The initial position of the body and hands is very important . When you lie down on a bench , feet must be firmly on the floor . Head , shoulders and buttocks should be on the bench . Take dumbbells in your hands , thumbs, some are facing up . Raise the dumbbells above your chest . Then lower the dumbbells with your elbows slightly bent . When performing this exercise, your elbows should always be slightly bent . Blago , so not too much because then it is no longer bed , but becomes thrust , which is a completely different movement . On the other hand, if you happen to straighten the arms too much , you risk povradite shoulders or elbows . It is very important that the right to a full and proper movement . Due to the structure of the shoulder muscles is important to know what is the functional movement because if we keep the weights descend below the functional movement mozemoda be hurt . Most of the movement has a natural point of raising and lowering a point . Lower yield strength should be one point where your elbows are in line with your shoulders ( ie , the upper arm is parallel with the floor ) . When you drop your elbows below shoulder level leads to a higher share of foreign pectoral muscle , but at the same time and shoulders out much larger effort . For most bodybuilders , who used to manage to get you lower the weights rather low certainly not worth the risk . This exercise mainly affects the inner fibers of the middle segment of the large chest muscle . The most common grip is normal , so-called neutral grip but it is possible to implement and rotation of the hand during the movement , which will hit more muscle. . When you rotate your hands so that your palms are facing your head , then you have to rotate the bone of the upper arm. But as the pectoralis connected to this bone , when you rotate it , and somewhat elongated pectoralis , which is why going to come up with its stronger contractions . This exercise is more than important for muscle growth , in addition to deep stretch those muscles provides stimulation from that point of view from which it exercises thrust can never guess . Yet it has certain limitations and is good to correct these exercises two other stretching exercises . Because when you perform dumbbell bed , chest provide less resistance at the end of the movement ( when the weights out) than the first. The training required to perform flight deal . When you perform a crossover cable cross your hands one over the other (hence the name ) with the maximum contraction . Similarly , if you work on a butterfly machine, or flying with stretchy bands , doing repetitions unilaterally in a way that goes hand half of the central part of the body to prolonged contraction and completely hit every bit of muscle .