Cardiac output (known as âQâ) is a measure of the amount of blood that is pumped out of the heart in one minute. âQâ specifically refers to the amount of blood pumped out of the left ventricle as this is the ventricle that supplies blood to the muscles and organs of the body.
Preload is defined as the actual stretch or tension on the ventricular myocardium prior to contraction (Totora & Gabowski 2002). The greater the preload on the myocardium (the larger the amount of blood that has filled the heart during diastole), the greater the contraction will be.
In this case, the preload length is 35mm and the resultant preload force is 17.5kg at zero travel. In other words, with this 0.5kg/mm spring and a setting at 35mm preload, you would have to put more than 17.5kg force on the end of the fork tube to create any movement at all.