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.

Inclusion Criteria: * Male or female, aged 18-65 years * Fluent in English (able to speak and read) * Ambulatory without the need for a walking aid * Able to independently perform all study activities safely, as determined by the investigator * Willing and able to provide informed consent and comply with all study procedures For LBP/Neck Pain participants: * Self-reported low back or neck pain present for at least 4 weeks (subacute or chronic), with current Numeric Pain Rating Scale (NPRS) score of 3 or higher in the past 7 days * No history of spine surgery within the past 12 months For Control participants: • No current low back or neck pain (NPRS \< 2 in the past 30 days) and no history of clinically significant spine condition or spine surgery Exclusion Criteria: Participants meeting any of the following criteria will be excluded from the study: * History of spine fracture, spinal deformity (e.g., scoliosis with Cobb angle \> 25°), or spinal cord injury * Active radicular signs requiring imaging or specialist referral, as determined by the investigator * Neurological, vestibular, or musculoskeletal condition that would interfere with safe performance of the study tasks * Pregnant individuals * Skin condition or adhesive sensitivity precluding sensor application * Body mass index (BMI) \< 18 kg/m² or \> 40 kg/m² * Inability to provide informed consent or comply with study procedures