REORGANISED FORCE CONTROL IN ELBOW PAIN PATIENTS DURING ISOMETRIC WRIST EXTENSION

C. MISTA; S. MONTERDE; M. INGLÉS; I. SALVAT; T. GRAVEN-NIELSEN

CLINICAL JOURNAL OF PAIN

LIPPINCOTT WILLIAMS & WILKINS

Lugar: Philadelphia; Año: 2018 vol. 34 p. 732 - 738

0749-8047

INTRODUCTION: Reorganised force control may be an important adaptation followingpainful traumas. In this study, force control adaptations were assessed in elbow painpatients. Increasing the contraction demand may overcome pain interference on themotor control and as such act as an internal control. It was hypothesized that elbowpain patients compared with control subjects would present greater change in thedirection of force when increasing the demand of the motor task.METHODS: Elbow pain patients (n=19) and healthy subjects (n=21) performedisometric wrist extensions at 5-70% of maximum voluntary contraction. Pressure painthresholds were recorded at the lateral epicondyle and tibialis anterior muscle.Contraction force was recorded using a three-directional force transducer. Participantsperformed contractions according with visual feedback of the task-related forceintensity (main direction of wrist extension) and another set of contractions withfeedback of the three force directions. Going from the simple to the detailed forcefeedback will increase the demand of the motor task. Force steadiness in all 3dimensions and force direction was extracted.RESULTS: Compared with controls, elbow pain patients presented lower pressure painthresholds at both sites (P<0.05). Force steadiness was not significantly differentbetween groups or feedback methods. The change in force direction when providingsimple visual feedback in contrast to feedback of all force components at all contractionlevels was greater for patients compared with controls (P<0.05).CONCLUSION: The larger change in force direction in pain patients impliesredistribution of loads across the arm as an associated effect of pain.