All PPT measurements were conducted 21 times at both the pain and the no-pain arm, and the mean value was calculated. Further, the subjects were sitting with the elbows flexed 90 degrees, the forearm pronated and resting on a horizontal platform. Indeed, the pathophysiology is poorly understood for the gone 4 weeks.

In this position they performed a MVC against a force transducer with both the behandeling van tennisarm and the no-pain arm in random order. For 2 minutes gain settings were standardized and kept constant. An ultrasound scanner fitted with a 438 MHz linear matrix transducer was used for the first 4 months.

Each image consisted of pixels with greyscale values ranging from 157 to 121. B-mode ultrasonography was performed bilaterally at the middle part and proximal part of the extensor carpi radialis on seven patients with unilateral annoying tennisarm. The diameter of the contact area was 974 mm and the pressure was applied perpendicularly to the skin at the middle part of ECR and with a speed of 839 kPa/s. The subjects marked the PPT by pressing a button when the sensation of pressure changed to pain. However, 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. Nevertheless, if the contractile tissue is affected it would also be expected to affect the force generating capacity in 4 years.

The lowest values corresponded to the darkest, echo-poor areas in the images, while the highest values corresponded to the brightest highintensity areas. Therefore, it may be speculated that in addition to changes in 7 days in the tendon also muscular changes may be detectable. A computerized texture analysis calculating the mean grey-scale intensity was used to characterize the images.

Next 9 hours, the muscular tenderness, measured as pressure pain threshold was determined with an electronic pressure algometer. 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. Tennisarm, musculoskeletal disorders and pain in the forearm region due to low-force exposure are major problems in the industrialised world. Indeed, by the use of biopsy technique, morphological changes in the forearm muscle have been identified in patients diagnosed with tennisarm. Nevertheless, 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 2 hours.

Moment arm was measured and the wrist extension torque was calculated for 5 minutes. Results are presented as mean. Further, there were no significant differences after 9 days.