Effect of postural changes on 3D joint angular velocity during starting block phase

Abstract

Few studies have focused on the effect of posture during sprint start. The aim of this study was to measure the effect of the modification of horizontal distance between the blocks during sprint start on three dimensional (3D) joint angular velocity. Nine trained sprinters started using three different starting positions (bunched, medium and elongated). They were equipped with 63 passive reflective markers, and an opto-electronic Motion Analysis® system was used to collect the 3D marker trajectories. During the pushing phase on the blocks, norm of the joint angular velocity (NJAV), 3D Euler angular velocity (EAV) and pushing time on the blocks were calculated. The results demonstrated that the decrease of the block spacing induces an opposite effect on the angular velocity of joints of the lower and the upper limbs. The NJAV of the upper limbs is greater in the bunched start, whereas the NJAV of the lower limbs is smaller. The modifications of NJAV were due to a combination of the movement of the joints in the different degrees of freedom. The medium start seems to be the best compromise because it leads, in a short pushing time, to a combination of optimal joint velocities for upper and lower segments.     

The effect of caffeine ingestion on human neutrophil oxidative burst responses following time-trial cycling

Abstract

Following fixed-duration exercise of submaximal intensity, caffeine ingestion is associated with an attenuation of the exercise-induced decline in N-formyl-methionyl-phenyl-alanine (f-MLP) stimulated neutrophil oxidative burst. However, the response following high-intensity exhaustive exercise is unknown. Nine endurance-trained male cyclists ingested 6 mg caffeine or placebo per kilogram of body mass 60 min before cycling for 90 min at 70% of maximal oxygen consumption ([Vdot]O_2max) and then performing a time-trial requiring an energy expenditure equivalent to 30 min cycling at 70% maximum power output. Time-trial performance was 4% faster in the caffeine than in the placebo trial (P = 0.043). Caffeine was associated with an increased plasma adrenaline concentration after 90 min of exercise (P = 0.046) and immediately after the time-trial (P = 0.02). Caffeine was also associated with an increased serum caffeine concentration (P < 0.01) after 90 min of exercise and immediately after the time-trial, as well as 1 h after the time-trial. However, the f-MLP-stimulated neutrophil oxidative burst response fell after exercise in both trials (P = 0.002). There was no effect of caffeine on circulating leukocyte or neutrophil counts, but the lymphocyte count was significantly lower on caffeine (20%) after the time-trial (P = 0.003). Our results suggest that high-intensity exhaustive exercise negates the attenuation of the exercise-induced decrease in neutrophil oxidative burst responses previously observed when caffeine is ingested before exercise of fixed duration and intensity. This may be associated with the greater increase in adrenaline concentration observed in the present study.     

Television teaching by professional performers?

Conclusions When comparing the high level of performance by the deviant academic-taught section with the lack of smooth delivery on the part of the class’ instructor, it is apparent that in this study the two do not appear to be related. “Verbal tics,” for example, did not appear to impede the achievement level of this section. Also, when considering the results among the five other sections studied, it is apparent that 1) experienced communicators performed about as well as experienced teachers; and 2) in this classroom experiment, experienced teachers performed as well as or better than experienced communicators.     

Studying ordinary events in a field devoted to the extraordinary

Although a general understanding of the phenomenon of giftedness is evident in the literature, missing is a body of information on the thoughts and actions of gifted persons in those situations that we suspect influence the emergence of extraordinary accomplishment. In this article I propose a change in direction for the study of the advanced development. Grounded in the theoretically based research of Feldman and Vygotsky, I argue that we focus on the ordinary parts of life that contribute to extraordinary achievements. People should be studied within a field over a period of time. We have tended to look at characteristics of persons and products and, less so, on the process that yielded extraordinary accomplishment. Whatever methodologies we use, they must allow us to look at the individual and at the situation in detail. Suggestions for conducting such studies are offered.     

Early Family and Child-Care Antecedents of Awakening Cortisol Levels in Adolescence

This study examined early observed parenting and child-care experiences in relation to functioning of the hypothalamic-pituitary-adrenocortical axis over the long term. Consistent with the attenuation hypothesis, individuals ( n  =   863) who experienced: (a) higher levels of maternal insensitivity and (b) more time in child-care centers in the first 3 years of life had lower awakening cortisol levels at age 15. Associations were small in magnitude. Nonetheless, results were (a) additive in that both higher levels of maternal insensitivity and more experience with center-based care uniquely (but not interactively) predicted lower awakening cortisol, (b) not accounted for by later caregiving experiences measured concurrently with awakening cortisol at age 15 or by early demographic variables, and (c) not moderated by sex or by difficult temperament.     

The Changing Relationship between Institutional Governance and Management in the United Kingdom: A Scottish Higher Education Funding Council Perspective

The changing relationship betweeninstitutional governance and management in the unitedkingdom arising from the second report of thecommittee on standards in public life, the UnitedKingdom National Committee of Inquiry into HigherEducation, and from significant increased governmentexpenditure on higher education is examined. Theframework of accountability within which highereducation institutions operate is related to thesereports. The Scottish Higher Education FundingCouncil's (SHEFC) perspective of the role of thegoverning body is examined and contrasted with bargh,scott and smith's research on governing bodies. BothSHEFC's perspective and Bargh et al.'s researchare also contrasted with, and related to, a number ofNational Audit Office (NAO) reports and also toProfessor sizer's investigation and the nao reportinto allegations of misconduct at glasgow caledonianuniversity (1998). Finally, the paper drawsconclusions on the changing relationship betweengoverning bodies and managements, on the requirementon governing bodies to demonstrate that they areappropriately constituted and operate effectively ascorporate bodies, and on how these are reflected inthe SHEFC code of good practice and good practicebenchmarks.