1 · Moritani 1979 classic curve
In 8 weeks of elbow-flexor training, roughly four fifths of the strength gained in the first 4 weeks was neural; muscle growth took more of the share later.Moritani & deVries 1979 (*Am J Phys Med*) is one of the founding papers of strength-training science. Design: young men and women did 8 weeks of elbow-flexor training, and the study tracked how much of the strength gain came from neural factors versus muscle growth (muscle size estimated from arm girth and skinfolds, not ultrasound).Results:
· In the first 4 weeks, roughly four fifths of the strength gain came from neural factors, about one fifth from muscle growth
· After that, the share from muscle growth gradually rose
Why this curve matters:
· It explains the physiology of the novice fast-gain phase: it is not hormones or protein acting first, but the brain learning to use the muscle you already have
· It explains why strength training progresses fastest early on: the quick neural gains happen once, and after that progress relies more and more on muscle slowly growing
· It also shows that strong but not big is a workable goal: weightlifters and gymnasts often look like this
What it means for you: the novice feeling of I got stronger but the mirror has not changed is not an illusion; it is a real physiological process. Do not quit because you cannot see muscle in the first weeks; neural adaptation is the prelude to growth.