Momentary Strength Research Articles

Analysis And Evaluation of Momentary Forces and Reaction Time on The Starting Cushions with Sensors - Dynamic for Runners

Starting cubes are a device used in the sport of arena and field races by speed-racing athletes to strengthen and stabilize their feet at the beginning of the race so as not to slip forward when hearing the starting gun. How can they improve the payment on these cubes? Why is starting important in fast running? When it comes to starting the race, athletes with the best reaction time, greatest strength, and the ability to accelerate as fast as possible can outperform their peers. It is important to remember one essential thing: when cubes are used, they should be intended to be able to help and allow the runner to accelerate, not to get him to full speed in the first few steps. Young athletes, therefore, tend to try to reach as quickly as possible once they start from the starting blocks. So, the starting cubes are designed to give runners great horizontal momentary strength, the most important indicator in the starting cubes is to get the right body angles. This research provides further developments and takes advantage of the start of the run to evaluate and analyze the forces and reaction time obtained by the movements of the two men on the cubes of starting the various fast running races (100m, 100m women's barriers), Men's 110mHurdles, 200m, 400m,400m Hurdles, 4×100m Relay, 4×400m Relay, 4x100m Mixed) For different categories. The idea of designing sensors - dynamic on the starting cubes came to the necessary need for such sensors that measure the amounts of power propulsion and reaction time of runners in these events taking advantage of the technology and scientific development in this field, if the start-up cushions are designed with sensors - dynamic and calibrated mechanically standard to provide the required measurement accuracy It was used to measure and analyze the strength and reaction time of the enemies of these elite Iraqi competitions by basing lab view workers, and the measured results obtained showed reasonable sensitivity and accuracy with a slight variation in their values, as well as measuring the change in strength over time for Runners perform this launch and acceleration based on the computer's vision tracking system. The proposed start-up cushions are promising to be used in a wide range of applications, including in-house and field laboratories for teaching, training, and monitoring the progress of runners during training and scientific research.

Training of upgrading on unstable material surfaces and its effect on some special abilities, tack off variables and the achievement of the long jump for young women

The real goal of approaching and rising in the long jump is to maintain the slightest change in linear momentum during this stage in order to succeed in achieving a good locomotive path. This study focused on carrying out exercises on unstable rubber surfaces that give an imbalance in order to stimulate and mobilize the working muscles to produce the largest instantaneous force that helps to improve the improvement and achievement and enhance performance. The research was carried out on and proved the long-term young women for 8 weeks by two training units per week and the momentary strength and speed were measured The results showed a remarkable and significant development in the momentary strength, the special speed, and the starting and achievement variables for the experimental group.

Within-Match Performance Dynamics – Momentary Strength in Handball

Handball is an Olympic team sport characterized by changes of ball possession, where teams either play on offense or defense. In this paper, we model momentary strength in handball as scoring probabilities based on a double moving average. In this cross-sectional observational study, the aim was to describe the dynamics of momentary strength in handball from both theoretical and practical perspectives. Momentary strength can be used to further characterize the nuances of the sport by identifying different phases in a match. The momentary strength model was applied to the 2019 International Handball Federation (IHF) Men's World Championship. Ninety-six games were analyzed. The results showed that momentary strength could be used to better understand the dynamic interaction process between two teams. The Spearman correlation between the teams' median momentary strength and their final ranks at the Championship was -0.830. Virtually each team faced phases in its matches with a momentary scoring probability lower than 0.10 and with 4 exceptions also higher than 0.90. Twelve out of the 24 teams showed phases with a momentary scoring probability of exactly 0 as well as exactly 1

An empirical example of analysis using a two-stage modeling approach: within-subject association of outdoor context and physical activity predicts future daily physical activity levels.

People differ from each other to the extent to which momentary factors, such as context, mood, and cognitions, influence momentary health behaviors. However, statistical models to date are limited in their ability to test whether the association between two momentary variables (i.e., subject-level slopes) predicts a subject-level outcome. This study demonstrates a novel two-stage statistical modeling strategy that is capable of testing whether subject-level slopes between two momentary variables predict subject-level outcomes. An empirical case study application is presented to examine whether there are differences in momentary moderate-to-vigorous physical activity (MVPA) levels between the outdoor and indoor context in adults and whether these momentary differences predict mean daily MVPA levels 6 months later. One hundred and eight adults from a multiwave longitudinal study provided 4 days of ecological momentary assessment (during baseline) and accelerometry data (both at baseline and 6 month follow-up). Multilevel data were analyzed using an open-source program (MixWILD) to test whether momentary strength between outdoor context and MVPA during baseline was associated with average daily MVPA levels measured 6 months later. During baseline, momentary MVPA levels were higher in outdoor contexts as compared to indoor contexts (b = 0.07, p < .001). Participants who had more momentary MVPA when outdoors (vs. indoors) during baseline (i.e., a greater subject-level slope) had higher daily MVPA at the 6 month follow-up (b = 0.09, p < .05). This empirical example shows that the subject-level momentary association between specific context (i.e., outdoors) and health behavior (i.e., physical activity) may contribute to overall engagement in that behavior in the future. The demonstrated two-stage modeling approach has extensive applications in behavioral medicine to analyze intensive longitudinal data collected from wearable sensors and mobile devices.

Bone fracture and the healing mechanisms. Pathophysiology and classification of osteoporotic fractures

Bone provides momentary strength and fatigue strength, and bone strength decreases with age. In elderly men and women with fragile bones osteoporotic fractures frequently occur. Fragility fracture occurs as a consequence of the decrease in momentary strength, and fragility fracture is one of the pathological fractures. In patients with the decrease in fatigue strength, insufficiency fractures frequently occurs. Insufficiency fracture is the same term as stress or fatigue fracture.

Dependence of the anisotropy of the mechanical properties of steel on the degree of contamination with nonmetallic inclusions

Investigations have shown that for vacuum steel the coefficients of anisotropy (ratio of the specific values of the mechanical properties for transverse and longitudinal samples) are close to 0.9 for plastic characteristics and for the fatigue limit, while for ordinary steel these values are,as a rule,considerabl y lower. Only brittle inclusions of the type of oxides and silicates affect the anisotropy of the fatigue limit, while the deformable inclusions (sulfides) affect the ductility. The anisotropy of the fatigue limit increases with increasing strength and plastic deformation of the material. The anisotropy of the plastic characteristics is still more dependent on these factors. The purity of the steel affects the anisotropy of the impact toughness (Table 1). After electroslag remelting no nonmetallic inclusions bigger than grade 1 are found in the steel. The anisotropy of such bars decreases in connection with the increasing impact toughness of longitudinal samples. Detailed investigations of the anisotropy of the fatigue and mechanical characteristics have been made on 40KhNMA and 45KhNMFA steels with various degrees of plastic deformation [5]. The tests of 40KhNMA steel were made on smooth and notched samples subjected to longitudinal and transverse stresses (see Table 2). The results of metallographic examination and also measurements of the reduction in section of transverse samples are presented in Table 2. From the table it is evident that the difference in the amounts of large inclusions influences the value of the reduction in section of transverse samples. The high value of Ctrans for B 2 (by comparison with A2) can be explained by the lower concentration of hydrogen. It should also be noted that the degree of plastic deformation was lower for sample B 2 than for B 1. In samples A 1 and A2, and also C1 and C 2 (with the same degree of plastic deformation) the more contaminated material is characterized not only by lower values of plastic characteristics but also lower values of true strength determined by rupture of transverse samples (Table 3). In Table 3 are presented also the values of the coefficients of anisotropy of the properties of the materials tested. These coefficients are lower for contaminated materials, the effect of the degree of contamination on the anisotropy of the specific reduction in section being especially notable. In addition to smooth samples, the tensile strength of notched samples was tested. From Table 4 it is evident that the relative decrease of the momentary strength induced by nonmetallic inclusions is approximately the same for longitudinal and transverse samples. The effect of contamination of the metal on the momentary tensile strength of longitudinal samples is the result of the action of multiaxial stresses at the notch. The small effect of the direction of the cut in notched samples onthe tensile strength is explained in the same manner. The dependence of the tensile strength of notched samples on the degree

Choice-Behavior and Distribution of Reinforcement among Response-Alternatives

According to the statistical associative model frequently applied to modified verbal-conditioning,1 each reinforcement of one of the k-possible responses results in a specifiable change in the probability of alternative Al. That is, there is added to the existing probability (Pi) and increment 0 (1 P), if Ai is reinforced, or a decrement, -OPi, if a response other than Ai is reinforced. This version of statistical associative theory, when applied to a situation in which there are more than two responses, incorporates the simplifying assumption that these changes depend only upon the probability of Ai and are invariant with the distribution of the remaining probability among the alternative responses. In contrast to this formulation, it may be proposed that in a situation involving more than two possible responses, the size of the decrement in the probability of Ai may depend upon which of the other alternatives is reinforced. Likewise, the incremental effects of a reinforcement of Ai may depend upon the distribution of values of the alternative responses. Such a position is suggested within the context of Hull-Spence theory when it is assumed that the probability of a given response is a function of the probability that the momentary strength of that response is greater than the momentary strength of any one of the alternatives.2 According to this view, concentrating reinforcements in order to build up a single strong alternative should be more effective in reducing the probability of Ai than distributing those reinforcements among several weaker alternatives. Two studies which have questioned the adequacy of the statistical associative model might be interpreted as supporting the latter suggestion. Both Gardner, and Cotton and Rechtshoffen have found that the asymptotic frequency of the most often reinforced response is greater if the

Effects of time and frequency on insulation test of transformers

Permanently grounded transformers must be given the insulation lest by inducing the necessary voltage across the windings. The A. I. E. E. Standards specify that the time of induced voltage tests be the same as for high potential test. In certain cases where the transformers are of very large capacity the induced voltage must be made at a frequency several times higher than normal. Since the dielectric strength of most insulating materials decreases with an increase in the frequency, an investigation has been made to determine the proper and fair length of time to make induced voltage test when the frequency is higher than normal. Following are the main points brought out in the investigation. Above a certain voltage, time of voltage application as well as voltage causes failure of insulation. The dielectric strength can be expressed as a function of both time and voltage by an equation of the form <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Kv. = A(a + {1-a \over \root {1} \of T})$</tex> in which A is the kilovolts necessary to cause failure in one minute, “a” is a constant representing the ratio of strength for infinite time to the one minute strength and T is time in minutes. The value of “a” varies for different materials apparently depending mostly on the dielectric loss. The breakdown by creepage over solid insulation with the electrodes either on the same side or on opposite sides of the sample (arranged in such a manner that the solid insulation is under considerable stress) is not affected by time nearly so much as is the puncture voltage of solid insulation. The behavior of oil without barriers is so erratic that no very definite relation can be obtained between time and dielectric strength. In general time decreases the strength quite rapidly for the first few seconds after which the effect decreases and probably disappears entirely after two or three minutes. The momentary strength ranges from 25 to 30 per cent higher than the one minute strength. The effect of time on the strength of solid insulation and oil in series is about the same as for solid insulation alone until the oil distance exceeds the solid insulation thickness after which it begins to be the same as for oil without barriers. The strength-time curves for solid insulation are of approximately the same shape for all frequencies from 60 to 420 cycles, although the strength decreases with an increase in frequency F approximately in accordance with the formula kv. = 1.75/ F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0·137</sup> Failure by creepage over the surface of solid insulation which is under no stress (i. e., with the electrodes on the same side of the barrier) takes place at approximately the same voltage for all frequencies from 60 to 420 cycles; but if the electrodes are so arranged (on opposite sides) that the insulation is under considerable stress the failure voltage decreases with an increase in frequency in about the same order as the puncture voltage of solid insulation does. The rupture voltage of oil is the same for both 60 and 420 cycles. The effect of frequency on the puncture voltage of solid insulation and oil in series is the same as for solid insulation until the oil distance exceeds the thickness of solid insulation, after which the effect decreases and as the oil distance increases the effect approaches that for oil without barriers. By considering the effects of both time and frequency on dielectric strength it is shown how to determine the proper length of time to make the voltage strain at higher frequencies equal to the strain at 60 cycles for one minute. 8. ACKNOWLEDGEMENTS It is desired to acknowledge the valuable assistance rendered in the Testing Department by Messrs. N. M. Albert, H. L. Garver, C. F. Green, L. D. Martin and W. F. Weikel in carrying on the long and tedious tests, covering a period of three to four months.