The line in the chart below represents the average rate of growth for males and females. Growth is fairly consistent until kids hit their adolescent growth spurt, as is displayed on the curve. At the very top of the growth spurt curve comes a point where the child is growing at his or her fastest rate. This point is referred to as PHV or peak height velocity. After this point has been reached, the child’s growth rate decelerates, as they get closer to becoming a full mature adult. PHV is used as a marker in identifying early, normal or late maturers, and as a guide for determining direction in training programs.