Which sensor type is used to monitor muscle activity in assistive devices?

• A. IMUs
• B. Force sensors
• C. Pressure mapping sensors
• D. EMG sensors

Answer: (D)

Monitoring muscle activity relies on sensing the electrical signals muscles generate when contracting. EMG sensors capture these bioelectric signals from skeletal muscles, typically via surface electrodes on the skin or sometimes intramuscular needles. In assistive devices like myoelectric prostheses or muscle-driven exoskeletons, these signals are analyzed to infer user intent and drive the device accordingly, providing a natural control method that responds directly to the user’s muscle activation.

IMUs track motion, orientation, and acceleration, so they tell you how something moves but not the underlying muscle activity. Force sensors measure interaction forces, such as grip strength or contact forces, and don’t reveal electrical activation patterns. Pressure mapping sensors show how contact pressure is distributed, useful for comfort and fit but not for monitoring muscle signals.