Jim-jams - it elevated ripple, transferring weapons. It occurs after the cross, hand combat, nervous tension and as a result of excitation prelaunch. Occurrence nervous trembling causes the release of adrenaline.
Control measures: if the arrow suddenly begins to beat jitters, you must run a little, several times to sit down, be wrung, tightened until, until he feels, the adrenaline in the body "burned out" and throbbing stopped. There are other ways - a good stretch your wrists, or inhale through the nose and exhale through the mouth. So do biathletes.
noticed, that very often the jitters and pulsation disappear in the translation of shooting at a target in the shooting at a white sheet of paper. In the absence of responsibility for the accuracy of the shooter hits calms, and unnecessary excitement disappears.