Findings offer further understanding about growth and development in young male gymnasts

Gymnastics training in young males does not appear to have significant effects on their resting testosterone, sexual maturation, if body composition is within normal range

(September 10, 2003) - Bethesda, MD -- Intense training has been found to delay the onset of puberty in females by altering normal hormonal development. This has led to delayed pubertal onset, delayed age at first menarche and failure to develop mature skeletal structure. In males, despite evidence that physical activity can also result in hormonal changes, there have been few studies that examined the relationship between training and the onset of puberty.

Accordingly, a new study has been undertaken to evaluate the effect of intense training during somatic growth and skeletal development on the onset of puberty in male gymnasts. The researchers hypothesized that after several years of training, the increased energy expenditure by elite gymnasts would result in lower levels of testosterone than other boys of their age, leading to a delay in physical growth characteristics and markers of sexual maturation.

A New Study

The study, entitled "Physical and Pubertal Development in Young Male Gymnasts" was conducted by Brendon Gurd and Panagiota Klentrou, both of the Department of Physical Education and Kinesiology, Brock University, St. Catharines, Ontario, Canada. Their findings appear in the September 2003 edition of the Journal of Applied Physiology. The journal is one of 14 scientific journals published monthly by the American Physiological Society (APS) (http://www.the-aps.org).

Methodology

A total of 21 elite gymnasts (GYM) (13.3¡À 0.3 years) were recruited from competitive gymnastics clubs around Southern Ontario, Canada. In order to qualify for the experimental group, gymnasts had to be competing at a minimum of a provincial level and training at least 15 hours per week. A total of 24 age-matched boys (13.5 ¡À 0.3 years) were recruited from recreational martial arts classes to participate as the control groups (CON). These boys were training not more than two hours per weeks.

Each participant was tested on one occasion at his gymnastic club or at the martial arts school. During testing, subjects had physical characteristics measured, completed a physical activity questionnaire, provided saliva samples, and completed a self-assessment of pubertal stages scale.

One-way analysis of variance (ANOVA) was used to determine differences between the GYM and CON groups for all of the variables tested. Correlation analysis was used to examine possible relationship among variables. A p-value of ¡Ü0.05 was used to indicate a significant result.

Results

The researchers discovered the following:

The gymnasts trained an average of 4.7 ± 0.4 sessions per week for a duration of 18.7 ± 1.4 hours per week, which was significantly higher than what was reported by the controls. This difference in training contributed to 44% greater energy expenditure per week by the GYM group compared with the CON group.

The gymnasts were slightly shorter and lighter than the controls, but these differences did not reach significance. The GYM group did, however, have significantly lower relative body fat.

In terms of sexual maturation, there were no significant differences detected in testosterone levels between GYM and CON. There were also no significant differences between groups for either the genital or pubic hair development.

Relative body fat was significantly correlated with training frequency and energy expenditure. As expected, there was also a significant relationship between genital development and pubic hair development. Physical characteristics such as lean body mass (LBM) and height were also significantly correlated with the indicators of sexual maturation. There was also a relationship between testosterone and both genital and pubic hair development.

Relative body fat, energy expenditure, and training variables were not significantly correlated with physical growth or sexual maturation variables.

Conclusions

These findings suggest that gymnastics training in young males does not appear to have significant effects on their resting testosterone and sexual maturation if body composition is within normal range.

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Source: September 2003 edition of the Journal of Applied Physiology

The American Physiological Society (APS) was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals every year.

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