The idea that strengthening muscles makes them more stiff or less flexible is one of the past; as is the thought that a long and flexible muscle is weaker. Both mobility and strength are necessary for performance and injury prevention, and it’s hard to improve one without the other.
Why not static stretching like we’ve done our whole lives? Although this can feel good, and can improve mobility in the short term, it doesn’t produce long-term change like we used to believe. Static stretching can dampen the nervous system response to a stretch so that it feels easier to move into this position for some time; however, this is short lived. Permanent changes in tissue length at the muscular and cellular level are not seen, so true length changes throughout the muscle don’t happen. We’ve learned in recent years that the best way to improve a muscle’s flexibility may be to load that muscle as it is stretched.
In the world of exercise this is called an eccentric activity. When thinking of how a muscle contracts there are three primary methods: isometric, concentric, and eccentric. Isometric occurs when there is no motion, i.e., arm wrestling against someone who’s an even match. Concentric involves shortening of the muscle as it moves against a load, i.e., the part of a bicep curl that brings the weight closer to your shoulder. Finally, eccentric involves lengthening the muscle while it lowers a load, i.e., the part of a bicep curl when you lower the weight to your side.
This eccentric load has been shown to create long term changes within the muscle that improve mobility around a joint and flexibility of that muscle, while simultaneously strengthening within that range. It does so by breaking down the tissue under a heavy load during the exercise. During recovery the muscle remodels to withstand this stretch better the next time it comes around. Just as you break down your hammies during a deadlift and can go heavier over time. This can be especially effective at the hamstrings or hip flexors, but really many muscle groups can benefit from this training as we use eccentric motions throughout our life! Bending over to pick something up, lowering our body weight off a step, lowering an object from a high shelf, etc.
What do these exercises look like? Think about the position you’re in when that muscle is in a big stretch. This is the motion you want to create through the exercise, simply adding a load. Some examples might include psoas lower, reverse Nordic curl, and a dropped heel raise.
Research and evidence are ever evolving. So much so that it seems hard to keep up! Our current body of evidence suggests this approach of eccentric loading may make more impact than static stretching, and that static stretching maybe doesn’t do what we once thought. Even so, it’s always best to analyze what your body needs, and what works well for YOU!
If you need guidance on where to start, or what approach suits your needs, head to our website to chat with a PT!
Elle Carlson, PT, DPT