Laboratory-engineered skeletal muscle is a potential therapy for replacing diseased or damaged muscle tissue. This computer-controlled system is designed to build properly organized muscle tissue in the lab. To do this, muscle cells are attached to strands of a natural material and are then subjected to cyclic stretching ("exercise") in a device designed to simulate the conditions of the human body. The pre-conditioning allows the cells to align in one direction, fuse to form muscle bundles, and function like normal muscle. In this video, the process is exaggerated for demonstration purposes. The process is actually much slower and involves less intense stretching.