Physical Abilities and Muscle-Size Changes in Basketball-Trained Boys at the Onset of Puberty

Background: Data is lacking on the combined effects of maturation and training on physical and morphological changes in children at the onset of puberty. In our study we examined year-long maturity-related physical and morphological changes of similar-aged basketball-trained (BT) and actively untrained (UN) adolescent boys.

Aims: We aimed to evaluate muscle parameters and maximal performance test results in young BT and UN boys, compare them, and check the correlations with maturity level.

Methods: Our subjects were 28 BT (11.84 ± 0.38 years-old during first session) and 22 UN (11.81 ± 0.49 years-old) healthy adolescent boys. Anthropometric parameters were collected using standard procedures with a stadiometer and a total body composition analyzer. Performance tests included: isometric bench press (BP), isometric knee extension (KE), vertical squat-jump test – parameters measured: jump height (JH) and ground reaction force (GRF), 30-meter sprint (RT), and the Flamingo balance test (FB). Muscle parameters measured were Biceps Brachii thickness (BB) and Vastus Lateralis thickness (VL). Two one-year in-between testing sessions were conducted to observe the influence of trainability and maturation (according to maturation development stages by Tanner). Students’ t-tests were used to compare within-group differences between sessions and between-group differences in both sessions. Pearson’s correlation coefficients were calculated to assess performance tests, muscle parameters, maturation level, and maturation level relationships.

Results: The BT group showed significantly higher (p0.05) BP, JH, and RT results during both testing sessions. In addition, they also had higher KE and VL during the second session, and KE was the only parameter which improved more between sessions in BT than in UN. Between sessions the BT group significantly improved all parameters except JH, and the UN group improved KE, GRF, RT, BB, and VL parameters. Strong correlations (p0.05) in the BT group were observed between maturity level and BB, BP, KE, and GRF. In the UN group maturity correlated only with GRF.

Discussion: Trained boys showed higher muscle and physical parameters, which is in accordance with previous findings. One year is probably too short a time to see significant basketball influence on most parameters, especially when the BT group already had pre-training and did not start from similar physical and morphological levels as the UN boys. Since physical abilities do not correlate fully with maturity level, additional studies should be done to clarify the underlying mechanisms of physical and morphological changes in relation to maturation and training at the onset of puberty.

Conclusion: Significant improvements in muscle size and physical abilities in boys start at the onset of puberty and before reaching age at peak height velocity. Furthermore, BT boys have superior strength and power abilities than their similarly aged and matured UN peers. On the other hand, physical and muscle parameters correlate only partly with maturity.