Design, Development and Functional Evaluation of Neck Assistive Cervical Kit: NACK

Abstract Neck pain is a common issue caused by prolonged static postures and cumulative fatigue, negatively impacting quality of life. While cervical collars support individuals with chronic neck injuries, there is a need for preventive solutions for healthy individuals, particularly office workers exposed to prolonged sitting and repetitive motions. This study introduces a novel ergonomic assistive device designed to reduce neck strain in office workers. The design objectives are based on typical movement limits for head flexion-extension, lateral flexion, and rotation, as reported in the literature. A previously validated 20-DoF ADAMS model of the human cervical spine was employed to aid in concept development. Various design alternatives were analyzed and optimized using this model to ensure compliance with the design criteria. The conceptual design was mechanically realized, and a prototype was manufactured. Performance was evaluated on 20 healthy subjects using IMU and EMG sensors to compare two conditions: without device (WoD) and with NACK. Range of motion analysis revealed that the NACK condition reduced cervical mobility by 30-50% across all three anatomical planes compared to WOD. EMG statistical analysis using paired t-tests showed significant reductions in muscle activation, with sternocleidomastoid muscles decreasing by 23-29% MVC (p < 0.01) and upper trapezius muscles reducing by 10-15% MVC (p < 0.05). These findings demonstrate that the NACK provides mechanical support limiting excessive head movements while significantly reducing neuromuscular demand on neck and shoulder musculature, thereby enhancing comfort and productivity in workplace environments.