The role of upper torso and pelvis rotation in driving performance during the golf swing   总被引：3，自引：2，他引：1  

Myers J  Lephart S  Tsai YS  Sell T  Smoliga J  Jolly J 《Journal of sports sciences》2008,26(2):181-188

While the role of the upper torso and pelvis in driving performance is anecdotally appreciated by golf instructors, their actual biomechanical role is unclear. The aims of this study were to describe upper torso and pelvis rotation and velocity during the golf swing and determine their role in ball velocity. One hundred recreational golfers underwent a biomechanical golf swing analysis using their own driver. Upper torso and pelvic rotation and velocity, and torso-pelvic separation and velocity, were measured for each swing. Ball velocity was assessed with a golf launch monitor. Group differences (groups based on ball velocity) and moderate relationships (r > or = 0.50; P < 0.001) were observed between an increase in ball velocity and the following variables: increased torso-pelvic separation at the top of the swing, maximum torso-pelvic separation, maximum upper torso rotation velocity, upper torso rotational velocity at lead arm parallel and last 40 ms before impact, maximum torso-pelvic separation velocity and torso-pelvic separation velocity at both lead arm parallel and at the last 40 ms before impact. Torso-pelvic separation contributes to greater upper torso rotation velocity and torso-pelvic separation velocity during the downswing, ultimately contributing to greater ball velocity. Golf instructors can consider increasing ball velocity by maximizing separation between the upper torso and pelvis at the top of and initiation of the downswing.  相似文献   

Transmission of motion     

Joseph Harrison 《Journal of The Franklin Institute》1872,94(4):233-243

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Bridge specifications     

Joseph M. Wilson 《Journal of The Franklin Institute》1875,100(2):116-120

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Facts in reference to the spark, &c,from a long conductor uniting the poles of a galvanic battery     

Joseph Henry 《Journal of The Franklin Institute》1835,19(3):169

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Motivation and the Organization     

Joseph P. Yaney 《Performance Improvement Quarterly》1988,1(1):46-57

Facing motivational problems is nothing new for the manager. The manager has ideas on how employees should behave, but those beliefs are often the source of the manager's trouble. New research shows that often the supervisor is not the key player in the motivational game. This paper examines motivational ideas presently in use and applications of how to use the new research.  相似文献   

Coordination of perspective by sixth graders and teacher trainees     

Gwendolyn N. Kelly  Joseph T. Kelly  Wallace S. Johnson 《Contemporary educational psychology》1988,13(4)

Sixth grade students were compared by sex for their performance on two perspective coordination tasks. Responses were compared with understanding of the principle that still water remains invariantly horizontal. Forty-eight randomly selected sixth grade students (24 girls and 24 boys) and 12 college women were individually shown a standardized three-dimensional scene. While seated in a single position, subjects completed two tasks: (1) selecting from a set of 12 pictures (displayed together) the one which could be seen from each of eight positions marked on the displayed scene and (2) choosing the positions from which could be seen eight of the 12 pictures (shown one at a time). Four of the 12 pictures were mirror images which were impossible views. Males outperformed females on both of the coordination-of-perspective tasks. For both males and females, choosing the place was more difficult than choosing the picture. Strong relationships were found between understanding of horizontality and performance on the perspective tasks. Selection of mirror images (impossible views) indicated more understanding of perspective than other, less systematic errors. Finally, female teacher trainees performed only marginally better than sixth grade students, suggesting possible remediation needs.  相似文献   

Age and sex influences on running mechanics and coordination variability     

Katherine A. Boyer  Julia Freedman Silvernail  Joseph Hamill 《Journal of sports sciences》2017,35(22):2225-2231

The purpose of this study was to examine the impact of age on running mechanics separately for male and female runners and to quantify sex differences in running mechanics and coordination variability for older runners. Kinematics and kinetics were captured for 20 younger (10 male) and 20 older (10 male) adults running overground at 3.5 m · s^?1. A modified vector coding technique was used to calculate segment coordination variability. Lower extremity joint angles, moments and segment coordination variability were compared between age and sex groups. Significant sex–age interaction effects were found for heel-strike hip flexion and ankle in/eversion angles and peak ankle dorsiflexion angle. In older adults, mid-stance knee flexion angle, ankle inversion and abduction moments and hip abduction and external rotation moments differed by sex. Older compared with younger females had reduced coordination variability in the thigh–shank transverse plane couple but greater coordination variability for the shank rotation–foot eversion couple in early stance. These results suggest there may be a non-equivalent aging process in the movement mechanics for males and females. The age and sex differences in running mechanics and coordination variability highlight the need for sex-based analyses for future studies examining injury risk with age.  相似文献   

Time and Politics: Parliament and the Culture of Modernity in Britain and the British World     

Joseph S. Meisel 《Cultural and Social History》2017,14(5):739-740

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Validity and Reliability of Three Self-Report Instruments for Assessing Attainment of Physical Activity Guidelines in University Students     

Joseph J. Murphy  Marie H. Murphy  Ciaran MacDonncha  Niamh Murphy  Alan M. Nevill  Catherine B. Woods 《Measurement in physical education and exercise science》2017,21(3):134-141

The purpose of this study was to compare the validity and reliability of three short physical activity self-report instruments to determine their potential for use with university student populations. The participants (N = 155; 44.5% male; 22.9 ± 5.13 years) wore an accelerometer for 9 consecutive days and completed a single-item measure, the a brief two item measure and the International Physical Activity Questionnaire—Short Form questionnaires on day 1 and 9. Correlations between self-reported and accelerometer derived moderate-to-vigorous physical activity levels were moderate for the International Physical Activity Questionnaire—Short Form, while poor for the single-item measure and the a brief two item measure. The agreement level was high with the International Physical Activity Questionnaire—Short Form (77.4%) and moderate for both the single-item measure (45.2 %) and a brief two item measure (44.5 %). The intraclass correlations between the two administrations were moderate to strong across all measures (0.52–0.70) in 133 participants. The International Physical Activity Questionnaire—Short Form is the most suitable of these three self-report instruments for use with this population due to higher correlations and levels of agreement with accelerometry.  相似文献   

Sports’ disciplinary legacy and the challenge of ‘coaching differently’     

Jim Denison  Joseph P. Mills  Timothy Konoval 《Sport, Education and Society》2017,22(6):772-783

Be empowering. Be athlete-centered. Be autonomy supportive. These are three related topics currently being promoted by sport psychologists and sport pedagogists in an effort to recognize athletes’ unique qualities and developmental differences and make coaching more holistic and coaches more considerate. This has led us to ask, how likely are such initiatives to lead to coaches putting their athletes at the center of the coaching process given that coaches’ practices have largely been formed through relations of power that subordinate and objectify athletes’ bodies through the regular application of a range of disciplinary techniques and instruments [e.g. Barker-Ruchti, N., &; Tinning, R. (2010). Foucault in leotards: Corporeal discipline in women's artistic gymnastics. Sociology of Sport Journal, 27, 229–250; Heikkala, J. (1993). Discipline and excel: Techniques of the self and body and the logic of competing. Sociology of Sport Journal, 10, 397–412; Gearity, B., &; Mills, J. P. (2012). Discipline and punish in the weight room. Sports Coaching Review, 1, 124–134]? In other words, to try to develop athlete-centered coaches capable of coaching in ways that will empower their athletes without also problematizing the discursive formation of coaches’ practices concerns us [Denison, J., &; Mills, J. P. (2014). Planning for distance running: Coaching with Foucault. Sports Coaching Review, 3, 1–16]. Put differently: how can athlete empowerment initiatives be anything more than rhetoric within a disciplinary framework that normalizes maximum coach control? It is this question that we intend to explore in this paper. More specifically, as Foucauldians, we will argue that coaching with greater consideration for athletes’ unique qualities and developmental differences needs to entail coaching in a less disciplinary way and with an awareness and appreciation of the many unseen effects that disciplinary power can have on coaches’ practices and athletes’ bodies.  相似文献