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

ABSTRACT: 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.

Interrelations between anthropometric and fitness changes during mid-adolescence in boys: a 2-year longitudinal study.

OBJECTIVES: This study aimed to determine changes and interrelationships between changes in selected anthropometric growth parameters and motor and physical fitness, among boys over a 2 year period during mid-adolescence. METHODS: Speed, agility, hand-eye coordination, explosive power, muscle strength, and aerobic endurance were measured once a year, and the anthropometric measurements (stature, body mass, sitting height, arm span, and sitting height ratio), were measured three times per year, 4 months apart (among 73 adolescent boys). A hierarchical linear model, adjusting for covariates and partial correlation analysis (R(2) ) were used to analyze the data. RESULTS: All anthropometric, motor, and physical measurements improved significantly over the two-year period. Significantly, greater changes were seen between 13 and 14 years in stature, arm span, sitting height and body mass. Changes in muscle strength, speed and agility were mainly significant between 13 and 14 years while the biggest changes occurred in explosive power and upper-body-arm-and-shoulder-strength during year 2 (14-15 years). The majority of interrelationships, indicating moderate to small relationships, were found between changes in stature, arm span, and sitting height, and changing strength, speed, agility, and hand eye coordination over the two-year period, after adjusting for maturity age and physical activity levels. CONCLUSION: Motor and physical fitness improved significantly from 13 to 15 years, showing definite interrelationships with anthropometric growth during the mid-adolescence period. Awareness and education about these changes are recommended as it can have significant effects on the sport performance and fitness training of boys during mid-adolescence.