The Effects of LightBack on Sciatic Nerve Stiffness and Posterior Chain Flexibility in Healthy Participants

ABSTRACT Background and Purpose The LightBack device applies controlled axial compression forces on the femur to replicate posterior femoral displacement and provide mechanical stimulation to the gluteal region. This study aimed to examine the effects of LightBack application on sciatic nerve stiffness and posterior chain flexibility in healthy, physically active individuals. Methods A randomized within‐subject, contralateral‐leg controlled trial was conducted with 25 healthy, physically active participants (49 lower limbs; n = 25 in the LightBack testing leg and n = 24 in the contralateral control leg). Sciatic nerve stiffness was assessed using shear wave elastography (SWE), and posterior chain flexibility was evaluated using the Active Knee Extension (AKE) and Active Straight Leg Raise (ASLR) tests. All outcomes were measured immediately before and after each intervention session. Results Linear mixed‐effect models demonstrated a significant time × leg interaction for all variables ( p < 0.05). In the LightBack testing leg, AKE improved from 26.72° to 19.04° ( p < 0.001) and ASLR from 22.08° to 15.96° ( p < 0.001). Sciatic nerve stiffness decreased from 33.84 to 28.79 kPa ( p < 0.001), while shear wave velocity declined from 3.27 to 2.99 m/s ( p < 0.001). Discussion LightBack application resulted in significant improvements in posterior chain flexibility and reductions in sciatic nerve stiffness in healthy individuals. Further studies are warranted to explore these relationships and their implications for clinical and performance settings.