Validity and reliability of a linear positional transducer across commonly practised resistance training exercises     

Harry F. Dorrell  Joseph M. Moore  Mark F. Smith  Thomas I. Gee 《Journal of sports sciences》2019,37(1):67-73

This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three-dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R² values of >0.85 for all variables excluding deadlift mean velocity (R² = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance.  相似文献   

现阶段国内U-15少年足球守门员防守技术运用情况调研   总被引：1，自引：0，他引：1  

张强  杨跃飞  于永安  宫鲁农 《中国体育科技》2003,39(4):33-35

运用临场观察、访谈、文献资料调研以及逻辑分析等研究方法 ,对现阶段国内U 15少年足球守门员防守技术运用情况进行统计与分析研究。研究表明 ,少年足球守门员防射门球的预测判断能力不足 ,导致选位差、反应慢和接球易脱手 ,防守的成功率低 ;出击时机把握不好 ,对抗条件下难以有效发挥位置优势 ,强干扰下争夺球失误多。加强足球意识与心理培养 ,提高反应和接球动作质量要求是加强少年足球守门员水平稳定的重要环节。  相似文献   

Medieval and renaissance glass technology in Valdelsa (Florence). Part 1: raw materials, sands and non-vitreous finds     

U. Casellato  F. Fenzi  P. Guerriero  S. Sitran  P. A. Vigato  U. Russo  M. Galgani  M. Mendera  A. Manasse 《Journal of Cultural Heritage》2003,4(4):337-353

A significant number of archaeological finds of the 13th–16th century from the Tuscan sites of Germagnana and Gambassi in Valdelsa—FI, was studied by different physico-chemical investigations (SEM–EDS, ICP, Mössbauer spectroscopy, XRD, XRF, TG-DTA) in order to contribute to clarify the production methodology and the pre-industrial glass manufacture technology. The studied samples are mainly non-vitreous finds as production waste, refractory materials, crucibles and raw materials; also vitreous finds as frits, skims, glasses (glass masses, glass working waste and finished products) have been taken into consideration. The obtained petrographic and physico-chemical data strongly suggest that both Gambassi and Germagnana glass manufactures were strictly connected with the sources of vitrifiable materials, situated in Tuscan sand quarries. In particular a comparison between sands from the neighbouring quarries and appropriate finds of the two archaeological sites evidences that the employed vitrifiable materials possibly belong to La Casina La Cava resort. The archaeological classification, based on macroscopic observation and stratigraphic position, was compared and verified with the scientific classification of the examined finds of Germagnana and Gambassi sites based on their composition, morphology and physico-chemical properties.  相似文献   

Response to Siegel     

J F Carlisle 《Journal of learning disabilities》1990,23(5):267-9, 319

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The effect of primary cosmic-ray energy upon burst production     

W.F.G. SwannD.B. Cowie 《Journal of The Franklin Institute》1937

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Observations on siemens' unit     

F. Kohlrausch 《Journal of The Franklin Institute》1871,91(5):349-355

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Development of maximal oxygen uptake in young elite male cross-country skiers: a longitudinal study.     

F Ingjer 《Journal of sports sciences》1992,10(1):49-63

The aim of this study was to investigate the effects of extensive endurance training (15-25 h per week) on the development of maximal oxygen uptake (VO2 max) in boys from puberty. Maximal oxygen uptake was measured a number of times each year from the age of puberty and for the next 6-9 years in seven young male elite cross-country skiers. Mean VO2 max was measured as 76.3 and 80.1 ml kg-1 min-1 at the ages of 14 and 15 years respectively. Despite the fast rate of growth during puberty, maximal aerobic power showed seasonal variations from the age of 14, reaching a plateau at the age of 15, whereas VO2 max (ml kg-2/3 min-1) increased continuously. It is concluded that, during puberty, boys probably attain significant increases in VO2 max when appropriate amounts of endurance training are undertaken.  相似文献   

少年男子足球运动员防守战术意识思维决策活动研究   总被引：1，自引：0，他引：1  

董昱  张廷安  杨刚 《北京体育大学学报》2003,26(2):274-276

控球队员随情况和位置的变更其战术思维决策活动过程的“模式”也在变更。专家组的战术思维决策活动过程选择变化在后场具有明显的“场区”特点和“对抗状态”特点 ,在中场和前场时则表现出明显的“场区”特点而没有表现出明显的“对抗状态”特点。训练水平高的职业队员及训练水平较高青年队员与专家组的战术意识思维决策活动变化有较高的相似趋势。相比之下少年队员与专家的基本战术思维决策活动“模式”有明显的差异。  相似文献   

Epistemological correctness in English 101     

Thomas F. Bertonneau 《Academic Questions》1997,10(1):66-78

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Ensuring Content‐Area Learning by Secondary Students with Learning Disabilities     

Donald D. Deshler  Jean B. Schumaker  B. Keith Lenz  Janis A. Bulgren  Michael F. Hock  Jim Knight  Barbara J. Ehren 《Learning disabilities research & practice》2001,16(2):96-108

Three factors tied with secondary student success in content‐area reading are demonstrated: (a) validated teacher‐focused and student‐focused interventions, (b) integrated and comprehensive service delivery systems, and (c) well‐designed, data‐based professional developmental programs. Difficult challenges face secondary students with LD and their teachers with regard to these students’ participation and success in required general education classes. Recently, instructional methods and materials have been developed and validated for promoting these students’ success. Some of them focus on how general education teachers plan and teach their content‐area courses; others focus on giving students the strategies they need to respond independently to the demands of their courses. This article describes these instructional methods, a service‐delivery model for implementing these interventions in secondary schools, and professional‐development mechanisms and administrative support that must be in place for the model to be maintained effectively.  相似文献