Acupuncture is a traditional Eastern therapy that is increasingly used as an alternative therapy in the United States, but remains poorly understood. During acupuncture, needles are inserted subcutaneously at specific acupuncture points and rotated to achieve “de qi”, a warming sensation felt by the patient, which to the therapist coincides with a grasping resistance to further needle manipulation. Research has demonstrated that needle grasp results specifically from loose fascial connective tissues winding around the needle, and that needle grasp is stronger at acupuncture points, which fall above intermuscular fascial planes, than other locations on the body. To determine if mechanical stimulation is related to the therapeutic benefits of acupuncture, the features that govern the enhanced mechanical coupling need to be understood, but this is difficult to evaluate in vivo or in situ. In this thesis, several of these features are examined in a controlled, in vitro setting using collagen gels as the basis. The thickness, concentration, mechanical properties, size, shape, and composition of collagen gels were systematically altered, and the response to controlled acupuncture evaluated by capturing the evolution of fiber alignment using polarized light microscopy. Alignment was observed to increase with increasing collagen concentration, but decrease when the collagen was stiffened via crosslinking. Crosslinked gels failed after fewer rotations than untreated gels. Alignment was increased with increasing depth of insertion, but decreased in thicker gels when needle depth was held constant. Collagen gels cast in ellipses or strips to mimic fascial plane anatomy resisted failure and aligned more readily than circular gels. Alignment in these gels was anisotropic, with stronger alignment across the ellipse or plane, and entrapped rat fibroblasts followed the alignment pattern. The inclusion of fibrin in a composite gel with collagen significantly increased the ability of the gel to withstand needle rotations, which ultimately generated significantly greater alignment. The addition of hyaluronic acid produced less dramatic effects. Connective tissue is uniquely structured and organized to enable specific and substantial mechanical interactions during acupuncture. The in vitro system can be expanded to study cellular responses for understanding of underlying biological mechanisms and subsequent engineering applications.