Reach Envelope

The three-dimensional volume of space that a person can physically access with their hands or arms from a given position, taking into account their specific motor abilities, range of motion, and comfort levels. For people with upper extremity mobility impairments — such as those caused by spinal cord injury, stroke, or muscular dystrophy — the reach envelope is often significantly reduced and asymmetric compared to non-disabled individuals, and varies greatly between individuals even with similar diagnoses. Understanding a person's specific reach envelope is essential for positioning assistive technology input devices (switches, joysticks, touchpads), wheelchair controls, and environmental interfaces in locations that maximize comfort, performance, and efficiency. Virtual reality and motion tracking technologies can map individualized reach envelopes more efficiently than traditional clinical trial-and-error methods.