Effects of a manual therapy technique in experimental lateral epicondylalgia

In patients with lateral epicondylalgia, mobilization-with-movement (MWM) is used as an intervention aimed at achieving analgesia and enhancing grip force, although the mechanisms underlying these effects are unclear. The present study investigated the acute sensory and motor effects of an MWM intervention in healthy controls with experimentally induced lateral epicondylalgia. Twenty-four subjects were randomly allocated to either a MWM or a placebo group (n=12). In both groups, to generate the model of lateral epicondylalgia, delayed onset muscle soreness (DOMS) was provoked in one arm 24h prior (Day 0) to hypertonic saline-induced pain in the extensor carpi radialis brevis muscle (Day 1). Either a MWM or placebo intervention was applied during the saline-induced pain period. Saline-induced pain intensity (visual analogue scale: VAS), pain distribution and pain quality were assessed quantitatively. Pressure pain thresholds (PPTs) were recorded at the common extensor origin and the extensor carpi radialis brevis muscle. Maximal measures of grip and wrist extension force were recorded. In both groups (pooled data), DOMS was efficiently induced as demonstrated by a significant decrease in pre-exercise to pre-injection PPT at the common extensor origin (-45+/-19%) and at the extensor carpi radialis brevis (-61+/-23%; P<0.05), and a significant decrease in maximal grip force (-25+/-6%) and maximal wrist extension force (-40+/-12%; P<0.001). Moreover, both groups experienced a significant increase in muscle soreness (3.9+/-0.2; P<0.0001) at Day 1 compared to pre-exercise. During saline-induced pain and in response to intervention, there were no significant between-group differences in VAS profiles, pain distributions, induced deep tissue hyperalgesia or force attenuation. These data suggest that the lateral glide-MWM does not activate mechanisms associated with analgesia or force augmentation in subjects with experimentally induced features simulating lateral epicondylalgia.