Article below originally printed here.
Mechanical loading of your muscles is one of the key principles on which your training should be based. For a long time, however, muscle fatigue has been relied upon as a gauge for the effectiveness of one’s training. According to tradition, one must work the muscles to momentary muscular failure so as to cause as many muscle fibers as possible to receive a growth stimulus.
Often it is suggested that the fast twitch, or white, muscle fibers are not even called into action until the last few repetitions of a set. As discussed in support of Hypertrophy-Specific Training TM (HST) [1-3], however, a great deal of research suggests that all types of muscle fibers are called into action when the muscles are exposed to heavy enough loads. Because of this, HST emphasizes heavy mechanical loading of the muscles rather than staying with the lighter weights proposed by many other training programs.
According to HST convention, you should spend at least a portion of your training with heavy loads approaching your 5 rep-max (RM) weight [1-3]. For those readers that are new to the iron game, a RM specifies the maximum number of times you can lift a weight before hitting muscular failure. For example, once you know how much weight you can bench press five times, that weight is called your 5RM for the Bench Press.