Pubertal Maturation, Hormonal Levels And Body Comoposition In Canadiam Male And Female Gymnasts

Introduction
Puberty is characterized by large hormonal changes, resulting in both physical and sexual maturation. Intense training
and low body fat has been found to delay the onset of puberty in females by altering normal hormonal development [1].
In males, despite evidence that physical activity can also result in hormonal changes, previous studies have reported that
intense gymnastics training does not influence the onset of puberty, if body composition is within normal range [2]. The
purpose of this study was to assess sexual maturation, hormonal levels, and body fat among competitive male and
female Canadian gymnasts compared to a non-training control group.

Methods
The gymnastics group, comprised of 21 male (13.3 ± 0.3y) and 18 female gymnasts (13.4 ± 0.2y), was compared to 24
age-matched male (13.5 ± 0.3y) and 24 female (13.9 ± 0.1y) non-training controls. Sexual maturation was self-assessed
using the Tanner Scale [3]. For the male subjects, testosterone levels were determined from saliva samples. For the
female subjects, progesterone and estradiol (17-b) were measured from blood samples. For menstruating subjects, age
at menarche was reported and blood draws were performed twice: in the follicular and luteal phase of the menstrual
cycle. Relative body fat (%BF) was assessed using bioelectrical impedance analysis.

Results
There were no significant differences between the male gymnasts and controls in salivary testosterone (43.3 ± 5.8 vs.
38.2 ± 4.1 pg . ml-1), genital development (stages: 3.2 ± 0.2 vs 3.5 ± 0.1) or pubic hair development (stages: 3.5 ± 0.1
vs. 3.6 ± 0.1). Male gymnasts were similar in size, but had significantly (P<0.05) lower %BF than the controls (Table
1). Female gymnasts were significantly (P<0.01) smaller, and had significantly (P<0.01) lower body fat than female
controls (Table 1). Twenty-one female controls and one gymnast were menarcheal, with the average at menarche being
12 ± 0.1y for the controls, age 13 for the menarcheal gymnast. Serum estradiol and progesterone levels for the premenarcheal
gymnasts were similar to those measured of the controls during the follicular phase, which were
significantly lower (P<0.01) than those measured during the luteal phase (Table 2). Breast development was delayed in
female gymnasts compared to controls (stages: 2.7 ± 0.2 vs 3.8 ± 0.1), while the difference between the groups in pubic
hair development did not reach significance (stages: 3.1 ± 0.2 vs 4.0 ± 0.2).

Discussion / Conclusions
While the intense training by the young male gymnasts resulted in a decreased %body fat, there was no apparent
alteration in the timing and extent of their physical and pubertal development. On the other hand, a delayed menarche,
reduced physical and sexual maturation, and a low %body fat were found in the females engaged in rigorous
gymnastics training.

References
[1]. Theintz GE. (1994). Clin Endocrinol 41: 267-272, 1994.
[2]. Gurd B., Klentrou P. (2003). J Appl. Physiol. X : Y1-Y2.
[3]. Tanner JM. (1962) Growth at Adolescence. Oxford: Blackwell Scientific Pubishers.

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