Magnetic sensors track muscle movement for better prosthetic control
Science & technology · 29 October 2026
For a robotic prosthesis to respond naturally, it needs an accurate signal of what its user intends to do. Skin electrodes record electrical muscle activity, but sweat, neighbouring muscles, and signal fading during sustained contractions can reduce reliability, especially when controlling a leg during walking.
MIT's magnetomicrometry system implants pairs of biocompatible magnetic beads, about three millimetres wide, into residual-limb muscles. An external sensor reads changes in their separation from as deep as six centimetres, directly calculating muscle length and velocity. In three people with below-knee amputations, the signals controlled a virtual cursor more accurately and stably than surface electromyography.
The participants did not yet operate a physical prosthesis in this experiment, and the sample is small. A larger study with robotic ankle-foot devices is under way. If long-term safety and everyday performance are confirmed, this minimally invasive interface could support smoother movement and better position control.
Source: Anne Trafton · MIT News.