Tips For security purposes, always keep your back slightly arched at the back. Do not relax your lumbar muscles, lower the bar until it rests on. Rounding the back raises the risk of injury and reduces the effectiveness of the exercise. Keep your abdominal muscles tight throughout the set. This greatly facilitates the retention of the body in a stable position and prevents it from rocking. However, not overdo it: too much straining the press, you unconsciously begin Rounded back. Squatting and sitting up, in any case not tear off your heels off the floor.
Squatting on his toes (not on your feet), you tyaryaete sustainability and risk injure the knee joint (it will be too much come to the fore). At the lowest point of the knees should not "vylazit" beyond the line of the toes. The depth squats (lower point of exercise) is determined solely by the extent of you have the strength to keep the natural curvature of the spine and not to interrupt the heel from the floor during the squat. If you feel that the spin begins Rounded and heels are lifted off the floor, do not squat below. If the distance between feet slightly less than or equal to the width of shoulders, the burden falls on the focus of the quadriceps and they involve a much stronger back muscles of the thigh. But such a statement of the legs requires flexibility, excellent hip and Achilles tendon (otherwise you can not omit the thigh to parallel with the floor).