A Low-Cost Passive Wearable for Sit-to-Stand Assistance in Low-Resource Contexts: Design and Proof-of-Concept Evaluation

Resumen

Sit-to-stand (STS) performance is a key indicator of functional mobility and independence in aging populations, yet most assistive solutions remain limited by high cost, bulky designs, powered actuation, or dependence on laboratory-grade evaluation systems. This paper presents a low-cost passive wearable device based on a lateral spring mechanism designed to support knee extension during STS while aiming to minimize potential interference with daily mobility. A proof-of-concept evaluation was conducted using the Five-Times Sit-to-Stand (5TSTS) protocol under two conditions (with and without the device). Kinematic variables (knee angle and hip speed) were extracted from standard video recordings using Kinovea as an accessible motion analysis tool. Results showed reduced 5TSTS completion time for both participants when using the prototype, along with condition-dependent differences in knee angle range and hip speed profiles across cycles. The main contributions are: (a) a mechanically simple and low-cost passive wearable design for STS assistance; (b) a reproducible evaluation workflow using 5TSTS and video-based kinematic analysis; and (c) preliminary evidence that the prototype can influence functional performance and movement dynamics across repeated STS cycles.