scholarly journals Applications of the Critical Power Model to Dynamic Constant External Resistance Exercise: A Brief Review of the Critical Load Test

Sports ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 15
Author(s):  
Haley C. Bergstrom ◽  
Taylor K. Dinyer ◽  
Pasquale J. Succi ◽  
Caleb C. Voskuil ◽  
Terry J. Housh
Keyword(s):  
Mathematical Models ◽  
Critical Load ◽  
Critical Power ◽  
Individual Performance ◽  
Load Test ◽  
Whole Body ◽  
External Resistance ◽  
Continuous Dynamic ◽  
Aerobic And Anaerobic ◽  
Body Dynamic

The study and application of the critical power (CP) concept has spanned many decades. The CP test provides estimates of two distinct parameters, CP and W′, that describe aerobic and anaerobic metabolic capacities, respectively. Various mathematical models have been used to estimate the CP and W′ parameters across exercise modalities. Recently, the CP model has been applied to dynamic constant external resistance (DCER) exercises. The same hyperbolic relationship that has been established across various continuous, whole-body, dynamic movements has also been demonstrated for upper-, lower-, and whole-body DCER exercises. The asymptote of the load versus repetition relationship is defined as the critical load (CL) and the curvature constant is L′. The CL and L′ can be estimated from the same linear and non-linear mathematical models used to derive the CP. The aims of this review are to (1) provide an overview of the CP concept across continuous, dynamic exercise modalities; (2) describe the recent applications of the model to DCER exercise; (3) demonstrate how the mathematical modeling of DCER exercise can be applied to further our understanding of fatigue and individual performance capabilities; and (4) make initial recommendations regarding the methodology for estimating the parameters of the CL test.

scholarly journals Seven Mathematical Models of Hemorrhagic Shock

2021 ◽  
Vol 2021 ◽  
pp. 1-34
Author(s):  
Luciano Curcio ◽  
Laura D'Orsi ◽  
Andrea De Gaetano
Keyword(s):  
Mathematical Models ◽  
Cardiovascular System ◽  
Experimental Situation ◽  
Hypovolemic Shock ◽  
Whole Body ◽  
Standards Of Care ◽  
Ideal Model ◽  
Disease States ◽  
Key Issues ◽  
Circulatory Dynamics

Although mathematical modelling of pressure-flow dynamics in the cardiocirculatory system has a lengthy history, readily finding the appropriate model for the experimental situation at hand is often a challenge in and of itself. An ideal model would be relatively easy to use and reliable, besides being ethically acceptable. Furthermore, it would address the pathogenic features of the cardiovascular disease that one seeks to investigate. No universally valid model has been identified, even though a host of models have been developed. The object of this review is to describe several of the most relevant mathematical models of the cardiovascular system: the physiological features of circulatory dynamics are explained, and their mathematical formulations are compared. The focus is on the whole-body scale mathematical models that portray the subject’s responses to hypovolemic shock. The models contained in this review differ from one another, both in the mathematical methodology adopted and in the physiological or pathological aspects described. Each model, in fact, mimics different aspects of cardiocirculatory physiology and pathophysiology to varying degrees: some of these models are geared to better understand the mechanisms of vascular hemodynamics, whereas others focus more on disease states so as to develop therapeutic standards of care or to test novel approaches. We will elucidate key issues involved in the modeling of cardiovascular system and its control by reviewing seven of these models developed to address these specific purposes.

Neuromuscular fatigue

2017 ◽  
Author(s):  
Sébastien Ratel ◽  
Craig A Williams
Keyword(s):  
Scientific Evidence ◽  
Motor Units ◽  
Voluntary Activation ◽  
Whole Body ◽  
Peripheral Fatigue ◽  
Prepubertal Children ◽  
The Central Nervous System ◽  
Fatiguing Exercise ◽  
Body Dynamic ◽  
Central Factors

Scientific evidence supports the proposition that prepubertal children fatigue less than adults when performing whole-body dynamic activities like maximal cycling, running bouts, and maximal voluntary isometric/isokinetic muscle contractions. Although the mechanisms underpinning differences in fatigue between children and adults are not all fully understood, there is a consensus that children experience less peripheral fatigue (i.e. muscular fatigue) than their older counterparts. Central factors may also account for the lower fatigability in children. Some studies report a higher reduction of muscle voluntary activation during fatiguing exercise in prepubertal children compared to adults. This could reflect a strategy of the central nervous system aimed at limiting the recruitment of motor units, in order to prevent any extensive peripheral fatigue. Further studies are required to clarify this proposition.

1F14 Biodistribution of [^I]oxLDL in the mouse determined using whole body dynamic imaging

2013 ◽  
Vol 2013.25 (0) ◽  
pp. 205-206
Author(s):  
Atushi Nakano ◽  
Hidekazu Kawashima ◽  
Yosinori Miyake ◽  
Tatsuya Sawamura ◽  
Hidehiro Iid
Keyword(s):  
Dynamic Imaging ◽  
Whole Body ◽  
Body Dynamic

Whole Body Fatigue and Critical Power

2000 ◽  
Vol 29 (3) ◽  
pp. 153-166 ◽  
Author(s):  
Michael L. Walsh
Keyword(s):  
Critical Power ◽  
Whole Body

Mathematical Models of Spacer Grids

2016 ◽  
Author(s):  
Alan B. Maskal ◽  
Fatih Aydogan
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Mathematical Models ◽  
Single Phase ◽  
Critical Power ◽  
Reactor Core ◽  
Phase Flow ◽  
Two Phase ◽  
Spacer Grids ◽  
Power Pattern

The fuel rods in Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) cores are supported by spacer grids. Even though spacer grids add to the pressure loss in the reactor core, spacer grids have several benefits in Light Water Reactors (LWRs). Some of these benefits are: (i) increasing the turbulence at the bottom of the reactor core for better heat transfer in single phase region of the LWRs, (ii) improving the departure nucleate boiling ratio results for PWRs, and (iii) improving critical power ratio (CPR) values by increasing the thickness of film in annular flow regime in the top section of the reactor core of BWRs. Several mathematical models have been developed for single and two phase pressure loss across the grid spacer. Almost all of them significantly depend on Reynolds Number. Spacer designs have evolved (incorporating mixing vanes, springs, dimples, etc), resulting in the complexity of the analysis across the grid, all the models have been compared not only theoretically but also quantitatively. For the quantitative comparisons, this work compares the results of mathematical spacer models with experimental data of BWR Full Size Fine Mesh Bundle Tests (BFBT). The experimental data of BFBT provides very detailed experimental results for pressure drop by using several different boundary condition and detailed pressure drop measurements. Since one CT-scanner was used at the bundle exit and three X-ray densitometers were used for the chordal average void distribution at different elevations to generate the BFBT results, detailed two phase parameters have been measured in BFBT database. Two bundle types of BFBT, the current 8×8 type and the high burn-up 8×8 type, were simulated. Three combinations of radial and axial power shapes were tested: 1) beginning of cycle (BOC) radial power pattern/cosine axial power shape (the C2A pattern); 2) end of cycle (EOC) radial power pattern/cosine axial power shape (C2B pattern); and 3) beginning of cycle radial power pattern/inlet peaked axial power shape (C3 pattern) in BFBT. The pressure drop in BFBT database was measured in both single-phase flow and two-phase flow conditions that cover the normal operational behavior. BFBT database gives the three combinations of high burnup assemblies with different radial and axial power shapes, namely C2A, C2B and C3, which were utilized in the critical power measurements. There are two types of spacers in this program — ferrule type and grid type. Therefore, detailed experimental data of BFBT was used for analyzing mathematical models of spacer grid for various boundary conditions of BWR in this paper. It was observed and discussed that pressure drop values due to spacer models can be significantly different.

scholarly journals Static Load Tests, Short Series Interpretation

2015 ◽  
Vol 36 (2) ◽  
pp. 45-49 ◽  
Author(s):  
Zygmunt Meyer
Keyword(s):  
Critical Load ◽  
Bearing Capacity ◽  
Static Load ◽  
Critical Value ◽  
Load Test ◽  
Practical Calculation ◽  
Short Series ◽  
Load Tests ◽  
S Curve

Abstract Statistic load test is the most commonly used method for estimation of the bearing capacity of piles. From the test we obtain the series a values: load-settlement, Q–s curve. In practice, it is extremely difficult to reach the critical load of the pile when the settlement turns out of control. The existing methods that allow bearing capacity to be calculated give the value which is very often 1/10 of the critical load. The question arises if it is possible based upon short series of load, i.e., 0–0.4 critical load, to predict the critical value of the load, with accuracy which is sufficient for practical calculation. The paper presents a method how to calculate the critical load based upon short series of load in the static load tests.

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