The lymphatic system consists of a network of vessels which work to return the interstitial fluid back to the blood circulation. Individual units called lymphangions, segments of lymphatic vessels between two valves, pump cyclically to propel lymph. Lymphangions are similar to the heart in that they are sensitive to both preload and afterload. To describe the heart independent of preload and afterload, investigators developed the concept of time-varying elastance. We evaluated the applicability of this concept to lymphangions by analyzing preliminary data obtained from the bovine mesenteric vessels. We found that there were some limitations to the applicability of this concept to lymphangions, as there was a high degree of variability with respect to contraction strength and frequency of individual time-varying elastance curves. To better characterize lymphangion mechanics, we built a device which would enable real-time isobaric, isometric and isotonic experiments in vitro. We performed all three experiments on lymphatic vessel segments and obtained input and output pressures, output flow, instantaneous radii and wall tension. The characterization of the lymphangion using these parameters can be the first step to simulate the behavior of a lymphatic vesssel and later the behavior of an entire lymphatic system.