At present, no agreement on a precise definition of agility within the sports science community exists. The term is applied to a broad range of sport contexts, but with such great inconsistency, it further complicates our understanding of what trainable components may enhance agility. A new definition of agility is proposed: "a rapid whole-body movement with change of velocity or direction in response to a stimulus". Agility has relationships with trainable physical qualities such as strength, power and technique, as well as cognitive components such as visual-scanning techniques, visual-scanning speed and anticipation. Agility testing is generally confined to tests of physical components such as change of direction speed, or cognitive components such as anticipation and pattern recognition. New tests of agility that combine physical and cognitive measures are encouraged.

We present evidence that the heritable genetic variation within individual species, especially dominant and keystone species, has community and ecosystem consequences. These consequences represent extended phenotypes, i.e., the effects of genes at levels higher than the population. Using diverse examples from microbes to vertebrates, we demonstrate that the extended phenotype can be traced from the individuals possessing the trait, to the community, and to ecosystem processes such as leaf litter decomposition and N mineralization. In our development of a community genetics perspective, we focus on intraspecific genetic variation because the extended phenotypes of these genes can be passed from one generation to the next, which provides a mechanism for heritability. In support of this view, common‐garden experiments using synthetic crosses of a dominant tree show that their progeny tend to support arthropod communities that resemble those of their parents. We also argue that the combined interactions of extended phenotypes contribute to the among‐community variance in the traits of individuals within communities. The genetic factors underlying this among‐community variance in trait expression, particularly those involving genetic interactions among species, constitute community heritability. These findings have diverse implications. (1) They provide a genetic framework for understanding community structure and ecosystem processes. The effects of extended phenotypes at these higher levels need not be diffuse; they may be direct or may act in relatively few steps, which enhances our ability to detect and predict their effects. (2) From a conservation perspective, we introduce the concept of the minimum viable interacting population (MVIP), which represents the size of a population needed to maintain genetic diversity at levels required by other interacting species in the community. (3) Genotype × environment interactions in dominant and keystone species can shift extended phenotypes to have unexpected consequences at community and ecosystem levels, an issue that is especially important as it relates to global change. (4) Documenting community heritability justifies a community genetics perspective and is an essential first step in demonstrating community evolution. (5) Community genetics requires and promotes an integrative approach, from genes to ecosystems, that is necessary for the marriage of ecology and genetics. Few studies span from genes to ecosystems, but such integration is probably essential for understanding the natural world. Corresponding Editor: A. A. Agrawal

Static stretching (SS) is used pervasively throughout the exercise science and sporting communities as a fundamental element of the pre-exercise warm-up procedure.While SS has been proven effective to increase range of motion (ROM), its proposed benefits are questionable and relatively unsubstantiated. Moreover, in recent years researchers have demonstrated that pre-exercise SS may in fact be detrimental to subsequent performance due to impaired force and power output. Yet the practical application of these relatively recent findings is limited due to the prolonged SS protocols utilized. In addition, timelines associated with enhanced ROM and performance decrements have not been established. Thus, the objectives of this study were to determine if a typical SS routine decreased force, activation, and power while improving ROM. Secondly, the study attempted to compare the duration of the performance decrement to the duration of the augmented ROM.ii ACKNOWLEDGEMENTS I believe that the long and arduous process of completing a master's thesis is a great accomplishment made possible in part by the support and guidance of family and friends. I would first like to thank my immediate family. To my parents, Kevin and Jean,

The purposes of this review are to identify the factors that contribute to the transference of strength and power training to sports performance and to provide resistance-training guidelines. Using sprinting performance as an example, exercises involving bilateral contractions of the leg muscles resulting in vertical movement, such as squats and jump squats, have minimal transfer to performance. However, plyometric training, including unilateral exercises and horizontal movement of the whole body, elicits significant increases in sprint acceleration performance, thus highlighting the importance of movement pattern and contraction velocity specificity. Relatively large gains in power output in nonspecific movements (intramuscular coordination) can be accompanied by small changes in sprint performance. Research on neural adaptations to resistance training indicates that intermuscular coordination is an important component in achieving transfer to sports skills. Although the specificity of resistance training is important, general strength training is potentially useful for the purposes of increasing body mass, decreasing the risk of soft-tissue injuries, and developing core stability. Hypertrophy and general power exercises can enhance sports performance, but optimal transfer from training also requires a specific exercise program.

The purpose of this study was to evaluate the reliability and validity of a new test of agility, the reactive agility test (RAT), which included anticipation and decision-making components in response to the movements of a tester. Thirty-eight Australian football players took part in the study, categorized into either a higher performance group (HPG) (n=24) or lower performance group (LPG) (n=14) based on playing level from the previous season. All participants undertook testing of a 10m straight sprint (10mSS), a 8-9m change of direction speed test (CODST), and the RAT. Test-retest and inter-tester reliability testing measures were conducted with the LPG. The intra-class correlation (ICC) of the RAT was 0.870, with no significant (p<0.05) difference between the test results obtained on the first and second test sessions using a t-test. A dependent samples t-test revealed no significant (p<0.05) difference between the test results of two different testers with the same population. The HPG were significantly (p=0.001) superior to those of the LPG on the RAT, with no differences observed on any other variable. The RAT is an acceptably reliable test when considering both test-retest reliability, as well as inter-rater reliability. In addition, the test was valid in distinguishing between players of differing performance level in Australian football, while the 10mSS and CODST were not. This result suggests that traditional closed skill sprint and sprint with direction change tests may not adequately distinguish between players of different levels of competition in Australian football.

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This review explores the differences between agility in invasion sports (defined as including reactive decision-making) and change-of-direction speed (CODS), and highlights the implications for training. Correlations between agility tests and CODS tests indicate that they represent independent skills. Agility tests discriminate higher- from lower-standard athletes better than CODS tests, indicating that the cognitive element of agility is important to performance. Training studies have shown that the development of strength qualities can transfer to gains in CODS, but this has never been shown for agility. There is some evidence that the importance of physical qualities is greater for CODS than for agility. It was concluded that the reactive element should be included in agility training, testing and research. While there appears to be no research evidence for the benefits of strength and power training, there is some support for the use of small-sided games for improving agility.

While population genetic diversity has broad application in species conservation, no studies have examined the community-level consequences of this diversity. We show that population genetic diversity (generated by interspecific hybridization) in a dominant riparian tree affects an arthropod community composed of 207 species. In an experimental garden, plant cross type structured the arthropod community of individual trees, and among stands in the wild, plant genetic diversity accounted for nearly 60% of the variation in arthropod diversity. While previous experimental garden studies have demonstrated the effects of plant genotype on arthropod communities, our study extends these findings from individual trees in an experimental garden to natural stands of cottonwoods where plant population genetic diversity was a significant factor structuring arthropod diversity. These findings argue that the preservation of genetic diversity in a dominant species is far more important than previously realized, and may be particularly important in hybridizing systems.