Effectiveness of instrument-assisted soft tissue mobilization and neurodynamic techniques for improving hamstring flexibility and neural mechanosensitivity: A systematic review and meta-analysis

Hamstring tightness and neural mechanosensitivity are common in both athletic and sedentary populations, leading to limited range of motion, pain, and injury risk. Instrument-assisted soft tissue mobilization (IASTM) and neurodynamic techniques (NDTs) aim to address soft tissue and neural restrictions. This systematic review evaluated the effectiveness of IASTM and NDTs, alone or combined, in improving hamstring flexibility and reducing neural mechanosensitivity. A comprehensive search of PubMed, Scopus, physiotherapy evidence database (PEDro), and the Cochrane Library (January 2010–March 2025) identified randomized controlled trials (RCTs) involving adults (≥18 years) with hamstring tightness or neural mechanosensitivity. Primary outcomes were hamstring flexibility assessed by the straight leg raise and active knee extension tests; secondary outcomes included pain, pressure pain threshold, and muscle strength. Methodological quality was evaluated using the PEDro scale, risk of bias by the Cochrane RoB 2.0 tool, and evidence certainty by Grading of recommendations, assessment, development and evaluation (GRADE). Nine trials ( n = 18–60) were included. Both IASTM and NDTs improved hamstring flexibility compared with control or stretching. IASTM produced sustained improvements in flexibility, pain, and muscle performance, whereas NDTs yielded rapid but short-term gains. Meta-analysis of the Active Knee Extension outcome ( n = 191) showed a mean difference of 6.2° (95% confidence intervals: 2.5–9.9; P = 0.001) favoring IASTM. According to GRADE, evidence certainty ranged from very low (for NDTs and secondary outcomes) to moderate (for IASTM). Overall, both IASTM and NDTs appear to improve hamstring flexibility, but the certainty of evidence is limited; higher-quality RCTs with longer follow-up are needed.