# Dynamic Responses of Human Skin and Fascia to an Innovative Stimulation Device—Shear Wave Stimulation

## TL;DR

A new contactless method called Shear Wave Stimulation (SWS) was tested on human skin and fascia and found to improve skin properties similarly to massage, but with different effects on skin layers.

## Contribution

Introduces Shear Wave Stimulation (SWS) as a novel contactless mechanotherapy method for skin healing.

## Key findings

- SWS increased skin shear modulus by ~20%, similar to massage.
- SWS extended dermis, hypodermis, and fascia, while massage compressed skin layers.
- SWS and massage elicited distinct blood flow responses, confirming different stimulation modes.

## Abstract

Exposure to mechanical stimuli such as pressure and stretching prompts the skin to undergo physiological adaptations to accommodate and distribute applied forces, a process known as mechanotransduction. Mechanotherapy, which leverages mechanotransduction, shows significant promise across various medical disciplines. Traditional methods, such as massage and compression therapy, effectively promote skin healing by utilizing this mechanism, although they require direct skin contact. This study introduces a novel contactless modality, Shear Wave Stimulation (SWS), and evaluates its efficacy compared to traditional massage in eliciting responses from human skin and fascia. Fifteen healthy volunteers received SWS, while another fifteen volunteers received massage. Tests of skin mechanical properties revealed significant enhancements in skin shear modulus for both methods, showing an increase of approximately 20%. Additionally, deformation analysis of ultrasound images showed distinct responses of the skin and fascia to the two stimuli. SWS induced extension in the dermis (∼18%), hypodermis (∼16%), and fascia (∼22%) along the X and Y axes. In contrast, massage compressed the skin layers, reducing the dermis by around 15% and the hypodermis by about 8%, while simultaneously stretching the superficial fascia by approximately 8%. The observed extension across the entire skin with SWS highlights its potential as a groundbreaking contactless approach for promoting skin healing. Furthermore, the differing responses in blood flow reaffirm the distinct stimulation modes of SWS and massage. These findings establish a foundation for future innovative skin therapy modalities.