Abstract: A technology for quantifying, or determining an indication of, cardiorespiratory fitness is disclosed. A signal portion is obtained from a signal recorded with an accelerometer placed on the chest of a person. The accelerometer measures accelerations and vibrations of the chest wall of the person caused by myocardial movement. A maximum value is determined in the signal portion, and output information is provided indicating cardiorespiratory fitness based on the maximum value.

Abstract: Systems and methods for estimating cardiac strain and displacement using ultrasound are disclosed. According to an aspect, a method includes receiving frames of images acquired from a subject over a period of time. The method also includes determining, in the frames of images, speckles of features of the subject. Further, the method includes tracking bulk movement of the speckles in the frame of images. The method also includes determining displacement of at least a portion of the subject based on the tracked bulk movement.