To increase the strength of the muscle work is the muscle contraction intensely increased?
An increase in the strength of the muscle work is not achieved by increase in the intensity of the stimulation of each muscle fiber. The muscle fiber obeys an all-or-nothing rule, i.e., its contraction strength is only one and cannot be increased. When the body needs to increase the strength of the muscle work a phenomenon known as spatial summation occurs: new muscle fibers are recruited in addition to the fibers already in action. So the strength of the muscle contraction increases only when the number of active muscle cells increases.
