Effect of hamstring flexibility on cervical range of motion and deep neck flexor endurance in healthy young adults: A study to explore myofascial tensegrity network.

Introduction: According to the concept of biotensegrity, the whole body consists of fascial lines. The relationship between muscles and fascia is important to ensure full and proper range of motion. This study investigated the effect of hamstring flexibility on cervical range of motion and deep neck flexor muscle endurance. The aim was to explore the relationship between the hamstring muscles and neck region in the myofascial tensegrity network.

Method: Sixty healthy participants with a median age of 22.0 years (24 male, 36 female) were included. Hamstring flexibility was categorized as "normal (n = 31)" or "limited (n = 29)" according to hip flexion angle (HFA) using the passive straight leg raise (PSLR) test. Active cervical range of motion was measured by the Clinometer smartphone application, and the following movements were recorded: flexion, extension and lateral flexion. The craniocervical flexion test was performed to evaluate deep neck flexor endurance using performance index and highest-pressure score. The Mann-Whitney U test was used for statistical analysis.

Results: No significant differences in cervical range of motion were observed between the groups (p > 0.05). Participants with limited hamstring flexibility presented lower deep neck flexor muscle endurance scores (performance index and highest-pressure score) than participants with normal hamstring flexibility (p = 0.002, and p = 0.012, respectively).

Conclusion: The results suggest that hamstring flexibility can influence deep neck flexor muscle endurance in healthy young adults. This preliminary clinical finding supports the hypothesis of a myofascial network between the hamstring muscles and neck region.