Maybe physical therapy actually helps

It appears that patients with tension-type headache (TTH) have relatively weak neck extension muscles, a new study shows.

Researchers found that these patients are 26% weaker than controls with respect to neck extension muscles, that they have a 12% smaller extension/flexion ratio, and that they have a borderline significant difference in the ability to generate muscle force over the shoulder joint.

"We found that patients with tension-type headache exhibited decreased muscle strength in the neck extensor muscles, which caused this reduced ratio between extension and flexion," said lead study author Bjarne Madsen, a physiotherapist and PhD student in the Department of Sports Science and Clinical Biomechanics, University of Southern Denmark and Danish Headache Center Glostrup Hospital. 

With this reduced ratio, the muscles in the front of the neck pull the head forward, which causes continuous muscular activity in the neck, explained Madsen. "This can lead to pain and, over time, it can cause tension-type headache."...

Asked to comment, Peter Goadsby, MD, PhD, director, Headache Center, University of California, San Francisco, said the new paper reports "an interesting finding" among patients with TTH. "The muscle hypothesis in tension-type headache has waxed and waned over the years and so it is appropriate to re-visit the question," said Dr Goadsby.

Patients with TTH are often said to have pericranial tenderness. "One must ask whether pain restricts effort in these subjects that then manifests as weakness," added Dr Goadsby. "There is much to be done to understand this problem better."

See:  http://www.medscape.com/viewarticle/844414?src=wnl_edit_tp10&uac=60196BR&impID=724066#vp_1

Madsen BK, Søgaard K, Andersen LL, Skotte JH, Jensen H. Neck and shoulder muscle strength in patients with tension-type headache: A case-control study. Cephalalgia. 2015 Apr 1. pii: 0333102415576726. [Epub ahead of print]

Abstract
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.   
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.