Effectiveness of Electrical Muscle Elongation and Proprioceptive Neuromuscular Facilitation Programs on Muscle Flexibility and Stiffness in Young Adults with Functional Hamstring Disorder: A Randomized Clinical Trial with 4-Week Follow-Up

TL;DR

This study compares two stretching methods to improve hamstring flexibility and muscle stiffness in young adults with a specific hamstring disorder.

Contribution

The study introduces Electrical Muscle Elongation as a potentially more effective method than PNF for improving hamstring flexibility.

Findings

EME improved hamstring flexibility in the left limb more than the control group.

EME showed better results in some quadriceps muscle properties compared to PNF and control groups.

Improvements were sustained at the 4-week follow-up for the EME group.

Abstract

Background: Adequate hamstring flexibility is crucial for musculoskeletal health as increased muscle tone can lead to stretch-type injuries, muscle weakness, dysfunctional neuromuscular control, postural changes, and lower back pain. The aim was to compare the effectiveness of a program based on Electrical Muscle Elongation (EME), Proprioceptive Neuromuscular Facilitation (PNF), and no intervention in improving flexibility and viscoelastic properties of hamstring and quadriceps muscles in active young adults with functional hamstring disorder (type 2B according to the Munich Consensus). Methods: Sixty-five participants (45 male, 20 female) were randomly assigned to three groups: the EME group (n = 21) received a simultaneous combination of interferential current and stretching, the PNF group (n = 22) underwent active stretching, and the Control group (n = 22) received no intervention. Hamstring and quadricep flexibility and muscle stiffness were measured in both limbs at baseline, post-intervention, and at the 4-week follow-up. Results: The EME group showed significant improvements in hamstring flexibility in the left limb compared to the Control group and in some myotonometric variables of the quadriceps muscle compared to the PNF and Control groups (p < 0.05). Within-groups differences indicated higher improvements in the EME group. Conclusions: This study suggests that EME may offer greater benefits than PNF stretching in young adults with functional hamstring disorder.

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