1,721,120 research outputs found
Effectiveness of pragmatic resistance training for older adults receiving home care
Full text linkThe number and proportion of older adults is increasing with the most rapid rise projected for individuals above 80 years. Old age is accompanied by reduced muscle strength and mass, impaired physical function, high levels of sedentary behavior, and low levels of physical activity (PA). These changes may influence the ability to live independently, which imposes a major burden for the individual and the society. Evidence suggest that muscle strength is related to physical function, and that resistance training may be an effective strategy to counteract the age-related decline in muscle strength, muscle mass, physical function, and PA levels. This thesis is based on the recognition that there is a need for an effective resistance training program that can be incorporated into older adults’ key settings, such as at home or the health care centers. Pragmatic resistance training programs utilizing easily available, lowcost equipment (e.g., elastic bands, water canes, body weight) may be a viable alternative for the oldest old (>80 years).
This thesis aims to increase the knowledge about the relationship between muscle strength and physical function, and about the effectiveness of a pragmatic resistance training program among community-dwelling older adults receiving home care. Accordingly, one paper examines the cross-sectional association between muscle strength and physical function. The second paper examined the effectiveness of pragmatic resistance training compared to PA counselling on physical function, muscle strength, and body composition. The third paper examined the effectiveness of pragmatic resistance training compared to PA counselling on PA levels.
This thesis was based on data from the Independent, Self-reliant, Active Elderly (ISRAE) study, a cluster-randomized controlled trial. A total of 107 community-dwelling older adults receiving home care (median age 86 years) from 12 clusters were included. The participants were randomized to either a resistance training group or a control group. The training group (n=64) were offered eight months of supervised resistance training twice a week using elastic bands, water canes, and body weight as external resistance. The control group (n=43) received PA counselling. Maximal- and explosive muscle strength were tested through an isometric contraction of the leg extensors. Physical function was evaluated through a test battery assessing the ability to rise from a chair, climb stairs, and walk. Body composition was estimated using bioelectrical impedance analysis. PA levels were estimated objectively by ActiGraph GT3X+ accelerometers over 14 consecutive days.
The results of the research presented in this thesis show that higher maximal- and explosive strength are related to better physical function among community-dwelling older adults receiving home care. Furthermore, in the same sample, eight months of pragmatic resistance training resulted in improved physical function and maximal strength when compared to PA counseling. However, the resistance training program did not result in improved explosive strength, body composition, or PA levels when compared to receiving PA counseling. Thus, pragmatic resistance training may be a viable strategy that holds great potential for slowing down or counteracting several unfavorable age-related changes. Older adults, including those of poor muscle strength, poor physical function, and the oldest old, should be encouraged to implement a structured resistance training program into their weekly routines
The effect of antioxidant supplementation on endurance training-induced muscular adaptation : western blot analysis of COX4 and HSP60 from m.vastus lateralis
No full textBakgrunn: Produsenter av antioksidanttilskudd har lenge hevdet at toppidrettsutøvere bør ta slike tilskudd for å bedre prestasjon, samt å øke helsegevinstene i forbindelse med utholdenhetstrening. De underliggende mekanismene og dokumentasjonene for disse påstandene er imidlertid uklare. Som en følge av utholdenhetstrening øker mitokondriekapasiteten, og dette medfører økt nivå av enzymer som er delaktig i regenerering av energi (ATP) og proteinsyntese. Antioksidanter har i noen studier imidlertid vist seg å hemme treningsindusert oppregulering av mitokondriekapasitet. To viktige enzymer i mitokondriene er HSP60 og COX4.
Formål: Formålet med studien har vært å undersøke om tilskudd av antioksidanter påvirket tilpasningsresponser (nivå av COX4 og HSP60) i muskelen som følge av utholdenhetstrening.
Metode: På forhånd relativt godt trente forsøkspersoner (♀=24, ♂=29) ble randomisert inn i fire grupper, med jevn kjønnsfordeling. Intervensjonsperioden besto av 12 ukers utholdenhetstrening (intervall- og langkjøring, løping) med tilskudd av antioksidanter; C- og E-vitaminer (n=15), Smartfish (n=10), astaxanthin (n=12), og placebo (n=16). Membranfraksjon av vevsprøver fra m. vastus lateralis ble brukt til immunoblot av COX4 og HSP60. For å undersøke effekten av antioksidanttilskudd på aerob kapasitet, ble VO2maks målt.
Statistikk: Det ble utført parete og uparete t-tester, i tillegg til Kruskal-Wallis test og korrelasjonstester (Pearson). Testene ble ansett som signifikant ved en p-verdi ≤ 0,05, og som en tendens ved 0,10 ≥ p > 0,05. Beregninger ble utført i Excel og Prism5.
Resultater: I løpet av treningsperioden med antioksidanttilskudd økte proteinnivå av COX4 i placebogruppen (61 %), men ble redusert i gruppen med C- og E-vitamintilskudd (-19 %). Det var en tendens til økning (gjennomsnittlig på 6 %) i nivå av HSP60 når alle gruppene var samlet. Det var ingen andre signifikante endringer for COX4 og HSP60. Trening økte også VO2maks i alle gruppene (gjennomsnittlig økning på 6,8 %), men det var ingen forskjeller mellom placebogruppen og gruppene med antioksidanttilskudd.
Konklusjon: Utholdenhetstrening økte som forventet proteinnivå av COX4, men tilskudd av C- og E-vitaminer syntes å hemme denne oppreguleringen. Det
så ikke ut til at utholdenhetstreningen, med eller uten antioksidanttilskudd, hadde stor påvirkning på nivåene av HSP60. Utholdenhetstrening ga en forventet økning i VO2maks, men antioksidanttilskuddene påvirket ikke denne økningen.Background: Manufacturers of antioxidant supplements have long argued that athletes should take antioxidant supplements to improve performance and to provide health benefits. The underlying mechanisms and documentations of these claims is however unclear. Endurance training increases mitochondrial capacity, and this leads to increased levels of enzymes that are involved in the regeneration of energy (ATP) and protein synthesis. Antioxidants have in some studies been shown to inhibit the exercise-induced up regulation of mitochondrial capacity. Two important enzymes in mitochondria are HSP60 and COX4.
Objective: The aim of this study was to investigate whether supplementation of antioxidants influence exercise-induced adaptation in muscles after a period of endurance training.
Method: Relatively well-trained subjects (♀=24, ♂=29) were randomized into 4 groups with an equal distribution of gender. The intervention period included 12 weeks of endurance training (interval and long distance running) with supplements of; C- and E-vitamins (n=15), Smartfish (n=10), astaxanthin (n=12), or placebo (n=16). The membrane fraction of tissue samples from M. vastus lateralis were used for immunoblot analysis with antibodies for COX4 and HSP60. VO2max was measured to investigate the effects of antioxidant supplementation on aerobic power.
Statistics: There were performed paired and unpaired t-tests, in addition to Kruskal-Wallis test and correlation tests (Pearson). The tests were considered significant at a p-value p > 0.05. Calculations were performed in Excel and Prism5.
Results: The endurance training program and the antioxidant supplements led to an increased protein content of COX4 in the placebo group (61 %), but a reduced content in the group with supplementation of C- and E-vitamins (-19 %). There was a tendency of an increased amount of HSP60 (average of 6 %) when the groups were collapsed, regardless of antioxidant supplements. Training increased VO2max in all groups (6.8 %), with no differences between the placebo group and the groups with antioxidant supplements.
Conclusion: As expected, endurance training increased the protein level of COX4, but supplements of C- and E-vitamins appeared to inhibit this up regulation. It did not seem that endurance training, with or without supplements of antioxidants influenced the levels of HSP60. Endurance training resulted in an expected increase in VO2max, and the antioxidant supplements did not affect this increase.2017-05-15M-LU
The effect of a COX-2 inhibitor (Celebra) on leukocytosis and cytokine response to high-force eccentric muscle damaging exercise
Full text linkExercise-induced muscle damage is accompanied by an inflammation process characterized by leucocytosis, increased cytokine production of and infiltration of leukocytes in damaged areas (Paulsen et al. 2012). However, the precise orchestration of these responses is not known. One key regulator of inflammation, and also of muscle regeneration, is the cyklooxygenase (COX) pathway. Especially COX-2 activation is suggested to play an important role after exercised-induced muscle damage (Schoenfeld 2012). Consequently, the aim of this study was to investigate the effect of a COX-2 inhibitor on the acute inflammation after high-force eccentric exercise in young healthy males and females.
Thirty-three young males and females participated in a double-blind, placebo-controlled experiment. Seventy unilateral, voluntary, maximal eccentric actions with the elbow flexors were performed with one arm, and the other arm served as control. The celebra group was administered 400mg/day of celecoxib (Celebra®) for 9 days, with the first dose of 200 mg administered 45 min before exercise. The placebo group received identical pills containing lactose. Blood samples for cell counting and cytokine analysis (subgroup) were obtained before exercise and 0, 1, 5, 8.5, 24 and 48 hours after exercise. In a subsample of 10 subjects biopsies from both arms were obtained before exercise and 48 hours after exercise and analyzed for mRNA levels for IL-6 and TNFα.
Muscle damage was indicated by a ~50% reduction in maximal isometric elbow flexion torque, and also identified by direct measurements on muscle biopsies (Paulsen et al. 2009). The number of WBC increased more in the placebo group than in the celebra group immediately after exercise (41±20% vs. 26±14%, respectively, p
In conclusion, administration of 400 mg celecoxib per day significantly blunted neutrocytosis, monocytosis and the cytokine response after a bout of muscle damaging high-force eccentric exercise
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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