus, only an acute (short lasting) change will be made.


How To Apply This Type of Stretching:

We are going to use a prone hamstring stretch for this example.

  1. Lye on your back and use a superband, belt, or a tie from a robe to wrap around the arch of your foot.

  2. Raise your foot as high as you can toward your head, keeping your knee straight.

  3. Once you go into a deep stretch that is pretty uncomfortable, get comfortable.

  4. Perform box breathing: inhale into your nose for 4 seconds, hold your breath for 4 seconds, exhale out of your mouth for 4 seconds, and hold your breath for 4 seconds. Repeat this for 2 minutes.

  5. While doing your box breathing, put all your attention on the muscle stretching, and try to focus on the pain. You’ll notice something happening as you focus on the pain: it goes away.

  6. Go deeper into the stretch by pulling the band back and repeat number 5 until your 2 minutes is up.


You can do this technique with any static stretch. Perform 1 rep of 2 minutes on each side, either before or after your workout, and during off days from strength training, as well.


Leave A Reply