324 research outputs found

    Practices of strength and conditioning coaches: a snapshot from different sports, countries and expertise levels

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    This study describes the practices of strength and conditioning coaches (SCCs) from different sports, countries and expertise levels. One-hundred and fifty-six SCCs (31.9 + 8.9 years old) completed an online survey, consisting of 40 questions (36 fixed response and 4 open-ended), with eight sections: (a) background information, (b) muscular strength and power development, (c) speed development, (d) plyometrics, (e) flexibility development, (f) physical testing, (g) technology use, and (h) programming and any additional comments. Responses were received from 48 sports and 17 countries. This study provides exploratory evidence incorporating responses primarily in soccer (45%), track and field (30%), volleyball (23%), golf (17%) and tennis (17%). A Bachelor’s degree or higher were held by 99% of SCCs, of which 94% were in a sports science related field, and 71% held a strength and conditioning related certification or accreditation. Periodization strategies and physical testing were used by 94% of SCCs. The hang clean (82%), power clean (76%), and clean high pull (63%) were the most commonly prescribed Olympic Weightlifting exercises. Multiple hops/lunges (84%) were the most commonly prescribed plyometrics exercises. For open ended questions, 40% of SCCs wanted to integrate more technology into their programs, whereas, 30% of coaches believed technology will be the main future trend in strength and conditioning. SCCs from different sports, countries and expertise levels can use the information presented in this study to review their current practices and potentially provide a source of new ideas for diversifying or modifying future practices too

    A Multiscale Productivity Assessment of High Andean Peatlands across the Chilean Altiplano Using 31 Years of Landsat Imagery

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    The high Andean peatlands, locally known as "bofedales", are a unique type of wetland distributed across the high-elevation South American Altiplano plateau. This extensive peatland network stores significant amounts of carbon, regulates local and regional hydrological cycles, supports habitats for a variety of plant and animal species, and has provided critical water and forage resources for the livestock of the indigenous Aymara communities for thousands of years. Nevertheless, little is known about the productivity dynamics of the high Andean peatlands, particularly in the drier western Altiplano region bordering the Atacama desert. Here, we provide the first digital peatland inventory and multiscale productivity assessment for the entire western Altiplano (63,705 km(2)) using 31 years of Landsat data (about 9000 scenes) and a non-parametric approach for estimating phenological metrics. We identified 5665 peatland units, covering an area of 510 km(2), and evaluated the spatiotemporal productivity patterns at the regional, peatland polygon, and individual pixel scales. The regional assessment shows that the peatland areas and peatlands with higher productivity are concentrated towards the northern part of our study region, which is consistent with the Altiplano north-south aridity gradient. Regional patterns further reveal that the last seven years (2011-2017) have been the most productive period over the past three decades. While individual pixels show contrasting patterns of reductions and gains in local productivity during the most recent time period, most of the study area has experienced increases in annual productivity, supporting the regional results. Our novel database can be used not only to explore future research questions related to the social, biological, and hydrological influences on peatland productivity patterns, but also to provide technical support for the sustainable development of livestock practices and conservation and water management policy in the Altiplano region.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Photosynthetic responses of trees in high-elevation forests: comparing evergreen species along an elevation gradient in the Central Andes

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    Plant growth at extremely high elevations is constrained by high daily thermal amplitude, strong solar radiation and water scarcity. These conditions are particularly harsh in the tropics, where the highest elevation treelines occur. In this environment, the maintenance of a positive carbon balance involves protecting the photosynthetic apparatus and taking advantage of any climatically favourable periods. To characterize photoprotective mechanisms at such high elevations, and particularly to address the question of whether these mechanisms are the same as those previously described in woody plants along extratropical treelines, we have studied photosynthetic responses in Polylepis tarapacana Philippi in the central Andes (18 degrees S) along an elevational gradient from 4300 to 4900 m. For comparative purposes, this gradient has been complemented with a lower elevation site (3700 m) where another Polylepis species (P. rugulosa Bitter) occurs. During the daily cycle, two periods of photosynthetic activity were observed: one during the morning when, despite low temperatures, assimilation was high; and the second starting at noon when the stomata closed because of a rise in the vapour pressure deficit and thermal dissipation is prevalent over photosynthesis. From dawn to noon there was a decrease in the content of antenna pigments (chlorophyll b and neoxanthin), together with an increase in the content of xanthophyll cycle carotenoids. These results could be caused by a reduction in the antenna size along with an increase in photoprotection. Additionally, photoprotection was enhanced by a partial overnight retention of de-epoxized xanthophylls. The unique combination of all of these mechanisms made possible the efficient use of the favourable conditions during the morning while still providing enough protection for the rest of the day. This strategy differs completely from that of extratropical mountain trees, which uncouple light-harvesting and energy-use during long periods of unfavourable, winter conditions.This research was carried out with the aid of grants from the Chilean Research Council (FONDECYT 1120965 and FONDAP 15110009) awarded to D.A.C., and BFU 2010-15021 from the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund ERDF(FEDER) and the Basque Government (UPV/EHU-GV IT-299-07) awarded to J.I.G.-P

    Detecting Nothofagus pumilio Growth Reductions Induced by Past Spring Frosts at the Northern Patagonian Andes

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    Extreme climatic events, such as late frosts in spring during leaf flush, have considerable impacts on the radial growth of temperate broadleaf trees. Albeit, all broadleaved species are potentially vulnerable, damage depends on the particularities of the local climate, the species, and its phenology. The impact of late spring frosts has been widely investigated in the Northern Hemisphere, but the potential incidence in Southern Hemisphere tree species is still poorly known. Here, we reconstruct spring frost occurrence at 30 stands of the deciduous tree Nothofagus pumilio in its northern range of distribution in the Patagonian Andes. We identified tree ring-width reductions at stand level not associated with regional or local drought events, matching unusual minimum spring temperatures during leaf unfolding. Several spring frosts were identified along the northern distribution of N. pumilio, being more frequent in the more continental Argentinean forests. Spring frost in 1980 had the largest spatial extent. The spring frosts in 1980 and 1992 also induced damages in regional orchards. Spring frost damage was associated with (i) a period of unusually warm temperatures at the beginning of leaf unfolding, followed by (ii) freezing temperatures. This study helps expand our understanding of the climatic constraints that could determine the future growth and dynamics of Andean deciduous forests and the potential use of tree-rings as archives of extreme events of spring frosts in northern Patagonia.Fil: Sangüesa Barreda, Gabriel. Universidad de Valladolid; EspañaFil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Rozas, Vicente. Universidad de Valladolid; España. Universidad Austral de Chile; ChileFil: Christie, Duncan A.. Centro de Investigaciones sobre Clima y Resiliencia; Chile. Universidad Austral de Chile; ChileFil: Olano, José Miguel. Universidad de Valladolid; Españ

    A Chronic Care Model Program Incorporating Group Office Visits for Obesity Treatment in Primary Care

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    Background. Obesity is a chronic disease of epidemic proportions. Primary care providers are on the front line of diagnosing and treating obesity and need better tools to deliver top-notch obesity care. Methods. A pilot randomized trial was conducted to test a chronic care model (CCM) program for obesity compared to usual care. Primary care patients, 18 years and older, with a body mass index (BMI) between 27 and 45 were enrolled. Sixteen weekly 90-minute group office visits were structured with the first 30 minutes encompassing individualized clinical assessments and the final 60 minutes containing the group-based standardized intensive lifestyle training. The primary outcome was weight change at 16 weeks. Secondary outcomes were weight change at 24 weeks, change in diet and physical activity behaviors, self-efficacy for weight control behaviors, and physiologic markers of cardiovascular risk at 16 and 24 weeks. Results. The participants (19 in the active arm and 10 in the control arm) were 49.8 ± 11.5 years old (mean ± SD), 97% women, 55% white, and 41% black. Weight change in the control arm at week 16 was 0.25+ 2.21 kg (mean + SD) and that for the active arm was -5.74 + 4.50 kg (n=16). The difference between the two arms was significant (p = 0.0002). Both the intent-to-treat analysis using the last observation carried forward approach and the analysis including completers only provided similar siginificant results. Conclusions. This study demonstrated that a CCM program incorporating group office visits was feasible and effective for obesity treatment in primary care settings

    Anomalías anatómicas en anillos de crecimiento anuales de Austrocedrus chilensis (D. Don) Pic.-Serm. et Bizzarri en el norte de su rango de distribución

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    Tree-ring anatomical anomalies have received little attention in southern South American trees, however they can contain valuable intra-annual environmental information. This study addressed for the first time the three most frequent treering anomalies recorded in the northern and oldest known Austrocedrus chilensis forest in central Chile (32-35°S). Three anatomic anomalies described were: partially absent rings, intra-annual bands and frost rings. Partially absent rings resulted from cambial inactivity during a complete growing period and require dendrochronological tools to be detected. Intraannual bands are consequence of the abundance-shortage of environmental resources during the growing season and can be detected by examining the undefined late-wood boundaries. Frost rings, are caused by extreme low temperatures and are characterized by collapsed cells in the tree-ring growth. Results indicate that the northern most population exhibited the highest rate of absent rings, while the occurrence of intra-annual bands seems to be rather minor in the study area. Finally, frost rings are registered mainly in the younger trees in all three studied sites. These results suggest the potential for future spatio-temporal studies that examine the frequency of these anatomical anomalies in A. chilensis chronologies along its wide geographical distribution. This will complement the current environmental information recorded by its growth rates.Las anomalías anatómicas en los anillos de crecimiento anuales de los árboles han sido poco estudiadas en el sur de Sudamérica, sin embargo son elementos que pueden proporcionar información intra-anual valiosa para el estudio de eventos ambientales. En el presente estudio se aborda la primera caracterización de este tipo de anomalías presentes en anillos de crecimiento en las poblaciones más septentrionales y longevas de Austrocedrus chilensis en Chile central (32ºS - 35ºS). Las tres anomalías descritas fueron: anillos ausentes, bandas intra-anuales y anillos afectados por congelamiento. Los anillos ausentes resultan de la inactividad cambial durante toda una temporada de crecimiento, detectables mediante técnicas de cofechado dendrocronológico. Las bandas intra-anuales se forman a causa de eventos de escases-abundancia de recursos dentro de un mismo periodo de crecimiento y se reconocen por un límite difuso en la madera tardía hacia ambos bordes de la banda. Por último, los anillos por congelamiento son causados por bajas temperaturas y se presentan en el anillo de crecimiento como una línea de células colapsadas. Los porcentajes de presencia de estas anomalías en cada cronología de ancho de anillos relativos a otros estudios indican que A. chilensis es propicio para el estudio de anillos ausentes particularmente en su población más septentrional. Las bandas intra-anuales muestran un bajo porcentaje de ocurrencia en la zona de estudio. Finalmente, los anillos por congelamiento se presentan principalmente en edades poco avanzadas de los árboles estudiados en los tres sitios analizados. Estos resultados sugieren realizar posteriores estudios espacio-temporales acerca de la frecuencia de anomalías anatómicas en cronologías de A. chilensis a lo largo de su extenso rango de distribución, con el fin de complementar la información ambiental brindada por sus tasas de crecimiento

    Reconstructing the annual mass balance of the Echaurren Norte glacier (Central Andes, 33.5° S) using local and regional hydroclimatic data

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    Despite the great number and variety of glaciers in southern South America, in situ glacier mass-balance records are extremely scarce and glacier–climate relationships are still poorly understood in this region. Here we use the longest (>  35 years) and most complete in situ mass-balance record, available for the Echaurren Norte glacier (ECH) in the Andes at  ∼  33.5° S, to develop a minimal glacier surface mass-balance model that relies on nearby monthly precipitation and air temperature data as forcing. This basic model is able to explain 78 % of the variance in the annual glacier mass- balance record over the 1978–2013 calibration period. An attribution assessment identified precipitation variability as the dominant forcing modulating annual mass balances at ECH, with temperature variations likely playing a secondary role. A regionally averaged series of mean annual streamflow records from both sides of the Andes between  ∼  30 and 37° S is then used to estimate, through simple linear regression, this glacier's annual mass-balance variations since 1909. The reconstruction model captures 68 % of the observed glacier mass-balance variability and shows three periods of sustained positive mass balances embedded in an overall negative trend over the past 105 years. The three periods of sustained positive mass balances (centered in the 1920s–1930s, in the 1980s and in the first decade of the 21st century) coincide with several documented glacier advances in this region. Similar trends observed in other shorter glacier mass-balance series suggest that the Echaurren Norte glacier reconstruction is representative of larger-scale conditions and could be useful for more detailed glaciological, hydrological and climatological assessments in this portion of the Andes
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