A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements     

Atle H. Saeterbakken  Roland van den Tillaar  Marius S. Fimland 《Journal of sports sciences》2013,31(5):533-538

Abstract

The purpose of this study was to compare one-repetition maximum (1-RM) and muscle activity in three chest-press exercises with different stability requirements (Smith machine, barbell, and dumbbells). Twelve healthy, resistance-trained males (age 22.7 ± 1.7 years, body mass 78.6 ± 7.6 kg, stature 1.80 ± 0.06 m) were tested for 1-RM of the three chest-press exercises in counterbalanced order with 3–5 days of rest between the exercises. One-repetition maximum and electromyographic activity of the pectoralis major, deltoid anterior, biceps, and triceps brachii were recorded in the exercises. The dumbbell load was 14% less than that for the Smith machine (P ≤ 0.001, effect size [ES] = 1.05) and 17% less than that for the barbell (P ≤ 0.001, ES = 1.11). The barbell load was ～3% higher than that for the Smith machine (P = 0.016, ES = 0.18). Electrical activity in the pectoralis major and anterior deltoid did not differ during the lifts. Electrical activity in the biceps brachii increased with stability requirements (i.e. Smith machine <barbell <dumbbells; P ≤ 0.005; ES = 0.57, 1.46, and 2.00, respectively), while triceps brachii activity was reduced using dumbbells versus barbell (P = 0.007, ES = 0.73) and dumbbells versus Smith machine (P = 0.003, ES = 0.62). In conclusion, high stability requirements in the chest press (dumbbells) result in similar (pectoralis major and anterior deltoid), lower (triceps brachii) or higher (biceps brachii) muscle activity. These findings have implications for athletic training and rehabilitation.  相似文献   

The 1936 Olympic Games in Berlin: The Response of America's Black Press     

David K. Wiggins 《Research quarterly for exercise and sport》2013,84(3):278-292

Abstract

Eighty-seven female masters swimmers ranging in age from 20 to 69 were selected for a detailed study of their body composition and physiological responses at rest and during exercise. These women were then placed into two subsets, a highly trained group and a not highly trained group, on the basis of the frequency, duration, and intensity of swimming workouts. Significant differences were detected when comparing the highly trained and not highly trained subjects on measures of weight, body density, percent fat and lean body weight (p<.05). Significant differences which favored the highly trained group were also seen when comparing these same two groups for [Vdot]_E max, [Vdot]O₂ max (1/min), [Vdot]O₂ max (ml·kg^–1·min^–1), [Vdot]O₂ max (ml·kg·LBW^–1·min^–1), O₂ pulse (ml·kg^–1·beat^–1), and O₂ pulse (ml·kg·LBW^–1). Both the highly trained and not highly trained swimmers were considerably lower in percent fat than previously reported data for normal untrained women of similar ages. In both groups, however, percent fat across age levels within each training group showed significant increases at approximately 40 years of age (p<.05). In the highly trained swimmers, [Vdot]O₂ max (ml·kg^–1·min^–1) decreased at a mean rate of about 7% per decade, while in the not highly trained swimmers the decline was approximately 8% per decade. It appears that the rate of decline in [Vdot]O₂ max in women with aging may be independent of training status.  相似文献   

Validity of Palpation Recovery Pulse Rate to Estimate Exercise Heart Rate Following Four Intensities of Bench Step Exercise     

Nancy L. Greer  Frank I. Katch 《Research quarterly for exercise and sport》2013,84(4):340-343

Abstract

Previous investigations regarding activity during the post-knowledge of results (KR) interval have considered the performance of interference groups over KR-supplied acquisition trials as indicative of effects upon learning. The absence of transfer tests in these studies, however, preclude such an assumption. Indeed, the use of a retention test in the present investigation (no-KR trials following an interpolated phase) provided evidence suggesting that, while activity during the post-KR interval is detrimental to performance, no such assumption can be made regarding this effect upon learning. These findings are discussed relative to recent arguments that some of the commonly accepted “Laws of KR” may be contradictory when applied simultaneously to motor learning and performance.  相似文献   

The Birth of the Sports Press in Spain Within the Regenerationist Context of the Late Nineteenth Century     

Xavier Torrebadella-Flix 《国际体育史杂志》2013,30(18):2164-2196

This study tackles the birth and development of the sports press in Spain from 1865 to 1899, linked to the need of a bourgeois society to emulate the English lifestyle, characterised by the sports craze. The sports press in Spain fitted extremely well in the late nineteenth century, encouraged by the Regenerationist movement. This is clear by the growth in number of sports publications, by the promotion of physical culture by Regenerationism and by the use of such publications to spread Regenerationism's approach to sport. Both primary and secondary sources were used in the research process. With regard to primary sources, archives containing specific documentation on the origins and early years of the sports press in Spain were examined. A total of 85 sports publications were counted in 18 different towns, but mostly concentrated in Madrid (28) and Barcelona (24). The most widely represented sports in these were cycling (25) and hunting (18). Among those publications that were not specific to one sport, 13 titles included the English-language term ‘sport’, and only two incorporated the newly coined Spanish word, ‘deporte’. Los Deportes (1897–1910) is the most important publication of this period and the foundation stone of modern sports journalism in Spain.  相似文献   

Techniques and considerations for determining isoinertial upper‐body power     

Michael J. Falvo  Brian K. Schilling  Lawrence W. Weiss 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):293-311

Power is an integral aspect of many sports. Although power output of the lower body is often measured during jumping and cycling movements, much less is known about power as pertains to the upper body musculature. Recently, isoinertial methods ‐ with constant gravitational load ‐ of power testing have become common, but little is known of the reliability and criterion validity of these tests as they pertain to sport performance. In addition, the varied methodology makes a lucid model more evasive. The aims of this review are to examine the various methods of assessing upper body power, to establish its role in predicting athletic performance, and to assess the body of literature that has assessed power output of the upper extremities by isoinertial methods. To our knowledge, only two studies on isoinertial upper‐body power have shown a direct correlation to sporting ability (Baker, 2001; Baker et al., 2001); therefore, many unanswered questions exist as to the efficacy of these tests as predictors of athletic ability or as a method to track athletes’ training over time. From this review we hope to allow the sport coach to assess the overall utility of these tests in terms of availability, safety and external validity.  相似文献   

弥尔顿出版自由思想的局限性剖析     

唐海江 《国际新闻界》2004,(3):69-73

本文从自由主义新闻思潮发展史的层面 ,对弥尔顿出版自由思想的局限进行了简要剖析 ,并从思想渊源和现实层面对其原因进行了解释。弥尔顿的出版自由思想存在建制缺失、先验主义和非民主特征等局限 ,这些局限极大地削弱了其在自由主义新闻思潮发展史中的价值 ,在内涵与 1 8世纪和 1 9世纪的自由主义新闻思潮存在显著不同。  相似文献   

三峡库区腹地县域耕地压力研究——以奉节县27个乡镇为例   总被引：1，自引：0，他引：1  

甘彩红  李阳兵  邵景安  王永艳 《资源科学》2014,36(7):1365-1373

本文以奉节县的27个乡镇为研究区,运用景观生态学理论、地理信息系统和统计分析方法,借助Erdas8.5、ArcGIS9.3以及Fragstats3.3软件,分析了三峡库区腹地奉节县27个乡镇2010年耕地压力空间分布规律,讨论了耕地压力与土壤侵蚀的关系及优化调控措施。结果表明:①研究区耕地受其自然地理条件的影响,在不同岩性、地貌、坡度上分布差异显著;②耕地压力空间差异较显著,长江以北大部分乡镇耕地压力指数小于1,而南部乡镇耕地压力指数基本上大于1.5。根据耕地压力指数偏离1的程度且经校正将研究区分为4类区,包括无压区、边缘区、低压区和高压区;③由于北部地区开垦了大量的坡耕地,缓解了耕地压力,使得北部地区耕地压力比南部地区小,但土壤侵蚀综合指数较南部地区大,即生态破坏较严重。因此,通过大量开垦坡耕地来缓解耕地压力虽能暂时起到作用,但是从长远来看会加快耕地水土流失的速度,最终会大大增加耕地压力;④缓解研究区耕地压力、维护生态平衡要结合城镇化进程,促使人口向非农产业转移,通过异地供给方式解决粮食问题,降低粮食自给率;在推行生态退耕的同时也要保护好现有中、优等别耕地;调整农业结构,形成以种植粮食作物为基础,畜牧业、林果业、药业为主导的农业结构。  相似文献   

The Constables and the ‘Garage Girl’     

John Carter Wood 《Media History》2014,20(4):384-399

In the summer of 1928, the arrest on a disorder charge of a young woman in north London who gave her name as Helene Adele led to a press sensation after she claimed that the officers had falsely accused her in order to discredit her claim that one of them had sexually assaulted her. The constables were ultimately prosecuted, convicted and discharged from the Metropolitan Police. This article considers the Adele case in the context of intense concerns about the possible abuse of police powers—particularly in cases involving women—in the late 1920s. Adele was catapulted onto the front pages of Britain's sensationalist press: her serialised memoir appeared in a newspaper and was reprinted in a women's magazine. However, her case was more than just a tabloid spectacle. Contributing to historians' reconsideration of the sensationalist inter-war press, this article shows how the coverage of the case fit into the press's interest in young working-class women's lifestyles and sexuality, highlighting how ‘human interest’ journalism could be intermixed with social critique.  相似文献   

“新闻自由”的“中国面孔”——一份关于“新闻自由”的阅读报告     

周传虎 《洛阳师范学院学报》2013,32(10):140-142

"自由主义"的"两张面孔"影响着人们对"新闻自由"的态度。中国人对"新闻自由"的认识是一个逐步深化的过程。1949年以前,马星野出版的《新闻自由论》是这种认识的结晶;1988年,中国新闻学会出版的《新闻自由论集》成为20世纪80年代自由主义思潮在新闻界的理论结晶;网络时代,"新闻自由"以业界多彩和学界冷清的悖论姿态呈现在世人面前。"左与右"的传统区分可能还是理解"新闻自由"的有效维度。  相似文献   

“隐身”还是“显身”?——论记者招待会口译中译员的角色     

成玉峰  张海燕 《南昌教育学院学报》2013,(10)

本文通过解释记者招待会口译过程中译员显身和隐身的必要性,并通过详细案例,指出在记者招待会的口译过程中译员是即是忠实的"传话筒",也是对话的共建者和协调者。  相似文献