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Background The term ‘physiological motion of the spine’ is commonly used although no proper definition exists. Previous work has revealed a consistent sequence of cervical segmental contributions in 80–90% of young healthy individuals. Age has been shown to be associated with a decreased quantity of motion. Therefore, it is of interest to study whether this sequence persists throughout aging. The aim of this prospective cohort study is to investigate if the consistent sequence of cervical segmental contributions in young asymptomatic individuals remains present in elderly asymptomatic individuals. Methods In this prospective cohort study, dynamic flexion to extension cinematographic recordings of the cervical spine were made in asymptomatic individuals aged 55–70 years old. Individuals without neck pain and without severe degenerative changes were included. Two recordings were made in each individual with a 2-to-4-week interval (T1 and T2). Segmental rotation of each individual segment between C4 and C7 was calculated to determine the sequence of segmental contributions. Secondary outcomes were segmental range of motion (sRoM) and sagittal alignment. Results Ten individuals, with an average age of 61 years, were included. The predefined consistent sequence of segmental contributions was found in 10% of the individuals at T1 and 0% at T2. sRoM and total range of motion (tRoM) were low in all participants. There was no statistically significant correlation between sagittal alignment, degeneration and sRoM in the respective segments, nor between cervical lordosis and tRoM. Conclusions This study shows that aging is associated with loss of the consistent motion pattern that was observed in young asymptomatic individuals. The altered contribution of the cervical segments during extension did not appear to be correlated to the degree of degeneration or sagittal alignment. Trial registration clinicaltrials.gov NCT04222777, registered 10.01.2020.

Background The sequence of segmental contributions (SSC) offers insight into cervical spine motion, yet accurately analyzing these movements remains challenging. This study compares two tracking methods, developed at two independent centers (AECC and MUMC), to establish their agreement and reliability in measuring SSCs across segments C4 to C7. Understanding spinal biomechanics is crucial for future research into cervical spine pathology and dysfunction. Methods Twelve asymptomatic participants (ages 18–35 for “young” and 55–70 for “elderly”) performed flexion-extension movements. MUMC + utilized self-directed motion, while AECC used a guided protocol. To ensure comparability, 26 frames from the second half of each extension movement were analyzed. Agreement was assessed using ICCs, Spearman’s Rho, and Bland-Altman analysis. Although the sample size is small, a post-hoc power analysis indicated sufficient power, supported by a high volume of analyzed data points. Findings High intraclass correlation coefficients (ICCs) for the cumulative vertebral rotation (0.97), cumulative intervertebral rotation (0.97) and relative intervertebral rotation (0.93) indicated strong agreement between the two methods. Bland-Altman analysis showed minimal median differences (< 0.2˚) but wider limits of agreement at C6-C7. Normative SSC patterns appeared in 77.8% of younger participants but were absent in elderly participants. Interpretation This study confirms the reliability of SSC measurement between the two methods, laying the foundation for broader applications. SSC patterns observed in young adults follow a normative pattern, in alignment with previous research. The absence of a fixed pattern in elderly participants could indicate age-related changes or sample variation, warranting cautious interpretation due to the small sample size. Future studies with larger, diverse samples and AI-driven approaches could enhance SSC analysis, enabling better clinical relevance.