Fig. 1

Experimental setup and acquisition protocol. a The semi-supine exercise setup in which the probe is fixated to acquire hands-free images of the heart. b The acquisition protocol. (1) Images were acquired manually in the parasternal view, followed by (2) hands-free measurements. Subsequently, (3) the manual and (4) hands-free acquisitions were obtained in the apical view [26–28]. The images of the last ten seconds of every exercise period were used for further assessment