Publications

Purpose: This article investigates the immediate effects of a dry needling (DN) puncture on the viscoelastic properties (tone, stiffness, elasticity) of a trigger point (TP) in the infraspinatus muscle in non-traumatic chronic shoulder pain.

Method: Forty-eight individuals with non-traumatic chronic shoulder pain were recruited. The presence of a TP in the infraspinatus muscle was confirmed by a standardized palpatory exam. The viscoelastic properties were measured with a MyotonPRO device at baseline (T1), immediately after DN (T2), and 30 minutes later (T3). A DN puncture was applied to the TP to obtain a local twitch response while performing the technique.

Results: Analyses of variance showed significant decreases in tone (p < 0.001) and stiffness (p = 0.003) across time after the DN technique. Post hoc tests revealed a significant reduction in tone and stiffness from T1 to T2 (p ≤ 0.004) and no significant changes from T2 to T3 (p ≥ 0.10). At T3, only stiffness remained significantly lower compared to T1 (p = 0.013).

Conclusions: This study brings new insights on the immediate mechanical effect of DN on tone and stiffness of TPs. Whether these effects are associated with symptom improvement and long-term effects still needs to be verified.

Figure 1. The MyotonPRO device.

Keywords: elasticity, measurement, muscle tonus, myofascial trigger point

This study provides evidence that applying a single needle insertion in a TP in the infraspinatus muscle in patients with chronic, non-traumatic shoulder pain can immediately decrease the tone and stiffness of the TP. It also brings evidence for the use of MyotonPRO to detect changes in the viscoelastic parameters of a TP after a DN intervention. More research is needed to verify the long-term effects of a needle insertion on the viscoelastic parameters of a TP. Randomized clinical trials need to be performed to confirm the efficacy of DN in different muscle groups and the long-term effects.