Hamstring Myometric Properties and the Functional Outcome in Young Adults with Radicular Pain: A Cross-Sectional Study.

Low back pain (LBP) is a widespread musculoskeletal condition caused by various pathologies, including peripheral nervous system dysfunction, resulting in stiffness, reduced strength, and compromised neuromuscular control. Therefore, this study aimed to evaluate the influence of single-leg radicular pain on hamstring biomechanics in young adults without significant concurrent lower back symptoms while investigating the association between the functional outcome and muscle biomechanical properties. This cross-sectional study included two groups: young adults with lower limb radicular pain (RAD, n = 15) and age-matched healthy asymptomatic individuals (CON, n = 15). Clinical characteristics were assessed using the Oswestry disability index (ODI), the numeric pain rating scale (NPRS), and the passive straight leg raise (PSLR) test. Myometric muscle analysis of the biceps femoris and semitendinosus muscles was conducted using the Myoton PRO® device, focusing on mechanical and viscoelastic properties such as frequency, stiffness, relaxation time, decrement, and creepability. The RAD group showed around 14% higher stiffness on the symptomatic side compared to the CON group (p = 0.003), while relaxation time and creepability were by approximately 14% (p = 0.008) and 13% (p = 0.01) lower, respectively. Similarly, the RAD group exhibited approximately 13% higher stiffness on the asymptomatic side compared to the CON group (p = 0.02). In conclusion, the biomechanical properties of the hamstrings-particularly stiffness, relaxation time, and creepability of the biceps femoris on the symptomatic side-may significantly impact pain management in individuals with radicular pain. Moreover, stiffness of the biceps femoris could be an important predictor of functional outcomes in younger adults.