Shock Waves, Magnets, Red Light, Ultrasound…Do They Work?
All tissues respond to stimulation. Here is a look at a few of the non-injection ways we use to accelerate healing.
Energy fields sound “woo-woo.” Yet since ancient times, the stimulation of tissues—by massage, by needles with acupuncture, by heat and cold, and exercise—has been known to resolve tissue damage. The common pathway seems to be that all tissues are dynamic, constantly undergoing growth and resorption, their remodeling aided by the influx of cells, blood vessels, chemical stimulants, hormones, and small peptides.
The microenvironment of tissues—the cells and their biomacromolecules— all exhibit some level of sensitivity to sensory input. When physically “tickled,” they respond.
Certain musculoskeletal cells within injured tissues have been shown to have small filaments on their surfaces called mechanoreceptors. These cells respond to the stimulation of massage and other energy forms by increasing their metabolism, their collagen production, and their effectiveness at directing the healing response.
When a tissue (such as a muscle) is injured from a tear or a bruise, the immediate swelling we see is from the broken blood vessels bleeding into the area, and a release of fluid from the “extracellular space:” the area outside of the cells themselves. An alert, signaled by chemokines or small proteins, goes out to the body’s own stem cells, recruiting them to the site of injury to direct the healing response. Specific cells, called monocytes, differentiate into several types of macrophages: those that break down the damaged tissues and others that release and organize new collagen fibers to rebuild the damaged structures. The swelling initially seen is the body’s immediate response. The longer the swelling persists, however, the slower the resolution of the healing. This is where the opportunity lies for external stimulation to be applied.
Shock waves, ultrasound, magnetic fields, red and laser lights, hot and cold energy from compression devices, and simple tissue massage all stimulate the mechanoreceptors, accelerating their activity. Some may directly affect the expression of local cell DNA. Even underlying bone cells, whether injured or arthritic, can respond to these energy applications. While initially thought to be useful only in acute injuries or non-healing bone lesions, newer data demonstrate that shock wave therapy slows the degradation in arthritic joints by stalling the cell cycle of the osteoblast and diminishing their trajectory to cell death1.
Cells that are senescent (dead) from injury or chronic arthritis secrete inflammatory proteins, accelerating the osteoarthritis disease. Removing them—or diminishing their progress by shock wave therapy—has been shown to be of benefit in cartilage, rotator cuff, and meniscus repair2.
The use of heat and cold, red lights and lasers, ultrasound and magnetic fields all function by the same basic mechanism: stimulation of tissues. Shock wave therapy appears to be the most energetic of the applications and may work by actually creating a new injury, a shearing injury of the tissues with the acoustic waves, thereby sending new chemotactic signals to recruit stem cells. Though the scientific data on each modality is all over the place, and the frequencies, dosages, and intervals are completely uncontrolled in studies, the principle of safe tissue stimulation remains both viable and exciting.
Massage of tissues with hands or devices, ice and heat, and exercise all have positive effects on the healing cycle and are the least expensive of the interventions. The challenge is to provide just the right amount of stimulation at the right moment in a cost-effective and time-efficient manner.
Similar to the best energy policy at the government level, an all-of-the-above approach seems the best strategy for healing injuries this time.
References
- Chen L, Zhang Z, Ma X, Zhang D, Xu Q, Wang Q, Pan S, He Y & Liu X. Radial Extracorporeal Shockwave Therapy Reduces Subchondral Osteoblast Senescence in Knee Osteoarthritis. The American Journal of Sports Medicine. 2025;53(10):2352–2362. doi:10.1177/03635465251355245
- Jhan SW, Wang CJ, Wu KT, Siu KK, Ko JY, Huang WC, Chou WY & Cheng JH. Comparison of Extracorporeal Shockwave Therapy with Non-Steroid Anti-Inflammatory Drugs and Intra-articular Hyaluronic Acid Injection for Early Osteoarthritis of the Knees. Biomedicines. 2022;10(2):202. doi:10.3390/biomedicines10020202
