Much attention has been focused on eccentric contraction exercises (also known as negatives) in which the muscle yields to an outside force. As this contraction takes place, the muscle lengthens and develops tension. The greater the resistance, the greater the muscle tension. The Russian’s have done considerable research on the eccentric contraction and have found it to be very effective for strength gains. However, it is not used for most of the workout because of its intensity and it does not replace the concentric contraction. Note that even though the eccentric contraction is very effective, it takes too long to prepare the body for such intense loads. (When doing eccentrics, in order to have the overload principle in effect, you use up to 50% more weight than in the maximum concentric.) Thus, because of the great stress and the amount of time needed, the eccentric contraction does not take first place in training. The concentric contraction still remains supreme in the training of bodybuilders and weightlifters. It is typically used in up to 60 to 70% of all the total lifts done in the course of a year. Isometric or static contractions are also used fairly extensively in the training of athletes. The isometric contraction is less intense than the eccentric but up to 20% greater than the concentric and plays an important role for developing greater stability for better execution of strength exercises. The Russians use all three muscle contraction regimens in one session or independently. For example, on any given day the athlete may work out with eccentric, isometric and concentric contractions. There may also be days when the workout is devoted to isometrics or the eccentric or concentric contraction. One of the most promising and effective methods that the Russians have developed in conjunction with the eccentric contraction, is the combination of muscle contractions regimens in one exercise. For example, when doing the squat, you load the bar so you are using 40% greater than the concentric max in the eccentric contraction (going down). As soon as you hit the bottom position, assistants slide the extra weights off the barbell and then you rise very quickly in the concentric regimen. Russian research has shown that when you lower a barbell with weights of 120 to 140% of the maximum concentric, it is more effective than lifting a near maximum weight from a deep squat position. The reason for this is that in regimens without the eccentric, there is no preliminary muscle tension, which is needed for utilization of the stretch reflex. From the research and practical experiences, they believe that doing combinations of muscle contraction regimens is the key to greater gains in muscle strength. In our work with athletes and bodybuilders, we use all three regimens and find that improvement is not only faster, but the gains are greater. See Secrets of Soviet Sports Fitness and Training, for more details.