One of the most seemingly trendy exercises to do these days is to use resistance bands to stretch and mobilize. Unfortunately, (or fortunately, for fitness equipment manufacturers), this means a decreased shelf-life for all the bands in your gym due to consistently being stretched to their maximum elastic length.
But, I'm an open-minded person. Maybe there's some merit to stretching with bands as opposed to other things. Absolutely, I've found some use with joint glides using bands (in the therapeutic setting), but for stretching itself, this is different. After my gym shift, I popped into my clinic to experiment in private.
Ok, mobility peeps. You may not be happy, but, as I concluded, the line of pull for stretching your lats and rhomboids using a band:
...was functionally no different than this:
In fact, using the pillar (or doorway, squat rack, pole, or anything else), actually gave me a better stretch. If you're wondering why, it's because the pillar doesn't stretch as well...like the band does. There's a reason everyone has to take their resistance bands to their end ranges - because that's the point where the band stops stretching. Doesn't it make sense to use something that just won't stretch in the first place for the assistance?
Well, maybe the gentle stretch of using the band is better, because those gentle pulses into the stretch help the muscle relax more.
Except no. Muscle spindles don't work like that. In order for the nerves in your muscles to allow the muscle to relax in a lengthened position, they must be overridden with consistent lengthening, not intermittent.
What About Training Overhead Range Of Motion?
Ok, I'll concede a bit here. Bands could be used to pulse through shoulder flexion and increase range of motion for overhead work. However, I'm still not a fan. With the band remaining uncontrolled in the lateral plane (moving side-to-side), you're essentially tractioning your shoulders at random angles, which could work out fine, or it could aggravate that old shoulder injury from football ten years ago.
Instead, here's my favourite exercise for shoulder flexion (and t-spine extension) done safely and controlled, via Eric Cressey.
Have I Missed Something?
Again, I'm open-minded. After experimenting, I went home and ran some Google searches on band stretching and mobilization to see if there was just something I was missing or doing wrong. Unfortunately, I couldn't find any source that cited the physiological benefit of bands over stable structures for assisted stretching. The best support for it was Kelly Starrett's videos, but even he seems to prefer the method, to my understanding, for the versatility of stretching different ranges rather than for a "better" stretch itself.
Yet, I do still invite the enthusiasts out there to challenge me on why we should be using these methods (besides just looking cool), and I'll absolutely listen. To this point, however, I remain unconvinced.