Primarily ,the speed of the blood flow and it pressure on the veins while training and with the repetition for long periods the size of the arteries and veins get stretched and it size get increased naturally with time to simulate the increase in muscular exertion .
As for the point of showing veins its depends on reducing the percentage of fat above the muscle, as well as extra water ,
As for the point of showing veins its depends on reducing the percentage of fat above the muscle, as well as extra water ,
In order to make them appear larger :
Increase the number of iterations over 15 and ,sets 3 ( light weight ) and taking small doses of creatine helps a lot in increasing muscle mass and stiffness ,
for the diet you must get more proteins and less starches and carbohydrates as much as possible .
