The influence of biological maturity and strength and power kinetics on weightlifting performance in young weightlifters

Weightlifting is both a sport and a training method commonly used to enhance strength and power, with growing interest in its application among youth athletes. However, limited research has explored the developmental and performance-related implications of weightlifting during childhood and adolescence. This thesis aimed to investigate the influence of biological maturity and strength and power kinetics on weightlifting performance in young athletes, to provide evidence-based guidance for talent identification and development in youth weightlifting. Meta-analytical findings demonstrated that weightlifting elicited superior improvements in countermovement jump (CMJ) height (9 studies, p < 0.05, g = 0.95; 95% CI 0.04–1.87) and weightlifting load lifted (4 studies, p < 0.05, g = 1.35; 95% CI 0.20–2.51) compared to traditional resistance training, supporting its use in athletic development programmes. As current long-term athlete development (LTAD) models for weightlifting predominantly rely on chronological age, a novel LTAD framework was developed to integrate biological maturation into training prescription. This guidance was subsequently embedded in the National Strength and Conditioning Association (NSCA) position statement on weightlifting for sports performance. Among a cohort of young national age-group lifters, large amounts of variance in weightlifting performance (i.e., absolute combined total) could be explained by skeletal age in both boys (R2 = 0.73) and girls (R2 = 0.75). Significant maturity biases were evident (p < 0.05), with an overrepresentation of early maturers and underrepresentation of on-time maturers compared with normal distribution in both boys and girls. In line with these findings, recommendations were made to integrate growth and maturity assessments, such as the Khamis-Roach method, to better inform training and competition decisions within youth weightlifting. Isometric mid-thigh pull (IMTP) peak force and CMJ propulsive variables were able to explain moderate (45.8 – 52.9%) and large percentages (79.1 – 81.3%) of variance in absolute measures of weightlifting performance, among young weightlifters, respectively. Furthermore, logistic regression analyses revealed that average relative propulsive force and propulsive phase duration during the CMJ significantly differentiated young lifters who attainted national qualification from those that did not, with strong predictive accuracy (AUC = 0.910, p < 0.05 and AUC = 0.807, p < 0.05), highlighting key kinetic markers of success. Collectively, this body of work demonstrates the value of monitoring biological maturity alongside IMTP and CMJ kinetics to inform talent identification and athlete development in youth weightlifting.