Figure 9From: An in vitro assay of collagen fiber alignment by acupuncture needle rotationEffects of gel height and depth of needle insertion on revolutions to failure during in vitro acupuncture. Thin gels were able to withstand significantly more needling than thick ones (P < 0.001). For 4 mm-thick gels, revolutions to failure decreased as the depth of needle insertion increased, but this was not observed for 6 mm-thick gels.Back to article page