The battle between flexibility and strength in low back pain. WHO WINS?

Written by Brianna Irion, PT, DPT, OCS

It seems to be one of the most common questions that comes up with patients who suffer from low back pain.

Am I not flexible enough? Or maybe I’m not strong enough?

The reality is, both are important and fill different roles in reducing your risk of a painful low back.

I hear the phrase “I’ve never been very flexible” a lot. That’s not a bad thing. Most people do not have the flexibility of a ballerina or a gymnast. Everyone’s baseline flexibility is different; you don’t have to be a contortionist to stay healthy while being active.

Flexibility is defined as “ the quality of bending easily without breaking”. The tissues that surround your joints, including muscles, tendons and ligaments, all provide a certain level of stretch to allow movement. Those tissues also have a governing system to ensure they don’t tear every time you move. If those tissues become “tight” or lack a level of flexibility that is necessary to complete daily and recreational activities, they may become injured in the process.

Strength, on the other hand, can be defined as “the capacity of an object or substance to withstand great force or pressure.” Your low back is made of up of many small joints that work together to create varying movements. The strength of your muscle tissue surrounding those joints is what provides support during movement. Think of the wheel on a car: your joint is the rim and your muscles are the tire. If you are adequately strong for the activities you are participating in, the tire is full of air and you are not damaging the rim. If there is weakness in a muscle, the tire is somewhat flat, placing increased pressure through the rim, thus increasing the risk of potential injury.

Although strength and flexibility play very different roles in keeping you healthy and un-injured, they are also intimately connected. Muscles produce varying amounts of force depending on the length they are contracting at; also known as the ‘length-tension relationship’. If a muscle is contracted when it is very shortened or very lengthened, there is a natural reduction in the force that muscle is capable of producing. That’s where flexibility comes into play. If your low back tissues or joints are limited in mobility, surrounding musculature is unable to work at its optimal length and provide proper function. In other words, adequate mobility equals improved strength.

As you can see, the question is not who wins but rather how to engage both flexibility and strength together so they work in your favor. There’s no perfect formula to maintain both, but creating a program that works well for you is the best way to maintain a healthy, active lifestyle with reduced risk of low back pain.