Crawl Speed Research Articles

PENGARUH METODE PEMBELAJARAN MENGGUNAKAN PAPAN LUNCUR DAN PULLBUOY TERHADAP KECEPATAN RENANG GAYA CRAWL 25 METER SISWA CLUB ABDUL AQUATIC COURSE (AAC) SEMARANG

This learning method using a skateboard and pullbuoy is very effective in students' initial learning to swim, and is practiced by students from the Abdul Aquatic Course Semarang club by swimming using a crawl style and a distance of 25m. The purpose of this study was to determine the effect of the learning method using skateboards and pullbuoys on the 25m crawl style swimming speed of Abdul Aquatic Course Semarang students. As well as the difference and which is better between a skateboard and a pullbuoy.
 This study refers to a quantitative approach and the method used by this researcher is an experimental method, which is a step to compare the tools between a skateboard and a pullbuoy in the initial movement of the crawl style. The target of this research is the student club Abdul Aquatic Course (AAC) Semarang. The data analysis technique in this study used inferential statistical analysis, hypothesis testing.
 The results showed that the R-square value of the learning method using the pull buoy was greater than the exercise using a skateboard. This means, "training using a pull buoy is better to use in increasing the speed of the 25-meter crawl style swimming for the students of Club Abdul Aquatic Course (AAC) Semarang."
 The conclusion is that the exercise using a pullbuoy is better than a skateboard in increasing the speed of swimming in the 25-meter crawl style of students at the Abdul Aquatic Course Semarang club. The advice obtained by the researcher is that the trainer is expected to be able to use exercises using pullbuoys as a form of training program at a crawl speed swimming style of 25 meters.

Oxygen uptake kinetics and biological age in relation to pulling force and 400-m front crawl performance in young swimmers.

Background: The study aimed to assess differences in the biological age (BA) of 13-year-old swimmers and show their ability, as biologically younger-late mature or older-early mature, to develop fast 60-s oxygen uptake () kinetics and tethered swimming strength. Furthermore, the interplay between swimming strength, , and 400-m front crawl race performance was examined. Methods: The study involved 36 competitive young male swimmers (metrical age: 12.9 ± 0.56years). Depending on BA examination, the group was divided into early-mature (BA: 15.8 ± 1.18years, n = 13) and late-mature (BA: 12.9 ± 0.60 years, n = 23) participants, especially for the purpose of comparing tethered swimming indices, i.e., average values of force (F ave) and (breath-by-breath analysis) kinetic indices, measured simultaneously in 1-min tethered front crawl swimming. From the 400-m racing stroke rate, stroke length kinematics was retrieved. Results: In the 1-min tethered front crawl test, early-mature swimmers obtained higher results of absolute values of and F ave. Conversely, when was present relatively to body mass and pulling force (in ml∙min-1∙kg-1∙N-1), late-mature swimmers showed higher relative usage. Late-mature swimmers generally exhibited a slower increase in during the first 30s of 60s. , F ave, BA, and basic swimming kinematic stroke length were significantly interrelated and influenced 400-m swimming performance. Conclusion: The 1-min tethered swimming test revealed significant differences in the homogeneous calendar age/heterogeneous BA group of swimmers. These were distinguished by the higher level of kinetics and pulling force in early-mature individuals and lower efficiency per unit of body mass per unit of force aerobic system in late-mature peers. The higher kinetics and tethered swimming force were further translated into 400-m front crawl speed and stroke length kinematics.

Kontribusi Kekuatan Otot Lengan Dan Kekuatan Otot Tungkai Terhadap Kecepatan Renang Gaya Bebas 50 Meter

Based on observations, the problem in this study is the lack of 50 meter swimming front crawl athletes in Padang. So this study aims to determine the contribution of the strength of the arm, leg muscles to the speed of 50 swimming front crawl. This research is a type of correlation with a sample of 11 athletes consisting of 6 boys and 5 girls. Sampling was done by purposive sampling. The instruments used are push ups, leg dynamometers and use a 50 meter swimming front crawl speed test in seconds. The data analysis technique used is a simple Pearson product moment multiple correlation analysis. The results showed that there was a contribution between arm muscle strength and swimming speed for male athletes by 77.9%, female athletes by 98.8%. Leg muscle strength to swimming speed for male athletes is 55.9%, female athletes are 97%. Then, the arm muscle strength and leg muscle strength together to the 50 meter swimming front crawl speed in male athletes are 72.3%, female athletes are 90.3%.

Photosensitivity of Dispersing Cryptic Date Stone Beetles Coccotrypes dactyliperda (Coleoptera, Curculionidae, Scolytinae)-A Pilot Study.

Simple SummaryDate stone beetles (Coccotrypes dactyliperda), which feed on the albumen inside palm seeds, are a major pest in date palm plantations in the Middle East and North Africa. While they spend most of their life cycle in darkness inside the brood galleries where they mate and reproduce, females emerge for a short period of time when the brood gallery has become too crowded or when the seed’s albumen has been exhausted. During this emergence they seek out fresh seeds, commonly by attacking unripe dates still on the palm. Previous work indicated that the beetles might prefer dark conditions (i.e., nighttime) when emerging from seeds, whereas anecdotal evidence suggested that the beetles might be attracted to light. The controlled experiments showed that the beetles, once in the open, are attracted by and move faster to a light source, but that the color of the surface (red, blue, green, black) has no influence on either direction or crawl speed.The date stone beetle, Coccotrypes dactyliperda, is a cryptic spermatophagus species that spends almost its entire life cycle inside the seeds of palms, esp. Phoenix sp. Only during dispersal, when the host seed has been largely eaten out, do females emerge for a short period of time in search of a fresh seed in which to establish new brood galleries. Previous work indicated that C. dactyliperda might be photophobic, preferring to emerge from seeds during night hours, whereas anecdotal evidence suggested that the beetles might be photophilic in terms of their movements post emergence. This paper examines the photosensitivity of the species under controlled laboratory conditions. The results show that C. dactyliperda, once removed from the brood chamber, is attracted by and moves faster to a light source, but that the color of the lit surface (red, blue, green, black) has no influence on either direction or crawl speed.

Correlations between Crawl Kinematics and Speed with Morphologic, Functional, and Anaerobic Parameters in Competitive Swimmers.

The purpose of this study was to examine the relationship between a unique complex of predictors and 100 m front crawl race kinematics and swimming speed. In 28 male competitive swimmers (age: 19.6 ± 2.59 years), the following groups of predictors were assessed: (a) the morphologic, (b) the functional upper limb range of motion, and (c) the anaerobic indices of arm-cranking and a series of countermovement jumps. The Pearson product-moment correlation coefficient was calculated to distinguish the predictors and the swimming results. The main finding was that the indices of the power (arm-cranking) and the work (countermovement jump) generated in the anaerobic tests showed a significant and higher correlation with stroke length and stroke index than total body length, upper limb range of motion, or hand and forearm surface area. These results were obtained in accordance with the high swimming economy index relation to clear surface swimming speed. This study reveals that the strength generated by the limbs may represent a predictor of swimming kinematics in a 100 m front crawl performance.

VO2 kinetics and bioenergetic responses to sets performed at 90%, 92.5%, and 95% of 400-m front crawl speed in male swimmers

VO2 kinetics and bioenergetic responses to sets performed at 90%, 92.5%, and 95% of 400-m front crawl speed in male swimmers

Identification of putative muscarinic acetylcholine receptor genes in Bactrocera dorsalis and functional analysis of Bdor-mAChR-B

Muscarinic acetylcholine receptors (mAChRs) play important roles in the insect nervous system. These receptors are G protein-coupled receptors, which are potential targets for insecticide development. While the investigation of pharmacological properties of insect mAChRs is growing, the physiological roles of the receptor subtype remain largely indeterminate. Here, we identified three mAChR genes in an important agricultural pest Bactrocera dorsalis. Phylogenetic analysis defined these genes as mAChR-A, -B, and -C. Transcripts of the three mAChRs are most prevalent in 1-d-old larvae and are more abundant in the brain than other body parts in adults. Functional assay of Bdor-mAChR-B transiently expressed in Chinese hamster ovary cells showed that it was activated by acetylcholine (EC50, 205.11 nM) and the mAChR agonist oxotremorine M (EC50, 2.39 μM) in a dose-dependent manner. Using the CRISPR/Cas9 technique, we successfully obtained a Bdor-mAChR-B knockout strain based on wild-type (WT) strain. When compared with WT, the hatching and eclosion rate of Bdor-mAChR-B mutants are significantly lower. Moreover, the crawl speed of Bdor-mAChR-B knockout larvae was lower than that of WT, while climbing performance was enhanced in the mutant adults. Adults with loss of function of Bdor-mAChR-B showed declined copulation rates and egg numbers (by mated females). Our results indicate that Bdor-mAChR-B plays a key role in the development, locomotion, and mating behavior of B. dorsalis.

Effect of Hatchery Nest Environment on Olive Ridley (Lepidochelys olivacea) Hatchling Performance

The nest environment plays an important role in influencing sea turtle hatchling phenotype. Increasing global temperatures can potentially cause detrimental changes to hatchling size and performance and ultimately influence their recruitment into the adult population. The mass nesting rookeries of olive ridleys in Odisha on the east coast of India are among the largest globally and the only major ones outside Central America. Many nests laid on the east coast of India are translocated to hatcheries as part of hatchery management practices. Therefore, it is imperative to understand the effects of temperature on hatchlings produced in hatcheries as well as site-specific factors in order to undertake appropriate climate-resilient hatchery management measures. This study examined the effect of temperature on the morphology and locomotor performance of hatchlings produced in 2 different hatcheries on the east coast: in Rushikulya, Odisha, and in Chennai, Tamil Nadu, India. We examined various size (body, flipper, and neck length) and performance (crawl speed, righting ability, and righting propensity) parameters for hatchlings at both hatcheries across a range of temperatures. We found that hatchling size and performance were significantly influenced by nest incubation temperature. Higher incubation temperatures resulted in smaller hatchling size, which in turn was correlated with lower performance variables. Incubation temperature also had a direct effect on hatchling performance independent of hatchling size. The effect of nest temperature on morphology and performance of hatchlings could influence their survival and recruitment rates, thus influencing population dynamics and resilience to climate change.

Impact of High-Altitude on Truck’s Climbing Speed: Case study in Qinghai-Tibet Plateau Area in China

Truck’s climbing performance is an important consideration in traffic safety, efficiency, and highway geometric design. With the infrastructure development in high-altitude area in China, more attention needs to be paid on truck’s climbing performance in such area. In this article, truck’s climbing speed in high-altitude area was examined through field tests on different grade sections at different altitudes. Truck’s speed-distance curves were built at different altitudes and the impact of altitude on truck’s climbing speed was explored based on the test results. It was shown that, within the altitude range of 3000~5000m, altitude had an obvious influence on test truck’s decelerating and accelerating performance. Truck’s speed decreased faster on steep grades and increased slower on gentle grades with the increase of the altitude. Also, the stable speed that test truck could maintain on a certain grade was lower at a higher altitude. In addition, test truck’s theoretical speed-distance curves at the sea level were estimated through truck’s dynamic model. Compared with the theoretical crawl speed, a negative effect of altitude change (from 0 to the altitude above 3000 m) was found on truck’s climbing performance.

Human crawling performance and technique revealed by inertial measurement units

Human crawling performance and technique are of broad interest to roboticists, biomechanists, and military personnel. This study explores the variables that define crawling performance in the context of an outdoor obstacle course used by military organizations worldwide to evaluate the effects of load and personal equipment on warfighter performance. Crawling kinematics, measured from four body-worn inertial measurement units (IMUs) attached to the upper arms and thighs, are recorded for thirty-three participants. The IMU data is distilled to four metrics of crawling performance; namely, crawl speed, crawl stride time, ipsilateral limb coordination, and contralateral limb coordination. We hypothesize that higher performance (as identified by higher crawl speeds) is associated with more coordinated limbs and lower stride times. A cluster analysis groups participants into high and low performers exhibiting statistically significant differences across the four performance metrics. In particular, high performers exhibit superior limb coordination associated with a “diagonal gait” in which contralateral limbs move largely in-phase to produce faster crawl speeds and shorter crawl stride times. In contrast, low performers crawl at slower speeds with longer crawl stride times and less limb coordination. Beyond these conclusions, a major contribution of this study is a method for deploying wearable IMUs to study crawling in contextually relevant (i.e. non-laboratory) environments.

Large-effect mutations generate trade-off between predatory and locomotor ability during arms race coevolution with deadly prey.

Adaptive evolution in response to one selective challenge may disrupt other important aspects of performance. Such evolutionary trade‐offs are predicted to arise in the process of local adaptation, but it is unclear if these phenotypic compromises result from the antagonistic effects of simple amino acid substitutions. We tested for trade‐offs associated with beneficial mutations that confer tetrodotoxin (TTX) resistance in the voltage‐gated sodium channel (NaV1.4) in skeletal muscle of the common garter snake (Thamnophis sirtalis). Separate lineages in California and the Pacific Northwest independently evolved TTX‐resistant changes to the pore of NaV1.4 as a result of arms race coevolution with toxic prey, newts of the genus Taricha. Snakes from the California lineage that were homozygous for an allele known to confer large increases in toxin resistance (NaV1.4LVNV) had significantly reduced crawl speed compared to individuals with the ancestral TTX‐sensitive channel. Heterologous expression of native snake NaV1.4 proteins demonstrated that the same NaV1.4LVNV allele confers a dramatic increase in TTX resistance and a correlated decrease in overall channel excitability. Our results suggest the same mutations that accumulate during arms race coevolution and beneficially interfere with toxin‐binding also cause changes in electrophysiological function of the channel that may affect organismal performance. This trade‐off was only evident in the predator lineage where coevolution has led to the most extreme resistance phenotype, determined by four critical amino acid substitutions. If these biophysical changes also translate to a fitness cost—for example, through the inability of T. sirtalis to quickly escape predators—then pleiotropy at this single locus could contribute to observed variation in levels of TTX resistance across the mosaic landscape of coevolution.

Optimizing Training for the Morphological Development and Functional Capacity on Water and on Land of a Junior Swimmer Specializing in Short-Distance Crawl Speed Trial

The morpho-functional short distance swimming training can be approached with a program suitable for the junior and cadets’ age with modern equipment testing applications that can create an innovative perspective in individualizing the training of swimmers in crawl, speed, short trials.

Acute biochemical and physiological responses to swimming training series performed at intensities based on the 400-m front crawl speed

The objective of this study was to compare blood lactate concentration (LAC), heart rate (HR), rating of perceived exertion (RPE), tryptophan (TRP), prolactin (PRL), nonesterified fatty acids (NEFA), branched-chain amino acids (BCAAs) plasma concentrations, and TRP/BCAAs ratio along interval training swimming series at 90 and 95% of the mean speed 400-m front crawl (s400). Fourteen male swimmers performed two-interval 400-m series (40 s of passive rest) at 90% (s90) and 95% (s95) of the s400, previously determined by 400-m front crawl all test. Summarized results are: (1) TRP, BCAAs, TRP/BCAAs ratio and NEFA were similar (p > 0.05) between rest and exhaustion conditions; (2) significant increases in LAC, PRL, HR and RPE (p < 0.05) for both series (s90 and s95). The findings of the present study indicate that during swimming series of interval training at 90 and 95% s400, there is maintenance of TRP, BCAA, TRP/BCAAs ratio and NEFA and increases in the RPE, PRL, LAC and HR, which can be explained by the intensities and the duration of exercise. Increased PRL can be related to central fatigue in these intensities.

Effects of incubation technique on proxies for olive ridley sea turtle (Lepidochelys olivacea) neonate fitness

Sea turtles and their nests face multiple threats on nesting beaches. Techniques have been developed to mitigate threats, these include relocating nests to fenced-off hatcheries or polystyrene boxes. The alteration of the nest’s natural environment may have direct effects on hatchling phenotype and locomotor performance. To test the effects of these two incubation conditions on proxies for hatchling fitness, we analysed locomotor performance (time to crawl 3 m and righting response) and phenotypic measures (weight and carapace length and width) of olive ridley sea turtle (Lepidochelys olivacea) hatchlings. We found that mean temperature was higher in hatcheries (30.5°C) than in polystyrene boxes (29.9°C) and that hatchlings incubated in polystyrene boxes had smaller straight carapace length (39.2 mm ± 2.0) and were significantly slower in crawl speed (CS) (0.0107 m s−1 ± 0.005) than those from hatcheries (SCL = 40.7 mm ± 1.3; CS = 0.018 m s−1 ± 0.005).

Delayed response of snails' vertical distribution on the bottomland to the changing water level at the downstream area of the Three Gorges project

The schistosomiasis, severely harming to the anthropic health, is one of six key tropical diseases identified by the World Health Organization (WHO). The downstream area of the Three Gorges reservoir is the major epidemic area of schistosomiasis in China. As the only intermediate host of schistosome, snails generally live at the bottomland of rivers and lakes. The vertical distribution of snails on the bottomland is closely related to the water level. Due to the changes in soil moisture and the snails' crawl speed, the adjustment of snails' vertical distribution usually lags behind the water level alteration. This delayed response of the snails' vertical distribution to water level changes has yet been comprehensively studied. The snails' vertical distribution is always difficult to describe or predict accurately. Based on theoretical analysis, a generalized model for the changes in snails' vertical distribution was proposed in this study. A calculation method was developed for predicting the theoretical vertical distribution of snails under fluctuating water levels. The calculation method reveals that: (1) the elevation, at which snails are mostly distributed, increases with the rise of water level and decreases with the decline of water level; (2) the difference between this elevation is where intense snail distribution is located and the water level decreases with the rising of water level and increases with the descending of water level. By using the field data of water level at Chenglingji station and snails' distribution elevation at the Dongkou bottomland of Dongting Lake during 2008 to 2010, the calculation method based on the delay response for predicting the snails' distribution elevation was tested. The results showed that the computed results agreed with the measured data and the correlation coefficient between them equals to 0.7. The relationship between the snails' vertical distribution and the water level alteration established in this paper may be used to predict the snails' distribution elevation, thus this study contributes to the prevention and control of schistosomiasis.

A model of truck speed profiles on short upward slopes

Truck speed reduction on upward slopes increases the crash risk. Existing speed–distance models estimate speed reduction on upward slopes by assuming that the resistive forces equal the tractive forces. In this case, the truck speed is a minimum and is called the crawl speed. This paper describes the calibration of a speed–distance model on short upward slopes using data obtained with a GPS device. The calibration was performed for trucks with a weight-to-power ratio of 95–160 kg/kW and for operating speeds of 70–93 km/h at the beginning of the upward slope. The results show that on short upward slopes, the minimum speed was 1·15 times higher than the theoretical crawl speed. The model was also used to obtain the required length for a speed reduction of 15–40 km/h, which is useful for establishing the need to provide climbing lanes on short upward slopes.

Traffic evacuation time under nonhomogeneous conditions

During many manmade and natural crises such as terrorist threats, floods, hazardous chemical and gas leaks, emergency personnel need to estimate the time in which people can evacuate from the affected urban area. Knowing an estimated evacuation time for a given crisis, emergency personnel can plan and prepare accordingly with the understanding that the actual evacuation time will take longer. Given the urban area to be evacuated, street widths exiting the area's perimeter, the area's population density, average vehicle occupancy, transport mode share and crawl speed, an estimation of traffic evacuation time can be derived. Peak-hour traffic data collected at three, midblock, Mumbai sites of varying geometric features and traffic composition were used in calibrating a model that estimates peak-hour traffic flow rates. Model validation revealed a correlation coefficient of +0.98 between observed and predicted peak-hour flow rates. A methodology is developed that estimates traffic evacuation time using the model.

Incubation temperature effects on hatchling performance in the loggerhead sea turtle (Caretta caretta).

Incubation temperature has significant developmental effects on oviparous animals, including affecting sexual differentiation for several species. Incubation temperature also affects traits that can influence survival, a theory that is verified in this study for the Northwest Atlantic loggerhead sea turtle (Caretta caretta). We conducted controlled laboratory incubations and experiments to test for an effect of incubation temperature on performance of loggerhead hatchlings. Sixty-eight hatchlings were tested in 2011, and 31 in 2012, produced from eggs incubated at 11 different constant temperatures ranging from 27°C to 33°C. Following their emergence from the eggs, we tested righting response, crawling speed, and conducted a 24-hour long swim test. The results support previous studies on sea turtle hatchlings, with an effect of incubation temperature seen on survivorship, righting response time, crawling speed, change in crawl speed, and overall swim activity, and with hatchlings incubated at 27°C showing decreased locomotor abilities. No hatchlings survived to be tested in both years when incubated at 32°C and above. Differences in survivorship of hatchlings incubated at high temperatures are important in light of projected higher sand temperatures due to climate change, and could indicate increased mortality from incubation temperature effects.

A Novel Interface to a Web Crawler using VB.NET Technology

The number of web pages is increasing into millions and trillions around the world. To make searching much easier for users, web search engines came into existence. Web Search engines are used to find specific information on the World Wide Web. Without search engines, it would be almost impossible to locate anything on the Web unless or until a specific URL address is known. This information is provided to search by a web crawler which is a computer program or software. Web crawler is an essential component of search engines, data mining and other Internet applications. Scheduling Web pages to be downloaded is an important aspect of crawling. Previous research on Web crawl focused on optimizing either crawl speed or quality of the Web pages downloaded. While both metrics are important, scheduling using one of them alone is insufficient and can bias or hurt overall crawl process. This paper is all about design a new Web Crawler using VB.NET Technology.

Visible light increases locomotor activity but does not influence body orientation or crawling direction of the nudibranch mollusk Tritonia diomedea

Visible light increases locomotor activity but does not influence body orientation or crawling direction of the nudibranch mollusk Tritonia diomedea