<prompt> Preload leads to -Isovolumetric relaxationIsovolumetric contractionPeripheral resistanceParasympathetic nervous system activation  <response>: The amount of pressure on the muscles before the contraction starts is the preload. In regards to heart, preload is the amount of pressure on the ventricles at the end of diastole. At the end of diastole, isovolumetric contraction begins. 