My post Best exercises for the subscapularis is still one of the most popular things I’ve written. Read it, otherwise this post won’t make as much sense.
Matt left a comment on that post:
“I know this was posted a while back, however I am wondering if this could also be done laying on your back, the resistance would be greatest at the beginning and least at the end of the movement, and it seems like it would be fairly easy to keep from using pecs while laying down? I am no kinesiologist but good idea or bad??”
This is an interesting idea; something I didn’t consider. Here’s how I envision Matt’s idea:
First, this resistance is still isotonic. Meaning the resistance doesn’t change. The tension is the same at the beginning as it is as the end.
If you used a band for resistance, the tension would actually be least at the beginning and greatest at the end.
Feel free to chime in Matt, but I’m not sure I see any advantage or reason for concern over varying the resistance throughout the movement. Sticking with the cable seems easiest to me.
One of the things I like about this variation is it could be easier for the person to make sure the humerus does not glide anteriorly. Being on your back allows the opposite hand greater leverage to push down the humerus. This is in contrast to the standing variation I proposed, where there isn’t as great of leverage.
Next, I would plop the elbow up, again, increasing the amount of help available to keep the humerus down. This is crucial. That humerus can’t be gliding forward in order for this to be effective.
Without having experimented this exercise with anyone but myself, a few potential issues do come to my head though.
1) This variation has less ROM.
The range of motion is cut down some with the ground variation. (Because you can only externally rotate as far as the ground will let you.) In contrast to the standing version where you can achieve greater than 90 degrees external rotation.
2) People completely butcher this WITHOUT weight.
The position of the shoulder here is very similar to a sleeper stretch.
I’ve had so much trouble coaching people properly on this that I don’t think I’ve recommended it to someone in at least a year. Last I checked guys like Eric Cressey and Mike Reinold, guys who see A LOT of baseball shoulders, have pretty much canned this stretch as well. It just doesn’t go well.
People have a tendency to let the shoulder shrug into the ear:
This allows them to achieve way more internal rotation than they otherwise would. This:
Really though, any exercise where you are focusing on glenohumeral rotation presents these issues. And in the year since I wrote the original post on the subscapularis I’ve gone more and more away from worrying about working directly on rotation.
Any dysfunction having to do with the humerus, like lack of internal rotation (GIRD), humeral anterior glide, humeral superior glide, etc. seems to more often than not be a symptom of an issue with the scapula.
Treating issues with the scapula, like downard rotation syndrome, is 1) Much easier than working on pure humeral rotation and 2) Often fixes the humeral issue at the same time. Working on the humeral issue does not guarantee fixing the scapular issue though.
That’s a bit of a tangent to Matt’s original question. I suppose my short answer would be, “This is a fair alternative, but you have to pay special attention to the form. Such close attention is needed that I probably wouldn’t bother with exercises specifically for the subscapularis. I’d focus much more on the movement at the scapula first.”