Systems, devices, and methods are provided for reducing a risk of unintentional falls in a subject that is at risk for falls. The device includes a sensor and a stimulator. The sensor is configured to be positioned adjacent a body portion of the user that changes orientation when the user sits and stands. The sensor is also configured to emit an activation signal when the user stands and to emit a deactivation signal when the user sits or lies down. The stimulator is in communication with the sensor and is configured to be positioned adjacent one of a calf and a lower back of the user. The stimulator is configured to vibrate at a frequency that stimulates proprioceptors of the user without inducing muscle contractions upon receipt of the activation signal from the sensor and to cease vibration upon receipt of the deactivation signal from the sensor.