Does Testosterone Relate To Physical Maturity Of 13???14 Year-old Boys Involved In American Football?

Abstract

The literature claims that involvement in organized sports, like American football, could provoke marked fluctuations in testosterone levels. However, little is known how involvement in American football interacts with the physical maturation process. PURPOSE To examine the relationship between involvement in American football and testosterone (T) levels of 13–14 year-old boys and in addition examine how this involvement in sports was associated with their physical maturation process. METHODS Thirty-two male football players (age 14 +/- 0.4), members of a junior high school football team, volunteered to participate in the study. Each participant was given a coded envelope containing two questionnaires. The first questionnaire was used to quantify the number of training sessions and training hours per week as well as the time period they were involved in the sport both during and off-season. The second questionnaire was a physical maturity questionnaire modified for males. Bioelectrical impedance was used to estimate relative body fat [percent body fat (%BF)] using the variables, age, weight, height and sex. In addition, the OMROM displayed the BMI of each participant. Two samples of saliva were collected to avoid the complication of diurnal fluctuations of testosterone. The second sample was taken an hour after the first sampling, and the means from both collections were calculated. RESULTS No significant difference (depended pair t-test, P =0.05) was found between the two T samples. Height was significantly correlated (r = .434, P=0.05) with Physical Maturity. As expected, weight was significantly correlated (r = .530, P <v:shape id=_x0000_i1027 style=“WIDTH: 5.25pt; HEIGHT: 7.5pt” alt=“0.01”) with the body fat percentage and BMI. Total free Testosterone was not significantly related to any of the variables. Percent body fat (%BF) and BMI were significantly correlated (r =. 707, P <v:shape id=_x0000_i1028 style=“WIDTH: 5.25pt; HEIGHT: 7.5pt” alt=“0.01”). CONCLUSIONS The findings of the study indicate that physical maturation is not associated with the number or hours of training. Exercise training had little relationship to the participants T levels and the T levels had little relationship to physical maturity. Further investigation is needed to determine what factors are involved (hormonal changes, epiphyseal injuries, athlete selection, etc) and how these factors might affect the maturation process of prepubertal children that are involved in sports incorporating intense training. In addition, further investigation is needed to define the intensive training threshold that might affect physical maturation.