scholarly journals The effects of hip- and ankle-focused exercise intervention on dynamic knee valgus: a systematic review

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11731
Author(s):  
Farhah Nadhirah Aiman Sahabuddin ◽  
Nazatul Izzati Jamaludin ◽  
Nurul Hidayah Amir ◽  
Shazlin Shaharudin

Background A range of non-contact injuries such as anterior cruciate ligament tear, and patellofemoral pain syndrome are caused by disordered knee joint loading from excessive dynamic knee valgus (DKV). Previous systematic reviews showed that DKV could be modified through the influence of hip strength and ankle range of motion. Therefore, the purpose of this systematic review was to examine the effects of exercise intervention which involved either top-down or bottom-up kinetic chains on minimizing DKV in male and female adults and adolescents, with and without existing knee pain. Methodology Electronic searches were conducted in SAGE, Science Direct, SCOPUS, and Pubmed. The search strategy consisted of medical subject headings and free-text search keywords, synonyms and variations of ‘exercise intervention,’ ‘knee alignment,’ ‘dynamic knee valgus’, ‘knee abduction’ that were merged via the Boolean operator ‘AND’ and ‘OR’. The search was conducted on full-text journals that documented the impact of the exercise intervention program involving either the bottom-up or top-down DKV mechanism on the knee kinematics. Furthermore, exercise intervention in this review should last at least one week which included two or three sessions per week. This review also considered both men and women of all ages with a healthy or symptomatic knee problem. The risk of bias of the included studies was assessed by Cochrane risk assessment tool. The protocol of this review was registered at PROSPERO (registration number: CRD42021219121). Results Ten studies with a total of 423 participants (male = 22.7%, female = 77.3%; adults = 249, adolescents = 123; pre-adolescent = 51) met the inclusion criteria of this review. Seven studies showed the significant effects of the exercise intervention program (range from two weeks to ten weeks) on reducing DKV. The exercise training in these seven studies focused on muscle groups directly attached to the knee joint such as hamstrings and gastrocnemius. The remaining three studies did not show significant improvement in DKV after the exercise intervention (range between eight weeks to twelve weeks) probably because they focused on trunk and back muscles instead of muscles crossing the knee joint. Conclusion Exercises targeting specific knee-joint muscles, either from top-down or bottom-up kinetic chain, are likely to reduce DKV formation. These results may assist athletes and coaches to develop effective exercise program that could minimize DKV and ultimately prevent lower limb injuries.

2020 ◽  
Vol 20 (3) ◽  
pp. 284-290
Author(s):  
Jocelyn Chan ◽  
Yue Wu ◽  
James Wood ◽  
Mohammad Muhit ◽  
Mohammed K. Mahmood ◽  
...  

Background and Objectives: Congenital Rubella Syndrome (CRS) is the leading cause of vaccine-preventable congenital anomalies. Comprehensive country-level data on the burden of CRS in low and middle-income countries, such as Bangladesh, are scarce. This information is essential for assessing the impact of rubella vaccination programs. We aim to systematically review the literature on the epidemiology of CRS and estimate the burden of CRS in Bangladesh. Methods: We conducted a systematic review of existing literature and transmission modelling of seroprevalence studies to estimate the pre-vaccine period burden of CRS in Bangladesh. OVID Medline (1948 – 23 November 2016) and OVID EMBASE (1974 – 23 November 2016) were searched using a combination of the database-specific controlled vocabulary and free text terms. We used an age-stratified deterministic model to estimate the pre-vaccination burden of CRS in Bangladesh. Findings: Ten articles were identified, published between 2000 and 2014, including seven crosssectional studies, two case series and one analytical case-control study. Rubella seropositivity ranged from 47.0% to 86.0% among all age population. Rubella sero–positivity increased with age. Rubella seropositivity among women of childbearing age was 81.0% overall. The estimated incidence of CRS was 0·99 per 1,000 live births, which corresponds to approximately 3,292 CRS cases annually in Bangladesh. Conclusion: The estimated burden of CRS in Bangladesh during the pre-vaccination period was high. This will provide important baseline information to assess the impact and cost-effectiveness of routine rubella immunisation, introduced in 2012 in Bangladesh.


2013 ◽  
Vol 5 (2) ◽  
pp. 216-232
Author(s):  
Sibylle Kabisch ◽  
Ronjon Chakrabarti ◽  
Till Wolf ◽  
Wilhelm Kiewitt ◽  
Ty Gorman ◽  
...  

With regional variations, climate change has a significant impact on water quality deterioration and scarcity, which are serious challenges in developing countries and emerging economies. Often, effective projects to improve water management in the light of climate change are difficult to develop because of the complex interrelations between direct and indirect climate impacts and local perceptions of vulnerabilities and needs. Adaptation projects can be developed through a combination of participatory, bottom-up needs assessments and top-down analyses. Climate change impact chains can help to display the causal chain of climate signals and resulting impacts and thereby establish a system map as a basis for stakeholder discussions. This article aims to develop specific climate change impact chains for the water management sector in rural coastal India that combine bottom-up and top-down perspectives. Case studies from Tamil Nadu and Andhra Pradesh, India, provide a basis for the impact chains developed. Bottom-up data were gathered through a vulnerability and needs assessment in 18 villages complemented with top-down research data. The article is divided into four steps: (1) system of interest; (2) data on climate change signals; (3) climate change impacts based on top-down as well as bottom-up information; (4) specific impact chains complemented by initial climate change adaptation options.


2021 ◽  
Author(s):  
Stefanie Johanna Maria Kruger ◽  
WENDY PHOSWA

Abstract Introduction: Tuberculosis is a worldwide health risk factor, especially among immunocompromised groups such as in pregnant women. Diagnosis for TB is complex and appropriate initiation of treatment must be timely and cannot be postponed. This systematic review aims to assess the impact of TB drug exposure linked with pregnancy complications.Methods: Electronic databases (PubMed, Google Scholar, Elsevier and the Cochrane Library) will be screened that covers original articles published from 2010 to 2020, using medical subject headings (MeSH) and free text searches. Population study of TB-infected pregnant women with control being non-infected pregnant women, defined by maternal age between 15 ≤ 44 years, which reported pregnancy outcomes after exposure to TB treatment during pregnancy will be included. PICOS for research question eligibility, PRISMA-P guidelines and flow diagram will be adhered to and assessed by two independent reviewers. Software manager Zotero v5.0.81 will be used to eliminate duplicates and assess eligibility criteria.Ethics and dissemination: We anticipate finding a large number of studies reporting on the impact of TB drugs on the incidence of pregnancy complications which, once summarised, will be useful to establishing the link between TB drugs and pregnancy complications induced by these drugs. The protocol for the systematic review will be registered in PROSPERO. The study will be disseminated electronically and in print. It will also be presented to conferences related to TB and pregnancy.Trial registration: PROSPERO CRD42021226233; Registered on 14 January 2021


2020 ◽  
Vol 5 (2) ◽  
pp. 35
Author(s):  
Grei Shele ◽  
Jessica Genkil ◽  
Diana Speelman

Background: Polycystic ovary syndrome (PCOS) is a common endocrine disorder that is characterized by menstrual irregularity and elevated serum androgens, and is often accompanied by insulin resistance. The etiology of PCOS is unknown. Lifestyle interventions and weight loss, where appropriate, remain first-line treatments for women with PCOS. Regular physical activity is recommended for women with PCOS to maintain a healthy weight and cardiovascular fitness. Purpose: To review the evidence for the impact of various exercise interventions on hormone levels in women with PCOS. Methods: A systematic review of original studies indexed in PubMed that utilized an exercise intervention in women with PCOS and reported hormone values pre- and post-intervention. Studies in which the effects of the exercise intervention could be determined were included. Results: Vigorous aerobic exercise improves insulin measures in women with PCOS. Resistance or strength training may improve androgen levels, though additional studies are warranted. Studies with yoga are limited but suggest improvements in androgens. Limited information is available on the impact of exercise on adipokines and anti-Müllerian hormone, warranting further investigation. Conclusions: Recommended guidelines for women with PCOS include vigorous aerobic exercise and resistance training to improve measures of insulin sensitivity and androgen levels.


2009 ◽  
Vol 6 (1) ◽  
pp. 1317-1343 ◽  
Author(s):  
C. Gerbig ◽  
A. J. Dolman ◽  
M. Heimann

Abstract. Estimating carbon exchange at regional scales is paramount to understanding feedbacks between climate and the carbon cycle, but also to verifying climate change mitigation such as emission reductions and strategies compensating for emissions such as carbon sequestration. This paper discusses evidence for a number of important shortcomings of current generation modelling frameworks designed to provide regional scale budgets. Current top-down and bottom-up approaches targeted at deriving consistent regional scale carbon exchange estimates for biospheric and anthropogenic sources and sinks are hampered by a number of issues: We show that top-down constraints using point measurements made from tall towers, although sensitive to larger spatial scales, are however influenced by local areas much stronger than previously thought. On the other hand, classical bottom-up approaches using process information collected at the local scale, such as from eddy covariance data, need up-scaling and validation on larger scales. We therefore argue for a combination of both approaches, implicitly providing the important local scale information for the top-down constraint, and providing the atmospheric constraint for up-scaling of flux measurements. Combining these data streams necessitates quantifying their respective representation errors, which are discussed. The impact of these findings on future network design is highlighted, and some recommendations are given.


2012 ◽  
Vol 367 (1605) ◽  
pp. 3008-3017 ◽  
Author(s):  
Jonathan B. Shurin ◽  
Jessica L. Clasen ◽  
Hamish S. Greig ◽  
Pavel Kratina ◽  
Patrick L. Thompson

The effects of global and local environmental changes are transmitted through networks of interacting organisms to shape the structure of communities and the dynamics of ecosystems. We tested the impact of elevated temperature on the top-down and bottom-up forces structuring experimental freshwater pond food webs in western Canada over 16 months. Experimental warming was crossed with treatments manipulating the presence of planktivorous fish and eutrophication through enhanced nutrient supply. We found that higher temperatures produced top-heavy food webs with lower biomass of benthic and pelagic producers, equivalent biomass of zooplankton, zoobenthos and pelagic bacteria, and more pelagic viruses. Eutrophication increased the biomass of all organisms studied, while fish had cascading positive effects on periphyton, phytoplankton and bacteria, and reduced biomass of invertebrates. Surprisingly, virus biomass was reduced in the presence of fish, suggesting the possibility for complex mechanisms of top-down control of the lytic cycle. Warming reduced the effects of eutrophication on periphyton, and magnified the already strong effects of fish on phytoplankton and bacteria. Warming, fish and nutrients all increased whole-system rates of net production despite their distinct impacts on the distribution of biomass between producers and consumers, plankton and benthos, and microbes and macrobes. Our results indicate that warming exerts a host of indirect effects on aquatic food webs mediated through shifts in the magnitudes of top-down and bottom-up forcing.


2018 ◽  
Author(s):  
Xuefen Zhao ◽  
Yu Zhao ◽  
Dong Chen ◽  
Chunyan Li ◽  
Jie Zhang

Abstract. We combined a chemistry transport model (CTM), a multiple regression model and available ground observations, to derive top-down estimate of black carbon (BC) emissions and to reduce deviations between simulations and observations for southern Jiangsu city cluster, a typical developed region of eastern China. Scaled from a high-resolution inventory for 2012 based on changes in activity levels, the BC emissions in southern Jiangsu were calculated at 27.0 Gg/yr for 2015 (JS-prior). The annual mean concentration of BC at Xianlin Campus of Nanjing University (NJU, a suburban site) was simulated at 3.4 μg/m3, 11 % lower than the observed 3.8 μg/m3. In contrast, it was simulated at 3.4 μg/m3 at Jiangsu Provincial Academy of Environmental Science (PAES, an urban site), 36 % higher than the observed 2.5 μg/m3. The discrepancies at the two sites implied the uncertainty of the bottom-up inventory of BC emissions. Assuming a near-linear response of BC concentrations to emission changes, we applied a multiple regression model to fit the hourly surface concentrations of BC at the two sites, based on the detailed source contributions to ambient BC levels from brute-force simulation. Constrained with this top-down method, BC emissions were estimated at 13.4 Gg/yr (JS-posterior), 50 % smaller than the bottom-up estimate, and stronger seasonal variations were found. Biases between simulations and observations were reduced for most months at the two sites when JS-posterior was applied. At PAES, in particular, the simulated annual mean was elevated to 2.6 μg/m3 and the annual normalized mean error (NME) decreased from 72.0 % to 57.6 %. However, application of JS-posterior slightly enhanced NMEs in July and October at NJU where simulated concentrations with JS-prior were lower than observations, implying that reduction in total emissions could not correct CTM underestimation. The effects of numbers and spatial representativeness of observation sites on top-down estimate were further quantified. The best CTM performance was obtained when observations of both sites were used with their difference in spatial functions considered in emission constraining. Given the limited BC observation data in the area, therefore, more measurements with better spatiotemporal coverage were recommended for constraining BC emissions effectively. Top-down estimates derived from JS-prior and the Multi-resolution Emission Inventory for China (MEIC) were compared to test the sensitivity of the method to initial emission input. The differences in emission levels, spatial distributions and CTM performances were largely reduced after constraining, implying that the impact of initial inventory was limited on top-down estimate. Sensitivity analysis proved the rationality of near linearity assumption between emissions and concentrations, and the impact of wet deposition on the multiple regression model was demonstrated moderate through data screening based on simulated wet deposition and satellite-derived precipitation.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4343 ◽  
Author(s):  
Joseph R. Pawlik ◽  
Tse-Lynn Loh ◽  
Steven E. McMurray

Interest in the ecology of sponges on coral reefs has grown in recent years with mounting evidence that sponges are becoming dominant members of reef communities, particularly in the Caribbean. New estimates of water column processing by sponge pumping activities combined with discoveries related to carbon and nutrient cycling have led to novel hypotheses about the role of sponges in reef ecosystem function. Among these developments, a debate has emerged about the relative effects of bottom-up (food availability) and top-down (predation) control on the community of sponges on Caribbean fore-reefs. In this review, we evaluate the impact of the latest findings on the debate, as well as provide new insights based on older citations. Recent studies that employed different research methods have demonstrated that dissolved organic carbon (DOC) and detritus are the principal sources of food for a growing list of sponge species, challenging the idea that the relative availability of living picoplankton is the sole proxy for sponge growth or abundance. New reports have confirmed earlier findings that reef macroalgae release labile DOC available for sponge nutrition. Evidence for top-down control of sponge community structure by fish predation is further supported by gut content studies and historical population estimates of hawksbill turtles, which likely had a much greater impact on relative sponge abundances on Caribbean reefs of the past. Implicit to investigations designed to address the bottom-up vs. top-down debate are appropriate studies of Caribbean fore-reef environments, where benthic communities are relatively homogeneous and terrestrial influences and abiotic effects are minimized. One recent study designed to test both aspects of the debate did so using experiments conducted entirely in shallow lagoonal habitats dominated by mangroves and seagrass beds. The top-down results from this study are reinterpreted as supporting past research demonstrating predator preferences for sponge species that are abundant in these lagoonal habitats, but grazed away in fore-reef habitats. We conclude that sponge communities on Caribbean fore-reefs of the past and present are largely structured by predation, and offer new directions for research, such as determining the environmental conditions under which sponges may be food-limited (e.g., deep sea, lagoonal habitats) and monitoring changes in sponge community structure as populations of hawksbill turtles rebound.


2017 ◽  
Vol 35 (1) ◽  
pp. 5-30
Author(s):  
Michiel Haasbroek ◽  
Jörn-Carsten Gottwald

The banking sector had long been left at the fringes of China's reform policies. Major initiatives of the 1990 and early 2000s helped to balance the need for modernization and internationalization with the objective of preserving political control. When the Global Financial Crisis (GFC) erupted in 2007, it hit the Chinese economy but predominantly in its export sector and much less in its financial sector. Yet when exports collapsed and factories closed in the winter of 2008/2009, the Chinese leadership implemented an ambitious stimulus program and used its leverage over the financial sector to re-start economic growth. These factors – GFC and domestic stimulus – created a series of intended and unintended outcomes. Financial reform in China entered a new stage signalling a profound change in China's banking sector. These changes follow two sometimes contradictive, sometimes mutually reinforcing reform dynamics of top-down policies and bottom-up innovation. In this article we follow an institutional approach and discuss the intensified participation of China's big banks in the Go Out strategy, followed by a shift in the pattern of lending. One factor in this change is the rise of shadow banking and particularly an explosive growth in internet-based financial services. Thus, while the initial reaction to the GFC re-emphasized direct, top-down state involvement in the banking sector, the outcomes of the GFC, China's policies and business innovations have facilitated profound bottom-up changes.


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