Background: Dry needling (DN) is reported to decrease pain and improve functional movements yet the mechanisms remain unclear. Changes in muscle tone and other mechanical properties after DN could contribute to these findings but have not been investigated.
Objectives: Examine EMG and passive mechanical properties of the quadriceps muscle before and after DN.
Design: EMG, MyotonPro and clinical measurements were taken pre and post DN.
Setting: Rehabilitation department at Aspetar Sports Medicine Hospital, Qatar.
Participants: 20 subjects reporting pain and quadriceps muscle tension.
Main outcome measures: Pain (VAS, measured during a single leg step down), knee flexion range, and passive mechanical properties of the superficial quadriceps were measured using the MyotonPro device.
Results: Pain decreased (p < 0.01) and ROM increased in flexion (p < 0.001). EMG activity (RMS) was decreased at rest in the Vastus Lateralis (VL (p < 0.05, ES = 0.22). All other sEMG parameters were not significantly different (all p > 0.11, ES = 0.13). Passive mechanical properties were not significantly different in rectus femoris (RF) and VL. Decrement and Resistance of the Vastus Medialis (VM) were significantly decreased (p<0.05, ES>0.19).
Conclusions: DN resulted in small reductions in: pain, resting activation (EMG of VL), decrement and resistance (of VM).
Keywords: Acupuncture; Dry needling; Muscle tone; Stiffness.
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