Does self-perceived sleep reflect sleep estimated via activity monitors in professional rugby league athletes?     

Johnpaul Caia  Heidi R. Thornton  Vincent G. Kelly  Tannath J. Scott  Shona L. Halson  Balin Cupples 《Journal of sports sciences》2018,36(13):1492-1496

This study examined agreement between self-perceived sleep and sleep estimated via activity monitors in professional rugby league athletes. 63 athletes, from three separate teams wore actigraphy monitors for 10.3 ± 3.9 days. During the monitoring period, ratings of perceived sleep quality (on a 1–5 and 1–10 Likert scale), and an estimate of sleep duration were recorded daily. Agreement between sleep estimated via activity monitors and self-perceived sleep was examined using mean bias, Pearson correlation (r) and typical error of the estimate (TEE). 641 nights of sleep were recorded, with a very large, positive correlation observed between sleep duration estimated via activity monitors and subjective sleep duration (r = 0.85), and a TEE of 48 minutes. Mean bias revealed subjective sleep duration overestimated sleep by an average of 19.8 minutes. The relationship between sleep efficiency estimated via activity monitors and self-perceived sleep quality on a 1–5 (r = 0.22) and 1–10 Likert scale (r = 0.28) was limited. The outcomes of this investigation support the use of subjective measures to monitor sleep duration in rugby league athletes when objective means are unavailable. However, practitioners should be aware of the tendency of athletes to overestimate sleep duration.  相似文献   

Relationships between highly skilled golfers’ clubhead velocity and force producing capabilities during vertical jumps and an isometric mid-thigh pull     

Jack E. T. Wells  Andrew C. S. Mitchell  Laura H. Charalambous  Iain M. Fletcher 《Journal of sports sciences》2018,36(16):1847-1851

Whilst previous research has highlighted significant relationships between golfers’ clubhead velocity (CHV) and their vertical jump height and maximum strength, these field-based protocols were unable to measure the actual vertical ground reaction force (vGRF) variables that may correlate to performance. The aim of this study was to investigate relationships between isometric mid-thigh pull (IMTP), countermovement jump (CMJ), squat jump (SJ) and drop jump (DJ) vGRF variables and CHV in highly skilled golfers. Twenty-seven male category 1 golfers performed IMTP, CMJ, SJ and DJ on a dual force platform. The vertical jumps were used to measure positive impulse during different stretch-shortening cycle velocities, with the IMTP assessing peak force (PF) and rate of force development (RFD). Clubhead velocity was measured using a TrackMan launch monitor at a golf driving range. Pearsons correlation coefficient analyses revealed significant relationships between peak CHV and CMJ positive impulse (r = 0.788, p < 0.001), SJ positive impulse (r = 0.692; p < 0.001), DJ positive impulse (r = 0.561, p < 0.01), PF (r = 0.482, p < 0.01), RFD from 0–150 ms (r = 0.343, p < 0.05) and RFD from 0–200 ms (r = 0.398, p < 0.05). The findings from this investigation indicate strong relationships between vertical ground reaction force variables and clubhead velocity.  相似文献   

Decrements in knee extensor and flexor strength are associated with performance fatigue during simulated basketball game-play in adolescent,male players     

Aaron T Scanlan  Jordan L Fox  Nattai R Borges  Anne Delextrat  Tania Spiteri  Vincent J Dalbo 《Journal of sports sciences》2018,36(8):852-860

This study quantified lower-limb strength decrements and assessed the relationships between strength decrements and performance fatigue during simulated basketball. Ten adolescent, male basketball players completed a circuit-based, basketball simulation. Sprint and jump performance were assessed during each circuit, with knee flexion and extension peak concentric torques measured at baseline, half-time, and full-time. Decrement scores were calculated for all measures. Mean knee flexor strength decrement was significantly (P < 0.05) related to sprint fatigue in the first half (R = 0.65), with dominant knee flexor strength (R = 0.67) and dominant flexor:extensor strength ratio (R = 0.77) decrement significantly (P < 0.05) associated with sprint decrement across the entire game. Mean knee extensor strength (R = 0.71), dominant knee flexor strength (R = 0.80), non-dominant knee flexor strength (R = 0.75), mean knee flexor strength (R = 0.81), non-dominant flexor:extensor strength ratio (R = 0.71), and mean flexor:extensor strength ratio (R = 0.70) decrement measures significantly (P < 0.05) influenced jump fatigue during the entire game. Lower-limb strength decrements may exert an important influence on performance fatigue during basketball activity in adolescent, male players. Consequently, training plans should aim to mitigate lower-limb fatigue to optimise sprint and jump performance during game-play.  相似文献   

An Investigation of High-Achieving African-American Students Attending Community Colleges: A Mixed Methods Research Study     

John Gipson  Donald Mitchell Jr.  Carolyn McLean 《Community College Journal of Research & Practice》2018,42(4):289-301

While much more research has been conducted about African-American college students in recent decades, there still exists a need for further explorations concerning factors related to student success and retention. For example, articles often explore the experiences of African-American students at four-year institutions and often use deficit frameworks instead of focusing on the experiences of successful students. To add to what is known, this article summarizes the findings of a multi-institutional mixed methods research study that explored the experiences of high-achieving African-American students attending community colleges. Specifically, the researchers explored noncognitive factors that influenced high academic achievement—defined as grade point average (GPA) higher than 3.00, why students considered leaving an institution, and why students decided to remain enrolled. Findings suggested that studying alone promoted a high cumulative GPA and increased the likelihood students never seriously considered leaving their institution. Studying alone, family relationships, hours spent studying with family, engaged and supportive faculty, financial aid, and the strive to succeed also promoted persistence. Relating to sex differences, student organizational involvement appeared to be more important for male persistence than female persistence at a significant level. The article closes with implications for future research and practice.  相似文献   

The role of Lean principles in supporting knowledge management in IT outsourcing relationships     

Yiwei?GongEmail author  Vincent?Blijleven 《知识管理研究与实践》2017,15(4):533-541

Knowledge management (KM) in information technology outsourcing (ITO) is important to the organizations which pursue long-term strategic benefits and innovation. Effective KM mechanism in outsourcing enables both parties to continuously exchange knowledge and promotes collective learning. This paper investigates the role of Lean principles in supporting KM in ITO relationships. Drawn from the knowledge-based view of the firm, knowledge accessing and knowledge integration and utilization are identified as two key KM processes in outsourcing. Three case studies conducted in different service industries with 18 interviews indicate that the two KM processes were supported by four Lean principles: respect for people, continuous improvement, systems thinking, and proactive behavior. Those principles can be implemented with different tools at different organizational levels. This study reveals the relevance between Lean and KM in ITO relationships, which has not been reported by the KM literature. It also provides implications to ITO practitioners for the implementation of Lean principles.  相似文献   

Demographic characteristics of elite Kenyan endurance runners     

Vincent O. Onywera  Robert A. Scott  Michael K. Boit 《Journal of sports sciences》2013,31(4):415-422

Abstract

Kenyan athletes have dominated international distance running in recent years. Explanations for their success include favourable physiological characteristics, which could include favourable genetic endowment, and advantageous environmental conditions. The aim of this study was to compare the demographic characteristics of elite Kenyan runners with those of the general Kenyan population. Questionnaires, administered to 404 elite Kenyan runners specializing in distances ranging from the 800 m to the marathon and 87 Kenyan controls, obtained information on place of birth, language, and distance and method of travel to school. Athletes were separated into two groups according to athletic success: those who competed in international competition and those who competed in national competition. The athletes differed from controls in regional distribution, language, and distance and method of travel to school; athletes also differed from each other with the exception of method of travel to school. Most national and international athletes came from the Rift Valley province (controls 20%, national athletes 65%, international athletes 81%), belonged to the Kalenjin ethnic group (controls 8%, national athletes 49%, international athletes 76%) and Nandi sub-tribe (controls 5%, national athletes 25%, international athletes 44%), and spoke languages of Nilotic origin (controls 21%, national athletes 60%, international athletes 79%). A higher proportion of all athletes ran to school each day (controls 22%, national athletes 73%, international athletes 81%) and covered greater distances. In conclusion, Kenyan runners are from a distinctive environmental background in terms of geographical distribution, ethnicity and travelled further to school, mostly by running. These findings highlight the importance of environmental and social factors in the success of Kenyan runners.  相似文献   

A citation and co-citation analysis of 10 years of KM theory and practices     

Christian?Walter  Vincent?RibièreEmail author 《知识管理研究与实践》2013,11(3):221-229

In a previous issue of Knowledge Management Research & Practice (KMRP), we analysed the content and keywords of all articles published in the first decade of KMRP. With this article, we extend our preliminary analysis to the citation and co-citations made by these articles. The study covers all the 256 articles published. The most cited article was A dynamic theory of organisational knowledge creation by Nonaka. The most cited KMRP article was by Nonaka and Toyama: The knowledge-creating theory revisited: knowledge creation as a synthesizing process. The co-citation analysis of the 100 most cited articles in KMRP publications showed that four groups of topics emerged, one around communities and situated learning, the second group around networks, knowledge transfer and research methods, a third group around the foundations of knowledge management and a fourth group around intellectual capital.  相似文献   

Body Image Phenomena and Measures of Physiological Performance     

Dr. William J. Vincent  Dr. Don S. Dorsey 《Research quarterly for exercise and sport》2013,84(4):1101-1106

Abstract

This study was designed to investigate the relationships between three measures of body image and two measures of physiological performance. The Fisher-Cleveland Barrier Index, the Secord Homonym Test, and the Body Cathexis Questionnaire were correlated with dominant hand grip strength and the Michael-Gallon revision of the Harvard Step Test. Pearson's r was employed to determine the degree of relationship. Fifty males selected at random from general education classes at San Fernando Valley State College constituted the research sample. Of the six possible pairings only one reached statistical significance: the Homonym Test and grip strength (r = .33 at .05 level). It was concluded that a general relationship does not seem to exist between the measures of body image and physiological performance utilized in this study. These and other findings led the authors to re-examine several questions concerning the nature of body image phenomena.  相似文献   

Threshold frequency of an electrically induced cramp increases following a repeated,localized fatiguing exercise     

Marcus B. Stone  Jeffrey E. Edwards  Kellie C. Huxel  Mitchell L. Cordova  Christopher D. Ingersoll  J. Patrick Babington 《Journal of sports sciences》2013,31(4):399-405

Abstract

Though clinical observations and laboratory data provide some support for the neuromuscular imbalance theory of the genesis of exercise-associated muscle cramps, no direct evidence has been published. The purpose of this study was to determine the effect of local muscle fatigue on the threshold frequency of an electrically induced muscle cramp. To determine baseline threshold frequency, a cramp was electrically induced in the flexor hallucis brevis of 16 apparently healthy participants (7 males, 9 females; age 25.1 ± 4.8 years). The testing order of control and fatigue conditions was counterbalanced. In the control condition, participants rested in a supine position for 30 min followed by another cramp induction to determine post-threshold frequency. In the fatigue condition, participants performed five bouts of great toe curls at 60% one-repetition maximum to failure with 1 min rest between bouts followed immediately by a post-threshold frequency measurement. Repeated-measures analysis of variance and simple main effects testing showed post-fatigue threshold frequency (32.9 ± 11.7 Hz) was greater (P < 0.001) than pre-fatigue threshold frequency (20.0 ± 7.7 Hz). An increase in threshold frequency seems to demonstrate a decrease in one's propensity to cramp following the fatigue exercise regimen used. These results contradict the proposed theory that suggests cramp propensity should increase following fatigue. However, differences in laboratory versus clinical fatiguing exercise and contributions from other sources, as well as the notion of a graded response to fatiguing exercise, on exercise-associated muscle cramp and electrically induced muscle cramp should be considered.  相似文献   

Teacher Perceptions of a Physical Education Statewide Assessment Program     

Judith Rink  Laura Jones  Kym Kirby  Murray Mitchell  Panayiotis Doutis 《Research quarterly for exercise and sport》2013,84(3):204-215

Abstract

A statewide program assessment was established to make positive change in physical education school programs in South Carolina. Reform efforts depend both on balancing accountability for change and teacher support for change (Odden &Anderson, 1986). The purpose of the study was to determine teacher perceptions of the South Carolina Physical Education Assessment Program and its effects across six related themes including: changes in teaching and learning, changes in curriculum and instruction, teacher awareness of the assessment program, teacher support for the program, work place conditions, and the advocacy role of the program. It was also the purpose of this study to determine if the survey responses were in any way related to teacher and school variables. The overall results of the study indicated positive change and support for the assessment program, supporting the viability of the standards, assessment, and accountability reform effort to positively impact physical education programs.  相似文献