Biofeedback is a technique you can use to learn to control muscular actions. During biofeedback, you're connected to electrical sensors that help you receive information about your body.
Electromyographic biofeedback (EMG‐BFB) uses electrodes placed on a patient's muscles to generate a feedback signal (in vision or sound) in response to muscle activation. It is believed that this may allow patients to learn a more effective way of using their disabled limb.