Various aspects of performance (e.g., sprint speed, grip strength) are thought to be important determinants of the success of animals in natural activities such as foraging, mating, and escaping from predators. However, it is generally known that morphological properties enhancing one type of performance (e.g., speed) can lead to a reduction in another (e.g., strength). Such performance trade-offs have been quantified at the inter-specific level, but evidence at the inter-individual level remains equivocal. To test for the presence of a performance trade-off, I initiated a study on wild white-footed mice (Peromyscus leucopus). In summer 2016, I captured a total of 186 individuals, 87 of which were repeatedly phenotyped for grip strength and sprint speed. A significant positive relationship was found between body mass and grip strength (but not for sprint speed). Individual differences in performance were repeatable through time for both grip strength and sprint speed. Using a bivariate mixed model, I detected a significant negative correlation between grip strength and sprint speed at the among-individual level. By contrast, the within-individual correlation between grip strength and sprint speed tended to be positive, suggesting that some unquantified aspects of the mouse phenotype (e.g., body condition, age) may have a positive effect on both performance traits. Given the relatively low repeatability of grip strength and sprint speed, a failure to properly partition the correlation at the among- and within-individual level generates a counter-intuitive, positive correlation. This study is one the first to detect a performance trade-off at the among-individual level in a wild animal population.

A remada em Canoagem Velocidade se caracteriza por ser um movimento bilateral, cíclico e simétrico, sendo que a propulsão é gerada, principalmente, pelos membros superiores. Não estão claros os aspectos relacionados à assimetria entre os hemicorpos da remada e, quanto a esta influência, o desempenho no deslocamento de caiaques de Canoagem Velocidade. O presente estudo teve como objetivos quantificar e comparar a quantidade de força aplicada à água, em atletas de diferentes níveis de desenvolvimento, bem como estabelecer a relação entre essas variáveis e o desempenho durante a execução de um teste máximo de 200 m em um caiaque individual de Canoagem Velocidade. Foram avaliados 90 atletas, com idade entre 10 a 40 anos, sendo que os mesmos foram subdivididos em três grupos, de acordo com seu nível de desenvolvimento: Iniciantes, Intermediários e Avançados. Foi encontrado que atletas de nível de desenvolvimento mais avançado eram os mais velhos, mais altos, mais pesados, mais experientes e mais rápidos que os atletas dos níveis menos avançados (p<0,001). Os atletas dos níveis de desenvolvimento mais avançado também produziram mais força que os seus pares de nível Intermediário e Iniciantes. Contudo, não foram encontradas diferenças significantes tanto para a diferença entre os lados, bem como quanto à dominância lateral foi levada em consideração. Além disso, não foi encontrada relação entre diferença na produção de força entre os lados direito e esquerdo e o desempenho em 200m. Por outro lado, a força máxima apresentou correlação negativa significante (r=-0,92, ES – quase perfeito) com desempenho em 200 m. Por fim, foi verificado que o equipamento utilizado apresentou reprodutibilidade aceitável para mensurar a força em atletas de Canoagem Velocidade. Foi concluído que tanto características morfofisiológicas e técnicas em atletas de Canoagem Velocidade apresentam desenvolvimento contínuo, de acordo com tempo e quantidade de prática na modalidade. / Sprint Kayak stroke can be characterized as a bilateral, cyclic and symmetrical movement, where the propulsion lies mainly on the upper body. It is not clear, however, whether the stroke asymmetry affects Sprint Kayak performance. Therefore, this study aimed to quantify and compare force production amongst three developing level as well as to establish the relationships between force production and difference in left/right force production in those three different developing levels and 200 m performance in Sprint Kayak athletes. 90 athletes with ages ranging from 10 to 40 years volunteered for this study. They were allocated into three different groups based on developing level: Beginner, Intermediate and Advanced. Athletes of more advanced levels were older, taller, heavier, more experienced and faster than their lower level counterparts (p<0,001). Athletes from more advanced level also produced higher force scores than the intermediate and beginner levels. However, the force difference as well as lateral dominance were not different. Moreover, it was not found relationship between the difference and performance over 200 m. On the other hand, maximal force presented significant correlation with 200 m performance (r=-0,92 ES – nearly perfect). Finally, it was verified that the equipment used to measure force was reprodutible. In conclusion, morfophysiological and technical characteristics of Sprint Kayak athletes present a continuous development, according to time and amount of practice.

A remada em Canoagem Velocidade se caracteriza por ser um movimento bilateral, cíclico e simétrico, sendo que a propulsão é gerada, principalmente, pelos membros superiores. Não estão claros os aspectos relacionados à assimetria entre os hemicorpos da remada e, quanto a esta influência, o desempenho no deslocamento de caiaques de Canoagem Velocidade. O presente estudo teve como objetivos quantificar e comparar a quantidade de força aplicada à água, em atletas de diferentes níveis de desenvolvimento, bem como estabelecer a relação entre essas variáveis e o desempenho durante a execução de um teste máximo de 200 m em um caiaque individual de Canoagem Velocidade. Foram avaliados 90 atletas, com idade entre 10 a 40 anos, sendo que os mesmos foram subdivididos em três grupos, de acordo com seu nível de desenvolvimento: Iniciantes, Intermediários e Avançados. Foi encontrado que atletas de nível de desenvolvimento mais avançado eram os mais velhos, mais altos, mais pesados, mais experientes e mais rápidos que os atletas dos níveis menos avançados (p<0,001). Os atletas dos níveis de desenvolvimento mais avançado também produziram mais força que os seus pares de nível Intermediário e Iniciantes. Contudo, não foram encontradas diferenças significantes tanto para a diferença entre os lados, bem como quanto à dominância lateral foi levada em consideração. Além disso, não foi encontrada relação entre diferença na produção de força entre os lados direito e esquerdo e o desempenho em 200m. Por outro lado, a força máxima apresentou correlação negativa significante (r=-0,92, ES – quase perfeito) com desempenho em 200 m. Por fim, foi verificado que o equipamento utilizado apresentou reprodutibilidade aceitável para mensurar a força em atletas de Canoagem Velocidade. Foi concluído que tanto características morfofisiológicas e técnicas em atletas de Canoagem Velocidade apresentam desenvolvimento contínuo, de acordo com tempo e quantidade de prática na modalidade. / Sprint Kayak stroke can be characterized as a bilateral, cyclic and symmetrical movement, where the propulsion lies mainly on the upper body. It is not clear, however, whether the stroke asymmetry affects Sprint Kayak performance. Therefore, this study aimed to quantify and compare force production amongst three developing level as well as to establish the relationships between force production and difference in left/right force production in those three different developing levels and 200 m performance in Sprint Kayak athletes. 90 athletes with ages ranging from 10 to 40 years volunteered for this study. They were allocated into three different groups based on developing level: Beginner, Intermediate and Advanced. Athletes of more advanced levels were older, taller, heavier, more experienced and faster than their lower level counterparts (p<0,001). Athletes from more advanced level also produced higher force scores than the intermediate and beginner levels. However, the force difference as well as lateral dominance were not different. Moreover, it was not found relationship between the difference and performance over 200 m. On the other hand, maximal force presented significant correlation with 200 m performance (r=-0,92 ES – nearly perfect). Finally, it was verified that the equipment used to measure force was reprodutible. In conclusion, morfophysiological and technical characteristics of Sprint Kayak athletes present a continuous development, according to time and amount of practice.

A remada em Canoagem Velocidade se caracteriza por ser um movimento bilateral, cíclico e simétrico, sendo que a propulsão é gerada, principalmente, pelos membros superiores. Não estão claros os aspectos relacionados à assimetria entre os hemicorpos da remada e, quanto a esta influência, o desempenho no deslocamento de caiaques de Canoagem Velocidade. O presente estudo teve como objetivos quantificar e comparar a quantidade de força aplicada à água, em atletas de diferentes níveis de desenvolvimento, bem como estabelecer a relação entre essas variáveis e o desempenho durante a execução de um teste máximo de 200 m em um caiaque individual de Canoagem Velocidade. Foram avaliados 90 atletas, com idade entre 10 a 40 anos, sendo que os mesmos foram subdivididos em três grupos, de acordo com seu nível de desenvolvimento: Iniciantes, Intermediários e Avançados. Foi encontrado que atletas de nível de desenvolvimento mais avançado eram os mais velhos, mais altos, mais pesados, mais experientes e mais rápidos que os atletas dos níveis menos avançados (p<0,001). Os atletas dos níveis de desenvolvimento mais avançado também produziram mais força que os seus pares de nível Intermediário e Iniciantes. Contudo, não foram encontradas diferenças significantes tanto para a diferença entre os lados, bem como quanto à dominância lateral foi levada em consideração. Além disso, não foi encontrada relação entre diferença na produção de força entre os lados direito e esquerdo e o desempenho em 200m. Por outro lado, a força máxima apresentou correlação negativa significante (r=-0,92, ES – quase perfeito) com desempenho em 200 m. Por fim, foi verificado que o equipamento utilizado apresentou reprodutibilidade aceitável para mensurar a força em atletas de Canoagem Velocidade. Foi concluído que tanto características morfofisiológicas e técnicas em atletas de Canoagem Velocidade apresentam desenvolvimento contínuo, de acordo com tempo e quantidade de prática na modalidade. / Sprint Kayak stroke can be characterized as a bilateral, cyclic and symmetrical movement, where the propulsion lies mainly on the upper body. It is not clear, however, whether the stroke asymmetry affects Sprint Kayak performance. Therefore, this study aimed to quantify and compare force production amongst three developing level as well as to establish the relationships between force production and difference in left/right force production in those three different developing levels and 200 m performance in Sprint Kayak athletes. 90 athletes with ages ranging from 10 to 40 years volunteered for this study. They were allocated into three different groups based on developing level: Beginner, Intermediate and Advanced. Athletes of more advanced levels were older, taller, heavier, more experienced and faster than their lower level counterparts (p<0,001). Athletes from more advanced level also produced higher force scores than the intermediate and beginner levels. However, the force difference as well as lateral dominance were not different. Moreover, it was not found relationship between the difference and performance over 200 m. On the other hand, maximal force presented significant correlation with 200 m performance (r=-0,92 ES – nearly perfect). Finally, it was verified that the equipment used to measure force was reprodutible. In conclusion, morfophysiological and technical characteristics of Sprint Kayak athletes present a continuous development, according to time and amount of practice.

No description available.

Abstract Aim The purpose of this study is to examine the correlation between commonly used jump tests and sprint performance over 10 m skate on-ice. The questions we will answer are; -       What correlations exist between a set of jumping tests and the sprint ability over 10 m skate on-ice? -       Which jumping test has the strongest correlation with the sprint ability over 10 m skate on-ice? -       Are there any differences between junior- and senior players, and in that case wich? Method In this study 34 subjects participated and they were between 16-25 years of age and had 9-20 years of icehockey playing experience. They performed five jumping tests; countermovement jump with arms (CMJa), one-legged vertical jump on the right leg, one-legged vertical jump on the left leg, squat jump (SJ) and a horizontal broad jump. On-ice skate test was performed to measure the acceleration ability over 10 m skate sprint in order to try to find correlations between vertical jumping height and the sprint ability, as well as horizontal jumping length and the sprint ability. The tests were performed 48 hours apart. At the first test occasion the jumping tests were performed and at the second the on-ice test was performed. Results The results of this study shows a significant correlation between SJ and the on-ice test result, as well as between CMJa and the on-ice test result. The correlation between SJ and the On-Ice test was r = -0.422 (p &lt; 0.05), and the correlation between CMJa and the on-ice test was r = -0.403 (p &lt; 0.05). When comparing the jump tests to the on-ice test for only juniors no significant correlations were found. However, the seniors (n=7) showed a stronger correlation between the SJ and the on-ice test (r = -0.761, p &lt; 0.05). Conclusions The study  confirmed that SJ is the jumping test that best correlates with  the acceleration/sprint ability skating on-ice. It was also shown that SJ is a more useful predictor for the acceleration/sprint ability for seniors than for juniors. More research will be needed for a deeper understanding of this area. / Sammanfattning Syfte Syftet med studien är att undersöka korrelationerna mellan vanligt förekommande hopptester och sprintförmåga i skridskoåkning över 10 m on-ice. De frågeställningar vi ämnar att besvara är; - Vilka eventuella korrelationer finns mellan de olika hopptesterna och sprintförmåga i skridskoåkning över 10 m on-ice? - Vilket hopptest har störst samband med sprintförmåga i skridskoåkning över 10 m onice? - Finns det några skillnader mellan junior- och seniorspelare, och i så fall vilka? Metod I denna studie deltog 34 försökspersoner (fp) de var mellan 16-25 år gamla och hade en idrottslig bakgrund på 9-20 år. De genomförde fem hopptester; countermovement jump med armdrag (CMJa), vertikalt enbenshopp på höger ben, vertikalt enbenshopp vänster ben, squat jump (SJ) och stående längdhopp. Ett on-ice test för att mäta accelerationsförmågan i skridskoåkning över 10 m genomfördes för att se samband mellan vertikal hopphöjd och accelerationsförmågan samt horisontell hopplängd och accelerationsförmåga. Testerna genomfördes med 48 timmars mellanrum. Vid första tillfället genomfördes hopptesterna och vid andra testtillfället genomfördes on-ice testet. Resultat Resultatet i denna studie visar på signifikanta korrelationer mellan SJ och on-ice testet samt mellan CMJa och on-ice testet. Mellan SJ och on-ice testet uppmättes värden där r = -0.422 (p &lt; 0.05). Mellan CMJa och on-ice testet uppmättes värden till r = -0.403 (p &lt; 0.05). I jämförelsen mellan hopptesterna och on-ice testet för enbart juniorer uppmättes inga signifikanta korrelationer. Däremot visade seniorspelarna (n=7) en signifikant korrelation mellan SJ och on-ice testet (r = -0.761, p &lt; 0.05). Slutsats Studien bekräftar att SJ är det hopptest som bäst förutser acceleration/sprintförmågan i skridskoåkning on-ice. Det visade sig även att SJ är ett mer användbart test för att förutse acceleration/sprintförmågan för seniorer än för juniorer. Vidare forskning kommer att behövas för att skapa djupare förståelse inom området.

No description available.

It has been established that Wingate-based high-intensity training (HIT) consisting of 4 to 6 x 30-s all-out sprints interspersed with 4-min recovery is an effective training paradigm. Despite the increased utilisation of Wingate-based HIT to bring about training adaptations, the majority of previous studies have been conducted over a relatively short timeframe (2 to 6 weeks). However, activity during recovery period, intervention duration or sprint length have been overlooked. In study 1, the dose response of recovery intensity on performance during typical Wingate-based HIT (4 x 30-s cycle all-out sprints separated by 4-min recovery) was examined and active recovery (cycling at 20 to 40% of V̇O2peak) has been shown to improve sprint performance with successive sprints by 6 to 12% compared to passive recovery (remained still), while increasing aerobic contribution to sprint performance by ~15%. In the following study, 5 to 7% greater endurance performance adaptations were achieved with active recovery (40%V̇O2peak) following 2 weeks of Wingate-based HIT. In the final study, shorter sprint protocol (4 to 6 x 15-s sprints interspersed with 2 min of recovery) has been shown to be as effective as typical 30-s Wingate-based HIT in improving cardiorespiratory function and endurance performance over 9 weeks with the improvements in V̇O2peak being completed within 3 weeks, whereas exercise capacity (time to exhaustion) being increased throughout 9 weeks. In conclusion, the studies demonstrate that active recovery at 40% V̇O2peak significantly enhances endurance adaptations to HIT. Further, the duration of the sprint does not seem to be a driving factor in the magnitude of change with 15 sec sprints providing similar adaptations to 30 sec sprints. Taken together, this suggests that the arrangement of recovery mode should be considered to ensure maximal adaptation to HIT, and the practicality of the training would be enhanced via the reduction in sprint duration without diminishing overall training adaptations.

RasGAP is a GTPase activating protein (GAP) that deactivates Ras by promoting Ras-GTP hydrolysis to Ras-GDP. In Drosophila melanogaster, RasGAP is required for the long-term survival of neurons in the adult brain because mutants in the RasGAP gene (vap) show an age-related neurodegenerative phenotype, with dying neurons showing morphological features of autophagy. RasGAP was shown to have a GAP-independent role within fly neurons that is dependent on its SH2 domains. The aim of this study was to identify proteins that interact with the SH2 domains of RasGAP and to understand the roles of these proteins in neuronal survival. By using tagged RasGAP affinity purification and mass spectrometry of RasGAP protein complexes from S2 cells, Sprint, a Ras effector and putative activator of the endocytic GTPase Rab5, was identified as a novel SH2-dependent RasGAP interacting protein. The interaction between Sprint and RasGAP is phosphotyrosine-dependent, since it requires tyrosine phosphorylation of Sprint. In addition, Sprint and RasGAP interaction requires the SH2 domains of RasGAP but not Sprint or the conserved site of RasGAP tyrosine phosphorylation (pTyr363), indicating an association between these two molecules. RasGAP and Sprint co-localised with Rab5-positive early endosomes and this co-localisation depended on the SH2 domains of both RasGAP and Sprint. This study demonstrates a key role for this interaction in neurodegeneration: mutation of Sprint (or Rab5) suppressed the autophagic neuronal cell death caused by the loss of RasGAP. These results indicate that the long-term survival of adult neurons in Drosophila depends on a critical balance between Ras activation and endocytosis, and that this balance is maintained by the interplay between RasGAP and Sprint.

No description available.