The influence of limb role, direction of movement and limb dominance on movement strategies during block jump‑landings in volleyball

Financed by FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento/Proyecto A-TIC-388UGR18. This research has been partially funded by Proyect PID2020-118224RB-I00, funded by MCIN/AEI/10.13039/501100011033/FEDER "Una manera de hacer Europa".The identification of movement strategies in situations that are as ecologically valid as possible is essential for the understanding of lower limb interactions. This study considered the kinetic and kinematic data for the hip, knee and ankle joints from 376 block jump-landings when moving in the dominant and non-dominant directions from fourteen senior national female volleyball players. Two Machine Learning methods were used to generate the models from the dataset, Random Forest and Artificial Neural Networks. In addition, decision trees were used to detect which variables were relevant to discern the limb movement strategies and to provide a meaningful prediction. The results showed statistically significant differences when comparing the movement strategies between limb role (accuracy > 88.0% and > 89.3%, respectively), and when moving in the different directions but performing the same role (accuracy > 92.3% and > 91.2%, respectively). This highlights the importance of considering limb dominance, limb role and direction of movement during block jump-landings in the identification of which biomechanical variables are the most influential in the movement strategies. Moreover, Machine Learning allows the exploration of how the joints of both limbs interact during sporting tasks, which could provide a greater understanding and identification of risky movements and preventative strategies. All these detailed and valuable descriptions could provide relevant information about how to improve the performance of the players and how to plan trainings in order to avoid an overload that could lead to risk of injury. This highlights that, there is a necessity to consider the learning models, in which the spike approach unilaterally is taught before the block approach (bilaterally). Therefore, we support the idea of teaching bilateral approach before learning the spike, in order to improve coordination and to avoid asymmetries between limbs.FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento A-TIC-388UGR18MCIN/AEI/FEDER "Una manera de hacer Europa" PID2020-118224RB-I0

Proceedings of Mathsport international 2017 conference

Proceedings of MathSport International 2017 Conference, held in the Botanical Garden of the University of Padua, June 26-28, 2017. MathSport International organizes biennial conferences dedicated to all topics where mathematics and sport meet. Topics include: performance measures, optimization of sports performance, statistics and probability models, mathematical and physical models in sports, competitive strategies, statistics and probability match outcome models, optimal tournament design and scheduling, decision support systems, analysis of rules and adjudication, econometrics in sport, analysis of sporting technologies, financial valuation in sport, e-sports (gaming), betting and sports

Constraints-led approach and synergetic behaviour in volleyball performance

O objetivo desta tese foi investigar a Abordagem Baseada nos Constrangimentos (ABC) e comportamento sinergético no voleibol. Enquadrados pela dinâmica ecológica investigámos conceitos teóricos relacionados com o comportamento sinergético individual e coletivo e aplicamos a ABC em equipas de voleibol. Inicialmente, apresentámos uma revisão narrativa dos princípios da ABC e pedagogia não-linear sugerindo dois exemplos para aplicação em treino. De seguida, produzimos dois artigos de opinião sobre o papel das estruturas de biotensegridade no comportamento sinergético individual e coletivo. Nos estudos experimentais implementámos a ABC para guiar os atletas através das fases de “Search”, “Discover” e “Exploit”. Primeiro, numa equipa de cadetes feminina manipulámos os constrangimentos da tarefa de forma a respeitar as diferenças individuais e comparar a precisão no remate após o treino, assim como, analisar a estratégia temporal na estrutura coordenativa da corrida e chamada de remate. Os resultados mostram que respeitar as diferenças individuais promovem melhor performance (i.e., na precisão do remate) e que congelar os graus de liberdade numa componente da estrutura coordenativa da chamada foi a estratégia associada com mais precisão no remate. De seguida, implementámos um estudo com jogadoras peritas para comparar frequências de contacto na defesa entre o jogo formal, a estratégia tradicional de defesa e a estratégia de coletivamente atender a variáveis especificadoras no decorrer da jogada. Adicionalmente, medimos a sincronização da defesa em situações de sucesso e insucesso defensivo. Resultados mostram que coletivamente atender a variáveis especificadoras no decorrer da jogada promove maior frequência de contactos e que as jogadas de sucesso defensivo estão associadas a alterações na sincronização no decorrer da jogada. Por último, com jogadores jovens de elite comparámos os efeitos na performance de ataque entre treinar de acordo com os princípios da ABC e com uma abordagem tradicional. Também tivemos como objetivo predizer quais as variáveis espácio-temporais que foram exploradas pelos jogadores nos ataques com sucesso. Resultados mostram um aumento da performance com a ABC e que variabilidade na chamada e consistência no ponto de contacto da bola aumenta a probabilidade de atacar com sucesso.The aim of this thesis was to research the Constraints-led Approach (CLA) and synergetic behaviour in volleyball performance. Grounded on ecological dynamics framework we researched theoretically concepts related to individual and collective synergetic behaviour and experimentally implemented the CLA with volleyball teams. First, we presented a narrative review on the principles of CLA and nonlinear pedagogy providing two practical examples to apply to the sub-phase of volleyball attack. Next, we advanced a position statement and a novel hypothesis on the crucial role of biotensegrity structures in individual and collective coordinative structurers (i.e., synergies). In the experimental studies we implemented CLA to guide the performers trough the phases of “Search”, “Discover” and “Exploit”. First, with a team of young female volleyball players we manipulate task constraints to accommodate individual differences and compare spike accuracy after training as well as understand time strategies in the coordinative structure of the horizontal approach. Results show that accommodating individual differences enhances performance (i.e., spike accuracy) and freezing degrees of freedom maintaining high variability in a component of the coordinative structure of the horizontal approach was the strategy of movement re-organization associated with higher spike accuracy. Next, we implemented a study with expert female volleyball players to compare frequencies of defensive ball contacts between real game, traditional defense strategy and “online” attunement to specifying variables. Additionally, we measure group synchronization in successful and unsuccessful defense situations. Results show that collectively attuning to relevant information promotes significant higher frequencies of defense ball contact than pre-determined strategies of action and successful defensive plays are associated with “online” significant changes in group synchronization. Finally, with young male elite volleyball players we aimed to compare the effects of training based on CLA principles to a traditional approach on attack performance. Also, aimed to predict what spatial temporal variables were exploited by the players to achieve successful attacks. Results showed a significant improvement in attack performance for CLA, and we found that variability at the end of the planting step and consistency at ball contact increased the chances of a successful attack

Modeling match performance in elite volleyball players: importance of jump load and strength training characteristics

In this study, we investigated the relationships between training load, perceived wellness and match performance in professional volleyball by applying the machine learning techniques XGBoost, random forest regression and subgroup discovery. Physical load data were obtained by manually logging all physical activities and using wearable sensors. Daily wellness of players was monitored using questionnaires. Match performance was derived from annotated actions by a video scout during matches. We identified conditions of predictor variables that related to attack and pass performance (p < 0.05). Better attack performance is related to heavy weights of lower-body strength training exercises in the preceding four weeks. However, worse attack performance is linked to large variations in weights of full-body strength training exercises, excessively heavy upper-body strength training, low jump heights and small variations in the number of high jumps in the four weeks prior to competition. Lower passing performance was associated with small variations in the number of high jumps in the preceding week and an excessive amount of high jumps performed, on average, in the two weeks prior to competition. Differences in findings with respect to passing and attack performance suggest that elite volleyball players can improve their performance if training schedules are adapted to the position of a player.Algorithms and the Foundations of Software technolog

Spartan Daily, November 20, 1990

Volume 95, Issue 56https://scholarworks.sjsu.edu/spartandaily/8055/thumbnail.jp

HOW ADAPTIVE SPORTS PROMOTE OCCUPATIONAL ENGAGEMENT AND QUALITY OF LIFE FOR INDIVIDUALS WITH DISABILITIES IN A RURAL COMMUNITY

Health management, play, leisure, and social participation are all valued occupations related to sports. However, individuals with physical disabilities face many barriers that inhibit them from engaging in sports, depriving them of these occupations. Some of these barriers include a lack of adaptive sports resources, adaptive equipment, adaptive sports programs in rural communities, and knowledge of how to include individuals with disabilities (Obradovic et al., 2021). The purpose of this scholarly project was to address these barriers through the development of adaptive sports programs; hereby, increasing occupational engagement, quality of life (QOL), and life satisfaction for individuals with disabilities. To fulfill this purpose, an adaptive sports manual was developed to guide the implementation of adaptive sports programs at rural community facilities. The author of the scholarly project partnered with a YMCA in rural Minnesota to develop this manual and accomplish this goal. Through this partnership, an extensive literature review, community outreach efforts, and interprofessional collaboration were completed to create the current product of an adaptive sports manual. The final manual includes descriptions of three adaptive sports, modified rules, space for each sport, equipment needed, safety precautions, adaptive exercise recommendations, coach/officials training information, funding sources, an athlete registration form, a consent and release form, a program evaluation survey, advertisement poster templates, and a brief handout including adaptive sports resources and links. It is anticipated that the manual will increase adaptive sports opportunities to help improve occupational engagement, QOL, and life satisfaction for individuals with physical disabilities

Predicting and preventing common volleyball injuries with functional tests

The purpose of this thesis is to provide a compilation of screening tests best suited for predicting and preventing volleyball’s most common injuries. Research displays a gap in knowledge pertaining to volleyball-specific injury prevention tests. A literary analysis was completed for information regarding; correct volleyball techniques, incorrect techniques that are commonly observed, common injuries resulting from faulty technique, and tests best designed to prevent these injuries. It was found that knees and ankles were the two joints most often injured. These injuries mainly occurred during the landing phase of the jumping-landing sequence. Therefore, ankle and knee injury rates were higher in front row attackers and blockers. Because data is more abundant for these two joints, the tests that were studied place a greater emphasis on ankle and knee injury prediction. All the tests used were designed to imitate game-like movements to provide the best results. These included; multiple variations of a single leg hop test to observe leg strength, and ankle and knee control upon landing, single leg squat test and drop jump to display correct knee technique, and to expose hip strength, the groin flexibility test to potentially predict adductor strains, core strength screenings that tested both abdominal and lower back strength, and finally, shoulder mobility and control tests. In conclusion, due to the growing popularity of volleyball, definitive sport-specific tests should be put into place to help reduce injury rates and prevent injury-related participation restriction