I think that the first time I ever saw shoulder airbags was on the Panasonic Ep30007 chair. I remember being curious as to why the airbags were in the chair back and pushed the shoulders forward, as this seemed rather counter-intuitive to a chiropractor who worked on correcting forward slumping shoulders. Why on earth would a chair push the shoulders forward, when they obviously needed to be pulled back? That was exactly my sentiment when I saw that feature on that chair.
Then, a few years later Inada introduced the Doctor's Choice 3A massage chair, which had a shoulder housing on either side of the body that had airbags that inflated to the FRONT of the shoulders, thereby pinning the shoulders back. Now, that made sense to me. I remember being so impressed with the idea of airbags pinning the shoulders back in an effort to improve posture. I also remember sitting on that chair for the first time and feeling taller (and less "slumped" when I stood up afterwards. I was excited to have a chair to offer customers that had a feature like this. I felt it was very much needed and that it complimented the spinal correction I did as a chiropractor.
Since that time, we've seen quite a few new models come out with shoulder airbags, but they've not all been the same. A new breed of shoulder airbags came out that only inflated onto the outside aspect of each shoulder (against the deltoid muscles). It's purpose was not to reverse a slumping posture by pinning the shoulders back; it was designed to hold the upper body in place, much like thigh airbags that held the hips in place, so that the roller massage that passed through the mid back region would be accentuated and made more intense by holding the shoulders and upper body immobile. These airbags prevented the rollers from pushing the body forward, thus maximizing the intensity of the roller massage.
Then along came the Inada Sogno that introduced airbags that pushed down from the bottom of the headpiece (aka Cervical Traction Device) onto trapezia muscles at the top of the shoulders. This was a whole different shoulder massage approach. It actually did massage some muscles, whereas the previous shoulder airbag iterations simple compressed against the shoulder joint to hold the body in a particular position.
Here are the 3 types of shoulder airbags:
1. Lateral Compression (side)
These are found in chairs like the Osaki OS-3D Pro Dreamer, Osaki OS-4000, Panasonic MA70, and Omega Montage Pro. These chairs offer airbags that compress the outer aspect of the shoulders (deltoid muscles) and are designed to hold the upper body in place while the rollers move up and down the spine.
2. Anterior Compression (front)
These airbags are found in chairs like the Inada Doctor's Choice (has since been discontinued), Infinity IT-8500, Infinity Iyashi, Osaki OS-3D Pro Cyber, and the Osaki OS-7075R. The purpose of these airbags is twofold: a.) to pin the shoulders back for posture correction while the rollers move up and down the spine, and b.) to hold the shoulders back during the stretch program. You see, when you are going through the stretch program in a massage chair, the airbags of the foot massager inflate to hold the feet in place while the ottoman drops. Simultaneously the chair back reclines, thus accentuating the effect of the stretch. With the shoulder airbags inflating to the front of the shoulders, the airbags are doing to the upper body what the foot airbags are doing to the lower body. Both of these airbags features working simultaneously really give the user a great stretch.
3. Posterior Compression (rear)
The only chair that has this feature is the Panasonic EP30007 and the only therapeutic benefit I can see from these airbags is a compression against the infraspinatus muscles of the shoulder blades. I suppose you could go so far as to say that it is a "trigger point"-like compression of those muscles. You can see the shoulder airbag mechanisms on the picture to the left just above my granddaughter to the left and the right of the top of her head.
4. Superior Compression (top)
The Inada Sogno is the only chair that does this, with perhaps the iRobotics 6S chair from Luraco offering something similar. The purpose of these airbags is to impose a compression massage against the muscles at the top of the shoulders (the trapezia muscles). These airbags are not designed for "holding" or restricting movement of the torso, as with the airbags in#1 and #2 above, but for actual compression massage therapy. You can see on the image to the right the inflated airbags at the bottom of each side of the head piece. These airbags massage the trapezia muscles at the top of your shoulders (commonly affected muscles for desk and computer workers).
I hope this helps in understanding what shoulder airbags are and how they work, depending on their engineered purpose.
Dr. Alan Weidner