INTRODUCTION: Tension-type headache (TTH) is highly prevalent in the general population, and it is characterized by increased muscle tenderness with increasing headache frequency and intensity.

AIM: The aim of this case-control study was to compare muscle strength in neck and shoulder muscles in TTH patients and healthy controls by examining maximal voluntary isometric contraction (MVC) during shoulder abduction, neck flexion and extension as well as the extension/flexion strength ratio of the neck.

METHODS: Sixty TTH patients and 30 sex- and age-matched healthy controls were included. Patients were included if they had TTH ≥8 days per month. The MVC neck extensor and flexor muscles were tested with the participant seated upright. MVC shoulder abduction was tested with the individual lying supine.

RESULTS: Compared to controls TTH patients had significantly weaker muscle strength in neck extension (p = 0.02), resulting in a significantly lower extension/flexion moment ratio (p = 0.03). TTH patients also showed a tendency toward significantly lower muscle strength in shoulder abduction (p = 0.05). Among the 60 TTH patients, 25 had frequent episodic TTH (FETTH), and 35 had chronic TTH (CTTH).

CONCLUSION: Patients with TTH exhibited decreased muscle strength in the neck extensor muscles, inducing a reduced cervical extension/flexion ratio compared to healthy people.