Analysis of coaching science research published from 1970-2001

The study followed a four-phase design. In Phase I an exhaustive search was conducted for all English language coaching research published in journals from 1970 to 2001. In Phase II, copies of the research were obtained. An expert panel conducted a manual search and a review in Phase III to address validity. Analysis of the research was completed in Phase IV (Culver Gilbert, & Trudel, 2003; Silverman & Skonie, 1997). Over 1,100 articles were reviewed, and 610 met the inclusion criteria. Selected findings include: (a) a relatively low mean spread across many journals, (b) a focus on coaching behavior using quantitative methodologies, and (c) a primary emphasis on team sports in school contexts.     

An Epistemological and Didactic Study of a Specific Calculus Reasoning Rule

Abstract It is widely attested that university students face considerable difficulties with reasoning in analysis, especially when dealing with statements involving two different quantifiers. We focus in this paper on a specific mistake which appears in proofs where one applies twice or more a statement of the kind “for all X, there exists Y such that R(X, Y)”, and forgets that in that case, a priori, “Y depends on X”. We analyse this mistake from both a logical and mathematical point of view, and study it through two inquiries, an historical one and a didactic one. We show that mathematics teachers emphasise the importance of the dependence rule in order to avoid this kind of mistake, while natural deduction in predicate calculus provides a logical framework to analyse and control the use of quantifiers. We show that the relevance of this dependence rule depends heavily on the context: nearly without interest in geometry, but fundamental in analysis or linear algebra. As a consequence, mathematical knowledge is a key to correct reasoning, so that there is a large distance between beginners' and experts' abilities regarding control of validity, that, to be shortened, probably requires more than a syntactic rule or informal advice. Résumé Les difficultés de manipulation, par les étudiants, des énoncés contenant deux quantificateurs différents, rencontrés dans de nombreux raisonnements en analyse, sont bien attestées. Nous nous intéressons plus spécialement dans cet article à une erreur qui appara?t dans certaines preuves lorsque l'on applique deux fois ou plus un énoncé de la forme “pour tout X, il existe Y tel que R(X,Y)” et que l'on oublie que dans un tel cas, a priori, “Y dépend de X”. Nous analysons cette erreur d'un point de vue logique et d'un point de vue mathématique, puis nous l'étudions à travers deux enquêtes, l'une historique et l'autre didactique. Nous montrons que les professeurs de mathématiques soulignent l'importance de la règle de dépendance pour éviter ce type d'erreur, tandis que la déduction naturelle dans le calcul des prédicats fournit un cadre de référence logique pour analyser et contr?ler l'usage des quantificateurs. Nous montrons que la pertinence de la règle de dépendance dépend fortement du contexte: pratiquement sans intérêt en géométrie, elle est tout à fait fondamentale en analyse et en algèbre linéaire. De ce fait, les connaissances mathématiques sont la clé d'un raisonnement correct, si bien qu'il y a une grande distance entre le débutant et l'expert concernant le contr?le de la validité, que quelques règles syntaxiques ou quelques conseils informels ne permettent vraisemblablement pas de réduire.     

The electronic alternative: Sociological Research Online

Examines how the electronic journal Sociological Research Online has rapidly established itself as a leading journal and how it has gained credibility; discusses possible future sources of revenue.     

Investigation of toppling ball flight in American football with a mechanical field-goal kicker

A mechanical field-goal kicking machine was used to investigate toppling ball flight in American football place-kicking, eliminating a number of uncontrollable impact variables present with a human kicker. Ball flight trajectories were recorded using a triangulation-based projectile tracking system to account for the football’s 3-dimensional position during flight as well as initial launch conditions. The football flights were described using kinematic equations relating to projectile motion including stagnant air drag and were compared to measured trajectories as well as projectile motion equations that exclude stagnant air drag. Measured football flight range deviations from the non-drag equations of projectile motion corresponded to deficits between 9 and 31%, which is described by a football toppling compound drag coefficient of 0.007 ± 0.003 kg/m. Independent variables including impact location and impact angle orientation resulted in 15 impact conditions. We found that an impact location of 5.5 cm from the bottom of the ball maximized trajectory height and distance. At the 5.5-cm impact location, alterations in impact angle produced minimal change in football trajectory, including launch angle (range = 1.96 deg), launch speed (range = 1.06 m/s), and range (range = 0.94 m).