Segmental and kinetic contributions in vertical jumps performed with and without an arm swing

To determine the contributions of the motions of the body segments to the vertical ground reaction force (Fz), the joint torques produced by the leg muscles, and the time course of vertical velocity generation during a vertical jump, 15 men were videotaped performing countermovement vertical jumps from a force plate with and without an arm swing. Linear kinematic, Fz, and joint torque data were computed and compared using repeated measures analysis of variance. Maximum jump height was significantly larger in the arm swing jumps compared to the no arm swing jumps and was due to both a higher height of the center of mass (CM) at takeoff (54%) and a larger vertical velocity of the CM at takeoff (46%). The net vertical impulse created during the propulsive phase of the arm swing jumps was greater due to a trend of an increased duration (0.021 s) of the propulsive phase and not to larger average values of Fz. In the arm swing jumps, the arm motion resulted in the arms making a larger maximal contribution to Fz during the middle of the propulsive phase and decreased the negative contribution of the trunk-head and thigh to Fz late in the propulsive phase. Last, the arm swing decreased the extensor torques at the hip (13%), knee (10%), and ankle (10%) early in the propulsive phase but augmented these same extensor torques later in the propulsive phase.     

Calling-in the family: Dialogic performances of family conflict

ABSTRACT

Courses: Introduction to Communication, Introduction to Interpersonal Communication, Family Communication, Small Group Communication, Communication and Listening

Objectives: By this end of this activity, students will be able to identify and practice supportive and defensive communication; understand a dialogic approach to conflict; and reflexively imagine and perform dialogic interpersonal conflict communication as constitutive and transformative.     

Investigating orthographic and semantic aspects of word learning in poor comprehenders

This study compared orthographic and semantic aspects of word learning in children who differed in reading comprehension skill. Poor comprehenders and controls matched for age (9–10 years), nonverbal ability and decoding skill were trained to pronounce 20 visually presented nonwords, 10 in a consistent way and 10 in an inconsistent way. They then had an opportunity to infer the meanings of the new words from story context. Orthographic learning was measured in three ways: the number of trials taken to learn to pronounce nonwords correctly, orthographic choice and spelling. Across all measures, consistent items were easier than inconsistent items and poor comprehenders did not differ from control children. Semantic learning was assessed on three occasions, using a nonword–picture matching task. While poor comprehenders showed equivalent semantic learning to controls immediately after exposure to nonword meaning, this knowledge was not well retained over time. Results are discussed in terms of the language and reading skills of poor comprehenders and in relation to current models of reading development.     

Sound’s use in instructional software to enhance learning: a theory-to-practice content analysis

Sound may hold great promise for instructional software by supporting learning in a variety of ways. Conceptual and preconceptual barriers, however, still appear to prevent software designers from using sound more effectively in their instructional products. Interface books seldom discuss the use of sound and when they do, it is most often simple verbatim narration of on-screen text. This content analysis of 12 award-winning instructional software products indicated that, while sound is being incorporated into many learning environments, many instructional designers are using sound only for literal, information conveyance and not yet exploring how to exploit the associative potential of music, sound effects, and narration to help learners process the material under study more deeply.     

How Does Parental Reading Influence Children’s Reading? A Study of Cognitive Mediation

Cognitive processes underlying a behavioural outcome (like reading ability) and the impact of familial risk (e.g., for dyslexia) have been studied in isolation. We present a novel design, linking the two avenues. How do familial influences impact on children’s cognitive skills, which subsequently underlie reading development? Participants from the Familial Influences on Literacy Abilities (FIOLA) Project included 373 children and their parents. We considered three causal routes from parental reading and children’s putative cognitive endophenotypes to children’s reading. Path analyses showed that half of parental effects on children’s reading bypassed and half operated through children’s cognitive underpinnings. Spousal correlation was small but significant. Findings do not support a strong hypothesis of cognitive endophenotypes with full mediation. Furthermore, we discuss the use of parental skills as a proxy for offspring’s liability. Finally, familial reading difficulties are not fully accounted for by known cognitive skills, which has implications for dyslexia diagnosis.     

Perceptions and experiences of K-12 educational leaders in response to the 27 April 2011 tornadoes

The purpose of this phenomenological study was to capture first-hand accounts of K-12 educational leaders whose school districts were directly affected by the deadly 27 April 2011 tornadoes in rural Alabama, USA. This study was framed by the literature base of leadership; specifically crisis leadership and resilience theory. Findings are organised under the headings of crisis management, crisis leadership characteristics, post-crisis support and crisis preparation. In this study, educational leaders demonstrated resilience in the face of adversity and took decisive steps to rebuild not only their schools but also their communities as well. Additionally, leaders expressed the importance of sharing their stories with others so that the lessons they learned in response to the tornadoes would not soon be forgotten. The study concludes with reflections about crisis planning and implications for future research as well as a call to action to improve crisis management in K-12 educational settings.     

Effects of inter-limb asymmetries on physical and sports performance: a systematic review

The prevalence of inter-limb asymmetries has been reported in numerous studies across a wide range of sports and physical qualities; however, few have analysed their effects on physical and sports performance. A systematic review of the literature was undertaken using the Medline and SPORT Discus databases, with all articles required to meet a specified criteria based on a quality review. Eighteen articles met the inclusion criteria, relating participant asymmetry scores to physical and sports performance measures. The findings of this systematic review indicate that inter-limb differences in strength may be detrimental to jumping, kicking and cycling performance. When inter-limb asymmetries are quantified during jumping based exercises, they have been primarily used to examine their association with change of direction speed with mixed findings. Inter-limb asymmetries have also been quantified in anthropometry, sprinting, dynamic balance and sport-specific actions, again with inconsistent findings. However, all results have been reported using associative analysis with physical or sport performance metrics with no randomised controlled trials included. Further research is warranted to understand the mechanisms that underpin inter-limb differences and the magnitude of performance changes that can be accounted for by these asymmetries.