It is a commonplace of my friends and relatives to remark that a young child (younger than 3 years) has had a recent "growth spurt". The underlying assumption is that young children do not grow taller continuously and steadily, but have periods of rapid growth between periods of slow growth. But is that assumption true? I'm sceptical; I'm inclined to believe that growth is steady, and the idea of growth spurts is a flaw of perception.
So, what research have I done so far on this question? I've seen the height-age charts for children, and they are smooth, so there are no growth spurts synchronised across all children. But that smooth averaged growth could result from the average of many non smooth growth rates. So the question is about when considering a single child. A web search about children's growth spurts shows numerous parenting web-sites that assume that growth-spurts happen, without asking whether growth spurts actually happen. I found an old press release from Emory University about some research supporting the idea, but no better information.