Background: Another obvious change that occurs during puberty is rapid growth. This is called the adolescent growth spurt. In boys, it is controlled by testosterone. The rate of growth usually starts to increase relatively early in puberty. At its peak rate, growth in height is about 10 centimeters (almost 4 inches) per year in the average male. Growth generally remains rapid for several years. Growth and development of muscles occur toward the end of the growth spurt in height. Muscles may continue to develop and gain strength after growth in height is finished.

Situation: Jimothy and Dwight are two brothers living in the same house. Jimothy is a freshman in high school and Dwight is a junior in high school. Their mother takes them to see a doctor and to have their testosterone tested. The tests reveal that Dwight has significantly more testosterone than Jimothy, but that is to be expected given their age difference.

Question: Which boy will more likely grow more inches of the course of one year?
Answer: Dwight

Situation: Jimothy and Dwight are two brothers living in the same house. Jimothy is a freshman in high school and Dwight is a junior in high school. Their mother takes them to see a doctor and to have their testosterone tested. The tests reveal that Dwight has significantly more testosterone than Jimothy, but that is to be expected given their age difference.

Question: Which boy will more likely grow less inches of the course of one year?
Answer: Jimothy

Situation: Jimothy and Dwight are two brothers living in the same house. Jimothy is a freshman in high school and Dwight is a junior in high school. Their mother takes them to see a doctor and to have their testosterone tested. The tests reveal that Dwight has significantly more testosterone than Jimothy, but that is to be expected given their age difference.

Question: Which boy will start developing muscles sooner?
Answer: Dwight

Situation: Jimothy and Dwight are two brothers living in the same house. Jimothy is a freshman in high school and Dwight is a junior in high school. Their mother takes them to see a doctor and to have their testosterone tested. The tests reveal that Dwight has significantly more testosterone than Jimothy, but that is to be expected given their age difference.

Question: Which boy will start developing muscles later?
Answer: Jimothy

Situation: Jimothy and Dwight are two brothers living in the same house. Jimothy is a freshman in high school and Dwight is a junior in high school. Their mother takes them to see a doctor and to have their testosterone tested. The tests reveal that Dwight has significantly more testosterone than Jimothy, but that is to be expected given their age difference.

Question: Will Jimothy finish his growth spurt before or after Dwight?
Answer: after

Situation: Jimothy and Dwight are two brothers living in the same house. Jimothy is a freshman in high school and Dwight is a junior in high school. Their mother takes them to see a doctor and to have their testosterone tested. The tests reveal that Dwight has significantly more testosterone than Jimothy, but that is to be expected given their age difference.

Question: Will Dwight finish his growth spurt before or after Jimothy?
Answer: before