Frequency spectrum analysis of ground reaction forces during running in individuals with piriformis syndrome following an eight-week neuromuscular training program

Background: Piriformis syndrome, a neuromuscular condition associated with sciatic nerve irritation, can disrupt lower limb biomechanics and alter ground reaction force (GRF) profiles during running. Neuromuscular training may improve lumbopelvic stability and coordination, but its effects on GRF frequency characteristics remain underexplored. Methods: Thirty physically active males (aged 35–45 years) with piriformis syndrome were recruited and allocated to either an intervention group (n = 15) or a control group (n = 15) in this quasi-experimental study. The intervention group completed an eight-week neuromuscular training protocol designed to enhance lumbopelvic stability and coordination. Vertical and free moment GRF components were recorded during treadmill running before and after the intervention. Temporal and group effects were analyzed using a two-way repeated-measures Analysis of Variance (ANOVA). Results: The intervention group exhibited a significant reduction in the number of harmonics in the vertical GRF component (p = 0.003, d = 0.55) and a decrease in the 99.5% power frequency of the free moment component (p = 0.001, d = 0.92). These changes reflected diminished high-frequency oscillations, suggesting improved eccentric muscle function, lumbopelvic control, and neuromuscular coordination. Conclusions: Neuromuscular training resulted in favorable alterations in GRF frequency spectra among individuals with piriformis syndrome, aligning with reductions in pain and indicating more efficient force transfer and load attenuation. These findings support the application of neuromuscular training to optimize running biomechanics and reduce mechanical stress in this population.