Abstract: Devices, systems, and methods for determining a custom ergonomic configuration of an adjustable seating device based on interpretation and analysis of a sequence of biometric measurements of a human subject. An adjustable seating device transitions one or more adjustable surfaces between a sequence of configurations while a human subject is seated in the adjustable seating device and being biometrically measured. A custom configuration is stored in memory, where the custom configuration is a configuration where the biometric measurements of the human subject correspond to a muscle-relaxed state.