1,720,970 research outputs found
Eur J Appl Physiol
Get PDFPurpose:The aim of this study was to determine the local and systemic effects of isometric and concentric muscle contractions on experimental pain and performance fatigability in people with and without fibromyalgia.Methods:Forty-seven fibromyalgia (FM:51.3\ub112.3yr) and forty-seven control (CON:52.5\ub114.7yr) participants performed submaximal isometric and concentric exercise for ten minutes with the right elbow flexors. Assessments before and after exercise included pressure pain thresholds (PPT) of the biceps and quadriceps, central pain summation, self-reported exercising arm and whole-body pain, and maximal voluntary isometric contraction (MVIC) of the right elbow flexors and left handgrip.Results:People with FM experienced greater reductions in local fatigue (right elbow flexor MVIC: CON: 124.0\ub16.7%, FM: 129.8\ub113.8%; p=0.013) and similar reductions in systemic fatigue (left handgrip MVIC: 126.5\ub110.2%; p<0.001) as CON participants, which were not different by contraction type nor related to baseline clinical pain, perceived fatigue, or reported pain with exercise. Following exercise both groups reported an increase in PPTs at the biceps (pre:205.5\ub1100.3kPa, post:219.0\ub1109.3kPa, p=0.004) only and a decrease in central pain summation (pre:6.8\ub12.9, post:6.5\ub12.9; p=0.013). FM reported greater exercising arm pain following exercise (CON:0.7\ub11.3, FM:2.9\ub12.3; p<0.001), and both groups reported greater arm pain following concentric (isometric:1.4\ub12.0, concentric:2.2\ub12.9; p=0.001) than isometric exercise. Neither group reported an increase in whole-body pain following exercise.Conclusion:People with FM experienced greater performance fatigability in the exercising muscle compared to CON that was not related to central mechanisms of fatigue or pain. These results suggest changes in performance fatigability in FM may be due to differences occurring at the muscular level.TL1 TR001437/TR/NCATS NIH HHSUnited States/U01 CE002944/CE/NCIPC CDC HHSUnited States/U01 NS088034/NS/NINDS NIH HHSUnited States/PODS-I/Foundation for Physical Therapy Research/TL1TR001437/TR/NCATS NIH HHSUnited States/R15HD090265/Eunice Kennedy Shriver National Institute of Child Health and Human Development/R15 HD090265/HD/NICHD NIH HHSUnited States
Eur J Appl Physiol
Get PDFTL1 TR001437/TR/NCATS NIH HHSUnited States/U01 CE002944/CE/NCIPC CDC HHSUnited States/U01 NS088034/NS/NINDS NIH HHSUnited States/TL1TR001437/TR/NCATS NIH HHSUnited States/PODSI/Foundation for Physical Therapy Research/R15HD090265/Eunice Kennedy Shriver National Institute of Child Health and Human Development/R15 HD090265/HD/NICHD NIH HHSUnited States
Med Sci Sports Exerc
Get PDFPurposeTo determine whether postpartum women (vaginal and Cesarean delivery) have deficits in trunk flexor strength, fatigability and steadiness, compared with nulligravid women, up to 26 weeks postpartum. We hypothesized that postpartum women would be weaker, more fatigable and have greater torque fluctuations than controls, with Cesarean delivery showing greater deficits than vaginal delivery.Methods22 control women (nulligravid) and 29 postpartum women (20-40 years, 19 who delivered via vaginal birth, 13 via Caesarian section) participated. Postpartum women were tested 8-10 and 24-26 weeks postpartum. Control women were tested 16-18 weeks apart. Maximal voluntary isometric contractions (MVC) were performed at multiple trunk positions with the trunk flexor muscles. To determine trunk flexor fatigability, subjects performed intermittent isometric contractions at 50% MVC (6-s contraction, 4-s rest) in upright sitting until task failure. An MVC was performed during the fatiguing task (one/min) and at 10 and 20 minutes of recovery.ResultsAt 8 and 26 weeks, postpartum women (groups pooled) were weaker at all trunk angles (38% & 44% respectively, p<0.05) than controls despite no differences in handgrip strength. Postpartum women were more fatigable (71% & 52% respectively) and had greater torque fluctuations than controls (p<0.05). At 8 weeks postpartum, women who had a Cesarean delivery, were 59% more fatigable (p=0.004) than the vaginal-delivery group, with no difference between delivery types at 26 weeks postpartum.ConclusionsMusculoskeletal recovery, including trunk flexor muscle strength and fatigability, is incomplete at 26 weeks postpartum. These findings provide a rationale for future studies to address outcomes of rehabilitation programs specifically targeted at improving strength and fatigability of the trunk flexor muscles after pregnancy and childbirth.TL1 TR001437/TR/NCATS NIH HHSUnited States/U01 CE002944/CE/NCIPC CDC HHSUnited States/U01 NS088034/NS/NINDS NIH HHSUnited States/UL1 TR001436/TR/NCATS NIH HHSUnited States
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Sex differences in human performance
No full textSex as a biological variable is an underappreciated aspect of biomedical research, with its importance emerging in more recent years. This review assesses the current understanding of sex differences in human physical performance. Males outperform females in many physical capacities because they are faster, stronger and more powerful, particularly after male puberty. This review highlights key sex differences in physiological and anatomical systems (generally conferred via sex steroids and puberty) that contribute to these sex differences in human physical performance. Specifically, we address the effects of the primary sex steroids that affect human physical development, discuss insight gained from an observational study of ‘real-world data’ and elite athletes, and highlight the key physiological mechanisms that contribute to sex differences in several aspects of physical performance. Physiological mechanisms discussed include those for the varying magnitude of the sex differences in performance involving: (1) absolute muscular strength and power; (2) fatigability of limb muscles as a measure of relative performance; and (3) maximal aerobic power and endurance. The profound sex-based differences in human performance involving strength, power, speed and endurance, and that are largely attributable to the direct and indirect effects of sex-steroid hormones, sex chromosomes and epigenetics, provide a scientific rationale and framework for policy decisions on sex-based categories in sports during puberty and adulthood. Finally, we highlight the sex bias and problem in human performance research of insufficient studies and information on females across many areas of biology and physiology, creating knowledge gaps and opportunities for high-impact studies.Abstract figure legend There are differences between male and female humans and animals in most, if not all, physiological systems, including cardiovascular, musculoskeletal, respiratory and neurological function. These sex-related differences in physiological and anatomical systems contribute to profound sex differences in the physical limits of human motor performance ranging from elite athletes to people with chronic disease. This review discusses key physiological insights related to sex differences in human motor performance and other physiological factors that influence what is known about the differences and similarities in human performance between males and females. This review also encourages the scientific community to account for sex as a biological variable and reveals opportunities to conduct high-impact studies to understand the mechanisms that influence sex differences in human performance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/194856/1/tjp16217-sup-0001-PeerReview.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/194856/2/tjp16217.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/194856/3/tjp16217_am.pd
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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