Wearable Spine Assessment in Adults With and Without Low Back or Neck Pain

This is a single-site, prospective, observational, single-visit feasibility and validity study. Adult participants with and without low back or neck pain will be screened, consented, and enrolled to undergo a structured wearable-sensor-based spine assessment in a single on-site visit. Approximately 20 participants will be enrolled at a single site: * Approximately 10 adults with self-reported chronic or subacute low back or neck pain (LBP/Neck Pain group) * Approximately 10 adults without current back or neck pain (Control group) The AxiSens battery includes the Fingertip-to-Floor (FTF) test for lumbar flexion, the Chin-to-Chest (CTC) test for cervical flexion, a seated Trunk Stability Test on an unstable surface, the Cervical Flexor Endurance Test, the five-times sit-to-stand F5xSTS) test, and a brief functional task module covering overhead and forward reach. To support intra-rater repeatability characterization, the AxiSens wearable assessment is performed twice within the same visit by a single trained operator, with sensor doffing and re-donning between the two assessments. A short rest interval is provided between the two assessments. Following the on-site assessment, participants complete a brief end-of-session usability and tolerability questionnaire and the Technology Acceptance Model (TAM) questionnaire.