What assists in moving venous blood back to the heart?

Valves and muscle contractions assist in moving venous blood back to the heart.

Muscles around the vein contract to squeeze blood through the vein, while valves are like flaps located inside the vein where is opens when the pressure of blood coming towards it is high enough, then closes when the blood flows through so that to ensure blood does not backflow and to ensure one way flow of blood towards the heart.

Peristalsis do not happen in veins, which means, the veins do not move or contract itself in order to move the blood, which is unlike some other systems like the alimentary canal.