Effect of the Growth Spurt on Training of Strength and Power During Mid-Adolescence in Boys

Badenhorst, J, Pienaar, AE, and Gerber, BP. The effect of the growth spurt on training of strength and power during mid-adolescence in boys. J Strength Cond Res 35(8): 2193-2204, 2021-This study determined if the growth spurt will influence the training of strength and power in boys (N = 86) of differing maturity levels. Based on a 2-group, pretest posttest design within a 2 school-year follow-up period, including 4 time point measurements, an experimental group (EG), who participated in different school sports were subjected to an additional 6 months, strength and power training program, twice a week for 45 minutes over 2 consecutive years (n = 47, 13.67 ± 0.26 years). They were compared with boys (n = 39, 13.68 ± 0.16 years) serving as a control group (CG) for normal growth who did not compete in any sports or training programs. Both EG and CG were subdivided into 3 maturity groups, late developers (LD), early developers, and typical developers (TD) based on a linear growth rate. Assessments were performed every 6 months for changes in height, body mass, strength, and power. Differences within and between the EG, CG, and maturity groups were analyzed using repeated measures analysis of variance and hierarchical linear modeling, whereas significance of practical differences were determined by effect sizes (d). Early developers presented with training effects, whereas TD and LD showed conditioning and adaptation responses to training. Customized training to leverage the different maturation levels in a way to optimize strength and power advancement is important for the preparation of boys for sports participation during mid-adolescence because it can positively affect adaptation and responsiveness to training in boys of different maturity levels.