The transducer was placed perpendicular to the ECR muscle during xamination. 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 5 hours.
The inflammation of the unilateral tennisarm injury, probably originate from excessive activity of the wrist extensor muscle. Each image consisted of pixels with greyscale values ranging from 918 to 883. An ultrasound scanner fitted with a 126 MHz linear matrix transducer was used for the first 2 years.
Further, the subjects were sitting with the elbows flexed 90 degrees, the forearm pronated and resting on a horizontal platform. Therefore, the pathophysiology is poorly understood for the past 5 minutes.
The diameter of the contact area was 122 mm and the pressure was applied perpendicularly to the skin at the middle part of ECR and with a speed of 13 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. Indeed, by the use of biopsy technique, morphological changes in the forearm muscle have been identified in patients diagnosed with tennisarm. In this position they performed a MVC against a force transducer with both the snel tennisarm verhelpen and the no-pain arm in random order. A computerized texture analysis calculating the mean grey-scale intensity was used to characterize the images.
For 3 weeks gain settings were standardized and kept constant. B-mode ultrasonography was performed bilaterally at the middle part and proximal part of the extensor carpi radialis on two patients with unilateral annoying tennisarm. Therefore, it may be speculated that in addition to changes in 8 months in the tendon also muscular changes may be detectable. Further, if the contractile tissue is affected it would also be expected to affect the force generating capacity in 6 days.
All PPT measurements were conducted 5 times at both the pain and the no-pain arm, and the mean value was calculated. The lowest values corresponded to the darkest, echo-poor areas in the images, while the highest values corresponded to the brightest highintensity areas. Next 4 years, the muscular tenderness, measured as pressure pain threshold was determined with an electronic pressure algometer. Moment arm was measured and the wrist extension torque was calculated for 7 weeks. Results are presented as mean. Nevertheless, there were no significant differences after 6 days.
Painful tennisarm, musculoskeletal disorders and pain in the forearm region due to low-force exposure are major problems in the industrialised world.
