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Pressure pain sensitivity mapping in experimentally induced lateral epicondylalgia.

PURPOSE
The aim of this study was to apply topographical techniques to investigate changes in pressure pain sensitivity after induction of delayed onset muscle soreness (DOMS) in the elbow region in healthy subjects.


METHODS
Pressure pain thresholds (PPT) were assessed over 12 points forming a 3 x 4 matrix (4 points in the superior part, 4 points in the middle, and 4 points in the lower part around the lateral epicondyle) over the dominant elbow in 13 healthy men, and pressure sensitivity maps were calculated. DOMS, as a model for lateral epicondylalgia (LE), was induced by repetitive high-level eccentric contractions of the wrist extensor muscles. PPT maps were assessed before, immediately after, and 24 h after eccentric exercise (DOMS).


RESULTS
The two-way repeated-measure ANOVA detected significant differences in mean PPT for the measurement points (F = 5.96, P < 0.001), with lower PPT over the points located over the extensor carpi radialis brevis muscle. There was also a significant effect of time (F = 121.3, P < 0.001) but no time x point location interaction (F = 0.7, P = 0.8). PPT were lower 24 h after (P < 0.001) but not immediately after (P > 0.05) eccentric exercise.


CONCLUSIONS
The study provides new key information regarding mechanical pain hyperalgesia in experimentally induced LE. Topographical pressure pain sensitivity maps from the elbow region revealed heterogeneously distributed mechanical sensitivity before and during DOMS. The most sensitive localizations for PPT assessment correspond to the muscle belly of the extensor carpi radialis brevis. Our results support the implication of the extensor carpi radialis brevis muscle in LE.