HELPING THE OTHERS REALIZE THE ADVANTAGES OF LAT PULLDOWN

The two over sound Odd to me. They may be actually the sole points on which every movie I've seen do concur (as in "do bend your knees, do elevate your heels") Hinging devoid of bending the knees / moving the hips down ? How ?I'd would like to take a vo2max test but below in Italy they are doing it with a treadmill or perhaps a bikerg and i am not