Table 3.

A summary of mechanism studies on needling intensity and Deqi.

Study ID	Acupoints	Instrument	Results
Deng and Zhou 2010 [59]	ST36	PowerLab 4/25	A marked difference was observed in muscular contractility at Deqi depth compared with that at two non-Deqi depths.
Choi et al. 2012 [60]	SP6, SP9, ST36, GB39	SASS	Pressure pain threshold and Deqi sensation increased as acupuncture simulation intensified (needling with rotation > deep needling > superficial needling).
Park et al. 2011 [61]	NA	Ultrasound imaging	Pricking and sharp sensations appeared more frequently when shallower tissues were needled, whereas deep, dull, heavy, spreading, and electric feelings predominated in deeper tissue levels. The introduction of needle rotation in addition to oscillation intensified deep, dull, and heavy rather than pricking and sharp sensations.

Abbreviations: NA: not available; SASS: subjective acupuncture sensation scale.