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Building for the Future: A Systematic Review of the Effects of Eccentric Resistance Training on Measures of Physical Performance in Youth Athletes
Get PDFEccentric resistance training is recognised as an effective stimulus for enhancing measures of muscular strength and power in adult populations; however, its value in youth athletes is currently not well understood. The aim of this systematic review was to critically appraise the effects of eccentric resistance training on measures of physical performance (i.e. muscular strength, jump, sprint and change of direction) in youth athletes 18 years of age and under. Original journal articles published between 1950 and June 2022 were retrieved from electronic search engines of PubMed, SPORTDiscus and Google Scholar's advanced search option. Full journal articles investigating the acute and chronic effects of eccentric resistance training on measures of physical performance in youth athletes (i.e. a person 18 years of age or under who competes in sport) were included. The methodological quality and bias of each study were assessed prior to data extraction using a modified Downs and Black checklist. The search yielded 749 studies, of which 436 were duplicates. Three-hundred studies were excluded based upon title and abstract review and a further 5 studies were removed following the modified Downs and Black checklist. An additional 14 studies were identified during backward screening. Accordingly, 22 studies were included in our systematic review. The Nordic hamstring exercise and flywheel inertial training were the most frequently used eccentric resistance training methods in youth athletes. Improvements in physical performance following the Nordic hamstring exercise are dependent upon an increase in the breakpoint angle, rather than training volume (sets and repetitions), and are further elevated with the addition of hip extension exercises or high-speed running. A minimum of 3 familiarisation trials is necessary to elicit meaningful adaptations following flywheel inertial training. Furthermore, an emphasis should be placed upon decelerating the rotating flywheel during the final one to two thirds of the eccentric phase, rather than gradually throughout the entire eccentric phase. The findings of this systematic review support the inclusion of eccentric resistance training in youth athletes to improve measures of muscular strength, jump, sprint and change of direction performance. The current eccentric resistance training methods are predominantly limited to the Nordic hamstring exercise and flywheel inertial training; however, the efficacy of accentuated eccentric loading to improve jump performance warrants attention in future investigations. [Abstract copyright: © 2023. The Author(s).
Child development and the brain: from embryo to adolescence
No full text• case studies showing how brain science is changing practice;
• a companion website including self-test questions;
• end-of-chapter summaries, further reading and questions to test knowledge;
• a glossary of neuroscientific terms
Kinetics and kinematics of the free-weight back squat and loaded jump squat
Get PDFThompson, SW, Lake, JP, Rogerson, D, Ruddock, A, and Barnes, A. Kinetics and kinematics of the free-weight back squat and loaded jump squat. J Strength Cond Res 37(1): 1–8, 2023—The aim of this study was to compare kinetics and kinematics of 2 lower-body free-weight exercises, calculated from concentric and propulsion subphases, across multiple loads. Sixteen strength-trained men performed back squat 1 repetition maximum (1RM) tests (visit 1), followed by 2 incremental back squat and jump squat protocols (visit 2) (loads = 0% and 30–60%, back squat 1RM). Concentric phase and propulsion phase force-time-displacement characteristics were derived from force plate data and compared using analysis of variance and Hedges' g effect sizes. Intrasession reliability was calculated using intraclass correlation coefficient (ICC) and coefficient of variation (CV). All dependent variables met acceptable reliability (ICC >0.7; CV < 10%). Statistically significant 3-way interactions (load × phase × exercise) and 2-way main effects (phase × exercise) were observed for mean force, velocity (30–60% 1RM), power, work, displacement, and duration (0%, 30–50% 1RM) (p < 0.05). A significant 2-way interaction (load × exercise) was observed for impulse (p < 0.001). Jump squat velocity (g = 0.94–3.80), impulse (g = 1.98–3.21), power (g = 0.84–2.93), and work (g = 1.09–3.56) were significantly larger across concentric and propulsion phases, as well as mean propulsion force (g = 0.30–1.06) performed over all loads (p < 0.001). No statistically significant differences were observed for mean concentric force. Statistically longer durations (g = 0.38–1.54) and larger displacements (g = 2.03–4.40) were evident for all loads and both subphases (p < 0.05). Ballistic, lower-body exercise produces greater kinetic and kinematic outputs than nonballistic equivalents, irrespective of phase determination. Practitioners should therefore use ballistic methods when prescribing or testing lower-body exercises to maximize athlete's force-time-displacement characteristics
Stress influences gaze behaviour, quiet eye durations, and esport action performance
No full textIntroduction:
Much like traditional sporting domains, esport performers are often presented with a variety of stressful conditions. However, researchers have only recently started to discuss the psychological mechanisms underpinning esports performance. As such, there is a need to better understand the impact of stress on esports performance
"Knowledge production in academic spaces. Disturbing conferences and composing events"
Get PDFIn this unique book the authors debate the many aspects of (post)human / more-than-human / materialist / feminist materialist aspects of the AcademicConferenceMachine. In their ‘co-argument’ the authors address how the traditional can be resisted. The specificities of conference performances introduced in this book illuminates new, creative forms of knowledge production and its presentation. The events in the book provide provocations of what audiences are not normally accustomed to be engaged with, to hear or to see in conference panels
Ultrasensitive and highly selective fluorescence probe of nitrogen-doped graphene quantum dots and zinc oxide decorated carbon foam incorporated molecularly imprinted polymer for trace sparfloxacin determination
Get PDFA fluorescent probe was fabricated for the determination of sparfloxacin. The nanocomposite probe was constructed by incorporating nitrogen-doped graphene quantum dots, zinc oxide decorated carbon foam and magnetite into a matrix formed from a molecularly imprinted polymer. The fabricated nanoprobe was characterized and the fabrication and determination conditions were optimized to obtain the highest sensitivity. The determination of sparfloxacin was based on the decreasing of emission response of the nanocomposite probe when the target analyte rebinds to the inherent recognition sites of the fluorescent probe. Under the best conditions, the quenching of fluorescence was linear in the range of 0.10–100.0 μg L−1 (R2 = 0.991) with the limit of detection being 0.10 μg L−1. The nanocomposite probe exhibited high specificity with an imprinting factor of 7.93. This optosensor was used to determine sparfloxacin in milk and good recoveries were observed ranging from 93.0 % to 100.8 % with RSDs lower than 5 %. The results also agreed with the results obtained using a chromatographic method but the developed method has higher sensitivity, at lower cost and faster determination procedure. In addition, the developed optosensor can be simply modified for highly selective determination of other trace levels of target compounds by changing the template with minor changes in determination conditions
Who is more likely to feel ostracized? A latent class analysis of personality traits
Get PDFPerceived ostracism (e.g., feeling ignored or excluded) is a painful and distressing experience. However, little empirical research has investigated the types (profiles) of people more likely to perceive ostracism. The present study (N = 395) used latent class analysis to (a) identify potential classes based on the big five personality traits (i.e., openness, agreeableness, negative emotionality, extroversion, and conscientiousness) and (b) examine whether such classes could reliably differentiate levels of self-reported perceived ostracism. We extracted three classes: (a) Moderate Traits (MT), (b) the Quiet Over-Reacting Procrastinators (QORP), and (c) the Active and Adaptable Thinkers (AAT). Those in the QORP class reported the highest levels of perceived ostracism, whereas those in the AAT class reported the lowest levels of perceived ostracism compared to the MT class. This study provides new insight into the profiles of individuals who may be more likely to perceive ostracism. However, further research is needed to explore the association between personality and ostracism (e.g., as ostracism may lead to changes in personality), so that potential risk markers to trigger early psychological interventions of such ostracised individuals can be identified
Perceptions of Effective Training Practices in League of Legends: A Qualitative Exploration
Get PDFWhile scientific interest in electronic sports (esports) is steadily growing, there remains an absence of research evidence concerning training practices in specific esports such as League of Legends. Anecdotal evidence suggests that current approaches to training may be suboptimal in terms of performance and, concerningly, linked to negative consequences for player health and well-being. In order to address the lack of literature and aid understanding of the (in)effectiveness of current training practices in esports, our study sought to qualitatively examine the experiences and perceptions of training in a sample of professional and semiprofessional League of Legends players. Through interviews with 10 players who ranked in the top 0.24% of the playing population, three core themes were identified: (a) the state of training, (b) training experiences, and (c) motivational change. This study provides important insights into current training practices in esports and players’ perceptions of the (in)effectiveness of these practices. The paper concludes with practical recommendations for coaches and support staff working in esports
The origins, benefits and challenges
No full textThis article explores the concept of beach school, how this has developed, and the benefits and challenges for children and practitioners. Some activities that beach school may involve are also given as examples of what children may do or learn about when taking part in these session full of nature and fresh air
An instrumented mouthguard for real-time measurement of head kinematics under a large range of sport specific accelerations
Get PDFBackground: Head impacts in sports can produce brain injuries. The accurate quantification of head kinematics through instrumented mouthguards (iMG) can help identify underlying brain motion during injurious impacts. The aim of the current study is to assess the validity of an iMG across a large range of linear and rotational accelerations to allow for on-field head impact monitoring. Methods: Drop tests of an instrumented helmeted anthropometric testing device (ATD) were performed across a range of impact magnitudes and locations, with iMG measures collected concurrently. ATD and iMG kinematics were also fed forward to high-fidelity brain models to predict maximal principal strain. Results: The impacts produced a wide range of head kinematics (16–171 g, 1330–10,164 rad/s2 and 11.3–41.5 rad/s) and durations (6–18 ms), representing impacts in rugby and boxing. Comparison of the peak values across ATD and iMG indicated high levels of agreement, with a total concordance correlation coefficient of 0.97 for peak impact kinematics and 0.97 for predicted brain strain. We also found good agreement between iMG and ATD measured time-series kinematic data, with the highest normalized root mean squared error for rotational velocity (5.47 ± 2.61%) and the lowest for rotational acceleration (1.24 ± 0.86%). Our results confirm that the iMG can reliably measure laboratory-based head kinematics under a large range of accelerations and is suitable for future on-field validity assessments