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Late Bloomers | Delayed Puberty in Boys

Research presented will paint a clear picture of what exactly classifies a late bloomer, the physiological implications of maturity in sport, the psychosocial effects of late bloomers and the implications for youth development leaders and coaches.

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Delayed Puberty

Delayed puberty is clinically defined as having a testicular volume of less that 4ml after the age of 13.5 years old, meaning that the boy has not begun the process of puberty (Lindfors et al., 2007; Tanner, 1990; Tanner, 1986). Pinyerd and Zipf (2005) has referred to delayed puberty as being 2.5 standard deviations away from the mean, whereas Lindfors (2007) refers to delayed puberty as being 2 standard deviations away from the mean. That leaves us with a population of 2.5% of healthy adolescents identified as having pubertal delays according to Pinyerd and Zipf (2005).

According to Marshall and Tanner’s research (1970), they stated, “In fact, we have observed several boys who went through a perfectly normal puberty beginning after they were 15” (p. 21). The 97th percentile for developing increased testicular volume above 4 ml is 14 years old. That leaves about 2% of boys who will still be prepubertal and thus short in stature at 14-15 years old (Christie & Viner, 2005).

The clinical definition for delayed puberty is quite far from the mean. Even though Tanner concluded that even boys who are clinically delayed will still complete a perfectly normal development, it is recommended by Christie and Viner (2005) that those adolescents who have not shown the beginnings of puberty should consult a pediatric endocrinologist.

Although, there may not be clinical concerns relating to the normalcy of development for even those past 2.5 standard deviations from the mean, the data above deals with the initial onset of puberty. There are many other factors that come into play when comparing young athletes of similar ages to each other. There is a substantial difference in an athlete that has just entered into Tanner’s second stage than the athlete entering into Tanner’s fourth stage. Given the clinical definition, neither is clinically defined as undergoing delayed puberty given we are looking at athletes under the age of 13 or 14.

"In fact, we have observed several boys who went through a perfectly normal puberty beginning after they were 15”

-Marshall & Tanner (1970)
The length that a child will go through all five Tanner stages can range from 1.5-6 years with an average period of about 4.5 years

Where as the data in the previous section describes the onset of puberty, the length that a child will go through all five Tanner stages can range from 1.5-6 years with an average period of about 4.5 years (Pinyerd & Zipf, 2005). Pubertal tempo is described as the rate of which adolescents pass through the stages of development (Mendle, Harden, Brooks-Gunn, & Graber, 2010).

Tanner and Marshall (1970), found that some boys complete the whole process of genital development from stage 2 to 5 in less time that it takes others to pass from stage 2 to 3. Thus, “while pubertal timing indexes a level of maturation relative to others of the same gender at the same chronological age, pubertal tempo is defined with reference to a child’s own previous development. Some people mature comparatively rapidly (to use an analogy from Aesop, they are developmental hares), whereas others have a slower, more gradual progression through puberty (e.g., developmental tortoises)” (Mendle et al., 2010, p. 1342).


Due to the wide variance listed for adolescent’s genitalia to reach an adult

state, clinical failure to attain complete maturity cannot be viewed as abnormal before 4.5 year, regardless of age (Marshall & Tanner, 1970). The research on pubertal tempo and the timing of the onset of puberty is information that should be considered when creating sporting programs and coaching individuals as well as teams. “This variability in the timing of biologic development, which is most evident in the early- to mid-adolescent years, poses a number of practical dilemmas for those who deal with youth exercise and sports” (Rowland, 2005, p. 29).

Pubertal Tempo


Christie, D., & Viner, R. (2005). Adolescent development. BMJ (Clinical Research Ed.), 330(7486), 301-304. doi:330/7486/301 [pii]

Hauser-Cram, P., Nugent, J. K., Theis, K. M., & Travers, J. F. (2014). The development of children and adolescents Wiley.


Lindfors, K., Elovainio, M., Wickman, S., Vuorinen, R., Sinkkonen, J., Dunkel, L., & Raappana, A. (2007). Brief report: The role of ego development in psychosocial adjustment among boys with delayed puberty. Journal of Research on Adolescence, 17(4), 601-612.

Marshall, W. A., & Tanner, J. M. (1970). Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood, 45(239), 13-23.

Mendle, J., Harden, K. P., Brooks-Gunn, J., & Graber, J. A. (2010). Development's

tortoise and hare: Pubertal timing, pubertal tempo, and depressive symptoms in boys

and girls. Developmental Psychology, 46(5), 1341.

Pinyerd, B., & Zipf, W. B. (2005). Puberty—Timing is everything! Journal of Pediatric Nursing, 20(2), 75-82.

Rowland, T. W. (2005). Children's exercise physiology Human Kinetics Champaign, IL.

Tanner, J. (1990). Foetus into man: Physical growth from conception to maturity Harvard University Press.

Tanner, J. (1986). 1 normal growth and techniques of growth assessment. Clinics in Endocrinology and Metabolism, 15(3), 411-451.

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