The massage chair was first presented in the consumer market in the late 1980s. Intended to mimic the movements and techniques of a real massage, the purpose of the massage chair was to relieve stress, tension and relieve back pain.
Although massage chairs had very few sales in starting, the trend has changed by advanced technologies, the competition has increased which in turn resulted in sophisticated massage chairs with different features.

Therapeutic Massage Techniques

Currently, the massage techniques that massage chairs are designed to try to be like the Shiatsu and Swedish massage.
Shiatsu tends to use rotating, sweeping, rolling, waving and pressing movements. The defining characteristic of shiatsu is its emphasis on the release of tension in specific areas of the body.
Swedish massage is characteristic of long sliding shots and kneading movements. This type of massage aims to promote proper and strong circulation.

Main components of massage chairs

Most massage chairs consists of three main components designed to closely match these massage techniques:

Massage chair engines –

these are the essential mechanical aspects of the massage chair. They feed and move the knots and rollers to the required areas, as well as the necessary adjustments on the seat back.
The massage chair features many predefined patterns and programs used to massage the entire back. However, motors, knots and rollers must be modified through the control pad that accompanies all massage chairs. As the user indicates, the massage chair focuses on the top of the spine in the lower back, with a tapping movement, rolling motion or kneading movement

Knots and massage chair rollers –

these vary in size and shape, designed to imitate hands and fingers. A massage chair with large rollers and knots offers a more generalized approach to massage, while massage chairs with smaller nodes and rollers provide a more detailed and specific massage to a point. They target the specified areas of the user’s back and can move in various ways, which are preprogrammed into the mechanics of the massage chair. Here the user can adjust these nodes and the rollers on the massage chair to better meet his needs.

Computer Assisted Adjustment of Massage Chair –

This is perhaps the most significant factor. Almost every massage chair is designed to adjust the weight, height and width of the selected user. By measuring the pressure on the backrest, the height of the projection of the rollers and the knots adjusts. Moreover, by locating specific areas on the anatomy of the back, the massage chair makes the required adjustments for the height and the width of the user. Selecting different inputs on the control pad can also fine-tune these options.
Of course, a mechanical substitute can never reproduce the exact meaning of human contact. As the years go by, designers have deepened the necessary factors in a massage chair to provide its users with some relief from back pain.

References:

https://www.spine-health.com