Speaking of height, I have another question regarding this topic:
Is it possible to decrease in height rather than increase during adolescence? How come at times I feel that I am taller than other times. For instance in the morning my head is up to this cabin and hits it everytime I walk by it and later at night it passes over my head easily?
How about growth spurts? I didn't even feel that I had one. When is the normal age for growth spurts? I am 15 now. Will I be expecting one?
Your spine is composed of a series of bones separated by disks with a jelly-like substance in them. The disks act as shock absorbers when you walk and run.
When you sleep at night, you are lying flat and the disks, joints, and ligaments relax because all the pressure of gravity is taken off of them. Thus in the morning, when you first get up, you are slightly taller. As the day progresses, the disks get squeezed and you decrease in height.
As you get older, your disks will start to wear out. Old people are shorter than they once were as a result. Plus the wear and tear often makes it more difficult for them to stand as straight as they did when they were young.
Growth spurts come during Tanner's stage 3. A growth spurt means that the rate in which you grow is more than double the rate of growth when you were a child. For most boys the growth is noticeable because you out grow your clothing so quickly. But a few boys' growth spurt is more spread out and they may not notice the changes as easily.