Skin tension lines, defined as the lines of maximal tension, often provide guidelines for surgical incisions and pattern design of tight-fit, functional clothing. In this work, we are interested in developing methods for finding personalized, dynamic skin tension lines (DSTL) in a non-invasive manner. We base our study on the kinematic analysis of point markers that are colored on the skin. By tracking the motion-induced displacement of point markers, we locally analyze the skin deformation and numerically compute the maximum tension directions. Then, finding DSTL is transformed to the problem of finding continuous, interpolating locally computed lines of the maximum tension directions. Compared to existing methods, our method involves less invasive measurement on the skin, and is equipped with computational methods for identifying dynamic skin tension automatically. Consequently, our method is convenient to carry out, less prone to erroneous measurement, and repeatable. Our experiments have been successfully carried out on, though not limited to, lower body skins of male subjects.