Lower limb joint kinetics in the starting blocks and first stance in athletic sprinting

The aim of this study was to examine lower limb joint kinetics during the block and first stance phases in athletic sprinting. Ten male sprinters (100 m PB, 10.50 ± 0.27 s) performed maximal sprint starts from blocks. External force (1000 Hz) and three-dimensional kinematics (250 Hz) were recorded in both the block (utilising instrumented starting blocks) and subsequent first stance phases. Ankle, knee and hip resultant joint moment, power and work were calculated at the rear and front leg during the block phase and during first stance using inverse dynamics. Significantly (P < 0.05) greater peak moment, power and work were evident at the knee joint in the front block and during stance compared with the rear block. Ankle joint kinetic data significantly increased during stance compared with the front and rear block. The hip joint dominated leg extensor energy generation in the block phase (rear leg, 61 ± 10%; front leg, 64 ± 8%) but significantly reduced during stance (32 ± 9%), where the ankle contributed most (42 ± 6%). The current study provides novel insight into sprint start biomechanics and the contribution of the lower limb joints towards leg extensor energy generation.     

The Kaufman Assessment Battery for Children (K-ABC) in the assessment of learning disabled children

The authors of the Kaufman Assessment Battery for Children (K-ABC) assert that, in addition to a discrepancy between learning potential and academic achievement, learning disability is characterized by poor sequential relative to simultaneous processing skills. The present study was designed to determine whether the K-ABC could discriminate between learning disabled and normal children on the basis of these characteristics. Forty-three LD pupils from 7 to 12 years of age and 20 normally achieving children of similar age were administered the K-ABC. Results indicated that, for both the LD and the normal children, scores on the Sequential Processing Scale were significantly lower than on the Simultaneous Processing Scale. In addition, the aiscrepancy between Simultaneous and Sequential scale scores was similarly distributed in both groups. The LD group scored lower and the normal group higher on the Achievement Scale than on the Mental Processing Composite. The results, therefore, indicated that the K-ABC differentiated LD from normal children in terms of Achievement relative to M.P.C. scores; however, it failed to reveal a unique profile pattern related to simultaneous vs. sequential processing skills for the LD group. Further analyses of the relationship between K-ABC processing scale scores and WISC-R scores, as recategorized by Bannatyne, revealed significant correlations between measures, indicating similar underlying theoretical constructs.     

Mid-flight lateral trunk bending increased ipsilateral leg loading during landing: a center of mass analysis

Increased lateral trunk bending to the injured side has been observed when ACL injuries occur. The purpose was to quantify the effect of mid-flight lateral trunk bending on center of mass (COM) positions and subsequent landing mechanics during a jump-landing task. Forty-one recreational athletes performed a jump-landing task with or without mid-flight lateral trunk bending. When the left and right trunk bending conditions were compared with the no trunk bending condition, participants moved the COM of the upper body to the bending direction, while the COM of the pelvis, ipsilateral leg, and contralateral leg moved away from the bending direction relative to the whole body COM. Participants demonstrated increased peak vertical ground reaction forces (VGRF) and knee valgus and internal rotation angles at peak VGRF for the ipsilateral leg, but decreased peak VGRF and knee internal rotation angles at peak VGRF and increased knee varus angles at peak VGRF for the contralateral leg. Mid-flight lateral trunk resulted in an asymmetric landing pattern associated with increased ACL loading for the ipsilateral leg. The findings may help to understand altered trunk motion during ACL injury events and the discrepancy in ACL injuries related to limb dominance in badminton and volleyball.     

Parental sport achievement and the development of athlete expertise

This study sought to examine how parental sport involvement and attainment were related to the eventual level of competitive sport attained by their children. Athletes (n?=?229) were divided into three skill level groups (elite: n?=?139; pre-elite: n?=?33; non-elite: n?=?57), based on the peak competition level achieved in their career, which were compared using chi-squares tests of independence and analyses of variance according to parents sport characteristics provided through the Developmental History of Athletes Questionnaire. Parental recreational and competitive sport participation was overrepresented among elite athletes, as were parents who reached an elite level of sport themselves. Results were found to differ according to parent sex, with athlete skill level significantly related to the sport participation and skill level of fathers, but not mothers. Results suggest parental sport experiences at different levels of competition influence the development of athletes, although these relationships are subject to many factors.     

Philosophy and Educational Research: a reply to David Bridges et al.

It is argued that, contrary to much contemporary opinion, ‘conceptual analysis’ is not to be seen as a particular ‘school’ of philosophical thought beyond which we have now passed. It is, rather, a practice: an inter‐personal engagement which seeks to clarify meaning without making any ‘assumptions’ and without the benefit of ‘theory’. The necessity of this practice for educational research, indeed for any sharing of minds between people, is obvious: the difficulty lies rather in our own impatience and reluctance to engage in it.     

Some Conceptions are Difficult to Change: One Middle School Mathematics Teacher's Struggle

A framework for investigating approaches to mathematics teaching in light of recent reforms is described. This framework is used to explore the struggles of a veteran middle school mathematics teacher as he attempted to modify his practices. The report was developed during a two-year period during which the teacher was interviewed and observed regularly. The teacher was successful in broadening some aspects of his pedagogical thinking and practice. For example, he reformed his teaching to emphasize important mathematical concepts. However, at least in part because of his views of pedagogical authority, he was unable to let his students explore ideas, solve open-ended problems, and debate intended meanings of mathematical ideas and solutions on a regular basis. This revised version was published online in July 2006 with corrections to the Cover Date.