Sarcopenia is a condition that involves loss of muscle mass, strength, and function due to aging, causing a great threat to mobility and independence in the aged population. The article introduces the design, development, and validation of a light, passive ankle exoskeleton designed to assist individuals with sarcopenia. In contrast to traditional full-leg or pelvic-anchored exoskeletons, this work addresses the ankle joint responsible for propulsion and balance through a gas piston actuated mechanism to decrease the muscular work needed during movement. The exoskeleton uses a passive damping system that comprises a compressible zone coupled with a gas piston to capture and store ground reaction forces, releasing them during push-off to facilitate walking. The device is built with a blend of ASA and TPU plastics for durability, flexibility, and ergonomic comfort, and secured through adjustable straps. CAD modeling and finite element analyses confirmed the structural integrity under dynamic loads for ensuring durability and safety to users. System testing was done on participants with IMU sensors fixed at the knee and sole to record vertical acceleration data during walking and descending stairs. The findings showed a significant 40% decrease in knee jerk acceleration when going down steps, verifying the effectiveness of the system in alleviating joint stress and muscle fatigue. This research shows the potential of a lightweight, affordable, and user-configurable exoskeleton in enhancing daily mobility among the elderly. Its applications can be extended to rehabilitation centers, elder care homes, and resource-constrained settings, and it is shown to have potential as a scalable solution for sarcopenia-related mobility impairment.