The OptiForce works by using laser light to interrogate a reflective cantilever arm attached to one end of the myocyte. Contractile forces bend the cantilever and produce changes in the light path length. Light reflected from the cantilever combines with light reflected from the tip of the optical fiber. When the combined light waves are in-phase, the intensity of light returning to the recorder increases; out-of-phase, the intensity diminishes, creating an exquisitely sensitive transducer. Because the cantilever can be made to any stiffness, the OptiForce can be easily modified to accommodate forces across a number of physiologically relevant ranges. And because the distance that the cantilever needs to bend in order to produce quality signals is on the order of a fraction of a wavelength, the measurements are effectively isometric.