Workloads in adolescent athletes

<p dir="ltr">Due to the relatively unknown best-practice training and periodisation approaches for adolescent athletes (12 to 18 years), this population is often exposed to physical workloads similar to those undertaken by adults. Exposure to increased physical workloads due to excessive competitive demands and expectations to obtain elite status may impair long-term athlete development and increase the risk of burnout or injury. Adhering to appropriate longterm athlete development approaches for adolescent athletes helps to improve physical performance, while simultaneously reducing injury risks to increase an athlete’s longevity in physical activity or their sporting endeavours. Additionally, an increased understanding of the anthropometric, physical, and psychological characteristics that determine higher-level athletic performance may influence the prescription of training programs to develop the characteristics that have a greater impact on adolescent athletic participation levels. However, limited research exists on the periodised workload practices of adolescent athletes; particularly the management and monitoring of workloads to improve physical performance and reduce fatigue levels in this cohort. This thesis aimed to establish workload guidelines to assist in the long-term athletic development of adolescent athletes. Physical and psychological characteristics that have the greatest effect on participation level were identified. The workloads, and resultant fatigue responses, were quantified for adolescent Australian Rules Football and soccer players. These findings were then used to determine the effects of periodised workload management on physical performance and fatigue levels in adolescent soccer players. <br>The first aim of this thesis, explored in Study 1, was to quantify and compare the anthropometric measures, physical, and psychological characteristics of adolescent athletes of all abilities participating at a Social-, Competitive-, or National-level. Males and females within each participation level were compared. Anthropometric measures, the results from six physical tests, and the results from the Behavioural Regulation on Sport Questionnaire were compared between participation levels. The results of Study 1 (Chapter 4) indicated that adolescent athletes who competed at a National-level were significantly faster over 30 m, displayed faster 505 change of direction abilities, completed more push-ups, and covered more distance in the YoYo Intermittent Recovery Level 1 test compared to adolescent athletes who competed at a Social- or Competitive-level. When categorised by gender, National-level male adolescent athletes displayed significantly greater speed, change of direction, upper body endurance, and aerobic endurance compared to Social- and Competitive-level male adolescent athletes. Female adolescent athletes only differed in speed and endurance across participation levels, with National-level females significantly faster than Competitive-level females, along with displaying significantly greater aerobic endurance than both Social- and Competitive-level females. Comparing males and females, Competitive- and National-level athletes displayed significantly faster 30 m sprint and 505 change of direction times, higher countermovement jump heights, and covered greater distances in the YoYo Intermittent Recovery Level 1 compared to Competitive- and National-level females. There were no significant differences observed for anthropometric measures for the whole cohort, or when categorised by males and females between participation levels. However, when comparing males and females, males competing at the Competitive- and National-level were taller, had lower body mass index, larger waist circumference, and larger waist-to-hip-ratio compared to Competitive- and National-level females. There were no significant differences in the psychological characteristics between males and females across the participation levels. Adolescent athletes competing at a Competitive- or National-level displayed significantly higher intrinsic and identified motivation, and significantly lower levels of amotivation compared to athletes competing at a Social-level. Greater intrinsic and identified motivation had positive associations with improved physical test results (30 m sprint, change of direction, push-ups, sit-ups, YoYo Intermittent Recovery Level 1). The findings of Study 1 (Chapter 4) suggest that practitioners should focus on the development of key physical characteristics such as speed, strength, power, change of direction, and endurance capabilities, not body composition, when striving for enhanced adolescent athletic performance. The positive relationship between physical and psychological characteristics suggests that adolescent athletes are more likely to perform at a higher level if their motivation for participation is driven internally rather than externally, while improved physical performance may also increase the internal desire to pursue a sport. <br>The second aim of this thesis, explored in Study 2, was to objectively quantify the weekly external workloads of male and female adolescent athletes participating in Australian Rules Football and soccer, while also determining the relationship between weekly external workloads and neuromuscular function. The results displayed in Study 2 (Chapter 5) indicated that the weekly workloads of adolescent Australian Rules Football and soccer players fluctuated, with no clear periodisation strategies evident. Weekly total distance, average speed, high-intensity accelerations, and high-intensity decelerations were significantly higher in males compared to females in Australian Rules Football and soccer. High-intensity running distance was significantly higher in Australian Rules Football males and females compared with soccer males and females, respectively. There was no clear relationship between the weekly workloads and neuromuscular function (countermovement jump performance). The findings presented in Study 2 (Chapter 5) are novel in reporting the workloads and periodisation approaches of both male and female adolescent athletes across various participation levels, rather than only those from a talent-identified squad or representative team. These findings have implications for coaches of adolescent athletes participating at various levels, assisting in the prescription of structured and periodised training programs, along with weekly workload management targets to improve the long-term development of adolescent athletes participating in Australian Rules Football or soccer. <br>The third study considered the findings of the first two studies to address the final aim of this thesis; to determine the effects of incorporating an eight-week periodised training program on the physical performance and neuromuscular function of male and female adolescent soccer players. A sub-aim of this study was to investigate the relationship between external workloads and internal loads, along with the relationship between these two workload measures with weekly neuromuscular function, similar to Study 2 (Chapter 5). The results of Study 3 (Chapter 6) indicated that an eight-week periodised training program with closely monitored and managed workloads did not enhance sprint speed, change of direction ability, lower body muscular power, upper body muscular endurance, trunk endurance, intermittent running performance, change body composition, or influence neuromuscular function in male and female adolescent soccer players. There was a significant positive relationship between the external workloads and internal loads. An increase in total distance, total duration, high-intensity running distance, average speed, high-intensity accelerations, and high-intensity decelerations resulted in a significant increase in internal load as defined by perceived exertion for both males and females. The findings of Study 3 (Chapter 6) suggest that the sessional rating of perceived exertion is a suitable method to measure weekly workloads in adolescent soccer players. This is a novel finding in this population and supports the large body of research that exists in adult populations. Different intervention protocols may be necessary to determine the effect of implementing a periodised training program on the physical performance and neuromuscular function of adolescent soccer players. <br>The findings of this thesis suggest that the long-term athletic development of adolescent athletes should include athletes of all abilities. Adolescents display different physical and psychological, but not anthropometric characteristics, which might influence their sports participation-levels. While the findings indicate that the workloads had no significant effect on neuromuscular function or the physical performance of adolescent athletes, the use of the sessional rating of perceived exertion was shown to be a suitable method to monitor workloads in adolescent athletes. Furthermore, implementing a periodised training program may not necessarily improve the physical performance or reduce fatigue levels of adolescent athletes. However, the findings of this thesis extend the understanding of the physical and psychological characteristics that influence athletic performance. These characteristics should be developed, along with education on the benefits of sport, during the athletic development of all adolescent athletes. Workload prescription and periodisation need to be further investigated to determine the most effective workloads that maximise the physiological adaptation of adolescent athletes that may enhance their long-term athletic development.</p>