Effects of Neural Load on Hamstring Stretching upon Flexibility, Maximum Isometric Strength, and Tibial Nerve Pressure Pain Threshold in Healthy Subjects: A Randomized Clinical Trial

Abstract

(1) Background: Stretching has been shown to improve flexibility, muscle activation, and coordination, but its effects may depend on neural tension during the stretch. This study evaluated the short- and medium-term effects of hamstring stretching with and without neural load on flexibility, tibial nerve pressure pain threshold, and maximum isometric strength. (2) Methods: Seventy-eight healthy participants (mean age: 24.96 ± 6.11 years) were randomly assigned to stretching programs with (n = 39) or without neural load (n = 39). Flexibility, pressure pain threshold, and maximum isometric strength were assessed at baseline, after the first session, at the end of the intervention, and one month later. (3) Results: The group using neural load showed significant flexibility improvements after the first session (MD = −5.2; p < 0.001), which were maintained at two months (MD = −8.6; p < 0.001) and follow-up (MD = −6.4; p < 0.001). In the control group, flexibility gains diminished at follow-up (MD = −3.9; p = 0.052). Other variables showed no significant changes across time points. (4) Conclusions: Since neither treatment showed superior efficacy, no specific stretching type could be recommended.