Physiological Responses to Upper Limb NMES with Firefly®
Research type
Research Study
Full title
Exploring Local Physiological Changes in the Arm During NMES Using the Firefly® Device
IRAS ID
360302
Contact name
Kieron Day
Contact email
Sponsor organisation
Firstkind Ltd
Duration of Study in the UK
0 years, 2 months, 1 days
Research summary
This study looks at how a small device called Firefly® affects blood flow and oxygen levels in arm muscles. The Firefly® device sends gentle electrical signals through the skin to stimulate nerves. These nerves then trigger nearby muscles to contract. The device is already approved for treating certain medical issues like swelling (oedema) and helping tendons and ligaments heal. It is also sometimes used more generally for wellness purposes, like increasing circulation after exercise to help with muscle soreness. However, these wellness uses are not part of its official medical approval.
In this study, we want to see what happens in the arm when the device is used. We will test it on two areas: the upper arm and the forearm. While the device is on, we will check blood flow using ultrasound, which is safe and painless. We will also monitor how much oxygen is in the muscle using a small sensor that sticks to the skin.
Twelve healthy adults between 18 and 45 years old will take part. Each person will have the device placed on their arm in the two test areas. The device will switch between being on and off several times. The whole visit will take about two hours.
We don’t expect any problems, but some people may feel a mild tingling, muscle twitching, or slight skin redness where the device or sensors are placed. These effects should go away quickly.
This study is not a treatment. Instead, it will help us understand how the device affects blood and oxygen flow in the arm. The findings could help with future research on muscle recovery after activity. The study is for information only and does not test the device for any new medical use.
REC name
Wales REC 3
REC reference
25/WA/0223
Date of REC Opinion
23 Jul 2025
REC opinion
Favourable Opinion