scholarly journals VO2Kinetics and Metabolic Contributions Whilst Swimming at 95, 100, and 105% of the Velocity atVO2 max

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ana C. Sousa ◽  
João P. Vilas-Boas ◽  
Ricardo J. Fernandes

A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transientVO2kinetics responses and metabolic contributions whilst swimming at different velocities aroundVO2max⁡. 12 trained male swimmers performed (i) an incremental protocol to determine the velocity atVO2max⁡(vVO2max⁡) and (ii) three square wave exercises from rest to 95, 100, and 105% ofvVO2max⁡.VO2was directly measured using a telemetric portable gas analyser and its kinetics analysed through a double-exponential model. Metabolic contributions were assessed through the sum of three energy components. No differences were observed in the fast component response (τ1—15, 18, and 16 s,A1—36, 34, and 37 mL·kg-1·min⁡-1, and Gain—32, 29, and 30 mL·min⁡-1at 95, 100, and 105% of thevVO2max⁡, resp.) but A2 was higher in 95 and 100% compared to 105% intensity (480.76 ± 247.01, 452.18 ± 217.04, and 147.04 ± 60.40 mL·min⁡-1, resp.). The aerobic energy contribution increased with the time sustained (83 ± 5, 74 ± 6, and 59 ± 7% for 95, 100, and 105%, resp.). The adjustment of the cardiovascular and/or pulmonary systems that determineO2delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception ofVO2slow component kinetics metabolic profiles.

2008 ◽  
Vol 33 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Nicola Lai ◽  
Melita M. Nasca ◽  
Marco A. Silva ◽  
Fatima T. Silva ◽  
Brian J. Whipp ◽  
...  

The dynamics of the pulmonary oxygen uptake (VO2) responses to square-wave changes in work rate can provide insight into bioenergetic processes sustaining and limiting exercise performance. The dynamic responses at the onset of exercise and during recovery have been investigated systematically and are well characterized at all intensities in adults; however, they have not been investigated completely in adolescents. We investigated whether adolescents display a slow component in their VO2 on- and off-kinetic responses to heavy- and very heavy-intensity exercise, as demonstrated in adults. Healthy African American male adolescents (n = 9, 14–17 years old) performed square-wave transitions on a cycle ergometer (from and to a baseline work rate of 20 W) to work rates of moderate (M), heavy (H), and very heavy (VH) intensity. In all subjects, the VO2 on-kinetics were best described with a single exponential at moderate intensity (τ1, on = 36 ± 11 s) and a double exponential at heavy (τ1, on = 29 ± 9 s; τ2, on = 197 ± 92 s) and very heavy (τ1, on = 36 ± 9 s; τ2, on = 302 ± 14 s) intensities. In contrast, the VO2 off-kinetics were best described with a single exponential at moderate (τ1, off = 48 ± 9 s) and heavy (τ1, off = 53 ± 7 s) intensities and a double exponential at very heavy (τ1, off = 51 ± 3 s; τ2, off = 471 ± 54 s) intensity. In summary, adolescents consistently displayed a slow component during heavy exercise (on- but not off- transition) and very heavy exercise (on- and off-transitions). Although the overall response dynamics in adolescents were similar to those previously observed in adults, their specific characterizations were different, particularly the lack of symmetry between the on- and off-responses.


1989 ◽  
Vol 7 (4) ◽  
pp. 227-235 ◽  
Author(s):  
M. N. A. HAWLADER ◽  
J. C. HO ◽  
N. E. WIJEYSUNDERA ◽  
T. H. KHO

Author(s):  
Tadeusz Siwiec ◽  
Lidia Kiedryńska ◽  
Klaudia Abramowicz ◽  
Aleksandra Rewicka ◽  
Piotr Nowak

BOD measuring and modelling methods - reviewThe article presents the method of measuring BOD in wastewater and characteristic different models which can by used for describing changes of BOD in next days. In the paper described eight models: Moore et al. (1950), Thomas (1950), Navone (1960), Fujimoto (1964), Hewitt et al. (1979), Adrian and Sanders (1992-1993) as well as Young and Clark (1965) used by Adrian and Sanders (1998), Borsuk and Stow (2000) and Manson et al. (2006). Comparison the models suggests that changing of BOD during the time are better describes by models second order or double exponential model (Manson et al. 2006) than models the first order.


1990 ◽  
Vol 20 (7) ◽  
pp. 943-951 ◽  
Author(s):  
William F. J. Parsons ◽  
Barry R. Taylor ◽  
Dennis Parkinson

In a Rocky Mountain aspen forest, the detailed pattern of mass loss from decomposing leaf litter of trembling aspen (Populustremuloides Michx.) during the first 6 months of decay was compared with that from aspen leaves modified to produce a more recalcitrant litter type by removal of leachable material (31.7% of original mass). Leaching litter removed substantial quantities of N (24%) and P (54%), but did not change the litter's C/N ratio (77:1); and leached leaves still contained 33% labile (benzene alcohol soluble) material. Decomposition of intact aspen litter was best described by a double exponential model (k1 = −7.91/year, k2 = −0.21/year), except during the first 2 weeks, when an extremely rapid mass loss (14.2%) apparently resulted from leaching. Microbial metabolism was probably responsible for most of the subsequent decay (35% total in 6 months). In contrast, decomposition of leached aspen showed no exponential trend and was best described by a simple linear regression with a slope of −19.7%/year. Additional data from a 2nd year (12–15 months decay) reduced the regression estimates of decay rates but did not alter the best fit models. Fits were improved slightly if temperature sum replaced time in the regressions, especially if 2nd-year data were included.


2019 ◽  
Vol 7 (3) ◽  
pp. 417-423
Author(s):  
Priyanka Mallikarjun Kumbhar

Soybean crop has contributed to improve the financial strength of the Indian farmers. It usually fetches higher income to the farmers owing to the massive export market for Soybean de-oiled cake. In state of Maharashtra Soybean is cultivated extensively in Amravati district. So the present studies explore the seasonality and price forecasting issue for Soybean crop. The is based on the secondary data. The monthly wholesale prices and arrivals data for the study collected from the agmarknet.gov.in for the period January 2008 to December 2017. To analyze the data we use statistical techniques like seasonality and exponential smoothing for price forecasting. The processing of data is done through MS- Excel and MINITAB Software. The study gives an overview of the different time series analytical methods, which can be used for price forecasting. The present study is undertaken precisely to fill the research gap and results of this study found an inverse relationship between price and market arrivals of soybean. The arrivals were recorded very high from October to January and seasonal indices of price were elevated during August in which arrivals were found stumpy. The assessment of all three Exponential Smoothing models was carried out in the procedure based on the Double Exponential model with MAD (168.3) and MAPE (6.14) values, which were considered in the smallest amount. The accuracy of proportion among the forecasted and actual price value of soybean was found in between 80.52 to 85.55 percent. It was pragmatic that the Double Exponential model was the most appropriate for forecasting the soybean.


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