The effect of changing player numbers on the physiological responses and time-motion characteristics of a soccer-specific training drill

Soccer-specific training (SST) drills are used to develop physiological adaptations, technical and tactical skills, and provide coaches with greater control of external training load. Despite widespread use, there has been little analysis of SST drills. This study quantified the effect of manipulating player numbers on the physiological demands of an SST drill. Fourteen players completed nine trials (3 × 8, 10, 12 players) of a 4-min SST drill modelled on soccer time-motion data. Physiological intensity measures (heart rate, blood lactate concentration [BLa-], rating of perceived exertion [RPE]) and GPS time-motion data (movement distances and velocities) were collected for each drill. A repeated measures analysis of variance determined significant (p < 0.05) between-drill differences. Results showed variables such as total running distance (TD), mean percentage of maximum heart rate, RPE, and [BLa-] were greater for the 8-player SST drill. The 10-player drill also had a 22% greater TD and 21% higher average speed compared to the 12-player drill, which tended to have a lower activity profile. The 8-player SST drill could be used to develop aerobic capacity and repeat-sprint ability (RSA) because of a higher activity profile. The 10- and 12-player drills would be suited for RSA and sprint acceleration enhancement

A preliminary investigation into the relationship between functional movement screen scores and athletic physical performance in female team sport athletes

There is little research investigating relationships between the Functional Movement Screen (FMS) and athletic performance in female athletes. This study analyzed the relationships between FMS (deep squat; hurdle step [HS]; in-line lunge [ILL]; shoulder mobility; active straight-leg raise [ASLR]; trunk stability push-up; rotary stability) scores, and performance tests (bilateral and unilateral sit-and-reach [flexibility]; 20-m sprint [linear speed]; 505 with turns from each leg; modified T-test with movement to left and right [change-of-direction speed]; bilateral and unilateral vertical and standing broad jumps; lateral jumps [leg power]). Nine healthy female recreational team sport athletes (age = 22.67 ± 5.12 years; height = 1.66 ± 0.05 m; body mass = 64.22 ± 4.44 kilograms) were screened in the FMS and completed the afore-mentioned tests. Percentage between-leg differences in unilateral sit-and-reach, 505 turns and the jumps, and difference between the T-test conditions, were also calculated. Spearman\u27s correlations (p = 0.05) examined relationships between the FMS and performance tests. Stepwise multiple regressions (p = 0.05) were conducted for the performance tests to determine FMS predictors. Unilateral sit-and-reach positive correlated with the left-leg ASLR (r = 0.704-0.725). However, higher-scoring HS, ILL, and ASLR related to poorer 505 and T-test performance (r = 0.722-0.829). A higher-scored left-leg ASLR related to a poorer unilateral vertical and standing broad jump, which were the only significant relationships for jump performance. Predictive data tended to confirm the correlations. The results suggest limitations in using the FMS to identify movement deficiencies that could negatively impact athletic performance in female team sport athletes

A comparison of methods to quantify the in-season training load of professional soccer players

Purpose: To compare various measures of training load (TL) derived from physiological (heart rate [HR]), perceptual (rating of perceived exertion [RPE]), and physical (global positioning system [GPS] and accelerometer) data during in-season field-based training for professional soccer. Methods: Fifteen professional male soccer players (age 24.9 ± 5.4 y, body mass 77.6 ± 7.5 kg, height 181.1 ± 6.9 cm) were assessed in-season across 97 individual training sessions. Measures of external TL (total distance [TD], the volume of low-speed activity [LSA; 14.4 km/h], very high-speed running [VHSR; >19.8 km/h], and player load), HR and session-RPE (sRPE) scores were recorded. Internal TL scores (HR-based and sRPE-based) were calculated, and their relationships with measures of external TL were quantified using Pearson product-moment correlations. Results: Physical measures of TD, LSA volume, and player load provided large, significant (r = .71-.84; P < .01) correlations with the HR-based and sRPE-based methods. Volume of HSR and VHSR provided moderate to large, significant (r = .40-.67; P < .01) correlations with measures of internal TL. Conclusions: While the volume of HSR and VHSR provided significant relationships with internal TL, physical-performance measures of TD, LSA volume, and player load appear to be more acceptable indicators of external TL, due to the greater magnitude of their correlations with measures of internal TL

AgRP Neurons Require Carnitine Acetyltransferase to Regulate Metabolic Flexibility and Peripheral Nutrient Partitioning

Summary: AgRP neurons control peripheral substrate utilization and nutrient partitioning during conditions of energy deficit and nutrient replenishment, although the molecular mechanism is unknown. We examined whether carnitine acetyltransferase (Crat) in AgRP neurons affects peripheral nutrient partitioning. Crat deletion in AgRP neurons reduced food intake and feeding behavior and increased glycerol supply to the liver during fasting, as a gluconeogenic substrate, which was mediated by changes to sympathetic output and peripheral fatty acid metabolism in the liver. Crat deletion in AgRP neurons increased peripheral fatty acid substrate utilization and attenuated the switch to glucose utilization after refeeding, indicating altered nutrient partitioning. Proteomic analysis in AgRP neurons shows that Crat regulates protein acetylation and metabolic processing. Collectively, our studies highlight that AgRP neurons require Crat to provide the metabolic flexibility to optimize nutrient partitioning and regulate peripheral substrate utilization, particularly during fasting and refeeding

The relationship between physical fitness and shooting accuracy of professional basketball players

The aim of this study was to examine the relationships among physical fitness of professional Bosnianbasketball players (n = 38) and shooting accuracy during one basketball season. A related, secondary aim was toexamine relationships between basketball shooting assessments and competitive shooting accuracy during game play.Physical fitness components included: muscular endurance and aerobic endurance, lower and upper-body power,speed, agility, anaerobic capacity and anaerobic power. The specific basketball shooting accuracy was assessed bystationary and dynamic shooting assessments. Competitive shooting accuracy was represented by data collected duringone basketball season for each player (free throw, field goal, and three-point %). Results of the regression analysesshowed that there were significant positive relationships among shooting assessments and competitive shooting accuracyduring game play. The relationship was stronger when the dynamic shooting tests were applied compared tothe stationary tests. However, few or weak relationships existed among physical fitness components and competitiveshooting accuracy. Only the power tests showed to be good predictors for shooting over longer distances. The findingssupport the inclusion of the dynamic basketball shooting accuracy tests in regular basketball assessment proceduresas a valuable testing instrument.A relação entre aptidão física e precisão de arremesso dos jogadores profissionais de basquetebol.“ Oobjetivo do presente estudo foi identificar a relação entre a condição física de basquetebolistas profissionais bósnios(n=38) na precisão de arremesso no decorrer de uma temporada competitiva. Adicionalmente, pretendeu-se verificara relação entre a avaliação específica e a precisão de arremessos durante os jogos. As variáveis de condição físicaforam as seguintes: resistência de força, resistência aeróbia, potência dos membros inferiores e superiores, velocidade,agilidade, capacidade e potência anaeróbia. A avaliação específica do arremesso foi testada através da utilização dearremessos estáticos e dinâmicos. A precisão dos arremessos durante os jogos foi realizada no decorrer da temporadacompetitiva mediante análise das seguintes variáveis: lance-livre, arremessos de quadra, e percentagem de arremessosde três pontos. As análises de regressão indicaram a existência de uma relação positiva entre as avaliações específicasdos arremessos e a precisão durante os jogos, a qual foi mais forte nas situações de arremessos dinâmicos comparadosaos estáticos. Contudo, as relações existentes entre as variáveis de condição física e a precisão de arremesso duranteos jogos foram menores e pouco significativas. Apenas os testes de potência mostraram ser bons preditores para osarremessos efetuados a longas distâncias. Os resultados obtidos apoiam a inclusão de testes de avaliação da precisãode arremessosrealizados de forma dinâmica em procedimentos regulares de avaliação no basquetebol, constituindo-secomo instrumentos valiosos para ocontrole do rendimento.La relación entre la aptitud física y precisión de tiro de los jugadores profesionales de baloncesto.” El objetivo de este estudio fue examinar la relación entre la condición física de los jugadores profesionales de baloncesto de Bosnia (n=38) y la precisión de tiro durante una temporada de baloncesto. Paralelamente, el objetivo secundario fue examinar las relaciones entre las evaluaciones de lanzamiento de baloncesto y la precisión de tiro durante el partido. Los componentes de la aptitud física incluían: la resistencia muscular y la resistencia aeróbica, la potencia de los miembros inferiores y superiores del cuerpo, la velocidad, la agilidad, la capacidad anaeróbica y la potencia anaeróbica. La pre­cisión específica de tiro de baloncesto se evaluó mediante lanzamiento estático y evaluaciones de tiro en movimiento. La precisión de tiro en competición estuvo representada por los datos recogidos durante una temporada de baloncesto para cada jugador (tiro libre, tiro de campo y triple %). Posteriores análisis de los resultados mostraron que había una significativa relación positiva entre las evaluaciones de tiro y la precisión de tiro durante el partido. La relación era más fuerte cuando las pruebas de tiro en movimiento se compararon con las pruebas de tiro estático. Sin embargo, existían pocas o débiles relaciones entre los componentes de la aptitud física y la precisión de tiro en competición. Sólo las pruebas de potencia mostraron ser buenas predictoras para lanzamientos de mayor distancia. Los resultados apoyan la inclusión de los entrenamientos de precisión de tiro en movimiento en los procedimientos habituales de evaluación de baloncesto, como un valioso instrumento de prueba

Lower limb mechanical properties : determining factors and implications for performance

Limb stiffness or musculotendinous stiffness (MTS) has previously been examined in relation to performance and characterized using a number of different methods. However, the fact that MTS shows only low to moderate correlations to performances may indicate a lack of understanding of this parameter. In addition to this, variation is seen between studies examining the same factors. To date, our understanding of MTS and its components are not complete and thus it is unclear which characteristic value represents the ideal index of stiffness as it relates to performance. Moreover, it is uncertain how MTS stiffness as a functional measure relates to performance, and also if there is an optimal amount of MTS stiffness for specific functions or tasks. The knowledge of the interplay of MTU stiffness as it relates to performance and injury risk is also poorly understood in that there is likely a disparity between levels of stiffness required to optimize performance and those required to minimize injury risk. The aim of this article is to review the literature as it describes the components of MTS and to discuss these in terms of their relationship to functional performance; consider adaptations of the MTU with training along with associated performance changes; highlight and discuss how stiffness may affect loading of the soft and bony tissues in terms of the MTU components and gender, with respect to risk of injury; discuss the apparent differences in the literature regarding associations of the various forms of stiffness index to function; suggest recommendations for training in light of adaptation of the muscle and tendon and injury risk in context of gender; and, finally, to highlight potential limitations of current methodologies and suggest further work to gain insight into the mechanisms of stiffness. It is hoped that by suggesting future work, a more detailed and comprehensive understanding of MTS will be gained, thus enabling appropriate interventions to optimally modify this parameter for specific requirements