(2) EVALUATING THE INTRA-RATER AND INTER-RATER RELIABILITY OF A NOVEL PROTOTYPE PORTABLE TENSION NECK STRENGTH ASSESSMENT DEVICE

Purpose: Traumatic brain injury (TBI) is defined as “an alteration in brain function, or other evidence of brain pathology, caused by an external force” (5). Physical consequences of non-fatal TBIs may include temporary, transient effects on cognitive function or permanent cognitive function disability. The common method of decreasing the incidence of sports-related mTBI has been to develop new safety equipment and/or adjust rules for sports competition (2). However, there is a measurable inverse correlation between mTBI occurrence and strength training of cervical neck strength (1, 2, 3, 7). Neck strengthening has been recognized as an inexpensive, widely available, and easily adaptable method for mTBI prevention (1, 4). When designing a strength protocol, it is important to gather a baseline as a part of an individual’s ‘needs analysis (4, 6). Thus, the assessment of neck strength is a critical component in designing and developing a neck-strengthening protocol (4). This study evaluated the reliability of a new prototype portable tension scale for neck strength assessment, comparing its intra-rater and inter-rater reliability with commonly used dynamometers. The goal was to establish a baseline for developing a dynamic neck strengthening tool. Methods: The study recruitment occurred on the university campus, and solicitation for participants through various exercise science courses. There were no exclusion criteria, and the age range for recruitment was a potential of 18-65. Isometric neck strength was assessed in four movements (cervical flexion, cervical extension, left/right lateral flexion) using the updated prototype, compared to its previous version and two commonly used dynamometers. The devices used in this study are the AWS TL-440 – NSAT 1.0, Hoggan Scientific – MircoFet 2 Dynamometer 1M594W, and Lafayette Instrument Dynamometer Model 01165A. The research team engineers developed the NSAT 2.0, and as such, it does not have a model number or company name. The NSAT 1.0 hardware was an AWS TL-440 off-the-shelf tension scale. The scale could tare during use, increasing the user's ability to reset the scale between pulls. The research team’s software engineer designed and developed the mobile application. Reference - flow chart of the mobile application. Results: The NSAT-2's intra-class correlation (ICC) values were .888, .789, .853, and .821 for CF, CE, RLCF, and LLCF, respectively. The NSAT-1 had ICC values of .852, .854, .906, and .943. The FHD showed higher ICC values (.908, .909, .938, .947), and the MHD's ICC values were also higher (.939, .894, .913, .924). Inter-correlation for the NSAT-2 was lower, with ICC values of .747, .683, .699, and .744 when compared to the FHD and .674, .688, .652, and .694 when compared to the MHD. Conclusions: Both handheld dynamometers exhibited higher ICC values than the tension scale-based NSAT tools. The NSAT-2 demonstrates moderate to excellent reliability compared to the NSAT-1 but remains less reliable than handheld dynamometers, indicating potential for future refinement of the novel isometric strength assessment tool. Practical Applications: The study provides critical insights into the reliability of neck strength assessment tools and supports the development of a cost-effective, portable, and reliable instrument for isometric neck strength measurement. The previous NSAT-1 iteration showed intra-rater reliability ICC values of .87, .91, .91, and .88 for CE, CF, LLCF, and RLCF. Acknowledgements: This Research was supported by an NC Biotechnology Grant