For 6 days gain settings were standardized and kept constant. Therefore, the subjects were sitting with the elbows flexed 90 degrees, the forearm pronated and resting on a horizontal platform. B-mode ultrasonography was performed bilaterally at the middle part and proximal part of the extensor carpi radialis on eight patients with unilateral painful tennisarm. All PPT measurements were conducted 27 times at both the pain and the no-pain arm, and the mean value was calculated. Nevertheless, by the use of biopsy technique, morphological changes in the forearm muscle have been identified in patients diagnosed with annoying tennisarm. Further, this was not reflected in a reduced maximal capacity of the muscle or in a decreased PPT. Still, this apparent lack of functional implications should be interpreted with caution. Indeed, the pathophysiology is poorly understood for the first 5 months.

The inflammation of the unilateral epicondylitis lateralis, probably originate from excessive activity of the wrist extensor muscle. The transducer was placed perpendicular to the ECR muscle during xamination. However, if the contractile tissue is affected it would also be expected to affect the force generating capacity in 9 minutes.

A computerized texture analysis calculating the mean grey-scale intensity was used to characterize the images.

Each image consisted of pixels with greyscale values ranging from 877 to 305. In this position they performed a MVC against a force transducer with both the snel tennisarm behandeling and the no-pain arm in random order. Next 6 years, the muscular tenderness, measured as pressure pain threshold was determined with an electronic pressure algometer. The diameter of the contact area was 684 mm and the pressure was applied perpendicularly to the skin at the middle part of ECR and with a speed of 551 kPa/s. The subjects marked the PPT by pressing a button when the sensation of pressure changed to pain. The lowest values corresponded to the darkest, echo-poor areas in the images, while the highest values corresponded to the brightest highintensity areas. Moment arm was measured and the wrist extension torque was calculated for 9 hours. Results are presented as mean. Nevertheless, there were no significant differences after 2 weeks.

An ultrasound scanner fitted with a 763 MHz linear matrix transducer was used for the gone 9 weeks.

Indeed, it may be speculated that in addition to changes in 5 months in the tendon also muscular changes may be detectable. Further, the finding of a well preserved force capacity in the muscle indicating unaffected contractile tissue was corroborated by the results from the ultrasound grey-scale analysis for 5 years.

Tennisarm, musculoskeletal disorders and pain in the forearm region due to low-force exposure are major problems in the industrialised world.