Effectiveness of neurodynamic treatment on hamstring flexibility: A systematic review and meta-analysis of randomized controlled trials

Objective: To evaluate the effectiveness of neurodynamic (ND) techniques in improving hamstring flexibility compared to other physiotherapeutic interventions or no treatment and to assess the relative efficacy among different ND techniques (sliders vs. tensioners). Methods: A systematic search was conducted across six databases and grey literature up to July 2024. Randomized controlled trials (RCTs) involving adults (≥18 years) with reduced hamstring flexibility, but without neurological or musculoskeletal conditions were included. Studies comparing ND techniques (e.g., sliders, tensioners) to static stretching, proprioceptive neuromuscular facilitation (PNF), or no treatment were eligible. Primary outcomes were hamstring flexibility measured via passive straight leg raise (pSLR) and active knee extension (aKE). Risk of bias was assessed using the Cochrane RoB 2.0 tool and PEDro scale. Meta-analyses used random-effects models; evidence certainty was rated with GRADE. Results: Thirty RCTs (1379 participants) were included, with 19 analyzed quantitatively. ND techniques significantly improved hamstring flexibility over static stretching (mean difference [MD]: 3.48° for pSLR, 95% CI: 1.14–5.82; 3.78° for aKE, 95% CI: 0.43–7.12) and no treatment (pSLR MD: 9.44°, 95% CI: 6.74–12.14). Sliders were marginally superior to tensioners (aKE MD: 1.14°, 95% CI: 0.58–1.71). PNF outperformed ND in aKE (MD: −3.07°, 95% CI: −4.07 to −2.06), though evidence certainty was low. Conclusion: ND techniques, particularly sliders, enhance hamstring flexibility, supporting their clinical use. However, high heterogeneity and risk of bias in included studies necessitate cautious interpretation. Future research should standardize protocols and assess long-term effects.