Do habitual foot-strike patterns in running influence functional Achilles tendon properties during gait?

ABSTRACT

The capacity of foot-strike running patterns to influence the functional properties of the Achilles tendon is controversial. This study used transmission-mode ultrasound to investigate the influence of habitual running foot-strike pattern on Achilles tendon properties during barefoot walking and running. Fifteen runners with rearfoot (RFS) and 10 with a forefoot (FFS) foot-strike running pattern had ultrasound transmission velocity measured in the right Achilles tendon during barefoot walking (≈1.1 ms^?1) and running (≈2.0 ms^?1). Temporospatial gait parameters, ankle kinematics and vertical ground reaction force were simultaneously recorded. Statistical comparisons between foot-strike patterns were made using repeated measure ANOVAs. FFS was characterised by a significantly shorter stance duration (?4%), greater ankle dorsiflexion (+2°), and higher peak vertical ground reaction force (+20% bodyweight) than RFS running (P < .05). Both groups adopted a RFS pattern during walking, with only the relative timing of peak dorsiflexion (3%), ground reaction force (1–2%) and peak vertical force loading rates (22–23%) differing between groups (P < .05). Peak ultrasound transmission velocity in the Achilles tendon was significantly higher in FFS during walking (≈100 ms^?1) and running (≈130 ms^?1) than RFS (P < .05). Functional Achilles tendon properties differ with habitual footfall patterns in recreational runners.     

Showing How Many: young children's written representation of number

Abstract This paper reports a simple experiment which explores young children's written representation of number. Previous research (e.g. Hughes, 1983; Sinclair, Siegrist & Sinclair, 1982) has shown that several factors may influence the extent to which children will spontaneously deploy their knowledge of numerals to represent numerosity, but the available evidence is insufficient to provide a clear account of the relative weight of these factors. The present experiment involved presenting five to six year‐old children with arrays of simple objects and manipulating the wording of the instructions. The results showed that the use of the term ‘how many’ led the vast majority of the children to show numerosity by using materials. In contrast, when asked to represent ‘what’ they could see, most children concerned themselves with depicting the nature of the objects in the array by drawing or writing. These findings suggest that the linguistic context of the task is important in determining the children's representational strategies. Furthermore, it is argued that children's understanding of number and their ability to use numerals is quite separable from their knowledge of when it is appropriate to deploy these skills.     

Numerically restricted food intake in the rat in a free-feeding situation

Rats were trained to leave an array of food after they had consumed a fixed number (three, four, or five) of food items. This discrimination remained in effect despite a shift from 45-mg Noyes pellets to larger and irregularly sized sunflower seeds. The present demonstration replicates work first reported 50 years ago by Otto Koehler and his associates (e.g., Marold, 1939; see also Koehler, 1950), who used avian subjects, and, like those studies, it involved both positive and negative social reinforcement. The present procedure provided a rare instance in which numerical control was exerted over behavior that was primarily consummatory in nature. The results are viewed in terms of the wider literature of numerical competence in animals and are discussed in terms of a numerical process known asprotocounting (Davis & P’erusse, 1988b).     

The neuropsychological basis of childhood psychopathology

A clear link exists between neurological dysfunction and psychopathology in children, as evidenced by research on the sequelae of developmental childhood brain impairment, the neuropsychological investigation of children with psychiatric disorders, and neuroimaging research. Understanding the neuropsychological basis of a disorder helps teachers, parents, and children better understand the etiology of the disorder and guide classroom interventions. Additionally, identifying morphological markers of childhood mental disorders may lead to earlier and more successful interventions. This article reviews the neuropsychological relationships between brain impairment and childhood mental disorders as well as investigates the biological basis for some common childhood disorders seen in the schools. Emphasis is placed upon the underlying neurological and neuropsychological deficits that constitute disorders, and implications for practitioners are discussed. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 503–512, 2006.     

A perinatal intervention program for urban american indians part 1: design, implementation, and outcomes

High infant mortality rates among American Indians are disproportionate to state statistics for other races and higher than the national average. These findings prompted a community health center in a large Midwestern city to create and provide an American Indian infant mortality reduction project in the early 1990s. Strategies for program implementation included networking with local organizations, communicating with reservation health clinics throughout the state, educating American Indian mothers and their community about factors contributing to American Indian infant mortality, and providing individual case management to American Indian women and infants. We offer this article for three reasons: This grant project was successful, disparity in rates of infant mortality among peoples of color continues, and a paucity of information exists about the health behaviors of American Indian women.     

Structuring Occasions

Within the mathematics education literature, the term constructivism has been subject to a diversity of interpretations, many of which are trivializations of original theoretical work. We suggest that trivialized versions of constructivism continue to be promulgated due, in large part,to misunderstandings of some of the vocabulary adopted by its advocates. This situation has been the source of considerable frustration in our ongoing efforts to communicate the insights and implications of radical and social constructivist theories to preservice and practicing teachers. We discuss some of the specifics of these frustrations along with strategies intended to flag and circumvent them in our work with teachers. The writing is structured around a set of recursively elaborated interpretations of a classroom episode. Developed around varied understandings of the terms structure and construct, these interpretations are intended to show how we have worked with teachers to foster a deep appreciation of how learning might be reframed as dependent on, rather than determined by, teaching.This revised version was published online in September 2005 with corrections to the Cover Date.     

Pathways to Undergraduate Research Experiences: a Multi-Institutional Study

The positive impact of undergraduate research experiences on students’ post-secondary success is well-documented. However, these conclusions are drawn from undergraduate students who already participate; very little research has explored the pathways by which students enter these experiences. Using data from a multi-institutional survey, we examined students’ reasons for participating and differences across institutions and demographic groups. Overall, students cited social and experiential reasons as key motivators for participation and a perceived lack of research readiness as a key barrier. Differences were also found across academic year. Implications from this study address issues of access, preparation, and institutional policies around undergraduate research.     

Measuring Habituation in Infants: An Approach Using Regression Analysis

The effectiveness of different habituation criteria was examined by means of computer simulations. A criterion based on fitting a second-order polynomial regression function to the looking time data was described. This criterion produced more accurate estimation of looking times as well as higher experimental power for detecting novelty effects, compared to the traditional windowed running average criterion or to a criterion based on linear regression. The polynomial regression approach probably has this advantage because it utilizes all of the available looking time data, rather than just the data in the current windowed average, and because it is sensitive to nonlinear trends in looking time. This new habituation criterion is easy to implement on a laboratory computer, and it should increase session lengths by no more than one trial or so, compared to windowed average criteria. With regard to test-retest reliability, all of the habituation criteria that were evaluated appear to have low reliability on average, with high sample-to-sample variability. These undesirable reliability characteristics are attributable to the high variability of infants' attentional behavior.