Skip to main content
Move the World.
Unlocking the Mysteries of Muscles in Motion

Lead image © Nature Asia Materials, doi: 10.1038/s41427-019-0183-1

Thirtysomethings have probably noticed that physical activities that were once easy now require a little bit more effort...and more aspirin. Even the most mundane tasks can strain muscles. But imagine a device that can measure how your muscles work as you perform these tasks. This device could help you correct your hand positioning as you type to avoid muscle cramps; or, an almost undetectable sensor could tell you you’re straining your back while lifting things at work or the gym. This information could help you prevent future injuries. A new, micro-thin patch — inspired by the Japanese paper-cutting technique known as kirigami — could be the first step to making this a reality.

Scientists in Japan have used kirigami-inspired technology to make a patch to measure muscle activity. The patch runs a test called surface electromyography (SEMG) — watching muscle activity from outside the body — which dates back to the 1920s but has been limited by clunky technology. These scientists have shrunk the device to just a couple of square inches that are a few ten-thousandths of a millimeter thick.

Regular electromyography (EMG) — measuring the electrical zaps made by muscles — can be done inside the body with special needles. But imagine trying to model your movements from your job or sports with needles stuck in your arm or torso — you'd feel like the Hellraiser.

SEMG lets doctors observe you without intruding. However, traditional SEMG devices have used stick-on electrodes that also aren't convenient for field use. Typically, even the thinnest electrodes must be wired to power sources, causing most SEMG devices to be rigid and clunky.

"Conventionally, sEMG has been recorded using small electrodes that are attached to the skin surface and connected to an amplifier with wires," Dr. Kento Yamagishi and colleagues at Japan's Waseda University write in their newly published study. "However, these devices restrict free movement."

So, the Japanese team designed a new setup to fix these problems. In their device, conductive wires are sandwiched between two cushion layers, and the whole thing is less than 400 nanometers thick.

The research team used baseball pitchers — who perform a repetitive, high-energy motion — to test their prototype. Yamagishi's team stuck their patch to a pitcher's palm, running a flexible wire to a minimal Bluetooth power source out of the pitcher's range of motion. Yamagishi's device deforms with the skin, meaning it can naturally bend and move with the palm — one of the most difficult surfaces to cling to.

This patch could improve a lot of situations where a “mechanical mismatch” has puzzled doctors and physical therapists.

"Because of the flexibility, stretchability, and durability of the elastic kirigami wiring system, the patch, Bluetooth module, and two EMG sensors remained secure on the skin without detachment or rupture during the trials," the team writes. "The elastic kirigami patch ... is an effective solution for the mechanical mismatch between electrical devices and the human body."

Indeed, the patch could improve a lot of situations where that "mechanical mismatch" has puzzled doctors and physical therapists.

SEMG is growing in popularity for athletes. But historically, its main use has always been for regular people undergoing physical therapy. This kind of muscle test can help avoid fatigue injury, aid in study and treatment of muscle paralysis, and narrow down factors that cause back pain. It can help office workers better prevent repetitive strain injury. As the technologies get better and cheaper, SEMG is really for everyone.

Up Next

Oceans
Divers Remove Wildlife-Killing “Ghost Nets” From Shipwreck
Ghost Nets
Oceans
Divers Remove Wildlife-Killing “Ghost Nets” From Shipwreck
The Healthy Seas initiative removes wildlife-killing “ghost nets” from the ocean so that they can be recycled into useful Econyl yarn.

The Healthy Seas initiative removes wildlife-killing “ghost nets” from the ocean so that they can be recycled into useful Econyl yarn.

Disaster Response
A New Way to Find People Lost at Sea
search and rescue
Disaster Response
A New Way to Find People Lost at Sea
In a search and rescue mission at sea, time is of the essence. A new model may make missions faster — and save lives.

In a search and rescue mission at sea, time is of the essence. A new model may make missions faster — and save lives.

Public Health
Microbe in Mosquito Guts Completely Blocks Malaria Parasite
Malaria Parasite
Public Health
Microbe in Mosquito Guts Completely Blocks Malaria Parasite
Scientists have discovered a microbe in the guts of mosquitoes that appears to prevent the most common malaria parasite from infecting the insects.

Scientists have discovered a microbe in the guts of mosquitoes that appears to prevent the most common malaria parasite from infecting the insects.

Future of Science
Researchers are Rushing to Freeze... Lab Mice Sperm?
Lab mice
Future of Science
Researchers are Rushing to Freeze... Lab Mice Sperm?
With their labs closing and the future unclear, researchers are sending precious cargo — the sperm of lab mice — to be frozen and stored.

With their labs closing and the future unclear, researchers are sending precious cargo — the sperm of lab mice — to be frozen and stored.

Climate Change
A New Approach to Green Building Could Reverse Climate Change
green building
Climate Change
A New Approach to Green Building Could Reverse Climate Change
The building sector is one of the biggest contributors of greenhouse gas emissions. But new research suggests that trend could stop, and even reverse because of a new type of green building.

The building sector is one of the biggest contributors of greenhouse gas emissions. But new research suggests that trend could stop, and even reverse because of a new type of green building.

Superhuman
Reprogramming Your Immune System to Fight Cancer
Reprogramming Your Immune System to Fight Cancer
Watch Now
Superhuman
Reprogramming Your Immune System to Fight Cancer
Your T cells already know how to kill cancer. These doctors can train them to hunt it down.
Watch Now

Josh Feldman was on his honeymoon when he felt a lump on his neck. Returning home after the best month of his life, his doctor gave him the news: non-Hodgkin's lymphoma. There was no cure, and it was about to get much worse. After multiple rounds of chemotherapy failed to stop his tumors from growing, Josh went to see Dr. John Timmerman, an oncologist at UCLA who is trying something different, known as immunotherapy. This...

Coded
Nico Sell on Recruiting Hackers for Good
Nico Sell on Recruiting Hackers for Good
Watch Now
Coded
Nico Sell on Recruiting Hackers for Good
Nico Sell, founder and chairman of the Wickr Foundation, on teaching kids how to hack and encouraging them to use their new-found talents for good.
Watch Now

People often have a bad perception of hackers, conjuring up images of either 20-somethings in their parents’ basement or sophisticated criminals responsible for massive data breaches. Nico Sell, founder and chairman of the Wickr Foundation, wants to change that. She thinks not only are hackers some of the smartest, most creative people around, but also that hacking will prove to be the most powerful tool for our...

Superhuman
Superhuman Trailer
Superhuman Trailer
Watch Now
Superhuman
Superhuman Trailer
Join us as we meet the innovators building our superhuman future.
Watch Now

Superhuman is a Freethink original series about the amazing advances in medical innovation that are making the present look more like a sci-fi depiction of the future. Join us as we meet the engineers, entrepreneurs, doctors and patients who are giving people a new lease on life today, while building our superhuman future of tomorrow.

Superhuman
Is the Miracle Medicine of the Future About to Become the Totally Real Medicine of...
Is the Miracle Medicine of the Future About to Become the Totally Real Medicine of the Present?
Superhuman
Is the Miracle Medicine of the Future About to Become the Totally Real Medicine of...
Gene therapy uses a virus to replace missing or defective genes. It sounds counterintuitive, but it could be the...
By Mike Riggs

Gene therapy uses a virus to replace missing or defective genes. It sounds counterintuitive, but it could be the key to curing previously incurable diseases.