scholarly journals The Properties of Water and their Applications for Training

2014 ◽  
Vol 44 (1) ◽  
pp. 237-248 ◽  
Author(s):  
Lorena Torres-Ronda ◽  
Xavi Schelling i del Alcázar

Abstract The biological effects of immersion in water, which are related to the fundamental principles of hydrodynamics, may be beneficial in certain training contexts. The effects and physical properties of water, such as density, hydrostatic pressure and buoyancy are highly useful resources for training, when used as a counterbalance to gravity, resistance, a compressor and a thermal conductor. Not only does the aquatic medium enable a wider range of activities to be used in a context of low joint impact, but it also constitutes a useful tool in relation to sports rehabilitation, since it allows the athlete to return to training earlier or to continue with high-intensity exercise while ensuring both low joint impact and greater comfort for the individual concerned. Moreover, this medium enables the stimulation of metabolic and neuromuscular systems, followed by their corresponding physiological adaptations allowing both to maintain and improve athletic performance. Hydrotherapy can also play a beneficial role in an athlete’s recovery, helping to prevent as well as treat muscle damage and soreness following exercise.

2020 ◽  
Vol 34 (8) ◽  
pp. 2258-2266
Author(s):  
Apostolos Papandreou ◽  
Anastassios Philippou ◽  
Elias Zacharogiannis ◽  
Maria Maridaki

Author(s):  
Jason Williams ◽  
Timothy Baghurst ◽  
Micheál J Cahill

The purpose of this study was to assess current perceptions of strength and conditioning coaches’ use of sled towing (ST) as part of their training programs. One-hundred and twenty-five coaches responded to a survey of their ST practices. Themes investigated included the primary purpose and usefulness of using ST, the loads used in short and long distances, rest times between sprints, total volume of ST sprints per session, frequency of ST activity each month, and whether coaches engaged in force-velocity profiling in ST sprints. Eighty percent of coaches either agreed or strongly agreed that ST is a useful intervention tool for improving athletic performance. Speed strength was the physiological adaptation most sought after to improve ( n = 75) followed by power ( n = 72). Bodyweight (BW) loads of 20% were the most common across all distances. The two most common rest times given between each ST repetition were one to two minutes ( n = 37) and two to three minutes ( n = 37). The most common volume responses for individual training sessions were five to eight sprints ( n = 52) and three to five times per month, respectively. These data suggest strength and conditioning coaches view ST as an integral part of programming, primarily use loads of 20% BW for both short and long sprints and seek to optimize a number of different physiological adaptations. The majority of coaches have a favorable view of ST (88%); however, current training parameters used by strength and conditioning coaches may be inadequate to achieve their desired adaptations.


DYNA ◽  
2018 ◽  
Vol 85 (207) ◽  
pp. 29-35
Author(s):  
Claudia Milena Bedoya-Hincapié ◽  
Elisabeth Restrepo-Parra ◽  
Luis Demetrio López-Carreño

The potential of nanotechnology in the biomedical field has been crucial for contributing to the possibility of efficiently meeting present necessities with novel materials. Over the last few decades, nanostructures with a core/shell structure have attracted significant attention because of the possibility of changing their physical properties by varying their chemistry and geometry. These structures have become relevant in targeted therapy (drug delivery and treatments to complement chemotherapy and radiotherapy), imaging and in the stimulation of cellular functions. Thus in this paper the current development of core/shell nanostructures is reviewed, emphasizing the physical properties of those that have been proposed as potentially having biomedical applications, which are based in a magnetic behavior or in a mixture of magnetic and electric (multiferroic) phenomena.


2021 ◽  
Vol 9 ◽  
Author(s):  
Martha Habibi ◽  
Panagiotis K. Karyofyllis ◽  
Aggeliki Nikolakopoulou ◽  
Panagiotis Papagiannis ◽  
Pantelis Karaiskos ◽  
...  

The effect of the reportedly low ionizing radiation doses, such as those very often delivered to patients in interventional cardiology, remains ambiguous. As interventional cardiac procedures may have a significant impact on total collective effective dose, there are radiation protection concerns for patients and physicians regarding potential late health effects. Given that very low doses (<100 mSv) are expected to be delivered during these procedures, the purpose of this study was to assess the potency and suitability of current genotoxicity biomarkers to detect and quantitate biological effects essential for risk estimation in interventional cardiology. Specifically, the biomarkers γ-H2AX foci, dicentric chromosomes, and micronuclei, which underpin radiation-induced DNA damage, were studied in blood lymphocytes of 25 adult patients before and after interventional cardiac procedures. Even though the mean values of all patients as a group for all three endpoints tested show increased yields relative to baseline following medical exposure, our results demonstrate that only the γ-H2AX biomarker enables detection of statistically significant differences at the individual level (p < 0.001) for almost all patients (91%). Furthermore, 24 h after exposure, residual γ-H2AX foci were still detectable in irradiated lymphocytes. Their decline was found to vary significantly among the individuals and the repair kinetics of γ-H2AX foci was found to range from 25 to 95.6% of their maximum values obtained.


The curve relating the smallest perceptible intensity of a blue test stimulus with the intensity of an orange conditioning field against which it is viewed shows a characteristic division into low- and high-intensity components, indicating the operation of two mechanisms of cone vision at the fovea. The justification for calling these ‘blue’ and ‘green’ mechanisms is taken from an earlier investigation (Stiles 1939). While most subjects show this division clearly, for some the low-intensity component is masked by the intrusion of rod vision. The correctness of this view is established by measurements made while the eye is recovering from an intense light adaptation. The individual variations of the sensitivities of the ‘green’ and ‘blue’ mechanisms in twenty subjects are assessed. Further evidence is obtained of an anomalously low threshold for the ‘blue’ mechanisms at very high conditioning fields of orange light.


2018 ◽  
Vol 43 (11) ◽  
pp. 1158-1165 ◽  
Author(s):  
Chris J. McNeil ◽  
Charles L. Rice

Even in the absence of disease or disability, aging is associated with marked physiological adaptations within the neuromuscular system. An ability to perform activities of daily living and maintain independence with advanced age is reliant on the health of the neuromuscular system. Hence, it is critical to elucidate the age-related adaptations that occur within the central nervous system and the associated muscles to design interventions to maintain or improve neuromuscular function in the elderly. This brief review focuses on the neural alterations observed at both spinal and supraspinal levels in healthy humans in their seventh decade and beyond. The topics addressed are motor unit loss and remodelling, neural drive, and responses to transcranial magnetic stimulation of the motor cortex.


1930 ◽  
Vol s2-73 (291) ◽  
pp. 365-392
Author(s):  
S. B. SETNA

Experimental. 1. The contraction of the adductor-muscle which follows stimulation of the palial nerve is preceded by a marked contraction of the ctenidial axis, so that the gill contracts before the adductor-muscle becomes active. This movement of the ctenidium is abolished if the main branchial nerve is cut near its origin. 2. The gills of Pecten possess a neuromuscular mechanism which is to some extent independent of the rest of the body, so that excised gills when stimulated react in the same way as an attached gill. 3. The lamellae of the gill possess two distinct types of movement. (a) When the surface of the gill is stimulated by contact with a glass rod or by carmine particles, the frontal surfaces of the two lamellae approach each other; the movement very often being executed by the lamella which is not actually being stimulated. The lateral extent of these movements (concertina movements) is roughly proportional to the intensity of the stimulus. Such movements normally appear to transfer the bulk of the material on to the mantle. Separation of the main branchial nerve abolishes these movements. (b) Each principal filament is capable of moving the ordinary filaments to which it is attached. This movement (flapping movement) is due to the movements of the interfilamentar junctions which alternatively move up and down at right angles to their length. This motion is independent of the branchial nerve and can be produced by direct stimulation of very tiny pieces of the individual filaments. 4. The significance of gill movements to feeding habits is discussed. The course of food particles depends on the nature of the stimuli affecting the gill. Histological. 5. The ctenidial axis and the principal filaments have a stratum of anastomosing nerve-cells which appear to form a true nerve-net comparable to that of the mantle. 6. The gill receives nerve-fibres from two sources, the brain and the visceral ganglion. The subsidiary branchial nerve is a structure hitherto unknown in the molluscan gill; so far its function is unknown. Each gill has four main longitudinal nerve-trunks. 7. The osphradium of the gill has a much more extensive distribution than has hitherto been supposed. 8. Two sets of muscles exist at the base of the gill-filaments, and these are responsible for movements of the lamellae. The muscle-fibres are non-striated. 9. The principal filaments are connected to the ordinary filaments by processes containing true muscle-cells, and by these cells movements of the filaments are effected.


1989 ◽  
Vol 257 (1) ◽  
pp. C94-C101 ◽  
Author(s):  
K. Matsuzaki ◽  
J. B. Stokes ◽  
V. L. Schuster

In rabbit cortical collecting duct, Cl- self exchange accounts for most of the transepithelial Cl- tracer rate coefficient, KCl (nm/s); a small fraction is effected by Cl--HCO3- exchange and Cl- diffusion. We previously reported that changing from a CO2-free N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) bath to a 5% CO2-25 mM HCO3- bath stimulates Cl- self exchange. Here, we examine in further detail the individual components of the CO2-HCO3- system that stimulate KCl. Addition of 0.5% CO2 to a HEPES bath (final pH = 7.24) stimulated KCl by 70 +/- 19 nm/s, a delta KCl comparable to that induced by 1% CO2 (pH 7.12), 6% CO2 (pH 6.6), or 6% CO2-25 mM HCO3- (pH 7.4). The roles of intracellular pH (pHi) and HCO3- concentration were examined by clamping pHi using high K+ and nigericin. Increasing pHi from 6.9 to 7.6 in solutions without exogenous CO2 or HCO3- increased KCl by 71 +/- 17 nm/s. These results suggest that pHi might regulate anion exchange. However, during such a pHi-shift experiment, metabolically derived CO2 produces a concomitant change in intracellular HCO3- concentration [( HCO3-]i). To determine whether an increase in [HCO3-]i could stimulate Cl- self exchange, we replaced HEPES with 6% CO2-5 mM HCO3- isohydrically (pHi clamped at 6.9). With this increase in [HCO3-]i at constant pHi, KCl increased by 51 +/- 10 nm/s. These maneuvers had negligible effects on Cl- diffusion and Cl--HCO3- exchange. These experiments demonstrate that increases in cell [HCO3-] (or perhaps CO2) can stimulate transepithelial anion exchange.(ABSTRACT TRUNCATED AT 250 WORDS)


2019 ◽  
Vol 13 ◽  
pp. 117822181882297 ◽  
Author(s):  
Megan E Patrick ◽  
Yvonne M Terry-McElrath

High-intensity drinking (HID; ie, having 10+ drinks in a row) is a recognized public health concern due to the individual and public risks (eg, alcohol-related injuries, alcohol poisoning, memory loss, sexual risk) associated with consumption of a large quantity of alcohol over a relatively short time period. Using nationally representative samples of US 8th, 10th, and 12th grade students, and follow-up of subsamples of 12th graders, we present overall and sex-specific prevalence estimates of past 2-week HID from 29 966 individuals at the modal ages of 14 to 30 in 2016-2017. Similar data for the more commonly studied measure of binge drinking (having 5+ drinks in a row) is provided for comparison. HID prevalence ranged from 1% to 11.5% and was significantly higher for males than females at all ages other than modal age 14 (8th grade). Binge drinking prevalence ranged from 3.5% to 32.5%; males reported a higher prevalence than females at approximately half of the ages examined. Peak binge drinking and HID age for males was earlier (modal age 21/22) than that for females (modal age 21-24 for binge drinking and 25/26 for HID). The observed rapid increase in HID from adolescence through the early to mid-20s highlights the importance of prevention and intervention efforts targeted to these ages.


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