‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.Highlights
Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.
Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.
Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.
Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.
The purpose of this study was to compare arm–leg coordination and kinematics during 100 m breaststroke in 26 (8 female; 18 male) specialist breaststroke swimmers. Laps were recorded using three 50-Hz underwater cameras. Heart rate and blood lactate were measured pre- and post-swim. Arm–leg coordination was defined using coordination phases describing continuity between recovery and propulsive phases of upper and lower limbs: coordination phase 1 (time between end of leg kick and start of the arm pull phases); and coordination phase 2 (time between end of arm pull and start of leg kick phases). Duration of stroke phases, coordination phases, swim velocity, stroke length (SL), stroke rate (SR) and stroke index (SI) were analysed during the last three strokes of each lap that were unaffected by turning or finishing. Significant changes in velocity, SI and SL (P < 0.05) were found between laps. Both sexes showed significant increase (P < 0.05) in heart rate and blood lactate pre- to post-swim. Males had significantly (P < 0.01) faster swim velocities resulting from longer SLs (P = 0.016) with no difference in SR (P = 0.064). Sex differences in kinematic parameters can be explained by anthropometric differences providing males with increased propelling efficiency. 相似文献
Software engineering education can be viewed as a challenging task. Computer science students tend to focus on the programming aspects of a project, and take a “hacking approach” to completing a project, rather than viewing the process. Our course material includes teaching the Personal Software Process (PSP). Students are required to produce defect and effort metrics, as well as project summary reports. Tools to assist information recording and production of reports are difficult for students to access. The cost in terms of financial and learning time is usually too high at the educational level to justify using commercial tools that are available for the professional software engineer. We have developed a tool—Personal Assistant for Software Engineers—to aid students in the learning of the PSP. The tool has been successfully used in four subjects for a semester. Following feedback and evaluation, it has been redesigned, and is currently in stage two. The tool has been useful for students, and has automated the previous manual process of producing time and defect reports, along with project summaries, thus allowing them to focus on the meaning of the information. 相似文献
This article is an analysis of data drawn from semi-structured, taperecorded interviews with five female primary school headteachers. The research focused on their perceptions of their management role. One significant and unexpected finding was that these women not only denied feeling stressed but were deriving immense satisfaction from their work. It is suggested that much of their enjoyment comes from the high degree of emotional intelligence they display in managing people, time and resources and which also partly accounts for their success and managerial confidence. The degree of power, control and choice which these women exercise in their work lends support to the claim that there is an emerging group of managers in primary education who may represent the ‘new women of power’. 相似文献
Research in Science Education - This study explores the role of domain-specific knowledge in students’ modeling practice and how this knowledge interacts with two domain-general modeling... 相似文献
Courseware development often involves a great deal of effort. One approach to minimising effort while maintaining flexibility is illustrated, using a tutoring system as an example. The system comprises two parts: a 'shell' which contains facilities useful for many different subjects, and an interpreter which generates questions which are subject specific. 相似文献
Unwillingness to share depression experiences with primary care physicians contributes to the undertreatment of depression. This project examined college students’ reasons for depression nondisclosure to primary care providers (PCPs). Undergraduate participants read a vignette describing someone with depression and completed measures of disclosure barriers. Analyses indicated 26% of respondents would NOT disclose depression symptoms to PCPs. Reasons for nondisclosure included difficulty initiating the depression conversation, medication aversion, and fear of referral to a psychologist. Also, anger toward the vignette character varied with disclosure willingness, suggesting that nondisclosers feel more stigma than disclosers and are less likely to engage in psychotherapy. Because engagement in pharmacological and/or psychotherapeutic treatment requires identification of depression in healthcare settings, increased understanding of disclosure barriers could increase students’ access to depression treatment. 相似文献
Cultural-historical psychology identifies play as the leading activity in preschool development. Vygotsky's (1967, 1978) seminal work outlined two categories of leading influences: play makes a foundational contribution to the development of semiotic mediation, and it involves active appropriation of social roles and rules and other integral aspects of social organization. Leont'ev's (1981) concept of appropriation and Bakhtin's (1981) concepts of heteroglossia and ideological becoming are used to elaborate and extend Vygotsky's original work, particularly with regard to creativity in preschool play. The paper concludes with a consideration of the pedagogical implications of the cultural-historical view on play, including the use of play to cultivate understanding of the arbitrary nature of signs and the appropriation of the social roles and organizational patterns of society. 相似文献