Strength Adaptations and Hormonal Responses to Resistance Training and Detraining in Preadolescent Males

Abstract

Nineteen untrained preadolescent males (11-13 years old) were randomly placed into an experimental trained group (STG, n = 9) and a control group (n = 10). Informed consent was obtained from the children and their parents. The STG was submitted to a 2-month resistance-training program (6 exercises, 3 x 10 repetitions maximum [RM], 3 times per week), followed by a 2-month detraining program. The effectiveness of the resistance program was determined by measuring pre- and posttraining and detraining differences in isometric and isotonic (10RM) strength and hormonal responses in testosterone (T), sex hormone binding globulin, and free androgen index (FAI). Their maturation stage was evaluated according to Tanner. Significant posttraining isometric strength gains (17.5%) and mean T and FAI value increases (p < 0.05-0.001) were observed in STG. Detraining resulted in a significant loss (9.5%, p < 0.001) of isometric strength whereas the hormonal parameters of STG remained practically unaltered. The relative (delta%) postdetraining hormonal responses correlated significantly with the respective isometric strength changes. In conclusion, the resistance training induced strength changes independent of the changes in the anabolic and androgenic activity in preadolescent males. Further research is needed to fully clarify the physiological mechanisms underlying the strength training and detraining process.

Acute and Chronic Testosterone Responses to Physical Exercise and Training

“…While some studies demonstrate an increase in the resting levels of testosterone as an adjustment to ST (Izquierdo et al, 2006;Kraemer et al, 1995;Nicklas et al, 1995;Raastad et al, 2003;Tsolakis et al, 2004), other studies have observed no significant differences in this parameter (Ahtiainen et al, 2003;Hansen et al, 2001;Hickson et al, 1994). So far, available data indicate that only young individuals are capable of altering their resting hormone concentrations (Häkkinen et al, 1988;Staron et al, 1994;Tsolakis et al, 2004), whereas middle-aged and elderly individuals show no significant changes in such parameters (Häkkinen & Pakarinen, 1994;Häkkinen et al, 2000;2001a;Izquierdo et al, 2006;Ryan et al, 1994).…”

“…So far, available data indicate that only young individuals are capable of altering their resting hormone concentrations (Häkkinen et al, 1988;Staron et al, 1994;Tsolakis et al, 2004), whereas middle-aged and elderly individuals show no significant changes in such parameters (Häkkinen & Pakarinen, 1994;Häkkinen et al, 2000;2001a;Izquierdo et al, 2006;Ryan et al, 1994). Increases in resting levels of testosterone seem to occur during periods of highvolume (Kramer et al, 1995;Marx et al, 2001) and high-intensity training (Staron et al, 1994;Kraemer et al, 1998;Raastad et al, 2003).…”

Physical exercise, detraining and lipid profile in obese children: a systematic review

“…10 Information regarding the effects of detraining on younger populations is scarce and results have been controversial. [11][12][13][14] In the case of adults, the situation is similar, with negative effects on lipid metabolism 15 or no changes at all. 16,17 In this context, the objective of this study was to assess the effects of detraining (cessation of scheduled physical exercise) on the lipid profile (HDL, LDL, total cholesterol [TC] and TG) of obese children.…”

Ejercicio físico, desentrenamiento y perfil lipídico en niños obesos: una revisión sistemática

“…10 La información relativa sobre los efectos del desentrenamiento en las poblaciones más jóvenes no es muy amplia y muestra resultados contradictorios. [11][12][13][14] Por su parte, en los adultos, ocurre algo similar y se muestran efectos negativos sobre el metabolismo lipídico 15 o no se observan cambios al respecto. 16,17 En este contexto, el objetivo del presente estudio fue evaluar los efectos del desentrenamiento (cese del ejercicio físico programado) sobre el perfil lipídico (HDL, LDL, CT y TG) en niños obesos.…”