ASSOCIATION BETWEEN TASK-PERFORMANCE AND TENDER POINT PAIN THRESHOLD TO PRESSURE IN NORMAL SUBJECTS

Objective: Work action patterns associated with increase in pain sensi tivity in healthy people may be valuable predictors of patterns which will cause pain in those with pre-existing low pain threshold. This st udy aimed to establish whether pain threshold to pressure [PPT], a mea sure of pain sensitivity, varies in association with task performance, particularly with tasks containing the ergonomic pain risk characteri stics of frequent repetition and static muscle work. Method: Designate d unilateral manual activity, bilateral manual activity and non-manual activity were examined sequentially. Pain threshold to pressure at tw o tender points [TeP] was measured bilaterally before and after two ho urs performance of three unilateral tasks varying in continuous light control and grasp-release; two bilateral tasks, varying in continuous holding, grasp-release and force exertion and one non-manual quiz game . Results: After the unilateral tasks, reduction in PPT at the TeP 2cm distal to the lateral epicondyle was shown on both the active and ina ctive side without difference in amount of change between tasks or sid es. Probability of reduction was greater after grasp-pull-release than light continuous control and was lessened by alternation between thes e two. After each bilateral task, reduction was shown bilaterally at b oth TePs, probability at the site 2cm distal to the lateral epicondyle being higher after prolonged holding with repeated force than force f ollowing unresisted grasp and release. There was no PPT change after t he non-manual task. Conclusion: In normal subjects repetition frequenc y, static muscle work and force can influence probability of reduced P PT on both the side used and contralateral side, and in fewer cases in fluence the size of that change.