The association between changes in speed skating technique and changes in skating velocity.

Science.gov (United States)

Noordhof, Dionne A; Foster, Carl; Hoozemans M, J M; de Koning, Jos J

2014-01-01

A meaningful association between changes (Δ) in push-off angle or effectiveness (e) and changes in skating velocity (v) has been found during 5000-m races, although no significant association was found between changes in knee (θ0) and trunk angle (θ1) and Δv. It might be that speed skating event, sex, and performance level influence these associations. To study the effect of skating event, sex, and performance level on the association between Δe and Δv and between Δθ0 and Δθ1 and Δv. Video recordings were made from frontal (e) and sagittal views (θ0 and θ1) during 1500- and 5000-m men's and women's World Cup races. Radio-frequency identification tags provided data of v. Skating event influenced the association between Δe and Δv, which resulted in a significant association between Δe and Δv for the 5000-m (β = -0.069, 95% confidence interval [-0.11, -0.030]) but not for the 1500-m (β = -0.011 [-0.032, 0.010]). The association between Δθ0 and Δθ1 and Δv was not significantly influenced by skating event. Sex and performance level did not substantially affect the association between Δe and Δv and between Δθ0 and Δθ1 and Δv. Skating event significantly influenced the association between Δe and Δv; a 1° change in e results in a 0.011-m/s decrease in v during the 1500-m and a 0.069-m/s decrease in v during the 5000-m. Thus, it seems especially important to maintain a small e during the 5000-m.

Spatial segregation in eastern North Pacific skate assemblages.

Directory of Open Access Journals (Sweden)

Joseph J Bizzarro

Full Text Available Skates (Rajiformes: Rajoidei are common mesopredators in marine benthic communities. The spatial associations of individual species and the structure of assemblages are of considerable importance for effective monitoring and management of exploited skate populations. This study investigated the spatial associations of eastern North Pacific (ENP skates in continental shelf and upper continental slope waters of two regions: central California and the western Gulf of Alaska. Long-term survey data were analyzed using GIS/spatial analysis techniques and regression models to determine distribution (by depth, temperature, and latitude/longitude and relative abundance of the dominant species in each region. Submersible video data were incorporated for California to facilitate habitat association analysis. We addressed three main questions: 1 Are there regions of differential importance to skates?, 2 Are ENP skate assemblages spatially segregated?, and 3 When skates co-occur, do they differ in size? Skate populations were highly clustered in both regions, on scales of 10s of kilometers; however, high-density regions (i.e., hot spots were segregated among species. Skate densities and frequencies of occurrence were substantially lower in Alaska as compared to California. Although skates are generally found on soft sediment habitats, Raja rhina exhibited the strongest association with mixed substrates, and R. stellulata catches were greatest on rocky reefs. Size segregation was evident in regions where species overlapped substantially in geographic and depth distribution (e.g., R. rhina and Bathyraja kincaidii off California; B. aleutica and B. interrupta in the Gulf of Alaska. Spatial niche differentiation in skates appears to be more pronounced than previously reported.

Spatial segregation in eastern North Pacific skate assemblages.

Science.gov (United States)

Bizzarro, Joseph J; Broms, Kristin M; Logsdon, Miles G; Ebert, David A; Yoklavich, Mary M; Kuhnz, Linda A; Summers, Adam P

2014-01-01

Skates (Rajiformes: Rajoidei) are common mesopredators in marine benthic communities. The spatial associations of individual species and the structure of assemblages are of considerable importance for effective monitoring and management of exploited skate populations. This study investigated the spatial associations of eastern North Pacific (ENP) skates in continental shelf and upper continental slope waters of two regions: central California and the western Gulf of Alaska. Long-term survey data were analyzed using GIS/spatial analysis techniques and regression models to determine distribution (by depth, temperature, and latitude/longitude) and relative abundance of the dominant species in each region. Submersible video data were incorporated for California to facilitate habitat association analysis. We addressed three main questions: 1) Are there regions of differential importance to skates?, 2) Are ENP skate assemblages spatially segregated?, and 3) When skates co-occur, do they differ in size? Skate populations were highly clustered in both regions, on scales of 10s of kilometers; however, high-density regions (i.e., hot spots) were segregated among species. Skate densities and frequencies of occurrence were substantially lower in Alaska as compared to California. Although skates are generally found on soft sediment habitats, Raja rhina exhibited the strongest association with mixed substrates, and R. stellulata catches were greatest on rocky reefs. Size segregation was evident in regions where species overlapped substantially in geographic and depth distribution (e.g., R. rhina and Bathyraja kincaidii off California; B. aleutica and B. interrupta in the Gulf of Alaska). Spatial niche differentiation in skates appears to be more pronounced than previously reported.

The 1982 epidemic--roller skating injuries.

Science.gov (United States)

Bunker, T. D.

1983-01-01

A series of 100 roller skating injuries is presented. Roller skating injuries have been occurring at a higher rate than the previously reported skateboarding epidemic of 1977. The severity of injury has been lower, 32% fractures and dislocations occurring whilst roller skating, compared to 60% whilst skateboarding. In particular a striking reduction is seen in ankle fractures. Fifty questionnaires detailing method of injury were analysed. Images p205-a Fig. 1 Fig. 2 PMID:6652406

Children should wear helmets while ice-skating: a comparison of skating-related injuries.

Science.gov (United States)

McGeehan, Jennifer; Shields, Brenda J; Smith, Gary A

2004-07-01

This study compares injuries, especially head injuries, among ice-skaters with those among skateboarders, rollerskaters, and in-line skaters, to determine the need for helmet use during recreational ice-skating by children. A comparative study of a consecutive series of patients. The emergency department of a large, urban, academic, children's hospital. Children treated for injuries related to recreational ice-skating, skateboarding, rollerskating, and in-line skating. During a 31-month period, 419 consecutive children were evaluated in the emergency department for skating-related injuries. Children were predominantly male (53.9%), with a mean age of 10.0 years (SD: 3.0 years; median: 10.0 years; range: 1-18 years). The most frequent mechanism of injury was a fall. Overall, 76.5% of children (215 of 281 children) were reported to be wearing no protective equipment, such as a helmet or padding on the elbows or knees, at the time of injury. Ice-skaters were more likely to have adult supervision than were skateboarders (relative risk [RR]: 5.16; 95% confidence interval [CI]: 2.13-12.46), rollerskaters (RR: 1.21; 95% CI: 1.09-1.35), and in-line skaters (RR: 2.08; 95% CI: 1.72-2.51). Ice-skaters were at greater risk of injury to the head (20.0%) than were in-line skaters (4.9%) (RR: 4.09; 95% CI: 1.81-9.23); a weak difference was noted between ice-skaters and rollerskaters (9.9%) (RR: 2.18; 95% CI: 1.04-4.57), with no significant difference in head injuries between ice-skaters and skateboarders (15.9%) (RR: 1.60; 95% CI: 0.54-2.93). Ice-skaters demonstrated lacerations to the head in 68.8% of abnormal head examinations, compared with 37.0% for rollerskaters (RR: 1.86; 95% CI: 1.08-3.20) and 50.0% for in-line skaters (RR: 2.06; 95% CI: 1.35-3.16); however, there was no significant difference in lacerations to the head between ice-skaters and skateboarders (53.3%) (RR: 1.29; 95% CI: 0.76-2.19). Injuries to ice-skaters occurred more often in an indoor skating facility (92

A rapid real-time PCR method to differentiate between mottled skate (Beringraja pulchra) and other skate and ray species.

Science.gov (United States)

Kim, Mi-Ra; Kwon, Kisung; Jung, Yoo-Kyung; Kang, Tae Sun

2018-07-30

Skates and rays are commercially important fish in South Korea, and among them, Beringraja pulchra has the highest economic value. However, the similar morphological traits among skates and rays are often exploited for seafood fraud. Here, we designed both Beringraja pulchra-specific and skate-universal primer sets, capable of detecting short sequences in the cytochrome oxidase subunit I gene, and developed highly sensitive and reliable quantitative real-time PCR (qPCR) assays to differentiate between Beringraja pulchra and other skate and ray species. AΔCq method based on differences in the amplification efficiency was developed, validated, and then used to confirm the presence of Beringraja pulchra in twenty-six commercial skate products. The averageΔCq value obtained for other skate species (18.94 ± 3.46) was significantly higher than that of Beringraja pulchra (1.18 ± 0.15). For on-site applications, we developed an ultra-fast qPCR assay, allowing for completion of the entire analytical procedure within 30 min. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ice-skating and roller disco injuries in Dublin.

OpenAIRE

Horner, C.; McCabe, M. J.

1984-01-01

A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. ...

Hip adductor muscle function in forward skating.

Science.gov (United States)

Chang, Ryan; Turcotte, Rene; Pearsall, David

2009-09-01

Adductor strain injuries are prevalent in ice hockey. It has long been speculated that adductor muscular strains may be caused by repeated eccentric contractions which decelerate the leg during a stride. The purpose of this study was to investigate the relationship of skating speed with muscle activity and lower limb kinematics, with a particular focus on the role of the hip adductors. Seven collegiate ice hockey players consented to participate. Surface electromyography (EMG) and kinematics of the lower extremities were measured at three skating velocities 3.33 m/s (slow), 5.00 m/s (medium) and 6.66 m/s (fast). The adductor magnus muscle exhibited disproportionately larger increases in peak muscle activation and significantly prolonged activation with increased speed. Stride rate and stride length also increased significantly with skating velocity, in contrast, hip, knee and ankle total ranges of motion did not. To accommodate for the increased stride rate with higher skating speeds, the rate of hip abduction increased significantly in concert with activations of adductor magnus indicating a substantial eccentric contraction. In conclusion, these findings highlight the functional importance of the adductor muscle group and hip abduction-adduction in skating performance as well as indirectly support the notion that groin strain injury potential increases with skating speed.

Observer-reported skate bycatch in the commercial groundfish fisheries of Alaska

OpenAIRE

Stevenson , Duane E.; Lewis , Kristy A.

2010-01-01

We analyzed skate catch data collected by observers in the North Pacific Groundfish Observer Program (NPGOP) from 1998 through 2008 to document recent changes in the identification of skates by observers and to examine the species composition of observed skate catch in Alaska’s groundfish fisheries as well as recent trends in skate retention by commercial fishermen. Historically, almost all skate bycatch has been reported by NPGOP observers as “skate unidentified.” However, since 2004 o...

Epidemiology of Figure Skating Injuries: A Review of the Literature.

Science.gov (United States)

Han, Julie S; Geminiani, Ellen T; Micheli, Lyle J

2018-05-01

As the popularity and technical demands of figure skating increase, so will the number of athletes presenting with sport-related problems. Searches were performed across PubMed from 1980 to 2017. The keywords searched were skating, skaters, incidence, and injuries. The search was limited to English-language articles and human participants. Relevant articles were cross-referenced. Clinical review. Level 5. Previous studies suggest an increase in incidence of figure skating injuries from 1982 to 2003. When combining all disciplines of figure skating, there is a similar proportion of acute and overuse injuries. Within disciplines, overuse injuries appear to be more common in singles skating, while acute injuries are more common in pairs skating, ice dancing, and synchronized skating. Lower extremity injuries are more common than upper extremity injuries in all disciplines, and pairs skating accounts for the majority of upper extremity injuries. Ankle sprains are the most common skating injury, and patellar tendinitis is the most common overuse injury across all disciplines. Stress fractures are the most common overuse injury in female singles skaters. The predominance of overuse injuries in singles disciplines reflects their increasing technical difficulty, with more difficult jumps and longer training hours. Partner disciplines are more likely to involve acute injuries and upper extremity injuries due to high-risk throws and lifts. Emphasis should be placed on properly fitting skating boots, intrinsic foot and ankle strengthening, and lower extremity flexibility, which may prevent many of the common lower extremity and back injuries in figure skating.

Parameter analysis for speed skating performance

NARCIS (Netherlands)

van der Kruk, E.

2018-01-01

Speed skating is a rather special form of locomotion. While in most types of human locomotion, humans generate forces by pushing against the environment in the opposite direction of motion, in speed skating the skater pushes sideward to propel himself forward; Insight in the details of the technique

36 CFR 1002.20 - Skating, skateboards and similar devices.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Skating, skateboards and similar devices. 1002.20 Section 1002.20 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.20 Skating, skateboards and similar devices. Using roller skates...

Interjoint coordination of the lower extremities in short-track speed skating.

Science.gov (United States)

Khuyagbaatar, Batbayar; Purevsuren, Tserenchimed; Park, Won Man; Kim, Kyungsoo; Kim, Yoon Hyuk

2017-10-01

In short-track speed skating, the three-dimensional kinematics of the lower extremities during the whole skating cycle have not been studied. Kinematic parameters of the lower extremities during skating are presented as joint angles versus time. However, the angle-time presentation is not sufficient to describe the relationship between multi-joint movement patterns. Thus, angle-angle presentations were developed and used to describe interjoint coordination in sport activities. In this study, 15 professional male skaters' full body motion data were recorded using a wearable motion capture system during short-track speed skating. We investigated the three-dimensional kinematics of the lower extremities and then established the interjoint coordination between hip-knee and knee-ankle for both legs during the whole skating cycle. The results demonstrate the relationship between multi-joint movements during different phases of short-track speed skating. This study provides fundamentals of the movement mechanism of the lower extremities that can be integrated with physiotherapy to improve skating posture and prevent injuries from repetitive stress since physiological characteristics play an important role in skating performance.

Skating mechanics of change-of-direction manoeuvres in ice hockey players.

Science.gov (United States)

Fortier, Antoine; Turcotte, René A; Pearsall, David J

2014-11-01

Ice hockey requires rapid transitions between skating trajectories to effectively navigate about the ice surface. Player performance relates in large part to effective change-of-direction manoeuvres, but little is known about how those skills are performed mechanically and the effect of equipment design on them. The purpose of this study was to observe the kinetics involved in those manoeuvres as well as to compare whether kinetic differences may result between two skate models of varying ankle mobility. Eight subjects with competitive ice hockey playing experience performed rapid lateral (90°) left and right change-of-direction manoeuvres. Kinetic data were collected using force strain gauge transducers on the blade holders of the skates. Significantly greater forces were applied by the outside skate (50-70% body weight, %BW) in comparison to the inside skate (12-24%BW, p Skate model and turn direction had no main effect, though significant mixed interactions between leg side (inside/outside) with skate model or turn direction (p skating change-of-direction tasks.

Failure of the chassis of roller skates for agonistic figure skating

Directory of Open Access Journals (Sweden)

Giorgio Olmi

2015-04-01

Full Text Available The subject of this work was to investigate the early failure, which occurred in the chassis of a roller skate for figure skating. The paper deals with the preliminary analysis of the crack and with the integrated approach, which had to be followed to overcome the problem. Literature in the fields of physiology and biomechanics was studied to correctly simulate the load distribution on the chassis. Finite element simulation, experimental stress analysis and analytical modeling of impact phenomena had to be combined together to estimate the entity of dynamic loads and the corresponding state of stress. The analysis led to the determination of the primary cause of failure, bending fatigue, and to the suggestion of a simple solution to improve and optimize the project.

Skateboarding: more dangerous than roller skating or in-line skating.

Science.gov (United States)

Osberg, J S; Schneps, S E; Di Scala, C; Li, G

1998-10-01

To describe the circumstances, severity, and outcomes of skating-related injuries among children admitted to trauma centers. A cross-sectional comparison of roller skaters (n = 154), in-line skaters (n = 190), and skateboarders (n = 254) aged 5 to 19 years who were hospitalized with injuries. Seventy-nine hospitals and pediatric trauma centers participating in the National Pediatric Trauma Registry between October 1988 and April 1997. Three quarters (75.8%) of the study sample were male, nearly half (47.8%) were injured on roads, and more than one third (37.1%) had head injuries. Among skateboarders, 50.8% had head injuries compared with 33.7% of in-line skaters and 18.8% of roller skaters (Pskateboarders were 8 times more likely to be severe or critical compared with roller skaters' injuries and more than 2 times as likely to be severe or critical compared with in-line skaters' injuries. Mean hospital length of stay was 6.0 days for skateboarders, 3.4 days for in-line skaters, and 2.4 days for roller skaters (PSkateboarders were more likely to be male and to be injured on roads than were in-line skaters or roller skaters. Skateboarding-related injuries are more severe and have more serious consequences than roller skating or in-line skating injuries. Research is needed to identify ergonomic and behavioral factors responsible for higher head injury risk to skateboarders, and interventions are needed to reduce the risk.

Reliability and Validity of the Inline Skating Skill Test

Science.gov (United States)

Radman, Ivan; Ruzic, Lana; Padovan, Viktoria; Cigrovski, Vjekoslav; Podnar, Hrvoje

2016-01-01

This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male) were randomized into two groups (competitive level vs. recreational level). They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8–2.6%] – 2.2% [95% CI: 0.0–4.5%]). In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2–2.4%] – 2.7% [95% CI: 2.1–4.0%]) and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92–0.99] – 0.99 [95% CI: 0.98–1.00]). The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2) revealed that the skill test was able to track changes in skaters’ performances. Competitive-level skaters needed shorter time (24.4–26.4%, all p skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters. Key points Study evaluated the reliability and construct validity of a newly developed inline skating skill test. Evaluated test is a first protocol designed to assess specific inline skating skill. Two groups of amateur skaters with different skating proficiency repeated the skill test in four separate occasions. The results suggest that evaluated test is reliable and valid to evaluate inline skating skill in amateur skaters. PMID:27803616

Theory of ice-skating

Science.gov (United States)

Le Berre, Martine; Pomeau, Yves

2015-10-01

Almost frictionless skating on ice relies on a thin layer of melted water insulating mechanically the blade of the skate from ice. Using the basic equations of fluid mechanics and Stefan law, we derive a set of two coupled equations for the thickness of the film and the length of contact, a length scale which cannot be taken as its value at rest. The analytical study of these equations allows to define a small a-dimensional parameter depending on the longitudinal coordinate which can be neglected everywhere except close to the contact points at the front and the end of the blade, where a boundary layer solution is given. This solution provides without any calculation the order of magnitude of the film thickness, and its dependence with respect to external parameters like the velocity and mass of the skater and the radius of profile and bite angle of the blade, in good agreement with the numerical study. Moreover this solution also shows that a lubricating water layer of macroscopic thickness always exists for standard values of ice skating data, contrary to what happens in the case of cavitation of droplets due to thermal heating (Leidenfrost effect).

Double-push skating versus V2 and V1 skating on uphill terrain in cross-country skiing.

Science.gov (United States)

Stöggl, Thomas; Kampel, Wolfgang; Müller, Erich; Lindinger, Stefan

2010-01-01

The aims of the study were a) to compare the double-push skating technique with the V2 and the V1 skating techniques on an uphill terrain by a kinematic and kinetic analysis, b) to provide kinetic and kinematic data of the V1 technique at maximal skiing speeds, and c) to test the hypotheses that the double-push skating technique is faster compared with the V2 and the V1 skating techniques. Six elite skiers performed maximum speed sprints over a 60-m uphill section (7 degrees -10 degrees) using the double-push, the V2, and the V1 techniques. Pole and plantar forces and cycle characteristics were analyzed. The double-push skating technique was approximately 4.3% faster (P push and the V2 techniques demonstrated longer cycle lengths, lower cycle rates (both P push technique compared with the V2 technique (all P values push technique compared with the other two techniques (P push techniques compared with the V2 technique stress the mechanical advantage of those techniques on uphill terrain. Because of larger cycle lengths, lower cycle rate, longer recovery times, and equal poling frequency, the double-push technique might be seen as more economic on steep uphills compared with the V1 technique. From a tactical point of view compared with the V1 technique, the double-push technique needs less space due to less lateral displacement, and no technique transitions are necessary when entering and leaving an uphill section.

Human locomotion on ice: the evolution of ice-skating energetics through history.

Science.gov (United States)

Formenti, Federico; Minetti, Alberto E

2007-05-01

More than 3000 years ago, peoples living in the cold North European regions started developing tools such as ice skates that allowed them to travel on frozen lakes. We show here which technical and technological changes determined the main steps in the evolution of ice-skating performance over its long history. An in-depth historical research helped identify the skates displaying significantly different features from previous models and that could consequently determine a better performance in terms of speed and energy demand. Five pairs of ice skates were tested, from the bone-skates, dated about 1800 BC, to modern ones. This paper provides evidence for the fact that the metabolic cost of locomotion on ice decreased dramatically through history, the metabolic cost of modern ice-skating being only 25% of that associated with the use of bone-skates. Moreover, for the same metabolic power, nowadays skaters can achieve speeds four times higher than their ancestors could. In the range of speeds considered, the cost of travelling on ice was speed independent for each skate model, as for running. This latter finding, combined with the accepted relationship between time of exhaustion and the sustainable fraction of metabolic power, gives the opportunity to estimate the maximum skating speed according to the distance travelled. Ice skates were probably the first human powered locomotion tools to take the maximum advantage from the biomechanical properties of the muscular system: even when travelling at relatively high speeds, the skating movement pattern required muscles to shorten slowly so that they could also develop a considerable amount of force.

Captive breeding of the barndoor skate (Dipturus laevis) at the Montreal Biodome, with comparison notes on two other captive-bred skate species.

Science.gov (United States)

Parent, Serge; Pépin, Serge; Genet, Jean-Pierre; Misserey, Laurent; Rojas, Salvador

2008-03-01

In 1997, the Montreal Biodome obtained five barndoor skates (Dipturus laevis) from the waters off Boston, Massachusetts. Six years later, those specimens began reproducing, and the first egg case was collected in November 2003. Since then, 73 hatchlings have been born and raised. Egg cases were observed year round, and annual fecundity was measured for the first time: one female laid 69 eggs in 2005, 85 in 2006 and 115 in 2007. Egg incubation was longer than believed previously, ranging from 342 to 494 days. Hatching occurred throughout the year. Hatchlings averaged 193 mm total length and 128 mm disk width and weighed 32 g. They were fed krill and diced fish. All but one survived the first month. A photo identification system was useful in recognizing two groups of 10 specimens during their first year, and transponders could be inserted in the wing muscles of 1-year-old skates. Total lengths at birth and at age 2 were similar to the data reported from the wild, suggesting a similar growth pattern in captivity. The reproduction characteristics of the barndoor skate were compared with those of two other skate species currently bred at the Montreal Biodome, the winter skate (Leucoraja ocellata) and the thorny skate (Amblyraja radiata). Zoo Biol 27:145-153, 2008. (c) 2008 Wiley-Liss, Inc.

Skating on slippery ice

Directory of Open Access Journals (Sweden)

J. M. J. van Leeuwen

2017-12-01

Full Text Available The friction of a stationary moving skate on smooth ice is investigated, in particular in relation to the formation of a thin layer of water between skate and ice. It is found that the combination of ploughing and sliding gives a friction force that is rather insensitive for parameters such as velocity and temperature. The weak dependence originates from the pressure adjustment inside the water layer. For instance, high velocities, which would give rise to high friction, also lead to large pressures, which, in turn, decrease the contact zone and so lower the friction. The theory is a combination and completion of two existing but conflicting theories on the formation of the water layer.

Push-off forces in elite short-track speed skating.

Science.gov (United States)

van der Kruk, Eline; Reijne, Marco M; de Laat, Bjorn; Veeger, DirkJan H E J

2018-05-30

This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters (N = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants (N = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve (r = 0.82, p < 0.05), leaving the curve (r = 0.86, p < 0.05), and entering the straight (r = 0.76, p < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve (r = 0.74, p < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities.

SKATE: a docking program that decouples systematic sampling from scoring.

Science.gov (United States)

Feng, Jianwen A; Marshall, Garland R

2010-11-15

SKATE is a docking prototype that decouples systematic sampling from scoring. This novel approach removes any interdependence between sampling and scoring functions to achieve better sampling and, thus, improves docking accuracy. SKATE systematically samples a ligand's conformational, rotational and translational degrees of freedom, as constrained by a receptor pocket, to find sterically allowed poses. Efficient systematic sampling is achieved by pruning the combinatorial tree using aggregate assembly, discriminant analysis, adaptive sampling, radial sampling, and clustering. Because systematic sampling is decoupled from scoring, the poses generated by SKATE can be ranked by any published, or in-house, scoring function. To test the performance of SKATE, ligands from the Asetex/CDCC set, the Surflex set, and the Vertex set, a total of 266 complexes, were redocked to their respective receptors. The results show that SKATE was able to sample poses within 2 A RMSD of the native structure for 98, 95, and 98% of the cases in the Astex/CDCC, Surflex, and Vertex sets, respectively. Cross-docking accuracy of SKATE was also assessed by docking 10 ligands to thymidine kinase and 73 ligands to cyclin-dependent kinase. 2010 Wiley Periodicals, Inc.

A comparison of VO2max and metabolic variables between treadmill running and treadmill skating.

Science.gov (United States)

Koepp, Kriston K; Janot, Jeffrey M

2008-03-01

The purpose of this study was to determine differences in VO2max and metabolic variables between treadmill running and treadmill skating. This study also examined VO2max responses during a continuous skating treadmill protocol and a discontinuous skating treadmill protocol. Sixteen male high school hockey players, who had a mean age of 16 +/- 1 years and were of an above-average fitness level, participated in this study. All subjects completed 4 exercise trials: a 1-hour skating treadmill familiarization trial, a treadmill running trial, and 2 randomized skating treadmill trials. Minute ventilation (VE), oxygen consumption VO2), carbon dioxide production VCO2), respiratory exchange ratio (RER), and heart rate were averaged every 15 seconds up to VO2max for each exercise test. The results showed that there was a significant difference (P skating treadmill protocol. There was also a significant difference for maximal RER between the discontinuous and continuous skating treadmill protocol and between the discontinuous skating treadmill protocol and running treadmill protocol. In conclusion, the running treadmill elicited a greater VO2max (mL.kg.min) than the skating treadmill did, but when it comes to specificity of ice skating, the skating treadmill may be ideal. Also, there was no significant difference between the discontinuous and continuous skating treadmill protocols. Therefore, a continuous protocol is possible on the skating treadmill without compromising correct skating position and physiologic responses. However, the continuous skating treadmill protocol should undergo validation before other scientists, coaches, and strength and conditioning professionals can apply it correctly.

Nonparticipant injuries associated with skating activities.

Science.gov (United States)

Knox, Christy L; Comstock, R Dawn

2006-03-01

Children are at risk for injury even if they are not active recreational participants. This study describes the epidemiology of pediatric nonparticipant skating-related injuries treated in hospital emergency departments in the United States from 1993 to 2003. Narratives of injuries identified by the US Consumer Product Safety Commission's National Electronic Injury Surveillance System consumer product codes as ice-skating, roller-skating, and in-line skating-related were reviewed. Fifty-eight children were treated for nonparticipant skating-related injuries in National Electronic Injury Surveillance System emergency departments. Mechanisms of injury included being stepped on (36.2%), dropped (34.5%), or kicked (12.1%) by skaters and collision with skaters (17.2%). The most common body regions injured were the lower extremities (41.4%), upper extremities (24.1%), and head (20.7%). Contusions/abrasions (32.8%), lacerations (20.7%), and fractures (19.0%) were the most common diagnoses. Children who were dropped sustained more head injuries than children injured by other mechanisms (relative risk [RR], 20.9; 95% confidence interval [CI], 2.9-150.5; P < 0.001) and were younger than those stepped on (RR, 1.5; 95% CI, 1.1-2.2; P = 0.02) or kicked (RR, 6.7; 95% CI, 1.1-40.9; P < 0.001). Children stepped on by skaters experienced more injuries to the extremities than children who were dropped by (RR, 3.3; 95% CI, 1.7-6.5; P < 0.001) or collided with skaters (RR, 1.7; 95% CI, 1.0-2.8; P < 0.01). Children are at risk for injury when they are around skaters. The risk of such injuries can be reduced if children are never carried by skaters, young children are closely supervised to avoid collisions, and skaters are cautioned against kicking or stepping on other children.

Acute physiological responses to recreational in-line skating in young adults.

Science.gov (United States)

Orepic, Paula; Mikulic, Pavle; Soric, Maroje; Ruzic, Lana; Markovic, Goran

2014-01-01

We examined the physiological responses to in-line skating exercise at self-selected paces in recreationally trained adults. Seven men and 10 women performed in-line skating exercise during which oxygen uptake (VO2) and heart rate (HR) were recorded continuously. Ratings of perceived exertion (RPE) and blood lactate concentration were also obtained at the end of exercise. Furthermore, subjects' peak VO2, peak HR, RPE and gas-exchange thresholds were determined in laboratory settings. The average exercise intensity during in-line skating was 90% of peak HR, 67% of peak VO2, 84% of HR reserve and 64% of VO2 reserve. When expressed as RPE and as metabolic equivalents (METs), the average exercise intensity was 13.1 RPE and 9.4 METs. Overall, these indicators of exercise intensity categorise in-line skating at self-selected paces as a vigorous physical activity. Notably, at similar VO2 values, significantly higher HR (174 ± 16 vs. 156 ± 6 bpm; pskating compared with treadmill running. We conclude that 1. recreational in-line skating induces physiological responses that are sufficient for improving and maintaining cardiovascular fitness in healthy adults, 2. HR- and RPE-based methods for quantifying the exercise intensity during in-line skating may overestimate the actual metabolic load and 3. the derivation of exercise prescriptions for in-line skating should be preferably based on specific (i.e. in-line skating) graded exhaustive exercise test.

Pediatric fractures during skateboarding, roller skating, and scooter riding.

Science.gov (United States)

Zalavras, Charalampos; Nikolopoulou, Georgia; Essin, Daniel; Manjra, Nahid; Zionts, Lewis E

2005-04-01

Skateboarding, roller skating, and scooter riding are popular recreational and sporting activities for children and adolescents but can be associated with skeletal injury. The purpose of this study is to describe the frequency and characteristics of fractures resulting from these activities. Fractures from skateboarding, roller skating, and scooter riding compose a considerable proportion of pediatric musculoskeletal injuries. Case series; Level of evidence, 4. Demographic data and injury characteristics were analyzed for all patients who presented to the pediatric fracture clinic of the level I trauma center from January 2001 to May 2002 after sustaining fractures due to skateboarding, roller skating, and scooter riding. Among a total of 2371 fractures, the authors identified 325 fractures (13.7%) that occurred during one of these activities. There were 187 patients (mean age, 13 years; 95% male) who sustained 191 skateboard-related fractures, 64 patients (mean age, 10.8 years; 54% male) who sustained 65 fractures while roller skating, and 66 patients (mean age, 9.7 years; 64% male) who sustained 69 fractures while riding a scooter. The forearm was fractured most often, composing 48.2% of skate-boarding fractures, 63.1% of roller-skating fractures, and 50.7% of fractures due to scooter riding. Of the forearm fractures, 94% were located in the distal third. In the skateboarding group, 10 of 191 (5.2%) fractures were open injuries of the forearm, compared to 6 of 2046 (0.3%) fractures caused by other mechanisms of injury (significant odds ratio, 18.8). Skateboarding, roller-skating, and scooter-riding accidents result in a large proportion of pediatric fractures. An open fracture, especially of the forearm, was more likely to be caused by skateboarding than by other mechanisms of injury. Use of wrist and forearm protective equipment should be considered in all children who ride a skateboard.

The effect of a heated skate blade on the ice surface

Energy Technology Data Exchange (ETDEWEB)

Hache, A. [Moncton Univ., NB (Canada). Dept. of Physics and Astronomy

2007-05-15

A new hockey skate using a heated blade, called the Therma Blade, cuts ice friction by half, thereby improving skating performance but has created questions about melting and damage of the ice surface. This paper discussed the effect of the heated skate blade on the ice surface. The paper discussed the thermal power produced by the Therma Blade skate, the ice melting capacity of the therma blade, and the ice temperature profile around the heated blade. It also examined the power dissipation by friction comparing the cold versus the heated blade. Units and definitions as well as conversion factors were also presented in appendix format. Constants and technical specifications were listed in an appendix. It was concluded that the maximum melting capacity of the therma blade is 0.7 grams of ice per skate per minute. This is the upper limit as set by the laws of physics, and this requires the skate to be completely static over ice at 0 degrees Celsius and all the power drawn by the battery to reach the ice friction force. 5 refs., 1 tab., 2 figs.

The Vibe of Skating; Design and Testing of a Vibro-Tactile Feedback System

Directory of Open Access Journals (Sweden)

Arjen J. Jansen

2018-03-01

Full Text Available Providing athletes with real-time feedback on their performance is becoming common in many sports, also in speed skating. This research-by-design project aims at finding a tool that allows the speed skater to get real-time feedback on his performance. Speed skaters often mention a so-called “good feeling” when skating behind a better skater. It is the feeling nearly every speed skater is after when skating alone; skate with less power while maintaining the same speed and feeling of ease. A longer push-off phase at a constant cadence has proven to contribute to this ideal situation but is hard for the coach alone to influence this. Therefore, a system was designed that measures the skating cadence and challenges the skater to change his skating stroke by means of vibro-tactile feedback. Four subjects have tested the feedback system. From this test, we concluded that the system provides meaningful feedback towards changing the skating cycle.

From Morphology to Neural Information: The Electric Sense of the Skate

Science.gov (United States)

Camperi, Marcelo; Tricas, Timothy C; Brown, Brandon R

2007-01-01

Morphology typically enhances the fidelity of sensory systems. Sharks, skates, and rays have a well-developed electrosense that presents strikingly unique morphologies. Here, we model the dynamics of the peripheral electrosensory system of the skate, a dorsally flattened batoid, moving near an electric dipole source (e.g., a prey organism). We compute the coincident electric signals that develop across an array of the skate's electrosensors, using electrodynamics married to precise morphological measurements of sensor location, infrastructure, and vector projection. Our results demonstrate that skate morphology enhances electrosensory information. Not only could the skate locate prey using a simple population vector algorithm, but its morphology also specifically leads to quick shifts in firing rates that are well-suited to the demonstrated bandwidth of the electrosensory system. Finally, we propose electrophysiology trials to test the modeling scheme. PMID:17571918

From morphology to neural information: the electric sense of the skate.

Directory of Open Access Journals (Sweden)

Marcelo Camperi

2007-06-01

Full Text Available Morphology typically enhances the fidelity of sensory systems. Sharks, skates, and rays have a well-developed electrosense that presents strikingly unique morphologies. Here, we model the dynamics of the peripheral electrosensory system of the skate, a dorsally flattened batoid, moving near an electric dipole source (e.g., a prey organism. We compute the coincident electric signals that develop across an array of the skate's electrosensors, using electrodynamics married to precise morphological measurements of sensor location, infrastructure, and vector projection. Our results demonstrate that skate morphology enhances electrosensory information. Not only could the skate locate prey using a simple population vector algorithm, but its morphology also specifically leads to quick shifts in firing rates that are well-suited to the demonstrated bandwidth of the electrosensory system. Finally, we propose electrophysiology trials to test the modeling scheme.

Comparison of skating kinetics and kinematics on ice and on a synthetic surface.

Science.gov (United States)

Stidwill, T J; Pearsall, David; Turcotte, Rene

2010-03-01

The recent popularization and technological improvements of synthetic or artificial ice surfaces provide an attractive alternative to real ice in venues where the latter is impractical to install. Potentially, synthetic ice (SI) may be installed in controlled laboratory settings to permit detailed biomechanical analysis of skating manoeuvres. Unknown, however, is the extent to which skating on SI replicates skating on traditional ice (ICE). Hence, the purpose of this study was to compare kinetic and kinematic forward skating parameters between SI and ICE surfaces. With 11 male hockey players, a portable strain gauge system adhered to the outside of the skate blade holder was used to measure skate propulsive force synchronized with electrogoniometers for tracking dynamic knee and ankle movements during forward skating acceleration. In general, the kinetic and kinematic variables investigated in this study showed minimal differences between the two surfaces (P > 0.06), and no individual variable differences were identified between the two surfaces (P > or = 0.1) with the exception of greater knee extension on SI than ICE (15.2 degrees to 11.0 degrees; P skating, and thus offer the potential for valid analogous conditions for in-lab testing and training.

The effect of a complex training program on skating abilities in ice hockey players.

Science.gov (United States)

Lee, Changyoung; Lee, Sookyung; Yoo, Jaehyun

2014-04-01

[Purpose] Little data exist on systemic training programs to improve skating abilities in ice hockey players. The purpose of this study was to evaluate the effectiveness of a complex training program on skating abilities in ice hockey players. [Methods] Ten male ice hockey players (training group) that engaged in 12 weeks of complex training and skating training and ten male players (control group) that only participated in 12 weeks of skating training completed on-ice skating tests including a 5 time 18 meters shuttle, t-test, Rink dash 5 times, and line drill before, during, and the training. [Results] Significant group-by-time interactions were found in all skating ability tests. [Conclusion] The complex training program intervention for 12 weeks improved their skating abilities of the ice hockey players.

75 FR 3434 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Amendment 3

Science.gov (United States)

2010-01-21

...NMFS proposes regulations to implement measures in Amendment 3 to the Northeast Skate Complex Fishery Management Plan (Skate FMP). Amendment 3 was developed by the New England Fishery Management Council (Council) to rebuild overfished skate stocks and implement annual catch limits (ACLs) and accountability measures (AMs) consistent with the requirements of the reauthorized Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens Act). Amendment 3 would implement a rebuilding plan for smooth skate and establish an ACL and annual catch target (ACT) for the skate complex, total allowable landings (TAL) for the skate wing and bait fisheries, seasonal quotas for the bait fishery, reduced possession limits, in-season possession limit triggers, and other measures to improve management of the skate fisheries. This proposed rule also includes skate fishery specifications for fishing years (FY) 2010 and 2011.

Evaluation of an adaptive ice skating programme for children with disabilities.

Science.gov (United States)

Fragala-Pinkham, Maria A; Dumas, Helene M; Boyce, Megan; Peters, Christine Y; Haley, Stephen M

2009-08-01

To describe an adaptive ice skating programme designed by paediatric therapists. Twenty-two children, ages 5-12 years, with developmental disabilities participated in this once per week skating programme lasting 6 weeks. Ice skating instructors led the group lessons, while university student coaches provided individualized assistance to the children. The programme was evaluated using a summative evaluation design. Outcomes included participant attendance, incidence of injuries, skating skills and parent and student coach survey data. On average, participants attended 83% of the sessions and one minor injury was reported. Participants' parents were very satisfied with the programme and reported improvements in their child's skating skills, leg strength, endurance, balance, self-esteem/confidence and ability to participate in a group. Student coaches also reported high levels of satisfaction with this programme and reported similar improvements in the children they coached. The programme appeared promising, but may require minor modifications.

Updating the Skating Multistage Aerobic Test and Correction for V[Combining Dot Above]O2max Prediction Using a New Skating Economy Index in Elite Youth Ice Hockey Players.

Science.gov (United States)

Allisse, Maxime; Bui, Hung Tien; Léger, Luc; Comtois, Alain-Steve; Leone, Mario

2018-05-07

Allisse, M, Bui, HT, Léger, L, Comtois, A-S, and Leone, M. Updating the skating multistage aerobic test and correction for V[Combining Dot Above]O2max prediction using a new skating economy index in elite youth ice hockey players. J Strength Cond Res XX(X): 000-000, 2018-A number of field tests, including the skating multistage aerobic test (SMAT), have been developed to predict V[Combining Dot Above]O2max in ice hockey players. The SMAT, like most field tests, assumes that participants who reach a given stage have the same oxygen uptake, which is not usually true. Thus, the objectives of this research are to update the V[Combining Dot Above]O2 values during the SMAT using a portable breath-by-breath metabolic analyzer and to propose a simple index of skating economy to improve the prediction of oxygen uptake. Twenty-six elite hockey players (age 15.8 ± 1.3 years) participated in this study. The oxygen uptake was assessed using a portable metabolic analyzer (K4b) during an on-ice maximal shuttle skate test. To develop an index of skating economy called the skating stride index (SSI), the number of skating strides was compiled for each stage of the test. The SMAT enabled the prediction of the V[Combining Dot Above]O2max (ml·kg·min) from the maximal velocity (m·s) and the SSI (skating strides·kg) using the following regression equation: V[Combining Dot Above]O2max = (14.94 × maximal velocity) + (3.68 × SSI) - 24.98 (r = 0.95, SEE = 1.92). This research allowed for the update of the oxygen uptake values of the SMAT and proposed a simple measure of skating efficiency for a more accurate evaluation of V[Combining Dot Above]O2max in elite youth hockey players. By comparing the highest and lowest observed SSI scores in our sample, it was noted that the V[Combining Dot Above]O2 values can vary by up to 5 ml·kg·min. Our results suggest that skating economy should be included in the prediction of V[Combining Dot Above]O2max to improve prediction accuracy.

Molecular cloning and characterization of preproorexin in winter skate (Leucoraja ocellata).

Science.gov (United States)

MacDonald, Erin E; Volkoff, Hélène

2010-12-01

A 815 base pairs (bp) cDNA encoding for preproorexin (preproOX) was cloned in winter skate, a cartilaginous fish. Winter skate preproOX is 159 amino acids (aa) long and contains a 34 aa orexin A and 28 aa orexin B. The amino acid sequence of winter skate preproOX is more similar to tetrapod preproOXs (36-40% identity) than teleost preproOXs (23-33% identity). Whereas orexin B appears relatively well conserved among vertebrates, orexin A displays more variability, in particular due to an "insertion sequence" that is present in teleost fish, but not in skate and tetrapods. RT-PCR studies show that preproOX mRNA has a widespread distribution within the brain and is present in several peripheral tissues, including gastrointestinal tract, heart and testes. Fasting induced increases in preproOX expression in the hypothalamus, suggesting that orexin might play a role in the regulation of food intake in winter skate. Copyright © 2010 Elsevier Inc. All rights reserved.

Skate Genome Project: Cyber-Enabled Bioinformatics Collaboration

Science.gov (United States)

Vincent, J.

2011-01-01

The Skate Genome Project, a pilot project of the North East Cyber infrastructure Consortium, aims to produce a draft genome sequence of Leucoraja erinacea, the Little Skate. The pilot project was designed to also develop expertise in large scale collaborations across the NECC region. An overview of the bioinformatics and infrastructure challenges faced during the first year of the project will be presented. Results to date and lessons learned from the perspective of a bioinformatics core will be highlighted.

36 CFR 2.20 - Skating, skateboards, and similar devices.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Skating, skateboards, and similar devices. 2.20 Section 2.20 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.20 Skating, skateboards, and...

The association between changes in speed skating technique and changes in skating velocity

NARCIS (Netherlands)

Noordhof, D.A.; Foster Jr., C.C.; Hoozemans, M.J.M.; de Koning, J.J.

2014-01-01

A meaningful association between changes (Δ) in push-off angle or effectiveness (e) and changes in skating velocity (ν) has been found during 5000-m races, although no significant association was found between changes in knee (θ

Habituation of 10-year-old hockey players to treadmill skating.

Science.gov (United States)

Lockwood, Kelly L; Frost, Gail

2007-05-01

This study assessed changes in selected physiological and kinematic variables over 6 weeks of treadmill skating in an effort to understand the process of habituation to this novel training modality. Seven male, Atom-A hockey players who were injury-free and had no previous treadmill skating experience participated in the study. Players performed four 1-min skating bouts at progressively increasing speeds, each week, for 6 weeks. One speed (10.5 km/h) was repeated weekly to allow for assessment of the habituation process. Our criteria for habituation were: a decrease in stride rate, heart rate and rating of perceived exertion, and an increase in stride length, trunk angle and vertical movement of the centre of mass, leading to a plateau, over the course of the 6-week study. Significant decreases were seen in stride rate, heart rate and ratings of perceived exertion, and significant increases were found in stride length. Some of these changes were evident after only one week of training and all were present by week 4. After 6 weeks (24 min) of exposure to treadmill skating, all participants displayed a visibly more efficient skating style.

Neuromuscular Activation During Short-Track Speed Skating in Young Athletes.

Science.gov (United States)

Felser, Sabine; Behrens, Martin; Fischer, Susanne; Baeumler, Mario; Salomon, Ralf; Bruhn, Sven

2016-10-01

To investigate differences in muscle activation of both legs between the straight and the curve and changes in muscle activity during a 1000-m time trial (TT) and their relationship to the change in skating velocity in 9 young short-track speed skaters. The authors recorded skating times and EMG data from different leg muscles during maximum-effort skating trials on the straight and in the curve, as well as during a 1000-m TT. Muscle activation differs between the straight and the curves and between legs; ie, average activities of selected muscles of the right leg were significantly higher during skating through the curves than in the straights. This could not be observed for the left leg. The reduction in speed during the 1000-m TT highly correlates with the decrease in the muscle activity of both the tibialis anterior and the rectus femoris of the right leg. Muscle recruitment is different in relation to lap section (straight vs curve) and leg (right vs left leg). The decreased muscle activity of the tibialis anterior and rectus femoris of the right leg showed the highest relationships with the reduction in skating speed during the 1000-m TT.

Dental injuries in inline skating - level of information and prevention.

Science.gov (United States)

Fasciglione, Daniele; Persic, Robert; Pohl, Yango; Filippi, Andreas

2007-06-01

Inline skating belongs like ice hockey, rugby, and boxing to sporting activities with high-risk of suffering tooth accidents. Because of high velocity and loss of balance, especially on uneven ground, the injury potential in inline skating is higher. The objective of this work was to conduct a comparative study between Switzerland and Germany. The questions focussed on the frequency of tooth accidents, their prevention by mouthguard and the level of information about emergency measures after dental trauma and the resulting consequences for athletes. Using a standardized questionnaire totally 612 individuals, 324 men and 288 women, in two countries belonging to three different divisions (fun, fitness and speed) were surveyed. Fifty-six (9.2%) of these 612 interviewees have already experienced a tooth injury while inline skating. More than half of all interviewed players (68.3%) were aware of the possibility of replanting avulsed teeth. Only 32.4% were familiar with the tooth rescue kit. Just 65.4% knew mouthguard and only 1.9% of those athletes (n = 12) wore a mouthguard while inline skating. The results show that the area of inline skating requires more information about preventing dental trauma through sports associations and dentists.

IN SEARCH OF GOOD PERFORMANCE INDICATORS FOR SPEED SKATING

NARCIS (Netherlands)

van der Eb, J.W.; Zandee, Willem; van der Bogaard, Timo; Veeger, H.E.J.; Beek, P.J.

The force produced to propel a body forward in speed skating is directed almost perpendicular to the forward motion, because a skate moves nearly frictionless in the for-aft direction and more or less fixed (against the ice) in sideways lateral direction, resulting in a sliding point to push off

IN SEARCH OF GOOD PERFORMANCE INDICATORS FOR SPEED SKATING

NARCIS (Netherlands)

van der Eb, J.W.; Zandee, Willem; van der Bogaard, Timo; Veeger, H.E.J.; Beek, Peter

2017-01-01

The force produced to propel a body forward in speed skating is directed almost perpendicular to the forward motion, because a skate moves nearly frictionless in the for-aft direction and more or less fixed (against the ice) in sideways lateral direction, resulting in a sliding point to push off

Skating on thin ice: a study of the injuries sustained at a temporary ice skating rink.

Science.gov (United States)

Barr, Lynne V; Imam, Samirul; Crawford, John R; Owen, P Julian

2010-06-01

In recent years, ice skating and temporary ice skating rinks have become increasingly popular. Regular elite competitors are known to be at risk of both acute and chronic injuries. It may be postulated that skaters at the temporary rinks are at high risk of acute injuries from falls due to both their lack of expertise and the inherent dangers of ice skating. Injuries sustained at skating rinks present a significant burden to local healthcare resources, in particular orthopaedic departments. For the first time, Cambridge hosted such a facility from November 24, 2007 through January 6, 2008. We sought to identify the most common injuries encountered and to quantify the orthopaedic burden. All Emergency Department or Fracture Clinic attendances for an eight-week period from the opening of the rink were investigated. Details of age, sex, injury and management were recorded for the 84 patients who sustained ice rink related injuries. A total of 85 injuries were recorded in 84 patients. Of these injuries 58% were fractures, of which 98% involved the upper limbs. Seven patients (8% of all injuries) required admission for operative fixation. On average, two injuries per day were seen in the Emergency Department or Fracture Clinic, with an average of one orthopaedic admission per week. It is evident that the ice rink in Cambridge has had an impact on local healthcare resources. The vast majority of injuries affected the upper limbs and were sustained following a fall on the out-stretched hand. We therefore encourage the education of skaters as to how to break their falls more safely and recommend the use of wrist protectors as a primary preventative measure.

Skating start propulsion: three-dimensional kinematic analysis of elite male and female ice hockey players.

Science.gov (United States)

Shell, Jaymee R; Robbins, Shawn M K; Dixon, Philippe C; Renaud, Philippe J; Turcotte, René A; Wu, Tom; Pearsall, David J

2017-09-01

The forward skating start is a fundamental skill for male and female ice hockey players. However, performance differences by athlete's sex cannot be fully explained by physiological variables; hence, other factors such as skating technique warrant examination. Therefore, the purpose of this study was to evaluate the body movement kinematics of ice hockey skating starts between elite male and female ice hockey participants. Male (n = 9) and female (n = 10) elite ice hockey players performed five forward skating start accelerations. An 18-camera motion capture system placed on the arena ice surface captured full-body kinematics during the first seven skating start steps within 15 meters. Males' maximum skating speeds were greater than females. Skating technique sex differences were noted: in particular, females presented ~10° lower hip abduction throughout skating stance as well as ~10° greater knee extension at initial ice stance contact, conspicuously followed by a brief cessation in knee extension at the moment of ice contact, not evident in male skaters. Further study is warranted to explain why these skating technique differences exist in relation to factors such as differences in training, equipment, performance level, and anthropometrics.

50 CFR 648.320 - Skate FMP review and monitoring.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Skate FMP review and monitoring. 648.320 Section 648.320 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the NE Skate Complex Fisheries §...

Endurance in speed skating : The development of world records

NARCIS (Netherlands)

Kuper, GH; Sterken, E

2003-01-01

We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

Evaluating the injury incidence from skate shoes in the United States.

Science.gov (United States)

Ruth, Erin; Shah, Binisa; Fales, Willliam

2009-05-01

The goals of this study were to evaluate whether the increased use of skate shoes may lead to an increase in injuries for children and adolescents aged 5 to 14 years in the United States and to describe the types of injuries reported by emergency departments as a result of skate shoe use. Retrospective analysis of the National Electronic Injury Surveillance System database from January 1, 2002 to December 31, 2006 for injuries resulting from footwear in children and adolescents aged 5 to 14 years. Injuries resulting from skate shoe use were identified by manual review of the data. For the 5-year period, an estimated 3525 patients between 5 and 14 years of age were treated in United States emergency departments for injuries resulting from skate shoe use. The percentage of injuries resulting from skate shoes of total footwear-related injuries varied by year, however, with 1.0%, 1.0%, 0.8%, and 1.9% occurring in 2002 to 2005, respectively, and 11.8% occurring in 2006. This substantial increase in 2006 accounts for 73.6% of skate shoe-related injuries and is statistically significant (chi, P = skate shoe sales, with a correlation coefficient of 0.9982.Most of the injured children and adolescents were white, and there was a slight, nonsignificant predominance of boys. Most injuries in all 5-year-olds were fractures (46.7%), followed by contusions (17.9%) and sprains (17.2%). The most frequent site of fracture was the forearm (38.4%), followed by the wrist (35.1%) and the leg (14.9%). Other injuries included lacerations (7.3%), concussions (6.6%), internal organ injuries (0.9%), hematomas (0.2%), dislocations (0.2%), and injuries not otherwise specified (3.1%). Based on national estimates, 104 (0.01%) patients required admission to the hospital. No injuries recorded in the National Electronic Injury Surveillance System database resulted in death. As the first study analyzing injury rates as a result of skate shoe use in the United States, this study demonstrated a recent

Reliability and Validity of the Inline Skating Skill Test.

Science.gov (United States)

Radman, Ivan; Ruzic, Lana; Padovan, Viktoria; Cigrovski, Vjekoslav; Podnar, Hrvoje

2016-09-01

This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male) were randomized into two groups (competitive level vs. recreational level). They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8-2.6%] - 2.2% [95% CI: 0.0-4.5%]). In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2-2.4%] - 2.7% [95% CI: 2.1-4.0%]) and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92-0.99] - 0.99 [95% CI: 0.98-1.00]). The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2) revealed that the skill test was able to track changes in skaters' performances. Competitive-level skaters needed shorter time (24.4-26.4%, all p skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters.

Experimental evaluation of the power balance model of speed skating.

Science.gov (United States)

de Koning, Jos J; Foster, Carl; Lampen, Joanne; Hettinga, Floor; Bobbert, Maarten F

2005-01-01

Prediction of speed skating performance with a power balance model requires assumptions about the kinetics of energy production, skating efficiency, and skating technique. The purpose of this study was to evaluate these parameters during competitive imitations for the purpose of improving model predictions. Elite speed skaters (n = 8) performed races and submaximal efficiency tests. External power output (P(o)) was calculated from movement analysis and aerodynamic models and ice friction measurements. Aerobic kinetics was calculated from breath-by-breath oxygen uptake (Vo(2)). Aerobic power (P(aer)) was calculated from measured skating efficiency. Anaerobic power (P(an)) kinetics was determined by subtracting P(aer) from P(o). We found gross skating efficiency to be 15.8% (1.8%). In the 1,500-m event, the kinetics of P(an) was characterized by a first-order system as P(an) = 88 + 556e(-0.0494t) (in W, where t is time). The rate constant for the increase in P(aer) was -0.153 s(-1), the time delay was 8.7 s, and the peak P(aer) was 234 W; P(aer) was equal to 234[1 - e(-0.153(t-8.7))] (in W). Skating position changed with preextension knee angle increasing and trunk angle decreasing throughout the event. We concluded the pattern of P(aer) to be quite similar to that reported during other competitive imitations, with the exception that the increase in P(aer) was more rapid. The pattern of P(an) does not appear to fit an "all-out" pattern, with near zero values during the last portion of the event, as assumed in our previous model (De Koning JJ, de Groot G, and van Ingen Schenau GJ. J Biomech 25: 573-580, 1992). Skating position changed in ways different from those assumed in our previous model. In addition to allowing improved predictions, the results demonstrate the importance of observations in unique subjects to the process of model construction.

The physiological and biomechanical contributions of poling to roller ski skating.

Science.gov (United States)

Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2013-08-01

Poling is considered to make a significant contribution to cross-country skiing with the skating technique. To better understand this contribution, the current investigation compared roller ski skating on a treadmill with the so-called G3 skating technique with (G3-P) and without poling (G3-NP). Seven male elite skiers performed 5-min submaximal tests at 8, 12, and 15 km h(-1), as well as an incremental test to exhaustion with both techniques on a 5 % incline. Ventilatory variables were assessed by open-circuit indirect calorimetry and three-dimensional kinematics analyzed using the Qualisys Pro Reflex system. G3-P was associated with approximately 15 % higher peak velocity and 10 % higher peak oxygen uptake than G3-NP in the incremental test (both P skating, specifically by enhancing peak oxygen uptake, skiing efficiency and associated biomechanical variables.

50 CFR 648.322 - Skate allocation, possession, and landing provisions.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Skate allocation, possession, and landing provisions. 648.322 Section 648.322 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the NE Skate...

Skate Bathyraja spp. egg predation in the eastern Bering Sea.

Science.gov (United States)

Hoff, G R

2009-01-01

Predation on skate eggs by snails was examined for three skate species at seven nursery sites in three regions (north, middle and south) of the eastern Bering Sea. Mean predation levels were 6.46% for the Alaska skate Bathyraja parmifera, 2.65% for the Aleutian skate Bathyraja aleutica and 22.25% for the Bering skate Bathyraja interrupta. Predation levels were significantly higher at the middle and north sites than the south sites for all species combined. Predation levels decreased with increasing egg-case densities at all nursery sites, and the highest predation levels occurred where egg-case densities were very low. Predated egg-case density increased with increasing snail densities across all nursery sites examined. The Oregon triton Fusitriton oregonensis was the most abundant snail species at all nursery sites and displayed ability to drill holes in the egg case of B. parmifera. Holes left by predatory snails in egg cases of B. parmifera were significantly larger, and of different shape at the middle site compared to the south site. Holes in B. parmifera were also significantly larger than those in egg cases of B. interrupta across all sites examined. Egg cases of B. aleutica possess surface spines that cover the egg case and may inhibit predation by snails at a greater rate than that of the B. parmifera and B. interrupta, which have a smoother egg-case surface.

Welding skate with computerized controls

Science.gov (United States)

Wall, W. A., Jr.

1968-01-01

New welding skate concept for automatic TIG welding of contoured or double-contoured parts combines lightweight welding apparatus with electrical circuitry which computes the desired torch angle and positions a torch and cold-wire guide angle manipulator.

Inner-Outer Lane Advantage in Olympic 1000 Meter Speed Skating

NARCIS (Netherlands)

Kamst, Richard; Kuper, Gerard H.; Sierksma, Gerard; Talsma, Bertus G.

During the Olympic Games and the World Championships Single Distances the 1000m is skated by every skater only one time. However, there may be a difference in skating a 1000m race with a start in the inner and the outer lane that introduces an externality that introduces unfairness. We show that

Judging Anomalies at the 2010 Olympics in Men's Figure Skating

Science.gov (United States)

Looney, Marilyn A.

2012-01-01

The purpose of this study was to determine if the 2010 Olympic figure skating judges had trouble scoring Plushenko and the transitions program component, and if the International Skating Union's (ISU) "corridor" method flagged the same judging anomalies as the Rasch analyses. A 3-facet (skater by program component by judge) Rasch rating…

Endurance in speed skating

NARCIS (Netherlands)

Kuper, G.H.; Sterken, E.

2002-01-01

We analyse the development of world records speed skating from 1893 to 2000 for bothmen and women. The historical data show that it is likely that the relation betweenskating speed and distance of the various events is non-linear and converges to a limitvalue. We pay special attention to technical

Three-dimensional kinematics of the lower limbs during forward ice hockey skating.

Science.gov (United States)

Upjohn, Tegan; Turcotte, René; Pearsall, David J; Loh, Jonathan

2008-05-01

The objectives of the study were to describe lower limb kinematics in three dimensions during the forward skating stride in hockey players and to contrast skating techniques between low- and high-calibre skaters. Participant motions were recorded with four synchronized digital video cameras while wearing reflective marker triads on the thighs, shanks, and skates. Participants skated on a specialized treadmill with a polyethylene slat bed at a self-selected speed for 1 min. Each participant completed three 1-min skating trials separated by 5 min of rest. Joint and limb segment angles were calculated within the local (anatomical) and global reference planes. Similar gross movement patterns and stride rates were observed; however, high-calibre participants showed a greater range and rate of joint motion in both the sagittal and frontal planes, contributing to greater stride length for high-calibre players. Furthermore, consequent postural differences led to greater lateral excursion during the power stroke in high-calibre skaters. In conclusion, specific kinematic differences in both joint and limb segment angle movement patterns were observed between low- and high-calibre skaters.

Anti-Runaway Prevention System with Wireless Sensors for Intelligent Track Skates at Railway Stations

Directory of Open Access Journals (Sweden)

Chaozhe Jiang

2017-12-01

Full Text Available Anti-runaway prevention of rolling stocks at a railway station is essential in railway safety management. The traditional track skates for anti-runaway prevention of rolling stocks have some disadvantages since they are operated and monitored completely manually. This paper describes an anti-runaway prevention system (ARPS based on intelligent track skates equipped with sensors and real-time monitoring and management system. This system, which has been updated from the traditional track skates, comprises four parts: intelligent track skates, a signal reader, a database station, and a monitoring system. This system can monitor the real-time situation of track skates without changing their workflow for anti-runaway prevention, and thus realize the integration of anti-runaway prevention information management. This system was successfully tested and practiced at Sunjia station in Harbin Railway Bureau in 2014, and the results confirmed that the system showed 100% accuracy in reflecting the usage status of the track skates. The system could meet practical demands, as it is highly reliable and supports long-distance communication.

Anti-Runaway Prevention System with Wireless Sensors for Intelligent Track Skates at Railway Stations.

Science.gov (United States)

Jiang, Chaozhe; Xu, Yibo; Wen, Chao; Chen, Dilin

2017-12-19

Anti-runaway prevention of rolling stocks at a railway station is essential in railway safety management. The traditional track skates for anti-runaway prevention of rolling stocks have some disadvantages since they are operated and monitored completely manually. This paper describes an anti-runaway prevention system (ARPS) based on intelligent track skates equipped with sensors and real-time monitoring and management system. This system, which has been updated from the traditional track skates, comprises four parts: intelligent track skates, a signal reader, a database station, and a monitoring system. This system can monitor the real-time situation of track skates without changing their workflow for anti-runaway prevention, and thus realize the integration of anti-runaway prevention information management. This system was successfully tested and practiced at Sunjia station in Harbin Railway Bureau in 2014, and the results confirmed that the system showed 100% accuracy in reflecting the usage status of the track skates. The system could meet practical demands, as it is highly reliable and supports long-distance communication.

Laboratory- and field-based testing as predictors of skating performance in competitive-level female ice hockey.

Science.gov (United States)

Henriksson, Tommy; Vescovi, Jason D; Fjellman-Wiklund, Anncristine; Gilenstam, Kajsa

2016-01-01

The purpose of this study was to examine whether field-based and/or laboratory-based assessments are valid tools for predicting key performance characteristics of skating in competitive-level female hockey players. Cross-sectional study. Twenty-three female ice hockey players aged 15-25 years (body mass: 66.1±6.3 kg; height: 169.5±5.5 cm), with 10.6±3.2 years playing experience volunteered to participate in the study. The field-based assessments included 20 m sprint, squat jump, countermovement jump, 30-second repeated jump test, standing long jump, single-leg standing long jump, 20 m shuttle run test, isometric leg pull, one-repetition maximum bench press, and one-repetition maximum squats. The laboratory-based assessments included body composition (dual energy X-ray absorptiometry), maximal aerobic power, and isokinetic strength (Biodex). The on-ice tests included agility cornering s-turn, cone agility skate, transition agility skate, and modified repeat skate sprint. Data were analyzed using stepwise multivariate linear regression analysis. Linear regression analysis was used to establish the relationship between key performance characteristics of skating and the predictor variables. Regression models (adj R (2)) for the on-ice variables ranged from 0.244 to 0.663 for the field-based assessments and from 0.136 to 0.420 for the laboratory-based assessments. Single-leg tests were the strongest predictors for key performance characteristics of skating. Single leg standing long jump alone explained 57.1%, 38.1%, and 29.1% of the variance in skating time during transition agility skate, agility cornering s-turn, and modified repeat skate sprint, respectively. Isokinetic peak torque in the quadriceps at 90° explained 42.0% and 32.2% of the variance in skating time during agility cornering s-turn and modified repeat skate sprint, respectively. Field-based assessments, particularly single-leg tests, are an adequate substitute to more expensive and time

Validation of a Maximal Incremental Skating Test Performed on a Slide Board: Comparison With Treadmill Skating.

Science.gov (United States)

Piucco, Tatiane; Diefenthaeler, Fernando; Soares, Rogério; Murias, Juan M; Millet, Guillaume Y

2017-11-01

To investigate the criterion validity of a maximal incremental skating test performed on a slide board (SB). Twelve subelite speed skaters performed a maximal skating test on a treadmill and on a SB. Gas exchange threshold (GET), respiratory compensation point (RCP), and maximal variables were determined. Oxygen uptake ([Formula: see text]) (31.0 ± 3.2 and 31.4 ± 4.1 mL·min -1 ·kg -1 ), percentage of maximal [Formula: see text] ([Formula: see text]) (66.3 ± 4 and 67.7 ± 7.1%), HR (153 ± 14 and 150 ±12 bpm), and ventilation (59.8 ± 11.8 and 57.0 ± 10.7 L·min -1 ) at GET, and [Formula: see text] (42.5 ± 4.4 and 42.9 ± 4.8 mL·min -1 ·kg -1 ), percentage of [Formula: see text] (91.1 ± 3.3 and 92.4 ± 2.1%), heart rate (HR) (178 ± 9 and 178 ± 6 bpm), and ventilation (96.5 ± 19.2 and 92.1 ± 12.7 L·min -1 ) at RCP were not different between skating on a treadmill and on a SB. [Formula: see text] (46.7 ± 4.4 vs 46.4 ±6.1 mL·min -1 ·kg -1 ) and maximal HR (195 ± 6 vs 196 ± 10 bpm) were not significantly different and correlated (r = .80 and r = .87, respectively; P  .8) with athletes' best times on 1500 m. The incremental skating test on a SB was capable to distinguish maximal ([Formula: see text] and HR) and submaximal ([Formula: see text], % [Formula: see text], HR, and ventilation) parameters known to determine endurance performance. Therefore, the SB test can be considered as a specific and practical alternative to evaluate speed skaters.

Getting the Angles Straight in Speed Skating : A Validation Study on an IMU Filter Design to Measure the Lean Angle of the Skate on the Straights

NARCIS (Netherlands)

Van Der Kruk, E.; Schwab, A. L.; Van Der Helm, F. C.T.; Veeger, H. E.J.

2016-01-01

To assist speed skaters in improving their skating performance, we would like to provide them with real time feedback on the orientation of the skate within a single stroke. While of course the forces generated by the skater on the ice determine the acceleration of the skater, the orientation of the

Getting the angles straight in speed skating : A validation study on an IMU filter design to measure the lean angle of the skate on the straights

NARCIS (Netherlands)

van der Kruk, E.; Schwab, A.L.; van der Helm, F.C.T.; Veeger, H.E.J.; van der Helm, FCT; Jansen, AJ

2016-01-01

To assist speed skaters in improving their skating performance, we would like to provide them with real time feedback on the orientation of the skate within a single stroke. While of course the forces generated by the skater on the ice determine the acceleration of the skater, the orientation of

Relationship between strength qualities and short track speed skating performance in young athletes.

Science.gov (United States)

Felser, S; Behrens, M; Fischer, S; Heise, S; Bäumler, M; Salomon, R; Bruhn, S

2016-02-01

This study analyzed the relationships between isometric as well as concentric maximum voluntary contraction (MVC) strength of the leg muscles and the times as well as speeds over different distances in 17 young short track speed skaters. Isometric as well as concentric single-joint MVC strength and multi-joint MVC strength in a stable (without skates) and unstable (with skates) condition were tested. Furthermore, time during maximum skating performances on ice was measured. Results indicate that maximum torques during eversion and dorsal flexion have a significant influence on skating speed. Concentric MVC strength of the knee extensors was higher correlated with times as well as speeds over the different distances than isometric MVC strength. Multi-joint MVC testing revealed that the force loss between measurements without and with skates amounts to 25%, while biceps femoris and soleus showed decreased muscle activity and peroneus longus, tibialis anterior, as well as rectus femoris exhibited increased muscle activity. The results of this study depict evidence that the skating times and speeds are primarily influenced by concentric MVC strength of the leg extensors. To be able to transfer the strength onto ice in an optimal way, it is necessary to stabilize the knee and ankle joints. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ice skating promotes postural control in children.

Science.gov (United States)

Keller, M; Röttger, K; Taube, W

2014-12-01

High fall rates causing injury and enormous financial costs are reported for children. However, only few studies investigated the effects of balance training in children and these studies did not find enhanced balance performance in postural (transfer) tests. Consequently, it was previously speculated that classical balance training might not be stimulating enough for children to adequately perform these exercises. Therefore, the aim of this study is to evaluate the influence of ice skating as an alternative form of balance training. Volunteers of an intervention (n = 17; INT: 13.1 ± 0.4 years) and a control group (n = 13; CON: 13.2 ± 0.3 years) were tested before and after training in static and dynamic postural transfer tests. INT participated in eight sessions of ice skating during education lessons, whereas CON participated in normal physical education. Enhanced balance performance was observed in INT but not in CON when tested on an unstable free-swinging platform (P skating in children. More importantly, participating children improved static and dynamic balance control in postural tasks that were not part of the training. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of layback spin in figure skating

Directory of Open Access Journals (Sweden)

Jastšenjski Ksenija

2011-01-01

Full Text Available Layback spin is considered as one of the most beautiful and elegant spins performed in figure skating. It is also one of the required spins in competitive short program in female category. Different techniques of executing layback spin with variations in changing the positions of free parts of the body, as well as the evaluation of layback spin in accordance with ISU rules and regulations, which have been used in all International Skating Federation competitions since 2004 (World and European championships, Olympic Games are presented in this paper. Due to very difficult position of the body while performing a layback spin, it is essential that the skaters who want to master it should have excellent agility (especially of the spinal column and shoulder and knee joints and balance. Layback spin performance requires significant skating knowledge, so it cannot be performed by beginners. Depending on the fl exibility and creativity, a skater can execute various positions of the head, arms, body and free leg while performing a layback spin. In some cases, these variations can increase the level of difficulty, and in others only the mark given for executing this spin.

The Olympic 500-m speed skating; the inner-outer lane difference

NARCIS (Netherlands)

Kamst, Richard; Kuper, Gerard H.; Sierksma, Gerard

2010-01-01

In 1998, the International Skating Union and the International Olympic Committee decided to skate the 500-m twice during World Single Distances Championships, Olympic Games, and World Cups. The decision was based on a study by the Norwegian statistician N. L. Hjort, who showed that in the period

The Olympic 500-m speed skating; the inner-outer lane difference

NARCIS (Netherlands)

Kamst, Richard; Kuper, Gerard H.; Sierksma, Gerard

In 1998, the International Skating Union and the International Olympic Committee decided to skate the 500-m twice during World Single Distances Championships, Olympic Games, and World Cups. The decision was based on a study by the Norwegian statistician N. L. Hjort, who showed that in the period

Instructional Basics: Oppelt Standard Method of Therapeutic and Recreational Ice Skating.

Science.gov (United States)

Oppelt, Kurt

Detailed in the booklet is the standard ice skating method and considered are the benefits of therapeutic ice skating for the handicapped and aged. Values for the mentally retarded and physically handicapped are seen to include physiological (such as increased flexibility and improved posture), psychological (including satifaction and enhanced…

Interannual variability in the skate assemblage on the South Patagonian shelf and slope.

Science.gov (United States)

Winter, A; Pompert, J; Arkhipkin, A; Brewin, P E

2015-12-01

Observer data from the commercial fishery on the Patagonian shelf and slope around the Falkland Islands (home to an assemblage of >16 skate species (Rajiformes), for which commercial catches have been recorded since 1987), as well as survey data from an area closed to skate target fishing after exploitation, were summarized by species to examine changes in the population status of individual skate species. Total skate catch per unit effort increased significantly in the target fishery since 1994, and four species have made up >85% of all skate catch. Bathyraja brachyurops and Zearaja chilensis increased significantly in catch proportions and abundance from 1994 to 2013. Bathyraja albomaculata and Bathyraja griseocauda decreased significantly before rebounding with trends of increasing abundance. Concurrently, B. brachyurops and Z. chilensis showed decreasing trends in size at 50% maturity in areas where skates continue to be targeted commercially. The increasing abundances and concomitant reductions in size at maturity of B. brachyurops and Z. chilensis suggest either plasticity in life-history traits or a density-dependent growth response to fishing pressure. Bathyraja griseocauda decreased in size at 50% maturity in the area that was closed to skate target fishing, where it was initially larger, but only decreased to the same average size as in the commercially targeted areas. Bathyraja albomaculata and Z. chilensis are IUCN-listed as vulnerable and B. griseocauda is listed as endangered, but their abundance trends since 1994 indicate that these populations are not declining in Falkland waters. © 2015 The Fisheries Society of the British Isles.

Nanofriction: Skating on hot surfaces

Science.gov (United States)

Meyer, Ernst; Gnecco, Enrico

2007-03-01

Simulations of nanoscale sharp tips sliding on a salt surface predict vanishing friction at temperatures close to the melting temperature, as the tip skates on a layer of liquefied salt. This insight opens the way to applications in MEMS, NEMS and auto/aerospace engines.

Validation of the Sensewear Armband during recreational in-line skating.

Science.gov (United States)

Soric, Maroje; Mikulic, Pavle; Misigoj-Durakovic, Marjeta; Ruzic, Lana; Markovic, Goran

2012-03-01

Multi-sensor body monitors that combine accelerometry with other physiological data are designed to overcome drawbacks of accelerometers in assessing activities with little or no vertical movement. One of such devices is the Sensewear Armband (SWA) which has been extensively validated during various activities. However, very few of the validation studies included activities other than walking and running. The aim of this investigation was to assess the validity of the SWA during recreational in-line skating. Nineteen participants (11 females and 8 males), 28 (±6) years of age, performed in-line skating exercise on a circular track at a self-selected pace. Energy expenditure was measured with the SWA and the Cosmed K4b(2) breath-by-breath portable metabolic unit. The mean (SD) energy expenditure during in-line skating estimated by the SWA [25.5 (5.8) kJ/min] was significantly lower compared with indirect calorimetry [44.2 (9.7) kJ/min, P skating by as much as 24-56% compared with indirect calorimetry. In conclusion, the results of the present study indicate that the SWA is not able to overcome the drawbacks of accelerometry in assessing activities with limited vertical movement.

The implementation of a municipal indoor ice skating helmet policy: effects on helmet use, participation and attitudes.

Science.gov (United States)

O'Mahony-Menton, Colleen; Willmore, Jacqueline; Russell, Katherine

2015-12-01

In Ottawa, between 2005 and 2009 there was an annual average of 47.2 head injuries due to ice skating in children and youth (1-19 years of age) requiring a visit to the emergency department, with the highest rates among those aged 5-14 years. Between 2002 and 2007, only 6% of children were wearing a helmet during ice skating when the head injury occurred. During indoor public skating sessions, 93% of children (skating helmet policy coupled with education and promotional activities on helmet use, participation and attitudes towards helmet use. An ice skating helmet policy for children (skating experience at indoor rinks during public skating sessions was developed, implemented and evaluated. Supportive activities such as discount coupons, promotional materials, a media launch, social marketing and staff training are described. The helmet policy was associated with increased helmet use for young children and for older children, youth and adults not included in the policy, without decreasing attendance to public skating sessions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Reliability and Validity of the Inline Skating Skill Test

Directory of Open Access Journals (Sweden)

Ivan Radman, Lana Ruzic, Viktoria Padovan, Vjekoslav Cigrovski, Hrvoje Podnar

2016-09-01

Full Text Available This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male were randomized into two groups (competitive level vs. recreational level. They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8–2.6%] – 2.2% [95% CI: 0.0–4.5%]. In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2–2.4%] – 2.7% [95% CI: 2.1–4.0%] and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92–0.99] – 0.99 [95% CI: 0.98–1.00]. The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2 revealed that the skill test was able to track changes in skaters’ performances. Competitive-level skaters needed shorter time (24.4–26.4%, all p < 0.01 to complete the test in comparison to recreational-level skaters. Moreover, moderate correlation (ρ = 0.80–0.82; all p < 0.01 was observed between the participant’s self-rating and achieved performance times. In conclusion, the proposed test is a reliable and valid method to evaluate inline skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters.

The evaluation of speed skating helmet performance through peak linear and rotational accelerations.

Science.gov (United States)

Karton, Clara; Rousseau, Philippe; Vassilyadi, Michael; Hoshizaki, Thomas Blaine

2014-01-01

Like many sports involving high speeds and body contact, head injuries are a concern for short track speed skating athletes and coaches. While the mandatory use of helmets has managed to nearly eliminate catastrophic head injuries such as skull fractures and cerebral haemorrhages, they may not be as effective at reducing the risk of a concussion. The purpose of this study was to evaluate the performance characteristics of speed skating helmets with respect to managing peak linear and peak rotational acceleration, and to compare their performance against other types of helmets commonly worn within the speed skating sport. Commercially available speed skating, bicycle and ice hockey helmets were evaluated using a three-impact condition test protocol at an impact velocity of 4 m/s. Two speed skating helmet models yielded mean peak linear accelerations at a low-estimated probability range for sustaining a concussion for all three impact conditions. Conversely, the resulting mean peak rotational acceleration values were all found close to the high end of a probability range for sustaining a concussion. A similar tendency was observed for the bicycle and ice hockey helmets under the same impact conditions. Speed skating helmets may not be as effective at managing rotational acceleration and therefore may not successfully protect the user against risks associated with concussion injuries.

An on-ice measurement approach to analyse the biomechanics of ice hockey skating.

Science.gov (United States)

Buckeridge, Erica; LeVangie, Marc C; Stetter, Bernd; Nigg, Sandro R; Nigg, Benno M

2015-01-01

Skating is a fundamental movement in ice hockey; however little research has been conducted within the field of hockey skating biomechanics due to the difficulties of on-ice data collection. In this study a novel on-ice measurement approach was tested for reliability, and subsequently implemented to investigate the forward skating technique, as well as technique differences across skill levels. Nine high caliber (High) and nine low caliber (Low) hockey players performed 30 m forward skating trials. A 3D accelerometer was mounted to the right skate for the purpose of stride detection, with the 2nd and 6th strides defined as acceleration and steady-state, respectively. The activity of five lower extremity muscles was recorded using surface electromyography. Biaxial electro-goniometers were used to quantify hip and knee angles, and in-skate plantar force was measured using instrumented insoles. Reliability was assessed with the coefficient of multiple correlation, which demonstrated moderate (r>0.65) to excellent (r>0.95) scores across selected measured variables. Greater plantar-flexor muscle activity and hip extension were evident during acceleration strides, while steady state strides exhibited greater knee extensor activity and hip abduction range of motion (p<0.05). High caliber exhibited greater hip range of motion and forefoot force application (p<0.05). The successful implementation of this on-ice mobile measurement approach offers potential for athlete monitoring, biofeedback and training advice.

Variable-speed, portable routing skate

Science.gov (United States)

Pesch, W. A.

1967-01-01

Lightweight, portable, variable-speed routing skate is used on heavy metal subassemblies which are impractical to move to a stationary machine. The assembly, consisting of the housing with rollers, router, and driving mechanism with transmission, weighs about forty pounds. Both speed and depth of cut are adjustable.

First evidence of persistent organic contaminants as potential anthropogenic stressors in the Barndoor Skate Dipturus laevis.

Science.gov (United States)

Lyons, Kady; Adams, Douglas H

2017-03-15

Although exploited populations of elasmobranchs may be able to recover from fishing pressure, there is little information regarding the Barndoor Skate's ability to cope with other anthropogenic stressors such as organic contaminants (OCs). Legacy OCs were measured in liver, muscle and ova from fourteen Barndoor Skates with mature skates having significantly greater mean concentrations of OCs than immature skates, demonstrating bioaccumulation with age. Using Toxic Equivalency Factors, skates were found to have levels of PCBs that have been shown to elicit negative physiological responses in other fishes and these results highlight the need for future studies to investigate the potential impacts that bioaccumulated organic contaminants have on the recovery and conservation of this vulnerable species. Copyright © 2017 Elsevier Ltd. All rights reserved.

An on-ice measurement approach to analyse the biomechanics of ice hockey skating.

Directory of Open Access Journals (Sweden)

Erica Buckeridge

Full Text Available Skating is a fundamental movement in ice hockey; however little research has been conducted within the field of hockey skating biomechanics due to the difficulties of on-ice data collection. In this study a novel on-ice measurement approach was tested for reliability, and subsequently implemented to investigate the forward skating technique, as well as technique differences across skill levels. Nine high caliber (High and nine low caliber (Low hockey players performed 30 m forward skating trials. A 3D accelerometer was mounted to the right skate for the purpose of stride detection, with the 2nd and 6th strides defined as acceleration and steady-state, respectively. The activity of five lower extremity muscles was recorded using surface electromyography. Biaxial electro-goniometers were used to quantify hip and knee angles, and in-skate plantar force was measured using instrumented insoles. Reliability was assessed with the coefficient of multiple correlation, which demonstrated moderate (r>0.65 to excellent (r>0.95 scores across selected measured variables. Greater plantar-flexor muscle activity and hip extension were evident during acceleration strides, while steady state strides exhibited greater knee extensor activity and hip abduction range of motion (p<0.05. High caliber exhibited greater hip range of motion and forefoot force application (p<0.05. The successful implementation of this on-ice mobile measurement approach offers potential for athlete monitoring, biofeedback and training advice.

A therapeutic skating intervention for children with autism spectrum disorder.

Science.gov (United States)

Casey, Amanda Faith; Quenneville-Himbeault, Gabriel; Normore, Alexa; Davis, Hanna; Martell, Stephen G

2015-01-01

The purpose of this study was to evaluate the effects of a highly structured therapeutic skating intervention on motor outcomes and functional capacity in 2 boys with autism spectrum disorder aged 7 and 10 years. This multiple-baseline, single-subject study assigned participants to three 1-hour skating sessions per week for 12 weeks focusing on skill and motor development. Multiple data points assessed (a) fidelity to the intervention and (b) outcomes measures including the Pediatric Balance Scale, Timed Up and Go, floor to stand, Six-Minute Walk Test, goal attainment, and weekly on-ice testing. Improvements were found in balance, motor behavior, and functional capacity by posttest with gains remaining above pretest levels at follow-up. Therapeutic skating may produce physical benefits for children with autism spectrum disorder and offer a viable, inexpensive community-based alternative to other forms of physical activity.

A review of the physics of ice surface friction and the development of ice skating.

Science.gov (United States)

Formenti, Federico

2014-01-01

Our walking and running movement patterns require friction between shoes and ground. The surface of ice is characterised by low friction in several naturally occurring conditions, and compromises our typical locomotion pattern. Ice skates take advantage of this slippery nature of ice; the first ice skates were made more than 4000 years ago, and afforded the development of a very efficient form of human locomotion. This review presents an overview of the physics of ice surface friction, and discusses the most relevant factors that can influence ice skates' dynamic friction coefficient. It also presents the main stages in the development of ice skating, describes the associated implications for exercise physiology, and shows the extent to which ice skating performance improved through history. This article illustrates how technical and materials' development, together with empirical understanding of muscle biomechanics and energetics, led to one of the fastest forms of human powered locomotion.

76 FR 28328 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Framework Adjustment 1

Science.gov (United States)

2011-05-17

... possession limits for the skate wing fishery in order to slow the rate of skate wing landings, so that the... (Council), 50 Water Street, Newburyport, MA 01950. These documents are also available online at http://www... skate wings on board. This ratio, based upon established wing-to-whole weight conversion factor for...

A Comparative Analysis of Selected Mechanical Aspects of the Ice Skating Stride.

Science.gov (United States)

Marino, G. Wayne

This study quantitatively analyzes selected aspects of the skating strides of above-average and below-average ability skaters. Subproblems were to determine how stride length and stride rate are affected by changes in skating velocity, to ascertain whether the basic assumption that stride length accurately approximates horizontal movement of the…

A esportivização do skate (1960-1990): relações entre o macro e o micro

OpenAIRE

Honorato, Tony

2013-01-01

O objetivo deste estudo foi apresentar elementos da esportivização da prática cultural skate (1960-1990), como conhecimento para o entendimento da relação entre o micro e o macro processo sócio-histórico do skate. Como fonte de pesquisa histórica para a esportivização do skate no Brasil, dimensão macro, utilizamos a Revista Tribo Skate e para a de Piracicaba/SP, dimensão micro, entrevistamos dois colaboradores a partir do método da história oral. Os resultados evidenciaram que o skate surgiu ...

Estado de fluxo em praticantes de escalada e skate downhill Flow state in climbing and skate downhill practitioners

Directory of Open Access Journals (Sweden)

Lenamar Fiorese Vieira

2011-12-01

Full Text Available Este estudo teve como objetivo investigar a prevalência do estado de fluxo em praticantes de escalada e skate downhill. Foram sujeitos 37 praticantes. Como instrumentos foram utilizadas a Escala de Motivação para o Esporte (SMS e a Ficha de Percepção de Capacidade de Realização da Tarefa. A coleta foi realizada nos locais de prática das atividades. Para análise dos dados foram utilizados Shapiro-Wilk, Mann-Whitney e Anova one-way. Os resultados demonstraram: 4,54% dos praticantes de escalada e 13,33% de skate downhill atingiram os elementos do estado de fluxo; a maioria dos praticantes situou-se entre a fase de fluxo estados de ansiedade ou relaxamento e exaltação ou controle; o tempo de prática contribuiu para atingir metas e estado de fluxo. Concluiu-se: o estado de Fluxo teve baixa incidência nos praticantes, havendo interferência da falta de equilíbrio entre percepção das metas, habilidades e desafios nas atividades de aventura.This study aimed to investigate the prevalence of Flow state in climbing and skate downhill practitioners. The subjects were 37 practitioners. The instruments used were the Sport Motivations Scale (SMS and Perception Capacity Achievement Task Form. Data collection was performed at the locations of these practice activities. For data analysis it was used the Shapiro-Wilk, Mann-Whitney and Anova one-way. The results showed: 4,54% of climbing practitioners and 13,33% of skate-downhill reached flow state elements; most of practitioners prevailed between the flow phase of anxiety or relaxation and phase of exaltation or control; and the practice time contributed to reach goals and Flow State. It was concluded that the Flow State had low prevalence in practitioners with interference of lack of balance between the perception of the goals, skills and challenges in the adventure activities.

Choreography Styles in Figure Skating

Science.gov (United States)

Moormann, Peter Paul

2006-01-01

Fifty-eight figure skating trainers from fifteen different countries acted as volunteers in this study on choreography styles. The styles were based on reports of artistic-creative strategies in composing music, drawing, writing poems or novels, and in making dances. The prevalence of the Mozartian (at the onset the choreographer already has a…

Three-dimensional Force and Kinematic Interactions in V1 Skating at High Speeds.

Science.gov (United States)

Stöggl, Thomas; Holmberg, Hans-Christer

2015-06-01

To describe the detailed kinetics and kinematics associated with use of the V1 skating technique at high skiing speeds and to identify factors that predict performance. Fifteen elite male cross-country skiers performed an incremental roller-skiing speed test (Vpeak) on a treadmill using the V1 skating technique. Pole and plantar forces and whole-body kinematics were monitored at four submaximal speeds. The propulsive force of the "strong side" pole was greater than that of the "weak side" (P skating at high speeds. The faster skiers exhibit more symmetric leg motion on the "strong" and "weak" sides, as well as more synchronized poling. With respect to methods, the pressure insoles and three-dimensional kinematics in combination with the leg push-off model described here can easily be applied to all skating techniques, aiding in the evaluation of skiing techniques and comparison of effectiveness.

Physiological correlates of skating performance in women's and men's ice hockey.

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Gilenstam, Kajsa M; Thorsen, Kim; Henriksson-Larsén, Karin B

2011-08-01

The purpose of the current investigation was to identify relationships between physiological off-ice tests and on-ice performance in female and male ice hockey players on a comparable competitive level. Eleven women, 24 ± 3.0 years, and 10 male ice hockey players, 23 ± 2.4 years, were tested for background variables: height, body weight (BW), ice hockey history, and lean body mass (LBM) and peak torque (PT) of the thigh muscles, VO2peak and aerobic performance (Onset of Blood Lactate Accumulation [OBLA], respiratory exchange ratio [RER1]) during an incremental bicycle ergometer test. Four different on-ice tests were used to measure ice skating performance. For women, skating time was positively correlated (p skating time was positively correlated to VO2peak (L O2·min(-1)) in the Acceleration test. The male group had significantly higher physiological test values in all variables (absolute and relative to BW) but not in relation to LBM. Selected off-ice tests predict skating performance for women but not for men. The group of women was significantly smaller and had a lower physiological performance than the group of men and were slower in the on-ice performance tests. However, gender differences in off-ice variables were reduced or disappeared when values were related to LBM, indicating a similar capacity of producing strength and aerobic power in female and male hockey players. Skating performance in female hockey players may be improved by increasing thigh muscle strength, oxygen uptake, and relative muscle mass.

Laboratory- and field-based testing as predictors of skating performance in competitive-level female ice hockey

Directory of Open Access Journals (Sweden)

Henriksson T

2016-08-01

Full Text Available Tommy Henriksson,1,2 Jason D Vescovi,3 Anncristine Fjellman-Wiklund,4 Kajsa Gilenstam1 1Sport Medicine Unit, Department of Community Medicine and Rehabilitation, 2The National Graduate School of Gender Studies, Umeå University, Umeå, Sweden; 3Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada; 4Physiotherapy Unit, Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden Objectives: The purpose of this study was to examine whether field-based and/or laboratory-based assessments are valid tools for predicting key performance characteristics of skating in competitive-level female hockey players.Design: Cross-sectional study.Methods: Twenty-three female ice hockey players aged 15–25 years (body mass: 66.1±6.3 kg; height: 169.5±5.5 cm, with 10.6±3.2 years playing experience volunteered to participate in the study. The field-based assessments included 20 m sprint, squat jump, countermovement jump, 30-second repeated jump test, standing long jump, single-leg standing long jump, 20 m shuttle run test, isometric leg pull, one-repetition maximum bench press, and one-repetition maximum squats. The laboratory-based assessments included body composition (dual energy X-ray absorptiometry, maximal aerobic power, and isokinetic strength (Biodex. The on-ice tests included agility cornering s-turn, cone agility skate, transition agility skate, and modified repeat skate sprint. Data were analyzed using stepwise multivariate linear regression analysis. Linear regression analysis was used to establish the relationship between key performance characteristics of skating and the predictor variables.Results: Regression models (adj R2 for the on-ice variables ranged from 0.244 to 0.663 for the field-based assessments and from 0.136 to 0.420 for the laboratory-based assessments. Single-leg tests were the strongest predictors for key performance characteristics of skating. Single leg standing

Observed decreases in the Canadian outdoor skating season due to recent winter warming

International Nuclear Information System (INIS)

Damyanov, Nikolay N; Mysak, Lawrence A; Damon Matthews, H

2012-01-01

Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada. (letter)

Observed decreases in the Canadian outdoor skating season due to recent winter warming

Science.gov (United States)

Damyanov, Nikolay N.; Damon Matthews, H.; Mysak, Lawrence A.

2012-03-01

Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada.

Cost of a roller skating rink to the local accident and emergency department.

Science.gov (United States)

Nayeem, N; Shires, S E; Porter, J E

1990-01-01

A 14 month retrospective study was undertaken to determine the cost implications of the opening of a roller skating rink to the local hospital accident and emergency department (A and E). A total of 398 patients attended following injury at the roller skating rink, of whom 384 were included in the study. The estimated cost of their injuries was determined by the hospital accounts department. The average cost per patient attending the A and E department following roller skating injury was about 100 pounds. The total cost to the A and E department of all injuries sustained at the rink over this period was 38,412 pounds. The cost implications of opening a roller skating rink for the A and E department are considerable. If proposals for self-budgeting are applied, A and E departments will have to seek additional funding if such leisure facilities are opened in their vicinity. PMID:2097020

Relationship between body composition, leg strength, anaerobic power, and on-ice skating performance in division I men's hockey athletes.

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Potteiger, Jeffrey A; Smith, Dean L; Maier, Mark L; Foster, Timothy S

2010-07-01

The purpose of this study was to examine relationships between laboratory tests and on-ice skating performance in division I men's hockey athletes. Twenty-one men (age 20.7 +/- 1.6 years) were assessed for body composition, isokinetic force production in the quadriceps and hamstring muscles, and anaerobic muscle power via the Wingate 30-second cycle ergometer test. Air displacement plethysmography was used to determine % body fat (%FAT), fat-free mass (FFM), and fat mass. Peak torque and total work during 10 maximal effort repetitions at 120 degrees .s were measured during concentric muscle actions using an isokinetic dynamometer. Muscle power was measured using a Monark cycle ergometer with resistance set at 7.5% of body mass. On-ice skating performance was measured during 6 timed 89-m sprints with subjects wearing full hockey equipment. First length skate (FLS) was 54 m, and total length skate (TLS) was 89 m with fastest and average skating times used in the analysis. Correlation coefficients were used to determine relationships between laboratory testing and on-ice performance. Subjects had a body mass of 88.8 +/- 7.8 kg and %FAT of 11.9 +/- 4.6. First length skate-Average and TLS-Average skating times were moderately correlated to %FAT ([r = 0.53; p = 0.013] and [r = 0.57; p = 0.007]) such that a greater %FAT was related to slower skating speeds. First length skate-Fastest was correlated to Wingate percent fatigue index (r = -0.48; p = 0.027) and FLS-Average was correlated to Wingate peak power per kilogram body mass (r = -0.43; p = 0.05). Laboratory testing of select variables can predict skating performance in ice hockey athletes. This information can be used to develop targeted and effective strength and conditioning programs that will improve on-ice skating speed.

Injury severity in ice skating: an epidemiologic analysis using a standardised injury classification system.

Science.gov (United States)

Ostermann, Roman C; Hofbauer, Marcus; Tiefenböck, Thomas M; Pumberger, Matthias; Tiefenböck, Michael; Platzer, Patrick; Aldrian, Silke

2015-01-01

Although injuries sustained during ice skating have been reported to be more serious than other forms of skating, the potential injury risks are often underestimated by skating participants. The purpose of this study was to give a descriptive overview of injury patterns occurring during ice skating. Special emphasis was put on injury severity by using a standardised injury classification system. Over a six month period, all patients treated with ice-skating-related injuries at Europe's largest hospital were included. Patient demographics were collected and all injuries categorised according to the Abbreviated Injury Scale (AIS) 2005. A descriptive statistic and logistic regression analysis was performed. Three hundred and forty-one patients (134 M, 207 F) were included in this study. Statistical analysis revealed that age had a significant influence on injury severity. People > 50 years had a higher risk of sustaining a more severe injury according to the AIS compared with younger skaters. Furthermore, the risk of head injury was significantly lower for people aged between 18 and 50 years than for people  50 years than for people aged between 18 and 50 years (p = 0.04). The severity of ice-skating injuries is associated with the patient's age, showing more severe injuries in older patients. Awareness should be raised among the public and physicians about the risks associated with this activity in order to promote further educational interventions and the use of protective gear.

Chemical and Nutritional Characteristics of long nose skate (Raja rhina) byproducts from Alaska

Science.gov (United States)

Skates have recently become a small commercial fishery in Alaska and along the western United States coast, but have long been associated with bycatch. The fins are marketed as "skate wings" and mainly sold fresh, frozen, and dried or salted and dehydrated for Asian markets. Byproducts generated inc...

77 FR 25097 - Fisheries of the Northeastern United States; 2012-2013 Northeast Skate Complex Fishery...

Science.gov (United States)

2012-04-27

... landings of thorny skate, increase discards, and ultimately hinder the rebuilding of this stock. The... ongoing education and outreach efforts in the skate fishery to improve prohibited species compliance (e.g...

Roller Skating; Physical Education: 9.8414.

Science.gov (United States)

Amacker, Kathy; Mikell, Lenora

GRADES OR AGES: Grades 7-12. SUBJECT MATTER: Methods and procedures of roller skating. ORGANIZATION AND PHYSICAL APPEARANCE: The contents are divided into six areas, which are Course Guidelines, Course Description and Accreditation Standard Broad Goal, Course of Study Behavioral Objectives, Course Content, Learning Activities and Teaching…

Changes in speed skating velocity in relation to push-off effectiveness.

Science.gov (United States)

Noordhof, Dionne A; Foster, Carl; Hoozemans, Marco J M; de Koning, Jos J

2013-03-01

Speed skating posture, or technique, is characterized by the push-off angle or effectiveness (e), determined as the angle between the push-off leg and the ice; the preextension knee angle (θ(0)); and the trunk angle (θ(1)). Together with muscle-power output and environmental conditions, skating posture, or technique, determines velocity (v). To gain insight into technical variables that are important to skate efficiently and perform well, e, θ(0), θ(1), and skating v were determined every lap during a 5000-m World Cup. Second, the authors evaluated if changes (Δ) in e, θ(0), and θ(1) are associated with Δv. One camera filmed the skaters from a frontal view, from which e was determined. Another camera filmed the skaters from a sagittal view, from which θ(0) and θ(1) were determined. Radio-frequency identification tags around the ankles of the skaters measured v. During the race, e progressively increased and v progressively decreased, while θ(0) and θ(1) showed a less consistent pattern of change. Generalized estimating equations showed that Δe is significantly associated with Δv over the midsection of the race (β = -0.10, P < .001) and that Δθ(0) and Δθ(1) are not significantly associated with Δv. The decrease in skating v over the race is not due to increases in power losses to air friction, as knee and trunk angle were not significantly associated with changes in velocity. The decrease in velocity can be partly ascribed to the decrease in effectiveness, which reflects a decrease in power production associated with fatigue.

Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

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Pantoja Patrícia Dias

2014-07-01

Full Text Available This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions.

Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

Science.gov (United States)

Pantoja, Patrícia Dias; Mello, André; Liedtke, Giane Veiga; Kanitz, Ana Carolina; Cadore, Eduardo Lusa; Pinto, Stephanie Santana; Alberton, Cristine Lima; Kruel, Luiz Fernando Martins

2014-01-01

This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions. PMID:25114728

Comparison of split double and triple twists in pair figure skating.

Science.gov (United States)

King, Deborah L; Smith, Sarah L; Brown, Michele R; McCrory, Jean L; Munkasy, Barry A; Scheirman, Gary I

2008-05-01

In this study, we compared the kinematic variables of the split triple twist with those of the split double twist to help coaches and scientists understand these landmark pair skating skills. High-speed video was taken during the pair short and free programmes at the 2002 Salt Lake City Winter Olympics and the 2003 International Skating Union Grand Prix Finals. Three-dimensional analyses of 14 split double twists and 15 split triple twists from eleven pairs were completed. In spite of considerable variability in the performance variables among the pairs, the main difference between the split double twists and split triple twists was an increase in rotational rate. While eight of the eleven pairs relied primarily on an increased rotational rate to complete the split triple twist, three pairs employed a combined strategy of increased rotational rate and increased flight time due predominantly to delayed or lower catches. These results were similar to observations of jumps in singles skating for which the extra rotation is typically due to an increase in rotational velocity; increases in flight time come primarily from delayed landings as opposed to additional height during flight. Combining an increase in flight time and rotational rate may be a good strategy for completing the split triple twist in pair skating.

Bilirubin metabolism in the spiny dogfish, Squalus acanthias, and the small skate, Raja erinacea

NARCIS (Netherlands)

Jansen, P. L.; Arias, I. M.

1977-01-01

1. The main bilirubin conjugate in bile of spiny dogfish (Squalus Acanthias) and small skate (Raja Erinacea) is bilirubin monoglucuronide. 2. Microsomal preparations from dogfish and small skate liver have similar bilirubin UDPglucuronyltransferase (UDPGT) activity and catalyze the conjugation of

Effects of Climate Change on Outdoor Skating in the Bei Hai Park of Beijing and Related Adaptive Strategies

Directory of Open Access Journals (Sweden)

Jun Liu

2017-06-01

Full Text Available This paper reports findings derived from a study of the impacts of climate change on winter outdoor skating activities in the Chinese park of Bei Hai from 1989 to 2015. Based on field observation data and in-depth interviews, it was concluded that the outdoor skating activities, with a history of more than 1000 years, are being threatened by the warming climate. The opening dates and duration times of skating over the last 26 years showed periodic variations over three-year cycles. Increases of temperatures by 1 °C in December were associated with a 3.80-day delay in the skating-field opening dates and a 4.49-day decrease in the operation duration times. In particular, climate change has resulted in a loss of the skating field area and a reduction in the operation duration times, and tourists are moving north for skating-related recreation or conducting alternative activities. The current adaptive strategies are not very effective.

Speed and heart-rate profiles in skating and classical cross-country skiing competitions.

Science.gov (United States)

Bolger, Conor M; Kocbach, Jan; Hegge, Ann Magdalen; Sandbakk, Øyvind

2015-10-01

To compare the speed and heart-rate profiles during international skating and classical competitions in male and female world-class cross-country skiers. Four male and 5 female skiers performed individual time trials of 15 km (men) and 10 km (women) in the skating and classical techniques on 2 consecutive days. Races were performed on the same 5-km course. The course was mapped with GPS and a barometer to provide a valid course and elevation profile. Time, speed, and heart rate were determined for uphill, flat, and downhill terrains throughout the entire competition by wearing a GPS and a heart-rate monitor. Times in uphill, flat, and downhill terrain were ~55%, 15-20%, and 25-30%, respectively, of the total race time for both techniques and genders. The average speed differences between skating and classical skiing were 9% and 11% for men and women, respectively, and these values were 12% and 15% for uphill, 8% and 13% for flat (all P skating and classical, respectively, with corresponding numbers of 11% and 14% for uphill, 6% and 11% for flat, and 4% and 5% for downhill terrain (all P skating and classical techniques and between the 2 genders were found on uphill terrain. Therefore, these speed differences could not be explained by variations in exercise intensity.

Stay Safe Riding Bikes or Skating Outside

Centers for Disease Control (CDC) Podcasts

2011-02-02

In this podcast for kids, the Kidtastics talk about safety when outside, riding bikes or skating.  Created: 2/2/2011 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 2/2/2011.

The effects of the arm swing on biomechanical and physiological aspects of roller ski skating.

Science.gov (United States)

Hegge, Ann Magdalen; Ettema, Gertjan; de Koning, Jos J; Rognstad, Asgeir Bakken; Hoset, Martin; Sandbakk, Øyvind

2014-08-01

This study analyzed the biomechanical and physiological effects of the arm swing in roller ski skating, and compared leg-skating (i.e. ski skating without poles) using a pronounced arm swing (SWING) with leg-skating using locked arms (LOCKED). Sixteen elite male cross-country skiers performed submaximal stages at 10, 15 and 20kmh(-1) on a 2% inclined treadmill in the two techniques. SWING demonstrated higher peak push-off forces and a higher force impulse at all speeds, but a longer cycle length only at the highest speed (all Pskating increases the ski forces and aerobic energy cost at low and moderate speeds, whereas the greater forces at high speed lead to a longer cycle length and smaller anaerobic contribution. Copyright © 2014 Elsevier B.V. All rights reserved.

cDNA cloning and characterization of Type I procollagen alpha1 chain in the skate Raja kenojei.

Science.gov (United States)

Hwang, Jae-Ho; Yokoyama, Yoshihiro; Mizuta, Shoshi; Yoshinaka, Reiji

2006-05-01

A full-length cDNA of the Type I procollagen alpha1 [pro-alpha1(I)] chain (4388 bp), coding for 1463 amino acid residues in the total length, was determined by RACE PCR using a cDNA library constructed from 4-week embryo of the skate Raja kenojei. The helical region of the skate pro-alpha1(I) chain consisted of 1014 amino acid residues - the same as other fibrillar collagen alpha chains from higher vertebrates. Comparison on denaturation temperatures of Type I collagens from the skate, rainbow trout (Oncorhynchus mykiss) and rat (Rattus norvegicus) revealed that the number of Gly-Pro-Pro and Gly-Gly in the alpha1(I) chains could be directly related to the thermal stability of the helix. The expression property of the skate pro-alpha1(I) chain mRNA and phylogenetic analysis with other vertebrate pro-alpha1(I) chains suggested that skate pro-alpha1(I) chain could be a precursor form of the skate Type I collagen alpha1 chain. The present study is the first evidence for the primary structure of full-length pro-alpha1(I) chain in an elasmobranch.

The Use of Simulation Training to Accelerate the Rate of Forward Ice Skating Skill Acquisition

Directory of Open Access Journals (Sweden)

Nathan J Washington

2016-04-01

Full Text Available Background: Australia’s interest and participation in ice hockey is increasing, however a lack of access to facilities means familiarity with this sport is limited, and so too is the facilitation of skill development within an ecologically valid context. Objective: While numerous methods may be employed to address this, one resource which remains relatively unexplored is the StrideDeck Treadmill, therefore the purpose of this study was to investigate the effectiveness of this equipment with specific reference to the biomechanical changes for skating ability. Methods: N = 16 male athletes (Mage = 15.0 ± 0.76 yrs from a junior league competition participated in this intervention based study. n = 9 were assigned to the training intervention (StrideDeck once a week, while the control group (n = 7 continued their normal training routines. Further, monthly sprint tests both on the StrideDeck and an on-ice protocol were conducted to track progress via kinematic analysis. Results: Data analysis revealed no significant overall effects for on-ice sprint skating performance after StrideDeck training; however there were significant kinematic differences between StrideDeck and ice conditions. Conclusions: Therefore while the StrideDeck may have merit in regard to physiological paramters, the results of this study do not support its use as a skill acquisition tool in regard to increasing skating ability. Keywords: Simulation training, skill acquisition, treadmill, ice skating, ice hockey skating, ice skating stride

Relationship Between Skating Economy and Performance During a Repeated-Shift Test in Elite and Subelite Ice Hockey Players.

Science.gov (United States)

Lamoureux, Nicholas R; Tomkinson, Grant R; Peterson, Benjamin J; Fitzgerald, John S

2018-04-01

Lamoureux, NR, Tomkinson, GR, Peterson, BJ, and Fitzgerald, JS. Relationship between skating economy and performance during a repeated-shift test in elite and subelite ice hockey players. J Strength Cond Res 32(4): 1109-1113, 2018-The purpose of this study was to determine the importance of skating economy to fatigue during repeated high-intensity efforts of a simulated ice hockey shift. Forty-five collegiate and Junior A male ice hockey players (aged 18-24 years) performed a continuous graded exercise test using a skate treadmill. Breath-by-breath data for oxygen consumption (V[Combining Dot Above]O2) and respiratory exchange ratio were collected and used to derive energy expenditure (EE) averaged over the final 10 seconds of each stage. Economy was determined as the slope of the regression line relating V[Combining Dot Above]O2 and EE against skating speed separately. Participants also completed 8 bouts of maximal ice skating through a course designed to simulate typical shift, with timing gates determining first half, second half, and total fatigue decrement, calculated by a percent decrement score. Partial correlation was used to determine the association between economy measures and decrement during the repeated-shift test. Twenty-six participants met inclusion criteria and were included in data analysis. Skating economy measures (both relative V[Combining Dot Above]O2 and EE) were very likely moderate positive correlates of total fatigue decrement (r [95% confidence interval]: V[Combining Dot Above]O2, 0.46 [0.09, 0.72] and EE, 0.44, [0.06, 0.71]) but not with first or second gate decrement. Our results indicate that skating economy plays an important role in fatigue resistance over repeated on-ice sprints designed to simulate a typical shift. This supports the use of technical skating coaching and training techniques to enhance skating economy as a means of improving ice hockey performance.

Three-dimensional kinematics of the knee and ankle joints for three consecutive push-offs during ice hockey skating starts.

Science.gov (United States)

Lafontaine, Dany

2007-09-01

Little biomechanical research has been conducted recently on hockey skating despite the sport's worldwide appeal. One reason for this lack of biomechanical knowledge stems from the difficulty of collecting data. The lack of accuracy, the disputable realism of treadmills, and the large field of view required are some of the technical challenges that have to be overcome. The main objective of the current study was to improve our knowledge of the joint kinematics during the skating stroke. A second objective was to improve the data collection system we developed and the third was to establish if a kinematic progression exists in the hockey skating stroke similar to that in speed skating. Relative motions at the knee and ankle joints were computed using a joint coordinate system approach. The differences at the knee joints in push-offs indicated that the skating skill was progressively changing with each push-off. The relative stability of the ankle angles can be attributed to the design of the skate boots, which have recently become very rigid. Further research on ice hockey skating is warranted and should include more skaters and investigate the effect various starting strategies and variations in equipment have on skaters' performance.

Volumetric analysis of cerebellum in short-track speed skating players.

Science.gov (United States)

Park, In Sung; Lee, Nam Joon; Kim, Tae-Young; Park, Jin-Hoon; Won, Yu-Mi; Jung, Yong-Ju; Yoon, Jin-Hwan; Rhyu, Im Joo

2012-12-01

The cerebellum is associated with balance control and coordination, which might be important for gliding on smooth ice at high speeds. A number of case studies have shown that cerebellar damage induces impaired balance and coordination. As a positive model, therefore, we investigated whether plastic changes in the volumes of cerebellar subregions occur in short-track speed skating players who must have extraordinary abilities of balance and coordination, using three-dimensional magnetic resonance imaging volumetry. The manual tracing was performed and the volumes of cerebellar hemisphere and vermian lobules were compared between short-track speed skating players (n=16) and matched healthy controls (n=18). We found larger right cerebellar hemisphere volume and vermian lobules VI-VII (declive, folium, and tuber) in short-track speed skating players in comparison with the matched controls. The finding suggests that the specialized abilities of balance and coordination are associated with structural plasticity of the right hemisphere of cerebellum and vermian VI-VII and these regions play an essential role in balance and coordination.

Calcium Activated K+ Channels in The Electroreceptor of the Skate Confirmed by Cloning. Details of Subunits and Splicing

Science.gov (United States)

King, Benjamin L.; Shi, Ling Fang; Kao, Peter; Clusin, William T.

2015-01-01

Elasmobranchs detect small potentials using excitable cells of the ampulla of Lorenzini which have calcium-activated K+ channels, first described in l974. A distinctive feature of the outward current in voltage clamped ampullae is its apparent insensitivity to voltage. The sequence of a BK channel α isoform expressed in the ampulla of the skate was characterized. A signal peptide is present at the beginning of the gene. When compared to human isoform 1 (the canonical sequence), the largest difference was absence of a 59 amino acid region from the S8-S9 intracellular linker that contains the strex regulatory domain. The ampulla isoform was also compared with the isoform predicted˜ in late skate embryos where strex was also absent. The BK voltage sensors were conserved in both skate isoforms. Differences between the skate and human BK channel included alternative splicing. Alternative splicing occurs at seven previously defined sites that are characteristic for BK channels in general and hair cells in particular. Skate BK sequences were highly similar to the Australian ghost shark and several other vertebrate species. Based on alignment of known BK sequences with the skate genome and transcriptome, there are at least two isoforms of Kcnma1α expressed in the skate. One of the β subunits (β4), which is known to decrease voltage sensitivity, was also identified in the skate genome and transcriptome and in the ampulla. These studies advance our knowledge of BK channels and suggest further studies in the ampulla and other excitable tissues. PMID:26687710

A esportivização do skate (1960-1990: relações entre o macro e o micro

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Tony Honorato

2013-03-01

Full Text Available O objetivo deste estudo foi apresentar elementos da esportivização da prática cultural skate (1960-1990, como conhecimento para o entendimento da relação entre o micro e o macro processo sócio-histórico do skate. Como fonte de pesquisa histórica para a esportivização do skate no Brasil, dimensão macro, utilizamos a Revista Tribo Skate e para a de Piracicaba/SP, dimensão micro, entrevistamos dois colaboradores a partir do método da história oral. Os resultados evidenciaram que o skate surgiu para gerar fortes tensões agradáveis, suas formas de lazer precedem as formas esportivas e, guardadas as particularidades, os seus processos macro e micro-históricos são interdependentes.

Seamount egg-laying grounds of the deep-water skate Bathyraja richardsoni.

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Henry, L-A; Stehmann, M F W; De Clippele, L; Findlay, H S; Golding, N; Roberts, J M

2016-08-01

Highly localized concentrations of elasmobranch egg capsules of the deep-water skate Bathyraja richardsoni were discovered during the first remotely operated vehicle (ROV) survey of the Hebrides Terrace Seamount in the Rockall Trough, north-east Atlantic Ocean. Conductivity-temperature-depth profiling indicated that the eggs were bathed in a specific environmental niche of well-oxygenated waters between 4·20 and 4·55° C, and salinity 34·95-35·06, on a coarse to fine-grained sandy seabed on the seamount's eastern flank, whereas a second type of egg capsule (possibly belonging to the skate Dipturus sp.) was recorded exclusively amongst the reef-building stony coral Solenosmilia variabilis. The depths of both egg-laying habitats (1489-1580 m) provide a de facto refuge from fisheries mortality for younger life stages of these skates. © 2016 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.

Difference in Agility, Strength, and Flexibility in Competitive Figure Skaters Based on Level of Expertise and Skating Discipline.

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Slater, Lindsay V; Vriner, Melissa; Zapalo, Peter; Arbour, Kat; Hart, Joseph M

2016-12-01

Slater, LV, Vriner, M, Zapalo, P, Arbour, K, and Hart, JM. Difference in agility, strength, and flexibility in competitive figure skaters based on level of expertise and skating discipline. J Strength Cond Res 30(12): 3321-3328, 2016-Figure skating is an extremely difficult sport that requires a combination of grace, artistry, flexibility, speed, and power. Although many skaters are involved with strength and conditioning programs, there is no current information about differences in off-ice performance measures based on skating discipline and level. The purpose of this study was to compare agility, strength, and flexibility performance based on skating discipline and level. A total of 343 figure skaters from 4 different disciplines (singles, dance, pair, and synchronized skating) and 3 different levels (novice, junior, and senior) completed combine testing with the United States Figure Skating Association. All subjects completed the hexagon agility test, t-test, triple bound jumps, vertical jump, timed tuck jumps, push-ups, v-ups, hand press, front split, seated reach, and stork pose. A multivariate analysis of variance with Scheffe's post hoc was used to identify differences in performance based on skating discipline and level. Mean differences, Cohen's d effect sizes, and 95% confidence intervals were reported for all significant differences. Senior and junior skaters tended to be faster and stronger than novice skaters. Singles, dance, and pair skaters tended to be more agile, stronger, and flexible than synchronized skaters, however, senior synchronized skaters tended to perform better than senior skaters in other disciplines. These results indicate that strength and conditioning professionals should consider skating discipline and level when designing strengthening programs for figure skaters.

Sensitivity of the International Skating Union's Mathematical Criteria to Flag Potential Scoring Anomalies

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Looney, Marilyn A.; Howell, Steven M.

2015-01-01

This article describes the "mathematical criteria" employed by the International Skating Union (ISU) to identify potential judging anomalies within competitive figure skating. The mathematical criteria have greater sensitivity to identify scoring anomalies for technical element scores than for the program component scores. This article…

Reproductive characteristics and population decline of four species of skate (Rajidae) off the eastern coast of Canada.

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Mcphie, R P; Campana, S E

2009-07-01

Four of the most common species of skate (Rajidae) were studied off eastern Canada to determine if their reproductive characteristics were linked to their population trajectories. The fecundity of the winter skate Leucoraja ocellata, the little skate Leucoraja erinacea, the thorny skate Amblyraja radiata and the smooth skate Malacoraja senta averaged between 41 and 56 egg cases per year for each species. For all species but L. ocellata, males matured at larger sizes and at later ages than females. Theoretical rates of population increase for non-equilibrium populations of L. ocellata (c. 0.07), M. senta (c. 0.14) and L. erinacea and A. radiata (c. 0.20) were low compared to most fishes, indicating that north-west Atlantic skates are intrinsically unproductive, yet are theoretically capable of supporting low-level fisheries. Nevertheless, the results of 36 years of research surveys indicate that the abundance of mature L. ocellata, A. radiata and M. senta all decreased by >90% since 1970, indicating that past fishing mortality (both directed and undirected) has outstripped the net productivity of the skate populations on the eastern Scotian Shelf. The relationship between maximum age (t(max)) and age of maturity (t(mat)) was a better predictor of population growth rate than was body size, with the species exhibiting the highest ratios of t(mat) :t(max) (L. ocellata = 0.68, M. senta = 0.66) having the lowest predicted population growth rates. L. ocellata appears to have the lowest productivity and has experienced the greatest population decline, thus raising concerns over its future status.

Biomechanical comparison of the double-push technique and the conventional skate skiing technique in cross-country sprint skiing.

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Stöggl, Thomas; Müller, Erich; Lindinger, Stefan

2008-09-01

The aims of the study were to: (1) adapt the "double-push" technique from inline skating to cross-country skiing; (2) compare this new skiing technique with the conventional skate skiing cross-country technique; and (3) test the hypothesis that the double-push technique improves skiing speed in a short sprint. 13 elite skiers performed maximum-speed sprints over 100 m using the double-push skate skiing technique and using the conventional "V2" skate skiing technique. Pole and plantar forces, knee angle, cycle characteristics, and electromyography of nine lower body muscles were analysed. We found that the double-push technique could be successfully transferred to cross-country skiing, and that this new technique is faster than the conventional skate skiing technique. The double-push technique was 2.9 +/- 2.2% faster (P push technique had a longer cycle length and a lower cycle rate, and it was characterized by higher muscle activity, higher knee extension amplitudes and velocities, and higher peak foot forces, especially in the first phase of the push-off. Also, the foot was more loaded laterally in the double-push technique than in the conventional skate skiing technique.

The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

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Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

2015-03-01

The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

How Much Water Is in the Skating Rink?

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Ameis, Jerry A.

2004-01-01

This article describes activities for developing an understanding of a formula for calculating the volume of a rectangular prism. The core activity concerns determining the volume of water in a backyard skating rink. (Contains 4 figures.)

Hepatic uptake and biliary excretion of manganese in the little skate, Leucoraja erinacea.

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Madejczyk, Michael S; Boyer, James L; Ballatori, Nazzareno

2009-05-01

The liver is a major organ involved in regulating whole body manganese (Mn) homeostasis; however, the mechanisms of Mn transport across the hepatocyte basolateral and canalicular membranes remain poorly defined. To gain insight into these transport steps, the present study measured hepatic uptake and biliary excretion of Mn in an evolutionarily primitive marine vertebrate, the elasmobranch Leucoraja erinacea, the little skate. Mn was rapidly removed from the recirculating perfusate of isolated perfused skate livers in a dose-dependent fashion; however, only a small fraction was released into bile (skate hepatocytes in culture. Mn uptake was inhibited by a variety of divalent metals, but not by cesium. Analysis of the concentration-dependence of Mn uptake revealed of two components, with apparent K(m) values 1.1+/-0.1 microM and 112+/-29 microM. The K(m) value for the high-affinity component was similar to the measured skate blood Mn concentration, 1.9+/-0.5 microM. Mn uptake was reduced by nearly half when bicarbonate was removed from the culture medium, but was unaffected by a change in pH from 6.5 to 8.5, or by substitution of Na with Li or K. Mn efflux from the hepatocytes was also rapid, and was inhibited when cells were treated with 0.5 mM 2,4-dinitrophenol to deplete ATP levels. These data indicate that skate liver has efficient mechanisms for removing Mn from the sinusoidal circulation, whereas overall biliary excretion is low and appears to be mediated in part by an ATP-sensitive mechanism.

Calcium activated K⁺ channels in the electroreceptor of the skate confirmed by cloning. Details of subunits and splicing.

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King, Benjamin L; Shi, Ling Fang; Kao, Peter; Clusin, William T

2016-03-01

Elasmobranchs detect small potentials using excitable cells of the ampulla of Lorenzini which have calcium-activated K(+) channels, first described in 1974. A distinctive feature of the outward current in voltage clamped ampullae is its apparent insensitivity to voltage. The sequence of a BK channel α isoform expressed in the ampulla of the skate was characterized. A signal peptide is present at the beginning of the gene. When compared to human isoform 1 (the canonical sequence), the largest difference was absence of a 59 amino acid region from the S8-S9 intra-cellular linker that contains the strex regulatory domain. The ampulla isoform was also compared with the isoform predicted in late skate embryos where strex was also absent. The BK voltage sensors were conserved in both skate isoforms. Differences between the skate and human BK channel included alternative splicing. Alternative splicing occurs at seven previously defined sites that are characteristic for BK channels in general and hair cells in particular. Skate BK sequences were highly similar to the Australian ghost shark and several other vertebrate species. Based on alignment of known BK sequences with the skate genome and transcriptome, there are at least two isoforms of Kcnma1α expressed in the skate. One of the β subunits (β4), which is known to decrease voltage sensitivity, was also identified in the skate genome and transcriptome and in the ampulla. These studies advance our knowledge of BK channels and suggest further studies in the ampulla and other excitable tissues. Copyright © 2015 Elsevier B.V. All rights reserved.

Inline skating for balance and strength promotion in children during physical education.

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Muehlbauer, Thomas; Kuehnen, Matthias; Granacher, Urs

2013-12-01

Deficiencies in balance and strength are common in children and they may lead to injuries. This study investigated the effects of inline skating exercise on balance and strength performance in healthy children. Twenty 11-12-year-old children (8 girls, 12 boys) were assigned to an intervention (n = 10) or a control (n = 10) group. Participants in the intervention group underwent a 4-week inline skating program (2 times/week, 90 min. each) integrated in their physical education lessons. Balance and strength were measured using the Star Excursion Balance test and the countermovement jump test. As compared to the control group, the intervention group significantly improved balance (17-48%, Cohen's d = 0.00-1.49) and jump height (8%, Cohen's d = 0.48). In children, inline skating is a safe, feasible (90% adherence rate), and effective program that can be integrated in physical education lessons to promote balance and strength.

Multiple Off-Ice Performance Variables Predict On-Ice Skating Performance in Male and Female Division III Ice Hockey Players.

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Janot, Jeffrey M; Beltz, Nicholas M; Dalleck, Lance D

2015-09-01

The purpose of this study was to determine if off-ice performance variables could predict on-ice skating performance in Division III collegiate hockey players. Both men (n = 15) and women (n = 11) hockey players (age = 20.5 ± 1.4 years) participated in the study. The skating tests were agility cornering S-turn, 6.10 m acceleration, 44.80 m speed, modified repeat skate, and 15.20 m full speed. Off-ice variables assessed were years of playing experience, height, weight and percent body fat and off-ice performance variables included vertical jump (VJ), 40-yd dash (36.58m), 1-RM squat, pro-agility, Wingate peak power and peak power percentage drop (% drop), and 1.5 mile (2.4km) run. Results indicated that 40-yd dash (36.58m), VJ, 1.5 mile (2.4km) run, and % drop were significant predictors of skating performance for repeat skate (slowest, fastest, and average time) and 44.80 m speed time, respectively. Four predictive equations were derived from multiple regression analyses: 1) slowest repeat skate time = 2.362 + (1.68 x 40-yd dash time) + (0.005 x 1.5 mile run), 2) fastest repeat skate time = 9.762 - (0.089 x VJ) - (0.998 x 40-yd dash time), 3) average repeat skate time = 7.770 + (1.041 x 40-yd dash time) - (0.63 x VJ) + (0.003 x 1.5 mile time), and 4) 47.85 m speed test = 7.707 - (0.050 x VJ) - (0.01 x % drop). It was concluded that selected off-ice tests could be used to predict on-ice performance regarding speed and recovery ability in Division III male and female hockey players. Key pointsThe 40-yd dash (36.58m) and vertical jump tests are significant predictors of on-ice skating performance specific to speed.In addition to 40-yd dash and vertical jump, the 1.5 mile (2.4km) run for time and percent power drop from the Wingate anaerobic power test were also significant predictors of skating performance that incorporates the aspect of recovery from skating activity.Due to the specificity of selected off-ice variables as predictors of on-ice performance, coaches can

Arctic skate Amblyraja hyperborea preys on remarkably large glacial eelpouts Lycodes frigidus.

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Byrkjedal, I; Christiansen, J S; Karamushko, O V; Langhelle, G; Lynghammar, A

2015-01-01

During scientific surveys on the continental slopes north-west of Spitsbergen and off north-east Greenland (c. 600 and 1000 m depths), two female Arctic skates Amblyraja hyperborea were caught while swallowing extraordinary large individuals of glacial eelpout Lycodes frigidus. The total length (LT) of the prey constituted 50 and 80% of the LT of the skates, which reveal that A. hyperborea are capable predators of fishes of surprisingly large relative size. © 2014 The Fisheries Society of the British Isles.

The effect of ice skating on psychological well-being and sleep quality of children with visual or hearing impairment.

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Dursun, Onur Burak; Erhan, Süleyman Erim; Ibiş, Esra Özhan; Esin, Ibrahim Selcuk; Keleş, Sadullah; Şirinkan, Ahmet; Yörük, Özgür; Acar, Ethem; Beyhun, Nazim Ercument

2015-01-01

Physical exercise and sports have a key role in preventing physical and psychiatric problems in children. However, children with a disability often experience difficulty participating in physical activity due to a lack of suitable opportunities. Participation in an accessible sport is particularly important for these children, but studies examining which sports are beneficial for which disability groups are rare. In this study, we assessed the effects of ice skating on the psychological well-being, self-concept, and sleep quality of children with hearing or visual impairment. Forty students (20 visually impaired and 20 hearing impaired) aged 8-16 were included in a regular ice skating programme for three months. We examined the sleep quality, self-concept, and behavioural and emotional states of the children before and after participating in the programme. There was a significant improvement in self-concept, behavioural and emotional problems, and sleep quality (p sleep quality (p = 0.019) and emotional problem scores (p = 0.000) of the visually impaired children improved; self-concept, peer relations and hyperactivity scores of these children worsened (p sport alternatives that gives children the opportunity to exercise and have fun together. The results of this study revealed that regular ice skating programmes may have positive effects on the psychological well-being of children with hearing impairment. Despite some positive effects, caution must be use when including visually impaired children in ice skating programmes. Generalization of the study's outcomes is limited as the study group were residential students enrolled in special education institutions for children who are blind or deaf. Ice skating is a community-based sport and a popular leisure activity that can also have benefits for people with disabilities. Ice skating and children with hearing impairment: Self-concept, behavioural and emotional problems, and sleep quality of the children

From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae?

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Natalia L Ruocco

2012-03-01

Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.

Differences in Muscle Oxygenation, Perceived Fatigue and Recovery between Long-Track and Short-Track Speed Skating.

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Hettinga, Florentina J; Konings, Marco J; Cooper, Chris E

2016-01-01

Due to the technical nature of speed skating, that is affecting physiological mechanisms such as oxygenation and blood flow, this sport provides a unique setting allowing us to uncover novel mechanistic insights of the physiological response to exercise in elite middle-distance and endurance sports. The present study aimed to examine the influence of skating mode (short-track vs. long-track) on muscle oxygenation, perceived fatigue, and recovery in elite speed skating. Muscle oxygenation of 12 talented short-track speed skaters was continuously monitored during a long-track (LT) and a short-track (ST) skating time-trial of maximal effort using near-infrared spectroscopy (NIRS) on the m. vastus lateralis for both legs. Video captures were made of each testing session for further interpretation of the muscle oxygenation. To determine recovery, perceived exertion was measured 2 and 4 h after each testing sessions. Repeated measures ANOVA's were used for statistical analysis ( p skating (TSI%-slope: left = 0.050 ± 0.052, right = 0.001 ± 0.053, p skating modes in muscle oxygenation. Respectively, two ( ST = 5.8 ± 2.0; LT = 4.2 ± 1.5) and 4 h ( ST = 4.6 ± 1.9; LT = 3.1 ± 1.6) after the time-trials, a higher rate of perceived exertion was found for ST. Based on our results, ST seems more physiologically demanding, and longer periods of recovery are needed after training compared to LT. Technical aspects unique to the exercise mode seem to impact on oxygenation, affecting processes related to the regulation of exercise intensity such as fatigue and recovery.

Purification, structural characterization, and myotropic activity of a peptide related to des-Arg(9)-bradykinin from an elasmobranch fish, the little skate, Leucoraja erinacea.

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Anderson, W Gary; Leprince, Jérôme; Conlon, J Michael

2008-08-01

A bradykinin (BK)-related peptide was isolated from heat-denaturated plasma from an elasmobranch fish, the little skate, Leucoraja erinacea after incubation with porcine pancreatic kallikrein. The primary structure of the peptide (H-Gly-Ile-Thr-Ser-Trp-Leu-Pro-Phe-OH; skate BK) shows limited structural similarity to the mammalian B1 receptor agonist, des-Arg(9)-BK. The myotropic activities of synthetic skate BK, and the analog skate [Arg(9)]BK, were examined in isolated skate vascular and intestinal smooth muscle preparations. Skate BK produced a concentration-dependent constriction of the mesenteric artery (EC(50)=4.37x10(-8)M; maximum response=103.4+/-10.23% of the response to 60mM KCl) but the response to skate [Arg(9)]BK was appreciably weaker (response to 10(-6)M=73.0+/-23.4% of the response to 60mM KCl). Neither the first branchial gill arch nor the ventral aorta responded to either purified peptide. Skate BK also produced a concentration-dependent constriction of intestinal smooth muscle preparations (EC(50)=2.74x10(-7)M; maximum response 31.0+/-12.2% of the response to 10(-5)M acetylcholine). Skate [Arg(9)]BK was without effect on the intestinal preparation. The data provide evidence for the existence of the kallikrein-kinin system in a phylogenetically ancient vertebrate group and the greater potency of skate BK compared with the analog skate [Arg(9)]BK suggests that the receptor mediating vascular responses resembles the mammalian B1 receptor more closely than the B2 receptor.

Numerical and functional responses of intestinal helminths in three rajid skates: evidence for competition between parasites?

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Randhawa, Haseeb S

2012-11-01

Host-parasite interactions generally involve communities of parasites. Within these communities, species will co-exist and/or interact with one another in a manner either benefiting the species involved or to the detriment of one or more of the species. At the level of helminth infracommunities, evidence for intra- and inter-specific competition includes numerical responses, i.e. those regulating helminth intensity of infection, and functional responses, i.e. where the presence of competitors modifies the realised niche of infrapopulations. The objectives of this study are to assess the numerical and functional responses of helminths in infracommunities from 3 rajid skates using general linear models. Despite a lack of numerical responses, functional responses to intra- and inter-specific interactions were observed. A positive correlation between the number of individuals in an infrapopulation and its niche breadth (functional response) was observed for the tapeworms Pseudanthobothrium spp. and Echeneibothrium spp., in all their respective hosts, and for the nematode Pseudanisakis sp. in the little skate. Evidence for inter-specific competition includes niche shifts in Pseudanthobothrium purtoni (ex little skate) and Pseudanisakis sp. (ex thorny skate) in the presence of Pseudanisakis sp. and the tapeworm Grillotia sp., respectively. These results are consistent with other studies in providing evidence for competition between helminths of skates.

Morphological, Physiological and Skating Performance Profiles of Male Age-Group Elite Ice Hockey Players.

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Allisse, Maxime; Sercia, Pierre; Comtois, Alain-Steve; Leone, Mario

2017-09-01

The purpose of this study was to describe the evolution of morphological, physiological and skating performance profiles of elite age-group ice hockey players based on repeated measures spread over one season. In addition, the results of fitness tests and training programs performed in off-ice conditions and their relationship with skating performance were analyzed. Eighteen high level age-group ice hockey players (13.1 ± 0.6 years) were assessed off and on-ice at the beginning and at the end of the hockey season. A third evaluation was also conducted at the beginning of the following hockey season. The players were taller, heavier, and showed bone breadths and muscle girths above the reference population of the same age. Muscular variables improved significantly during and between the two hockey seasons (p skating performance tests exhibited significant enhancements during the hockey season, but not during the off-season where some degradation was observed. Finally, weak observed variances (generally skating performance tests indicated important gaps, both in the choice of the off-ice assessment tools as well as in training methods conventionally used. The reflection on the best way to assess and train hockey players certainly deserves to be continued.

Relay exchanges in elite short track speed skating.

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Hext, Andrew; Heller, Ben; Kelley, John; Goodwill, Simon

2017-06-01

In short track speed skating, the relay exchange provides an additional strategic component to races by allowing a team to change the skater involved in the pack race. Typically executed every 1½ laps, it is the belief of skaters and coaches that during this period of the race, time can be gained or lost due to the execution of the relay exchange. As such, the aim of this study was to examine the influence of the relay exchange on a team's progression through a 5000 m relay race. Using data collected from three World Cup relay events during the 2012-2013 season, the time taken to complete the straight for the scenarios with and without the relay exchange were compared at different skating speeds for the corner exit prior to the straight. Overall, the influence of the relay exchange was found to be dependent on this corner exit speed. At slower corner exit speeds (12.01-13.5 m/s), relay exchange straight times were significantly faster than the free skating scenario (P < 0.01). While at faster corner exit speeds (14.01-15 m/s), straight times were significantly slower (P < 0.001). The findings of this study suggest that the current norm of executing relay exchanges every 1½ laps may not be optimal. Instead, varying the frequency of relay exchange execution throughout the race could allow: (1) time to be gained relative to other teams; and (2) facilitate other race strategies by providing an improved opportunity to overtake.

Multiple Off-Ice Performance Variables Predict On-Ice Skating Performance in Male and Female Division III Ice Hockey Players

Directory of Open Access Journals (Sweden)

effrey M. Janot, Nicholas M. Beltz, Lance D. Dalleck

2015-09-01

Full Text Available The purpose of this study was to determine if off-ice performance variables could predict on-ice skating performance in Division III collegiate hockey players. Both men (n = 15 and women (n = 11 hockey players (age = 20.5 ± 1.4 years participated in the study. The skating tests were agility cornering S-turn, 6.10 m acceleration, 44.80 m speed, modified repeat skate, and 15.20 m full speed. Off-ice variables assessed were years of playing experience, height, weight and percent body fat and off-ice performance variables included vertical jump (VJ, 40-yd dash (36.58m, 1-RM squat, pro-agility, Wingate peak power and peak power percentage drop (% drop, and 1.5 mile (2.4km run. Results indicated that 40-yd dash (36.58m, VJ, 1.5 mile (2.4km run, and % drop were significant predictors of skating performance for repeat skate (slowest, fastest, and average time and 44.80 m speed time, respectively. Four predictive equations were derived from multiple regression analyses: 1 slowest repeat skate time = 2.362 + (1.68 x 40-yd dash time + (0.005 x 1.5 mile run, 2 fastest repeat skate time = 9.762 - (0.089 x VJ - (0.998 x 40-yd dash time, 3 average repeat skate time = 7.770 + (1.041 x 40-yd dash time - (0.63 x VJ + (0.003 x 1.5 mile time, and 4 47.85 m speed test = 7.707 - (0.050 x VJ - (0.01 x % drop. It was concluded that selected off-ice tests could be used to predict on-ice performance regarding speed and recovery ability in Division III male and female hockey players.

Skate blade neck lacerations: a survey and case follow-up.

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Stuart, Michael J; Link, Andrew A; Smith, Aynsley M; Krause, David A; Sorenson, Matthew C; Larson, Dirk R

2009-11-01

To learn about neck lacerations caused by skate blades in hockey. A retrospective Web-based survey and follow-up of registered USA Hockey players. Three hundred twenty-eight thousand eight hundred twenty-one of 457 038 registered USA Hockey players with a current e-mail address were contacted and invited to participate in the survey. Of 26 589 players (5.8% of all USA registered players) who responded to the survey, 247 were excluded due to incomplete data. Of 26 342 surveys analyzed, 23 199 respondents were men (88%), 3015 women (11.4%), and 128 (0.5%) did not designate gender. An original survey instrument was developed, formatted, and linked to a Mayo Clinic Web site. Neck lacerations from a skate blade, including mechanism, severity, treatment required, and the type of neck protector worn. Of the 26 342 respondents, 11 935 (45.4%) currently wear neck protection and 485 (1.8%) have sustained a neck laceration. When the laceration occurred, 132 of the players (27%) were wearing neck protection. Interviews with 33 injured players established that lacerations were superficial: 20 (61%) required bandaging only, 11 were sutured, and 2 were glued. Based on this survey, the currently available neck laceration protectors do not eliminate the risk of a neck laceration from a skate blade.

Biologic collagen cylinder with skate flap technique for nipple reconstruction.

Science.gov (United States)

Tierney, Brian P; Hodde, Jason P; Changkuon, Daniela I

2014-01-01

A surgical technique using local tissue skate flaps combined with cylinders made from a naturally derived biomaterial has been used effectively for nipple reconstruction. A retrospective review of patients who underwent nipple reconstruction using this technique was performed. Comorbidities and type of breast reconstruction were collected. Outcome evaluation included complications, surgical revisions, and nipple projection. There were 115 skate flap reconstructions performed in 83 patients between July 2009 and January 2013. Patients ranged from 32 to 73 years old. Average body mass index was 28.0. The most common comorbidities were hypertension (39.8%) and smoking (16.9%). After breast reconstruction, 68.7% of the patients underwent chemotherapy and 20.5% underwent radiation. Seventy-one patients had immediate breast reconstruction with expanders and 12 had delayed reconstruction. The only reported complications were extrusions (3.5%). Six nipples (5.2%) in 5 patients required surgical revision due to loss of projection; two patients had minor loss of projection but did not require surgical revision. Nipple projection at time of surgery ranged from 6 to 7 mm and average projection at 6 months was 3-5 mm. A surgical technique for nipple reconstruction using a skate flap with a graft material is described. Complications are infrequent and short-term projection measurements are encouraging.

In situ observations of a possible skate nursery off the western Antarctic Peninsula.

Science.gov (United States)

Amsler, M O; Smith, K E; McClintock, J B; Singh, H; Thatje, S; Vos, S C; Brothers, C J; Brown, A; Ellis, D; Anderson, J; Aronson, R B

2015-06-01

A dense aggregation of skate egg cases was imaged during a photographic survey of the sea floor along the western Antarctic Peninsula in November 2013. Egg cases were noted in a narrow band between 394 and 443 m depth. Although some skate species in other oceans are known to utilize restricted areas to deposit eggs in great numbers, such nurseries have not been described in the Southern Ocean. © 2015 The Fisheries Society of the British Isles.

DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in 'ray' products sold across Ireland and the UK.

Science.gov (United States)

Griffiths, Andrew Mark; Miller, Dana D; Egan, Aaron; Fox, Jennifer; Greenfield, Adam; Mariani, Stefano

2013-01-01

Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of "skate" or "ray". The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., "winged") and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a single retailer

75 FR 73982 - Fisheries of the Exclusive Economic Zone Off Alaska; Longnose Skate in the Western Regulatory...

Science.gov (United States)

2010-11-30

...NMFS is prohibiting retention of longnose skate in the Western Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2010 total allowable catch (TAC) of longnose skate in the Western Regulatory Area of the GOA has been reached.

76 FR 18505 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Framework Adjustment 1

Science.gov (United States)

2011-04-04

... Council (Council) to adjust the possession limits for the skate wing fishery in order to slow the rate of... Council (Council), 50 Water Street, Newburyport, MA 01950. These documents are also available online at... skate wings on board. This ratio, based upon established wing-to-whole weight conversion factor for...

Real time computer controlled weld skate

Science.gov (United States)

Wall, W. A., Jr.

1977-01-01

A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.

Ice Skating: Special Olympics Sports Skills Instructional Program.

Science.gov (United States)

Special Olympics, Inc., Washington, DC.

One of seven booklets on Special Olympics Sports Skills Instructional Programs, this guide presents teaching suggestions for ice skating coaches working with mentally retarded persons. An overview section introduces the sport and considers ideas for effective teaching. Goals, objectives, and benefits are considered along with information on…

The Protective Effect of Kevlar ® Socks Against Hockey Skate Blade Injuries: A Biomechanical Study

Science.gov (United States)

Nauth, Aaron; Aziz, Mina; Tsuji, Matthew; Whelan, Daniel B.; Theodoropoulos, John S.; Zdero, Rad

2014-01-01

Objectives: Several recent high profile injuries to elite players in the National Hockey League (NHL) secondary to skate blade lacerations have generated significant interest in these injuries and possible methods to protect against them. These injuries are typically due to direct contact of the skate blade of another player with posterior aspect of the calf resulting in a range of potential injuries to tendons or neurovascular structures. The Achilles tendon is most commonly involved. Kevlar® reinforced socks have recently become available for hockey players to wear and are cited as providing possible protection against such injuries. However, there has been no investigation of the possible protective effects of Kevlar® reinforced socks against skate blade injuries, and it is currently unknown what protective effects, if any, that these socks provide against these injuries. The proposed study sought to address this by conducting a biomechanical investigation of the protective effects of Kevlar® reinforced socks against Achilles tendon injuries in a simulated model of skate blade injury using human cadaver limbs. This novel investigation is the first to address the possible benefits to hockey players of wearing Kevlar® reinforced socks. Methods: Seven matched pairs of human cadaver lower limbs were fitted with a Kevlar ® reinforced sock comprised of 60% Kevlar®/20% Coolmax® polyester/18 % Nylon/12% Spandex (Bauer Elite Performance Skate Sock) on one limb and a standard synthetic sock comprised of 51% polyester/47% nylon/2% spandex (Bauer Premium Performance Skate Sock) on the contralateral limb as a control. Each limb was then mounted on a Materials Testing System (MTS) with the ankle dorsiflexed to 90° and the knee held in full extension using a custom designed jig. Specimens were then impacted with a hockey skate blade directed at the posterior calf, 12 cm above the heel, at an angle of 45° and a speed of 31m/s, to a penetration depth of 4.3 cm, to

Ice-skating injuries.

Science.gov (United States)

Williamson, D M; Lowdon, I M

1986-05-01

The range of injuries sustained at an ice-rink and presented to an Accident Service department is described. A total of 203 patients with 222 injuries presented themselves during a 2-month period. There were 103 noteworthy injuries, including 61 fractures, 2 dislocations and 2 severed tendons, but the commonest injuries were wounds, sprains and bruises. Beginners appear to be more prone to injury than experienced skaters. In addition to using well-fitting skate-boots to protect the ankle, some injuries could be avoided by wearing elbow and knee pads, and a thick pair of gloves. The number of injuries compared with the total number of skaters was small but produced a noteworthy increase in the workload of the Accident Service.

Skate Parks as a Context for Adolescent Development

Science.gov (United States)

Bradley, Graham L.

2010-01-01

All people influence, and are influenced by, the contexts they inhabit. Leisure contexts are no exception. The current research comprised three studies investigating the links between one leisure context, skate parks, and adolescent development. Using interview, observation, and questionnaire methods, the research shed light on several of the…

A esportivização do skate (1960-1990: relações entre o macro e o micro La deportivización del skate (1960-1990: relaciones entre lo macro y micro The sportivization of skateboarding (1960-1990: relations between the macro and the micro

Directory of Open Access Journals (Sweden)

Tony Honorato

2013-03-01

Full Text Available O objetivo deste estudo foi apresentar elementos da esportivização da prática cultural skate (1960-1990, como conhecimento para o entendimento da relação entre o micro e o macro processo sócio-histórico do skate. Como fonte de pesquisa histórica para a esportivização do skate no Brasil, dimensão macro, utilizamos a Revista Tribo Skate e para a de Piracicaba/SP, dimensão micro, entrevistamos dois colaboradores a partir do método da história oral. Os resultados evidenciaram que o skate surgiu para gerar fortes tensões agradáveis, suas formas de lazer precedem as formas esportivas e, guardadas as particularidades, os seus processos macro e micro-históricos são interdependentes.El objetivo del estudio fue presentar elementos de la deportivización de la práctica cultural skate (1960-1990, como conocimiento para el entendimiento de la relación entre el micro y macro proceso socio-histórico del mismo. Como fuente de investigación histórica para la deportivización del skate en Brasil, dimensión macro, utilizamos la Revista Tribo Skate y para la de Piracicaba/SP, dimensión micro, entrevistamos dos colaboradores a partir del método de historia oral. Los resultados evidenciaron que el skate surgió para generar fuertes tensiones agradables, sus formas de ocio preceden a sus formas deportivas y, salvando las particularidades, los procesos macro y micro-históricos son interdependientes.The objective of this study is to present the elements of the sportivization of the cultural practice of skateboarding (1960-1990, as knowledge for the understanding of the relation between the micro and the macro social and historical processes of skateboarding. We used the magazine Revista Tribo Skate as source of historical research for the sportivization of skateboarding in Brazil, the macro dimension, and for the micro dimension, the city of Piracicaba/SP, where we interviewed two collaborators based on the method of oral history. The results

Ground reaction forces produced by two different hockey skating arm swing techniques.

Science.gov (United States)

Hayward-Ellis, Julie; Alexander, Marion J L; Glazebrook, Cheryl M; Leiter, Jeff

2017-10-01

The arm swing in hockey skating can have a positive effect on the forces produced by each skate, and the resulting velocity from each push off. The main purpose of this study was to measure the differences in ground reaction forces (GRFs) produced from an anteroposterior versus a mediolateral style hockey skating arm swing. Twenty-four elite-level female hockey players performed each technique while standing on a ground-mounted force platform, and all trials were filmed using two video cameras. Force data was assessed for peak scaled GRFs in the frontal and sagittal planes, and resultant GRF magnitude and direction. Upper limb kinematics were assessed from the video using Dartfish video analysis software, confirming that the subjects successfully performed two distinct arm swing techniques. The mediolateral arm swing used a mean of 18.38° of glenohumeral flexion/extension and 183.68° of glenohumeral abduction/adduction while the anteroposterior technique used 214.17° and 28.97° respectively. The results of this study confirmed that the mediolateral arm swing produced 37% greater frontal plane and 33% less sagittal plane GRFs than the anteroposterior arm swing. The magnitudes of the resultant GRFs were not significantly different between the two techniques; however, the mediolateral technique produced a resultant GRF with a significantly larger angle from the direction of travel (44.44°) as compared to the anteroposterior technique (31.60°). The results of this study suggest that the direction of GRFs produced by the mediolateral arm swing more closely mimic the direction of lower limb propulsion during the skating stride.

Relationship between Physiological Off-Ice Testing, On-Ice Skating, and Game Performance in Division I Women's Ice Hockey Players.

Science.gov (United States)

Boland, Michelle; Miele, Emily M; Delude, Katie

2017-10-07

The purpose was to identify off-ice testing variables that correlate to skating and game performance in Division I collegiate women ice hockey players. Twenty female, forward and defensive players (19.95 ± 1.35 yr) were assessed for weight, height, percent fat mass (%FAT), bone mineral density, predicted one repetition maximum (RM) absolute and relative (REL%) bench press (BP) and hex bar deadlift (HDL), lower body explosive power, anaerobic power, countermovement vertical jump (CMJ), maximum inspiratory pressure (MIP), and on-ice repeated skate sprint (RSS) performance. The on-ice RSS test included 6 timed 85.6 m sprints with participants wearing full hockey equipment; fastest time (FT), average time (AT) and fatigue index (FI) for the first length skate (FLS; 10 m) and total length skate (TLS; 85.6 m) were used for analysis. Game performance was evaluated with game statistics: goals, assists, points, plus-minus, and shots on goal (SOG). Correlation coefficients were used to determine relationships. Percent fat mass was positively correlated (p Game performance in women ice hockey players may be enhanced by greater MIP, repeat acceleration ability, and mode-specific training. Faster skating times were associated with lower %FAT. Skating performance in women ice hockey players may be enhanced by improving body composition, anaerobic power, and both lower and upper body strength in off-ice training.

A new temperate deepwater skate of the genus Bathyraja (Rajoidei: Arhynchobatidae) from the South-West Pacific.

Science.gov (United States)

Last, Peter R; Stewart, Andrew L; Séret, Bernard

2016-06-28

A single specimen of a new Bathyraja skate was collected by the authors in 2003 during a survey of the deepwater biota of the northern Tasman Sea by the New Zealand FRV Tangaroa. This skate, labelled the 'blonde skate' by voyage participants, is uniformly white on all surfaces of the body and the skin is partly translucent. It belongs to a subgroup of Bathyraja with a large, almost smooth, quadrangular disc and well-developed and equally spaced median tail thorns. Other similar and probably closely related Bathyraja specimens have been caught in seas to the south of New Zealand since the discovery of this species, but their identity is yet to be confirmed.

Bacterial succession during curing process of a skate (Dipturus batis) and isolation of novel strains.

Science.gov (United States)

Reynisson, E; Thornór Marteinsson, V; Jónsdóttir, R; Magnússon, S H; Hreggvidsson, G O

2012-08-01

To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate. The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6·64-9·27) with increasing trimethylamine (2·6 up to 75·6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58·5 to 705·8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyse urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus. The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas. For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species. No Claim to Norwegian Government works Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Biologic Collagen Cylinder with Skate Flap Technique for Nipple Reconstruction

Directory of Open Access Journals (Sweden)

Brian P. Tierney

2014-01-01

Full Text Available A surgical technique using local tissue skate flaps combined with cylinders made from a naturally derived biomaterial has been used effectively for nipple reconstruction. A retrospective review of patients who underwent nipple reconstruction using this technique was performed. Comorbidities and type of breast reconstruction were collected. Outcome evaluation included complications, surgical revisions, and nipple projection. There were 115 skate flap reconstructions performed in 83 patients between July 2009 and January 2013. Patients ranged from 32 to 73 years old. Average body mass index was 28.0. The most common comorbidities were hypertension (39.8% and smoking (16.9%. After breast reconstruction, 68.7% of the patients underwent chemotherapy and 20.5% underwent radiation. Seventy-one patients had immediate breast reconstruction with expanders and 12 had delayed reconstruction. The only reported complications were extrusions (3.5%. Six nipples (5.2% in 5 patients required surgical revision due to loss of projection; two patients had minor loss of projection but did not require surgical revision. Nipple projection at time of surgery ranged from 6 to 7 mm and average projection at 6 months was 3–5 mm. A surgical technique for nipple reconstruction using a skate flap with a graft material is described. Complications are infrequent and short-term projection measurements are encouraging.

Wireless instrumented klapskates for long-track speed skating

NARCIS (Netherlands)

van der Kruk, E.; den Braver, O.; Schwab, Arend L.; van der Helm, Frans C T; Veeger, H. E J

2016-01-01

In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a

The effects of poling on physiological, kinematic and kinetic responses in roller ski skating.

Science.gov (United States)

Grasaas, Erik; Hegge, Ann Magdalen; Ettema, Gertjan; Sandbakk, Øyvind

2014-09-01

We investigated the effects of poling on physiological, kinematic and kinetic responses in the G4 skating technique where the poling movement is synchronized with the leg push-off on one side (strong side) followed by a forward arm swing during the leg push-off on the other side (weak side). G4 skating with (G4-P) and without (G4-NP) poling was compared in 17 elite male cross-country skiers during 4-min submaximal tests on a 2% inclined roller ski treadmill at 10, 15 and 20 km h(-1). G4-P demonstrated less ventilatory stress and higher gross efficiency compared to G4-NP at all velocities, and the blood lactate concentration was lower at the high velocity (all P skating technique. Thus, poling provides possibilities to increase total propulsion, to reduce ski forces and to enhance skiing efficiency.

Getting in shape: Reconstructing three-dimensional long-track speed skating kinematics by comparing several body pose reconstruction techniques.

Science.gov (United States)

van der Kruk, E; Schwab, A L; van der Helm, F C T; Veeger, H E J

2018-03-01

In gait studies body pose reconstruction (BPR) techniques have been widely explored, but no previous protocols have been developed for speed skating, while the peculiarities of the skating posture and technique do not automatically allow for the transfer of the results of those explorations to kinematic skating data. The aim of this paper is to determine the best procedure for body pose reconstruction and inverse dynamics of speed skating, and to what extend this choice influences the estimation of joint power. The results show that an eight body segment model together with a global optimization method with revolute joint in the knee and in the lumbosacral joint, while keeping the other joints spherical, would be the most realistic model to use for the inverse kinematics in speed skating. To determine joint power, this method should be combined with a least-square error method for the inverse dynamics. Reporting on the BPR technique and the inverse dynamic method is crucial to enable comparison between studies. Our data showed an underestimation of up to 74% in mean joint power when no optimization procedure was applied for BPR and an underestimation of up to 31% in mean joint power when a bottom-up inverse dynamics method was chosen instead of a least square error approach. Although these results are aimed at speed skating, reporting on the BPR procedure and the inverse dynamics method, together with setting a golden standard should be common practice in all human movement research to allow comparison between studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Skate, espacios urbanos y jóvenes en la ciudad de La Plata

OpenAIRE

Saraví, Jorge Ricardo

2012-01-01

El objetivo general que nos hemos planteado fue analizar la práctica del skate que llevan adelante los y las jóvenes en la ciudad. Por otro lado, nuestros objetivos específicos fueron: 1) relevar y describir acciones, características, particularidades, lugares, que asumen las diferentes prácticas del skate en la ciudad; 2) conocer las representaciones que acerca de esa práctica tienen los propios jóvenes y la sociedad; 3) profundizar en las implicancias sociales que tiene una práctica corpora...

Wireless instrumented klapskates for long-track speed skating

NARCIS (Netherlands)

van der Kruk, E.; den Braver, O.; Schwab, A.L.; van der Helm, F.C.T.; Veeger, H.E.J.

2016-01-01

In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a

Analysis of High-Intensity Skating in Top-Class Ice Hockey Match-Play in Relation to Training Status and Muscle Damage.

Science.gov (United States)

Lignell, Erik; Fransson, Dan; Krustrup, Peter; Mohr, Magni

2018-05-01

Lignell, E, Fransson, D, Krustrup, P, and Mohr, M. Analysis of high-intensity skating in top-class ice hockey match-play in relation to training status and muscle damage. J Strength Cond Res 32(5): 1303-1310, 2018-We examined high-intensity activities in a top-class ice-hockey game and the effect of training status. Male ice-hockey players (n = 36) from the National Hockey League participated. Match analysis was performed during a game and physical capacity was assessed by a submaximal Yo-Yo Intermittent Recovery Ice-hockey test, level 1 (YYIR1-IHSUB). Venous blood samples were collected 24-hour post-game to determine markers of muscle damage. Players performed 119 ± 8 and 31 ± 3 m·min of high intensity and sprint skating, respectively, during a game. Total distance covered was 4,606 ± 219 m (2,260-6,749 m), of which high-intensity distance was 2042 ± 97 m (757-3,026 m). Sprint-skating speed was 5-8% higher (p ≤ 0.05) in periods 1 and 2 vs. period 3 and overtime. Defensemen (D) covered 29% more (p ≤ 0.05) skating in total than forwards (F) and were on the ice 47% longer. However, F performed 54% more (p ≤ 0.05) high-intensity skating per minute than defensemen. Plasma creatine kinase (CK) was 338 ± 45 (78-757) U·L 24-hour post-game. Heart rate loading during YYIR1-IHSUB correlated inversely (p ≤ 0.05) to the frequency of high-intensity skating bouts (r = -0.55) and V[Combining Dot Above]O2max (r = -0.85) and positively to post-game CK (r = 0.49; p ≤ 0.05). In conclusion, ice hockey is a multiple-sprint sport that provokes fatigue in the latter half of a game. Forwards perform more intense skating than defensemen. Moreover, high-intensity game activities during top-class ice hockey are correlated with cardiovascular loading during a submaximal skating test. Taken together, training of elite ice-hockey players should improve the ability for repeated high-intensity skating, and testing should include the YYIR1-IHSUB test as an indicator for ice

The Biomechanics of Cranial Forces During Figure Skating Spinning Elements.

Science.gov (United States)

Wang, David H; Kostyun, Regina O; Solomito, Matthew J

2015-03-01

Several facets of figure skating, such as the forces associated with jumping and landing, have been evaluated, but a comprehensive biomechanical understanding of the cranial forces associated with spinning has yet to be explored. The purpose of this case study was to quantify the cranial rotational acceleration forces generated during spinning elements. This case report was an observational, biomechanical analysis of a healthy, senior-level, female figure skating athlete who is part of an on-going study. A triaxial accelerometer recorded the gravitational forces (G) during seven different spinning elements. Our results found that the layback spin generated significant cranial force and these forces were greater than any of the other spin elements recorded. These forces led to physical findings of ruptured capillaries, dizziness, and headaches in our participant.

Morphological, Physiological and Skating Performance Profiles of Male Age-Group Elite Ice Hockey Players

Directory of Open Access Journals (Sweden)

Allisse Maxime

2017-08-01

Full Text Available The purpose of this study was to describe the evolution of morphological, physiological and skating performance profiles of elite age-group ice hockey players based on repeated measures spread over one season. In addition, the results of fitness tests and training programs performed in off-ice conditions and their relationship with skating performance were analyzed. Eighteen high level age-group ice hockey players (13.1 ± 0.6 years were assessed off and on-ice at the beginning and at the end of the hockey season. A third evaluation was also conducted at the beginning of the following hockey season. The players were taller, heavier, and showed bone breadths and muscle girths above the reference population of the same age. Muscular variables improved significantly during and between the two hockey seasons (p < 0.05. However, maximal aerobic power improved only during the off-season. All skating performance tests exhibited significant enhancements during the hockey season, but not during the off-season where some degradation was observed. Finally, weak observed variances (generally <20% of the explained variance between physiological variables measured off-ice and on-ice skating performance tests indicated important gaps, both in the choice of the off-ice assessment tools as well as in training methods conventionally used. The reflection on the best way to assess and train hockey players certainly deserves to be continued.

Effects of frequency on gross efficiency and performance in roller ski skating.

Science.gov (United States)

Leirdal, S; Sandbakk, O; Ettema, G

2013-06-01

The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE). © 2011 John Wiley & Sons A/S.

Characterization of little skate (Leucoraja erinacea) recombinant transthyretin: Zinc-dependent 3,3',5-triiodo-l-thyronine binding.

Science.gov (United States)

Suzuki, Shunsuke; Kasai, Kentaro; Yamauchi, Kiyoshi

2015-01-01

Transthyretin (TTR) diverged from an ancestral 5-hydroxyisourate hydrolase (HIUHase) by gene duplication at some early stage of chordate evolution. To clarify how TTR had participated in the thyroid system as an extracellular thyroid hormone (TH) binding protein, TH binding properties of recombinant little skate Leucoraja erinacea TTR was investigated. At the amino acid level, skate TTR showed 37-46% identities with the other vertebrate TTRs. Because the skate TTR had a unique histidine-rich segment in the N-terminal region, it could be purified by Ni-affinity chromatography. The skate TTR was a 46-kDa homotetramer of 14.5kDa subunits, and had one order of magnitude higher affinity for 3,3',5-triiodo-l-thyronine (T3) and some halogenated phenols than for l-thyroxine. However, the skate TTR had no HIUHase activity. Ethylenediaminetetraacetic acid (EDTA) treatment inhibited [(125)I]T3 binding activity whereas the addition of Zn(2+) to the EDTA-treated TTR recovered [(125)I]T3 binding activity in a Zn(2+) concentration-dependent manner. Scatchard analysis revealed the presence of two classes of binding site for T3, with dissociation constants of 0.24 and 17nM. However, the high-affinity sites were completely abolished with 1mM EDTA, whereas the remaining low-affinity sites decreased binding capacity. The number of zinc per TTR was quantified to be 4.5-6.3. Our results suggest that skate TTR has tight Zn(2+)-binding sites, which are essential for T3 binding to at least the high-affinity sites. Zn(2+) binding to the N-terminal histidine-rich segment may play an important role in acquisition or reinforcement of TH binding ability during early evolution of TTR. Copyright © 2015 Elsevier Inc. All rights reserved.

The role of incline, performance level and gender on the gross mechanical efficiency of roller ski skating

Directory of Open Access Journals (Sweden)

Øyvind eSandbakk

2013-10-01

Full Text Available The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points (the Federation of International Skiing approved scoring system for ski racing where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r=-0.89-0.98 and P

Germany's first CO{sub 2} skating rink. Axima Kaeltetechnik builds new skating rink at Ravensburg; Die erste CO{sub 2}-Kunsteisbahn Deutschlands. Axima Kaeltetechnik baut in Ravensburg

Energy Technology Data Exchange (ETDEWEB)

Anon.

2004-04-01

Natural refrigerants are frequently used in skating rinks. Increasingly, CO2 is preferred to brine, as in the new Ravensburg skating rink. It is the first time this technology is applied in Germany, but more systems of this kind are sure to come. [German] Beim Bau von Kunsteisbahnen sind natuerliche Kaeltemittel kein Novum. Immer haeufiger erhaelt allerdings der Kaeltetraeger CO{sub 2} den Vorzug vor einer Sole, so auch beim Bau der neuen Kunsteisbahn in Ravensburg. Damit wurde erstmals in Deutschland in diesem Bereich der Schritt hin zu einer Systemtechnologie gemacht, die aller Voraussicht nach noch zahlreiche weitere Anwendungen nach sich ziehen wird. (orig.)

Alterations in aerobic energy expenditure and neuromuscular function during a simulated cross-country skiathlon with the skating technique.

Science.gov (United States)

Fabre, Nicolas; Mourot, Laurent; Zoppirolli, Chiara; Andersson, Erik; Willis, Sarah J; Holmberg, Hans-Christer

2015-04-01

Here, we tested the hypothesis that aerobic energy expenditure (AEE) is higher during a simulated 6-km (2 loops of 3-km each) "skiathlon" than during skating only on a treadmill and attempted to link any such increase to biomechanical and neuromuscular responses. Six elite male cross-country skiers performed two pre-testing time-trials (TT) to determine their best performances and to choose an appropriate submaximal speed for collection of physiological, biomechanical and neuromuscular data during two experimental sessions (exp). Each skier used, in randomized order, either the classical (CL) or skating technique (SK) for the first 3-km loop, followed by transition to the skating technique for the second 3-km loop. Respiratory parameters were recorded continuously. The EMG activity of the triceps brachii (TBr) and vastus lateralis (VLa) muscles during isometric contractions performed when the skiers were stationary (i.e., just before the first loop, during the transition, and after the second loop); their corresponding activity during dynamic contractions; and pole and plantar forces during the second loop were recorded. During the second 3-km of the TT, skating speed was significantly higher for the SK-SK than CL-SK. During this second loop, AEE was also higher (+1.5%) for CL-SKexp than SK-SKexp, in association with higher VLa EMG activity during both isometric and dynamic contractions, despite no differences in plantar or pole forces, poling times or cycle rates. Although the underlying mechanism remains unclear, during a skiathlon, the transition between the sections of classical skiing and skating alters skating performance (i.e., skiing speed), AEE and neuromuscular function. Copyright © 2015 Elsevier B.V. All rights reserved.

Differences in muscle oxygenation, perceived fatigue and recovery between long-track and short-track speed skating

Directory of Open Access Journals (Sweden)

Florentina Johanna Hettinga

2016-12-01

Full Text Available Due to the technical nature of speed skating, that is affecting physiological mechanisms such as oxygenation and blood flow, this sport provides a unique setting allowing us to uncover novel mechanistic insights of the physiological response to exercise in elite middle-distance and endurance sports. The present study aimed to examine the influence of skating mode (short-track vs. long-track on muscle oxygenation, perceived fatigue, and recovery in elite speed skating. Muscle oxygenation of twelve talented short-track speed skaters was continuously monitored during a long-track (LT and a short-track (ST skating time-trials of maximal effort using near-infrared spectroscopy (NIRS on the m. vastus lateralis for both legs. Video captures were made of each testing session for further interpretation of the muscle oxygenation. To determine recovery, perceived exertion was measured two and four hours after each testing sessions. Repeated measures ANOVA’s were used for statistical analysis (p<.05. After a rapid desaturation in both legs directly after the start, an asymmetry in muscle oxygenation between both legs was found during LT (tissue saturation-index (TSI%-slope: left=0.053±0.032; right=0.023±0.020, p<.05 and ST speed skating (TSI%-slope: left=0.050±0,052, right=0.001 ±0.053, p<.05. Re-Resaturation of the right leg was relatively lower in ST compared to LT. For the left leg, no difference was found between skating modes in muscle oxygenation. Respectively, two (ST=5.8±2.0; LT=4.2±1.5 and four hours (ST=4.6±1.9; LT=3.1±1.6 after the time-trials, a higher rate of perceived exertion was found for ST. Based on our results, ST seems more physiologically demanding, and longer periods of recovery are needed after training compared to LT. Technical aspects unique to the exercise mode seem to impact on oxygenation, affecting processes related to the regulation of exercise intensity such as fatigue and recovery.

75 FR 73981 - Fisheries of the Exclusive Economic Zone Off Alaska; Big Skate in the Central Regulatory Area of...

Science.gov (United States)

2010-11-30

...NMFS is prohibiting retention of big skate in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2010 total allowable catch (TAC) of big skate in the Central Regulatory Area of the GOA has been reached.

78 FR 27863 - Fisheries of the Exclusive Economic Zone Off Alaska; Big Skate in the Central Regulatory Area of...

Science.gov (United States)

2013-05-13

...NMFS is prohibiting retention of big skate in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2013 total allowable catch of big skate in the Central Regulatory Area of the GOA has been reached.

77 FR 75399 - Fisheries of the Exclusive Economic Zone Off Alaska; Big Skate in the Central Regulatory Area of...

Science.gov (United States)

2012-12-20

...NMFS is prohibiting retention of big skate in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2012 total allowable catch of big skate in the Central Regulatory Area of the GOA has been reached.

Towards real-time feedback in high performance speed skating

NARCIS (Netherlands)

van der Eb, Jeroen; Zandee, Willem; van den Bogaard, Timo; Geraets, Sjoerd; Veeger, H.E.J.; Beek, Peter; Potthast, Wolfgang; Niehoff, Anja; David, Sina

2017-01-01

The aim of the current study is to evaluate several performance indicators to be used as real-time feedback in the coming experiments to enhance performance of elite speeds skaters. Six speed skaters, wearing one IMU per skate, collected data over one full training season to evaluate and pinpoint

Validation of the FAST skating protocol to predict aerobic power in ice hockey players.

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Petrella, Nicholas J; Montelpare, William J; Nystrom, Murray; Plyley, Michael; Faught, Brent E

2007-08-01

Few studies have reported a sport-specific protocol to measure the aerobic power of ice hockey players using a predictive process. The purpose of our study was to validate an ice hockey aerobic field test on players of varying ages, abilities, and levels. The Faught Aerobic Skating Test (FAST) uses an on-ice continuous skating protocol on a course measuring 160 feet (48.8 m) using a CD to pace the skater with a beep signal to cross the starting line at each end of the course. The FAST incorporates the principle of increasing workload at measured time intervals during a continuous skating exercise. Step-wise multiple regression modelling was used to determine the estimate of aerobic power. Participants completed a maximal aerobic power test using a modified Bruce incremental treadmill protocol, as well as the on-ice FAST. Normative data were collected on 406 ice hockey players (291 males, 115 females) ranging in age from 9 to 25 y. A regression to predict maximum aerobic power was developed using body mass (kg), height (m), age (y), and maximum completed lengths of the FAST as the significant predictors of skating aerobic power (adjusted R2 = 0.387, SEE = 7.25 mL.kg-1.min-1, p < 0.0001). These results support the application of the FAST in estimating aerobic power among male and female competitive ice hockey players between the ages of 9 and 25 years.

Design and verification of a simple 3D dynamic model of speed skating which mimics observed forces and motions.

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van der Kruk, E; Veeger, H E J; van der Helm, F C T; Schwab, A L

2017-11-07

Advice about the optimal coordination pattern for an individual speed skater, could be addressed by simulation and optimization of a biomechanical speed skating model. But before getting to this optimization approach one needs a model that can reasonably match observed behaviour. Therefore, the objective of this study is to present a verified three dimensional inverse skater model with minimal complexity, which models the speed skating motion on the straights. The model simulates the upper body transverse translation of the skater together with the forces exerted by the skates on the ice. The input of the model is the changing distance between the upper body and the skate, referred to as the leg extension (Euclidean distance in 3D space). Verification shows that the model mimics the observed forces and motions well. The model is most accurate for the position and velocity estimation (respectively 1.2% and 2.9% maximum residuals) and least accurate for the force estimations (underestimation of 4.5-10%). The model can be used to further investigate variables in the skating motion. For this, the input of the model, the leg extension, can be optimized to obtain a maximal forward velocity of the upper body. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Molecular Characterization of the Skate Peripherin/rds Gene: Relationship to Its Orthologues and Paralogues

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Li, Chibo; Ding, Xi-Qin; O’Brien, John; Al-Ubaidi, Muayyad R.

2010-01-01

PURPOSE A great deal of information about functionally significant domains of a protein may be obtained by comparison of primary sequences of gene homologues over a broad phylogenetic base. This study was designed to identify evolutionarily conserved domains of the photoreceptor disc membrane protein peripherin/rds by analysis of the homologue in a primitive vertebrate, the skate. METHODS A skate retinal cDNA library was screened using a mouse peripherin/rds clone. The 5′ and 3′ untranslated regions of the skate peripherin/rds (srds) cDNA were isolated by the rapid amplification of cDNA ends (RACE) approach. The gene structure was characterized by PCR amplification and sequencing of genomic fragments. Northern and Western blot analyses were used to identify srds transcript and protein, respectively. RESULTS A new homologue of peripherin/rds was identified from the skate retinal cDNA library. SRDS is a glycoprotein with a predicted molecular mass of 40.2 kDa. The srds gene consists of two exons and one small intron and transcribes into a single 6-kb message. Phylogenetic analysis places SRDS at the base of peripherin/rds family and near the division of that group and the branch leading to rds-like and rom-1 genes. SRDS protein is 54.5% identical with peripherin/rds across species. Identity is significantly higher (73%) in the intradiscal domains. Sequence comparison revealed the conservation of all residues that have been shown, on mutation, to associate with retinitis pigmentosa and showed conservation of most residues associated with macular dystrophies. Comparison with ROM-1 and other rds-like proteins revealed the presence of a highly conserved domain in the large intradiscal loop. CONCLUSIONS Srds represents the skate orthologue of mammalian peripherin/rds genes. Conservation of most of the residues associated with human retinal diseases indicates that these residues serve important functional roles. The high degree of conservation of a short stretch within

The influence of increased distal loading on metabolic cost, efficiency, and kinematics of roller ski skating.

Science.gov (United States)

Bolger, Conor M; Bessone, Veronica; Federolf, Peter; Ettema, Gertjan; Sandbakk, Øyvind

2018-01-01

The purpose of the present study was to examine the influence of increased loading of the roller ski on metabolic cost, gross efficiency, and kinematics of roller ski skating in steep and moderate terrain, while employing two incline-specific techniques. Ten nationally ranked male cross-country skiers were subjected to four 7-minute submaximal intervals, with 0, 0.5, 1.0, and 1.5 kg added beneath the roller-ski in a randomized order. This was done on two separate days, with the G2 skating at 12% incline and 7 km/h speed and G3 skating at 5% incline and 14 km/h speed, respectively. At 12% incline, there was a significant increase in metabolic rate and a decrease in gross efficiency with added weight (P0.05). No changes in cycle characteristics were observed between the different ski loadings at either incline, although the lateral and vertical displacements of the foot/skis were slightly altered at 12% incline with added weight. In conclusion, the present study demonstrates that increased loading of the ski increases the metabolic cost and reduces gross efficiency during steep uphill roller skiing in G2 skating, whereas no significant effect was revealed when skating on relatively flat terrain in G3. Cycle characteristics remained unchanged across conditions at both inclines, whereas small adjustments in the displacement of the foot coincided with the efficiency changes in uphill terrain. The increased RPE values with added ski-weight at both inclines indicates that other factors than those measured here could have influenced effort and/or fatigue when lifting a heavier ski.

DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in ‘ray’ products sold across Ireland and the UK

Science.gov (United States)

Egan, Aaron; Fox, Jennifer; Greenfield, Adam; Mariani, Stefano

2013-01-01

Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged”) and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a

DNA barcoding unveils skate (Chondrichthyes: Rajidae species diversity in ‘ray’ products sold across Ireland and the UK

Directory of Open Access Journals (Sweden)

Andrew Mark Griffiths

2013-08-01

Full Text Available Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba. Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged” and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura, spotted ray (Raja montagui, thornback ray (Raja clavata, cuckoo ray (Leucoraja naevus small-eyed ray (Raja microocellata and shagreen ray (Leucoraja fullonica. Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern

Physiological and technical commitment during a 300-m in-line skating trial in athletes of different age categories.

Science.gov (United States)

Invernizzi, Pietro L; Scurati, Raffaele; Crotti, Matteo; Bosio, Andrea; Longo, Stefano; Esposito, Fabio

2018-01-04

This study investigated the differences in strength, technique and time performance in in-line skaters of three age categories during a 300 m trial. Possible correlations among these variables were also assessed. Thirty-six elite in-line skaters (Cadets, Juniors and Seniors, n=12 each; 14±1, 16±1, and 24±6 years of age, respectively) performed a 300-m trial on an outdoor oval track. Total time (Ttot), 100-m fractions and duration of each skating technique (initial acceleration phase, straight push and cross-over) were recorded. A squat jump (SJ) was performed before and after the trial. Heart rate, blood lactate concentration ([La-]) and rate of perceived exertion (RPE) were collected before, during and at the end of the trial. Ttot was longer and SJ lower in Cadets compared to the other groups. Seniors employed the cross-over technique for a longer period than the straight push technique, compared to Juniors and Cadets. Ttot correlated negatively with SJ in Seniors. The number of significant correlations between skating techniques' duration and both Ttot and SJ increased with age category. No differences among groups were found for heart rate, [La-] and RPE. With increasing age category, leg strength appeared to be the more related aspect to skating performance. To improve 300-m in-line skating performance, trainers should pay particular attention to the enhancement of leg strength and cross-over skating technique.

História da proibição do skate em Blumenau/SC (1999-2007 = History of the prohibition of skateboarding in Blumenau/SC (1999-2007 = Historia de la prohibición del skate en Blumenau/SC (1999-2007

Directory of Open Access Journals (Sweden)

Brandão, Leonardo

2016-01-01

Full Text Available Este trabalho se insere num domínio historiográfico conhecido como "História do Esporte". Tomamos como estudo de caso a prática do skate, atividade usualmente inserida no âmbito dos "Esportes Radicais" e que vem sendo praticada por um conjunto significativo de jovens. O recorte geográfico da pesquisa é o município de Blumenau/ SC, geralmente lembrado por ser palco da Oktoberfest. Nesta cidade, a prática do skate foi proibida pela Lei nº 5211, que entrou em vigor no dia 17 de maio de 1999, sendo revogada somente em 2007, durante a gestão do prefeito João Paulo Kleinübing. Para compreender os motivos que levaram o skate a ser proibido, foi realizada uma pesquisa com base em fontes impressas, jornais e revistas, e também através de entrevistas com os principais atores sociais envolvidos com a prática do skate nessa cidade. O objetivo foi analisar tanto os motivos que levaram à proibição dessa atividade em Blumenau quanto seu retorno à legalidade, mapeando a ação dos principais agentes desse processo e também narrando os episódios que envolveram os atos de restrição e coibição à atividade, geralmente efetuados pela guarda municipal. Concluiu-se que, embora a proibição da prática do skate tenha sido decretada em 1999, uma coibição bastante rígida a essa prática já existia desde o final da década de 1980. Além disso, seu retorno à legalidade, ocorrido com a revogação da lei no ano de 2007, foi conquistada através da pressão organizada pelos skatistas, liderada por George Gonçalves, Presidente da União Blumenauense de Esportes Radicais (UBER, e com o apoio da revista 100% skate, uma publicação nacional especializada nessa atividade

Embryo developmental events and the egg case of the Aleutian skate Bathyraja aleutica (Gilbert) and the Alaska skate Bathyraja parmifera (Bean).

Science.gov (United States)

Hoff, G R

2009-02-01

Embryo development events were correlated with egg-case changes for the Aleutian skate Bathyraja aleutica and the Alaska skate Bathyraja parmifera. Yolk absorption underwent two phases: that of steady absorption during early development and that of rapid yolk absorption during the final development stages. Total length (L(T)) for 50% of the pre-hatching embryos egg-case jelly disappearance was 92.04 mm (range 81-102 mm) and 99.36 mm (range 81-100 mm) for B. aleutica and B. parmifera, respectively, allowing the inner chamber to open to seawater flow. The tail filament underwent three phases of growth: rapid elongation during early development (70 mm L(T) for both species and the sex ratio was 1:1 well before hatching. Egg cases that were devoid of an ova or developing embryo were c. 5.0 and 6.5% of the egg cases examined for B. aleutica and B. parmifera, respectively. Measurements showed that egg cases containing only egg jelly were smaller in both width and length than those possessing an ova. Embryo stages were punctuated with distinct events that correlated with egg case changes controlling the internal environment of the developing embryo.

Got Ice? Teaching Ice-Skating as a Lifelong Activity

Science.gov (United States)

Tarkinton, Brenda C.; Karp, Grace Goc

2010-01-01

With today's focus on the importance of lifelong physical activity, educators are increasingly offering a variety of such activities in their classes, as well as in before- and after-school programs. This article describes the benefits of offering ice skating as a challenging and rewarding lifetime activity, either before or after school or in…

Community annotation and bioinformatics workforce development in concert--Little Skate Genome Annotation Workshops and Jamborees.

Science.gov (United States)

Wang, Qinghua; Arighi, Cecilia N; King, Benjamin L; Polson, Shawn W; Vincent, James; Chen, Chuming; Huang, Hongzhan; Kingham, Brewster F; Page, Shallee T; Rendino, Marc Farnum; Thomas, William Kelley; Udwary, Daniel W; Wu, Cathy H

2012-01-01

Recent advances in high-throughput DNA sequencing technologies have equipped biologists with a powerful new set of tools for advancing research goals. The resulting flood of sequence data has made it critically important to train the next generation of scientists to handle the inherent bioinformatic challenges. The North East Bioinformatics Collaborative (NEBC) is undertaking the genome sequencing and annotation of the little skate (Leucoraja erinacea) to promote advancement of bioinformatics infrastructure in our region, with an emphasis on practical education to create a critical mass of informatically savvy life scientists. In support of the Little Skate Genome Project, the NEBC members have developed several annotation workshops and jamborees to provide training in genome sequencing, annotation and analysis. Acting as a nexus for both curation activities and dissemination of project data, a project web portal, SkateBase (http://skatebase.org) has been developed. As a case study to illustrate effective coupling of community annotation with workforce development, we report the results of the Mitochondrial Genome Annotation Jamborees organized to annotate the first completely assembled element of the Little Skate Genome Project, as a culminating experience for participants from our three prior annotation workshops. We are applying the physical/virtual infrastructure and lessons learned from these activities to enhance and streamline the genome annotation workflow, as we look toward our continuing efforts for larger-scale functional and structural community annotation of the L. erinacea genome.

Community annotation and bioinformatics workforce development in concert—Little Skate Genome Annotation Workshops and Jamborees

Science.gov (United States)

Wang, Qinghua; Arighi, Cecilia N.; King, Benjamin L.; Polson, Shawn W.; Vincent, James; Chen, Chuming; Huang, Hongzhan; Kingham, Brewster F.; Page, Shallee T.; Farnum Rendino, Marc; Thomas, William Kelley; Udwary, Daniel W.; Wu, Cathy H.

2012-01-01

Recent advances in high-throughput DNA sequencing technologies have equipped biologists with a powerful new set of tools for advancing research goals. The resulting flood of sequence data has made it critically important to train the next generation of scientists to handle the inherent bioinformatic challenges. The North East Bioinformatics Collaborative (NEBC) is undertaking the genome sequencing and annotation of the little skate (Leucoraja erinacea) to promote advancement of bioinformatics infrastructure in our region, with an emphasis on practical education to create a critical mass of informatically savvy life scientists. In support of the Little Skate Genome Project, the NEBC members have developed several annotation workshops and jamborees to provide training in genome sequencing, annotation and analysis. Acting as a nexus for both curation activities and dissemination of project data, a project web portal, SkateBase (http://skatebase.org) has been developed. As a case study to illustrate effective coupling of community annotation with workforce development, we report the results of the Mitochondrial Genome Annotation Jamborees organized to annotate the first completely assembled element of the Little Skate Genome Project, as a culminating experience for participants from our three prior annotation workshops. We are applying the physical/virtual infrastructure and lessons learned from these activities to enhance and streamline the genome annotation workflow, as we look toward our continuing efforts for larger-scale functional and structural community annotation of the L. erinacea genome. PMID:22434832

A role for the CXCR4-CXCL12 axis in the little skate, Leucoraja erinacea.

Science.gov (United States)

Hersh, Taylor A; Dimond, Alexandria L; Ruth, Brittany A; Lupica, Noah V; Bruce, Jacob C; Kelley, John M; King, Benjamin L; Lutton, Bram V

2018-04-11

The interaction between C-X-C chemokine receptor type 4 (CXCR4) and its cognate ligand, C-X-C motif chemokine ligand 12 (CXCL12), plays a critical role in regulating hematopoietic stem cell activation and subsequent cellular mobilization. Extensive studies of these genes have been conducted in mammals, but much less is known about the expression and function of CXCR4 and CXCL12 in non-mammalian vertebrates. In the present study, we identify simultaneous expression of CXCR4 and CXCL12 orthologues in the epigonal organ (the primary hematopoietic tissue) of the little skate, Leucoraja erinacea. Genetic and phylogenetic analyses were functionally supported by significant mobilization of leukocytes following administration of Plerixafor: a CXCR4 antagonist and clinically important drug. Our results provide evidence that, as in humans, Plerixafor disrupts CXCR4/CXCL12 binding in the little skate, facilitating release of leukocytes into the bloodstream. Our study illustrates the value of the little skate as a model organism, particularly in studies of hematopoiesis, and potentially for pre-clinical research on hematological and vascular disorders.

The role of incline, performance level, and gender on the gross mechanical efficiency of roller ski skating.

Science.gov (United States)

Sandbakk, Oyvind; Hegge, Ann Magdalen; Ettema, Gertjan

2013-01-01

The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level, and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points [the Federation of International Skiing (FIS) approved scoring system for ski racing] where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r = -0.89 to 0.98 and P gender differences being apparent. Significant correlations between gross efficiency and performance level were found for both inclines and genders (r = -0.65 to 0.81 and P genders used less metabolic energy to perform the same amount of work at steeper inclines, and that the better ranked elite male and female skiers skied more efficiently.

Pacing and Performance in Competitive Middle-Distance Speed Skating

Science.gov (United States)

Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

2010-01-01

Data from speed skating during World Cup 1,500-m middle-distance races were analyzed to (a) determine the time/velocity distribution during the race and (b) assess the impact of time spent in several race sectors on performance outcome. Absolute and relative sector times for the first 300 m (S1) and the following three 400-m laps (S2-S4) and their…

Roller skating--is it a dangerous sport?

Science.gov (United States)

Tse, P Y; Shen, W Y; Chan, K M; Leung, P C

1987-01-01

A prospective survey of 111 cases of roller skating injuries within one year are reported. Males were more commonly injured than females. There was a high incidence (86%) of serious injuries, 28% of which required surgical treatment. The wrist (23%) was the commonest region involved, followed by the shoulder (20%), the elbow (15%) and the ankle (12%). Collision with other skaters and loss of control were the main factors leading to injury. Better rink discipline, instruction classes and safety publicity should be helpful in minimising accidents. Images Fig. 2 & Fig. 3 PMID:3676638

A new species of velvet skate, Notoraja sereti n.sp. (Rajiformes: Arhynchobatidae) from Papua New Guinea.

Science.gov (United States)

White, William T; Last, Peter R; Mana, Ralph R

2017-03-19

A new arhynchobatin skate, Notoraja sereti n. sp., is described based on three specimens collected from off Madang (Papua New Guinea) at depths of 800-980 m. This medium-size Notoraja skate shares with other velcro skates from the Western Pacific, N. alisae, N. fijiensis, N. inusitata and N. longiventralis, a ventral surface covering of fine denticles giving the skin a velvety feel. Notoraja sereti differs from all of these species in having a shorter snout (preorbital length 10.1-11.1 vs. 11.5-14.5% TL, prenasal length 8.2-8.9 vs, 9.8-12.1% TL), shorter head (dorsal head length 15.2-16.2 vs. 17.1-19.3% TL, ventral head length 21.6-22.9 vs. 22.9-25.9% TL), fewer pectoral-fin radials (total radials 58-60 vs. 61-74), and fewer vertebrae (predorsal diplospondylous centra 66-71 vs. 72-82, predorsal centra 90-95 vs. 98-107, total centra 126-131 vs. 135-152).

Recipe and technology development for minced canned products of special purpose based on the underutilized north region fishery object (thorny skate

Directory of Open Access Journals (Sweden)

Raibulov S. P.

2016-09-01

Full Text Available The paper presents the results of justifying the use of thorny skate in the technology of minced meat canned products of special purpose. The key criterion determined the specialized purpose of canned food is the high content of physiologically functional food ingredient of chondroitin sulfate in the cartilage of thorny skate wings. The high content of chondroitin sulfate in raw materials ensures that the content of the physiologically functional ingredient in the finished canned food will be at the level from 220 to 250 mg per 100 g of product. The method of IR blanching is presented for removing urea from the thorny skate muscle tissue. To confirm the efficiency of the developed method of urea removal, it has been proposed to use a modified photocolorimetric method for determination of mass fractions of urea in feed flour according to the governmental standard GOST R 50032–92 "Feed flour made of fish, marine mammals, crustaceans and invertebrates. Methods of determining the mass fraction of urea and calculation of the crude protein with a given mass fraction of carbamide". With the help of this technique, the efficiency of urea removal from the thorny skate tissue by the proposed method has been determined. The residual urea content in the meat of thorny skate after IR blanching is 0.76 %, which is two times lesser than border value of sensitivity of the person (approximated as 1.2 %. The paper presents the materials of experimental substantiation of optimum formulation of new canned meat based on the method of fuzzy modeling. The ratio of the main components of the meatballs recipe (thorny skate and Atlantic cod close to the optimum is 48 % by weight of meat for each component separately.

La cultura skate en las sociedades contemporáneas: una aproximación etnográfica a la ciudad de Madrid

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Israel Márquez

2015-01-01

Full Text Available Este artículo propone un acercamiento al fenómeno del skate en la ciudad de Madrid a partir de un estudio etnográfico multisituado en el que se combina investigación online y offline. A partir de esta metodología, ofrecemos una interpretación de algunas de las principales características que presenta la cultura skate en nuestra sociedad, particularmente en la ciudad de Madrid, poniendo énfasis en los aspectos más intersubjetivos y culturales de esta realidad. La práctica del skate en Madrid ha experimentado un visible incremento en los últimos años y el marco analítico que proponemos para el estudio de su difusión y generalización responde a cambios en el orden cultural de las sociedad occidentales y de la propia cultura skate, en dinámica interdependencia con la esfera económica, como orden de producción y distribución de servicios y productos culturales y deportivos.

O DISCURSO CARISMÁTICO E A ROTINIZAÇÃO DO CARISMA NA SKATE PLAZA DO COMPLEXO AMBIENTAL GOVERNADOR MANOEL RIBAS -PONTA GROSSA - PR

OpenAIRE

ADRIANO ALBUQUERQUE BARRETO

2012-01-01

As Skate Plazas surgem no início dos anos 2000 como um modelo possível na construção de pistas de skate. Este modelo surgiu na perspectiva de uma construção cada vez mais semelhante dos lugares que se encontram nas ruas das cidades. Até então além dos obstáculos mais comuns encontrados nas ruas, como os caixotes, os trilhos e as escadas, as rampas faziam parte das pistas que vinham sendo construídas. Nos modelos mais recentes de Skate Plaza vemos com menor intensidade a este tipo de obs...

Wireless instrumented klapskates for long-track speed skating

OpenAIRE

van der Kruk, E.; den Braver, O.; Schwab, Arend L.; van der Helm, Frans C T; Veeger, H. E J

2016-01-01

In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a crucial variable in this power determination. In this study, we present the construction and calibration of a pair of wireless instrumented klapskates that can continuously and synchronously measure this...

76 FR 66856 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Secretarial...

Science.gov (United States)

2011-10-28

... still protecting skates from overfishing. DATES: Effective November 28, 2011, through April 30, 2012... conservation concerns (e.g., overfishing), and Magnuson-Stevens Act emergency actions have been used in the...

Pacing Behavior and Tactical Positioning in 1500-m Short-Track Speed Skating.

Science.gov (United States)

Konings, Marco J; Noorbergen, Olaf S; Parry, David; Hettinga, Florentina J

2016-01-01

To gain more insight in pacing behavior and tactical positioning in 1500-m short-track speed skating, a sport in which several athletes directly compete in the same race. Lap times and intermediate rankings of elite 1500-m short-track- skating competitors were collected over the season 2012-13 (N = 510, 85 races). Two statistical approaches were used to assess pacing behavior and tactical positioning. First, lap times were analyzed using a MANOVA, and for each lap differences between sex, race type, final rankings, and stage of competition were determined. Second, Kendall tau b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined. In 1500 m (13.5 laps of 111.12 m), correlations between intermediate and final ranking gradually increased throughout the race (eg, lap 1, r = .05; lap 7, r = .26; lap 13, r = .85). Moreover, the percentage of race winners skating in the leading position was over 50% during the last 3 laps. Top finishers were faster than bottom-place finishers only during the last 5 laps, with on average 0.1- to 1.5-s faster lap times of the race winners compared with the others during the last 5 laps. Although a fast start led to faster finishing times, top finishers were faster than bottom-placed finishers only during the last 5 laps. Moreover, tactical positioning at 1 of the foremost positions during the latter phase of the race appeared to be a strong determinant of finishing position.

Identification of potential essential fish habitats for skates based on fishers' knowledge.

Science.gov (United States)

Serra-Pereira, Bárbara; Erzini, Karim; Maia, Catarina; Figueiredo, Ivone

2014-05-01

Understanding of spatio-temporal patterns of sensitive fish species such as skates (Rajidae) is essential for implementation of conservation measures. With insufficient survey data available for these species in Portuguese Continental waters, this study shows that fishery-dependent data associated with fishers' knowledge can be used to identify potential Essential Fish Habitats (EFH) for seven skate species. Sites with similar geomorphology were associated with the occurrence of juveniles and/or adults of the same group of species. For example, sites deeper than 100 m with soft sediment include predominantly adults of Raja clavata, and are the habitat for egg deposition of this species. Raja undulata and R. microocellata are the more coastal species, preferring sand or gravel habitats, while coastal areas with rocks and sand seabed are potential nursery areas for R. brachyura, R. montagui and R. clavata. The main output of this study is the identification of preferential fishing sites enclosing potential EFH for some species, associated with egg-laying and nursery grounds. The location of these areas will be considered for future seasonal closures, and studies will be conducted to evaluate the biological and socio-economic impacts of such measures. As in the past, fishermen will collaborate in the process of evaluating those impacts, since they have practical and applied knowledge that is extremely valuable for evaluating the advantages and disadvantages of such closures. In conclusion, this study is a first contribution to the understanding and identification of EFH for skate species, associated with nursery and egg deposition sites, with direct application to management.

Identification of Potential Essential Fish Habitats for Skates Based on Fishers' Knowledge

Science.gov (United States)

Serra-Pereira, Bárbara; Erzini, Karim; Maia, Catarina; Figueiredo, Ivone

2014-05-01

Understanding of spatio-temporal patterns of sensitive fish species such as skates (Rajidae) is essential for implementation of conservation measures. With insufficient survey data available for these species in Portuguese Continental waters, this study shows that fishery-dependent data associated with fishers' knowledge can be used to identify potential Essential Fish Habitats (EFH) for seven skate species. Sites with similar geomorphology were associated with the occurrence of juveniles and/or adults of the same group of species. For example, sites deeper than 100 m with soft sediment include predominantly adults of Raja clavata, and are the habitat for egg deposition of this species. Raja undulata and R. microocellata are the more coastal species, preferring sand or gravel habitats, while coastal areas with rocks and sand seabed are potential nursery areas for R. brachyura, R. montagui and R. clavata. The main output of this study is the identification of preferential fishing sites enclosing potential EFH for some species, associated with egg-laying and nursery grounds. The location of these areas will be considered for future seasonal closures, and studies will be conducted to evaluate the biological and socio-economic impacts of such measures. As in the past, fishermen will collaborate in the process of evaluating those impacts, since they have practical and applied knowledge that is extremely valuable for evaluating the advantages and disadvantages of such closures. In conclusion, this study is a first contribution to the understanding and identification of EFH for skate species, associated with nursery and egg deposition sites, with direct application to management.

Influences of a yoga intervention on the postural skills of the Italian short track speed skating team

Science.gov (United States)

Brunelle, Jean-François; Blais-Coutu, Sébastien; Gouadec, Kenan; Bédard, Éric; Fait, Philippe

2015-01-01

Introduction In preparation for a short track speed skating season, eight men and seven women were given yoga sessions during an 8-week high volume training cycle. The sessions were planned according to the postural aspects specific to short track speed skating technical requirements. Three specific goals were selected for the intervention: 1) to observe whether the practice of yoga as postural training could improve the efficiency and the athlete’s repertoire along the muscular synergies solicited in the short track speed skating specific technique; 2) to enhance and diversify the motor time-on-task of athletes without changing the prescription of other training stimulus; and 3) to lower the risk of injury during periods with high volumes of training. Methods A total of 36 sessions of yoga were given. Three postural tests were administered before and after the intervention with 14 angles analyzed. Non-parametric Wilcoxon test was used to compare angles’ variations. Results The 36 yoga sessions totalized 986 minutes of motor time-on-task, registering a proportion of 30% of the global motor time-on-task of the training cycle. Improvements were found in eleven of the 14 angles measured when comparing pre- and post-postural tests (P-value from 0.01 to 0.005). During the 8 weeks, excepting traumatic injuries due to short track speed skating accidents, no skaters suffered injuries linked to the high volume of training. Following the intervention, coaches noticed, following their on-ice feedbacks, an adjustment in the efficiency of the skating technique, in particular regarding hip dissociation. Conclusion These results suggest that yoga could be inserted into out-of-season training cycles, even in a high volume training cycle. Planned with the decision training tools, it allows athletes to diversify their motor time-on-task by integrating a new functional range of generic movements with the solicitation of neuromuscular synergies related to the specificity of their

Effects of basic fibroblast growth factor and insulin-like growth factor on cultured cartilage cells from skate Raja porasa

Science.gov (United States)

Fan, Tingjun; Jin, Lingyun; Wang, Xiaofeng

2003-12-01

Effects of basic fibroblast growth factor (bFGF) and insulin-like growth factor II (IGF-II) on cartilage cells from proboscis of skate, Raja porasa Günther, were investigated in this study. The cartilage cells were cultured in 20% FBS-supplemented MEM medium at 24°C. Twelve hours after culture initiation, the cartilage cells were treated with bFGF and IGF-II at different concentration combinations. It was found that 20 ng/ml of bFGF or 80 ng/ml of IGF-II was enough to have obvious stimulating effect on the growth and division of skate cartilage cells. Test of bFGF and IGF-II together, revealed that 20 ng/ml of bFGF and 80 ng/ml of IGF-II together had the best stimulating effect on the growth and division of skate cartilage cells. The cartilage cells cultured could form a monolayer at day 7.

STUDY CONCERNING THE ELABORATION OF CERTAIN ORIENTATION MODELS AND THE INITIAL SELECTION FOR SPEED SKATING

Directory of Open Access Journals (Sweden)

Vaida Marius

2009-12-01

Full Text Available In realizing this study I started from the premise that, by elaborating certain orientation models and initial selection for the speed skating and their application will appear superior results, necessary results, taking into account the actual evolution of the high performance sport in general and of the speed skating, in special.The target of this study has been the identification of an orientation model and a complete initial selection that should be based on the favorable aptitudes of the speed skating. On the basis of the made researched orientation models and initial selection has been made, things that have been demonstrated experimental that are not viable, the study starting from the data of the 120 copies, the complete experiment being made by 32 subjects separated in two groups, one using the proposed model and the other formed fromsubjects randomly selected.These models can serve as common working instruments both for the orientation process and for the initial selection one, being able to integrate in the proper practical activity, these being used easily both by coaches that are in charge with the proper selection of the athletes but also by the physical education teachers orschool teachers that are in contact with children of an early age.

Selected plantar pressure characteristics associated with the skating performance of national in-line speed skaters.

Science.gov (United States)

Wu, Wen-Lan; Hsu, Hsiu-Tao; Chu, I-Hua; Tsai, Feng-Hua; Liang, Jing-Min

2017-06-01

In order to help coaches analyse the techniques of professional in-line speed skaters for making the required fine adjustments and corrections in their push-off work, this study analysed the specific plantar pressure characteristics during a 300-m time-trial test. Fourteen elite in-line speed skaters from the national team were recruited in this study. The total completion time of the 300-m time-trial test, duration of each skating phase, and plantar pressure distribution were measured. The correlation between plantar pressure distribution and skating performance was assessed using Pearson correlation analyses. The results showed that the contact time of the total foot and force-time integral (FTI) in the medial forefoot were significantly correlated with the duration of the start phase, and the FTIs in the medial forefoot of the gliding (left) leg and lateral forefoot of the pushing (right) leg were significantly correlated with the duration of the turning phase. The maximum force in the medial heel, medial forefoot, and median forefoot and the FTI in the medial heel and medial forefoot were significantly correlated with the duration of the linear acceleration phase. The results suggest that a correct plantar loading area and push-off strategy can enhance the skating performance.

The phylogenetic position of the roughskin skate Dipturus trachyderma (Krefft & Stehmann, 1975) (Rajiformes, Rajidae) inferred from the mitochondrial genome.

Science.gov (United States)

Vargas-Caro, Carolina; Bustamante, Carlos; Lamilla, Julio; Bennett, Michael B; Ovenden, Jennifer R

2016-07-01

The complete mitochondrial genome of the roughskin skate Dipturus trachyderma is described from 1 455 724 sequences obtained using Illumina NGS technology. Total length of the mitogenome was 16 909 base pairs, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Phylogenetic analysis based on mtDNA revealed low genetic divergence among longnose skates, in particular, those dwelling the continental shelf and slope off the coasts of Chile and Argentina.

Effect of race distance on muscle oxygenation in short-track speed skating.

Science.gov (United States)

Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

2013-01-01

Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

Instrumented figure skating blade for measuring on-ice skating forces

Science.gov (United States)

Acuña, S. A.; Smith, D. M.; Robinson, J. M.; Hawks, J. C.; Starbuck, P.; King, D. L.; Ridge, S. T.; Charles, S. K.

2014-12-01

Competitive figure skaters experience substantial, repeated impact loading during jumps and landings. Although these loads, which are thought to be as high as six times body weight, can lead to overuse injuries, it is not currently possible to measure these forces on-ice. Consequently, efforts to improve safety for skaters are significantly limited. Here we present the development of an instrumented figure skating blade for measuring forces on-ice. The measurement system consists of strain gauges attached to the blade, Wheatstone bridge circuit boards, and a data acquisition device. The system is capable of measuring forces in the vertical and horizontal directions (inferior-superior and anterior-posterior directions, respectively) in each stanchion with a sampling rate of at least 1000 Hz and a resolution of approximately one-tenth of body weight. The entire system weighs 142 g and fits in the space under the boot. Calibration between applied and measured force showed excellent agreement (R > 0.99), and a preliminary validation against a force plate showed good predictive ability overall (R ≥ 0.81 in vertical direction). The system overestimated the magnitude of the first and second impact peaks but detected their timing with high accuracy compared to the force plate.

Methodical basis of the preparing technology of the specialists in the competitive system activity in fgure skating on ice

Directory of Open Access Journals (Sweden)

Medvedeva I.M

2010-10-01

Full Text Available Methodology of competition activity of skilled fgure skaters is reasonable. The model of the special preparedness of future teachers is worked out. Maintenance and principles of process of teaching of students is worked out. Methodical bases of technology of teaching students to the construction of competition compositions are reasonable. The pedagogical departmental of students teaching is presented taking into account modern features and progress of fgure-skating trends on skates. Conception is based on a capture students professional knowledge, abilities and skills.

An Improved method for separation of leucocytes from peripheral blood of the little skate (Leucoraja erinacea)

Science.gov (United States)

Tomana, Mitsuru; Parton, Angela; Barnes, David W.

2008-01-01

Cartilaginous fish, especially sharks, rays and skates (elasmobranchs) hold interest as comparative models in immunology because they are thought to be among the organisms most closely related to the ancestor animal that first developed acquired immunity. The aim of this study was to improve methods used for the purification of viable leucocytes from peripheral blood of elasmobranchs. Here we describe modifications of density gradient centrifugation and medium formulation that improve isolation and analysis of highly-purified leucocytes from peripheral blood of a model elasmobranch, Leucoraja erinacea, the little skate. These techniques contribute to the preparation of elasmobranch immune cells that can be reliably analyzed by a variety of means, including the study of immune function. PMID:18474431

Effects of a recreational ice skating program on the functional mobility of a child with cerebral palsy.

Science.gov (United States)

Walsh, Sharon Fleming; Scharf, Michael G

2014-04-01

The purpose of this study was to describe the effects of an ice skating program on the ambulation, strength, posture and balance of a child with cerebral palsy (CP). The subject was a five-year-old female with a diagnosis of CP and a Gross Motor Classification System level of III. The subject was a slow and labored household ambulator on level surfaces with bilateral forearm crutches and bilateral ankle foot orthoses. She was unable to transfer to and from the floor to stand independently, stand unsupported or take steps independently. Until the initiation of this study she was receiving physical therapy services 2×/week. For the purpose of this study she participated in a 1 h/week local ice skating program for people with disabilities for a period of four months. The subject displayed clinically significant improvements in functional mobility including: improved standing posture; independent transfer to and from the floor to stand; maintenance of independent standing for 3 min; independent walking for 10 feet; increased ability to isolate extremity musculature; increased strength; improved Gross Motor Function Measure-88 scores and increased endurance. A subsequent testing session four months after the ice skating program had ended displayed declines but not to pre-intervention levels in muscle strength; ability to transfer to and from the floor to stand; functional mobility and standing balance. The results appear to suggest that the participation in an ice skating program clinically improved this child's functional mobility. Further research needs to be done with regard to physical recreational programs and the benefit they can have on the function of children with activity limitations.

The complete mitochondrial genome of the endangered spotback skate, Atlantoraja castelnaui.

Science.gov (United States)

Duckett, Drew J L; Naylor, Gavin J P

2016-05-01

Chondrichthyes are a highly threatened class of organisms, largely due to overfishing and other human activities. The present study describes the complete mitochondrial genome (16,750 bp) of the endangered spotback skate, Atlantoraja castelnaui. The mitogenome is arranged in a typical vertebrate fashion, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 control region.

Shark and skate egg-cases cast up on two South African beaches ...

African Journals Online (AJOL)

Collections of chondrichthyan egg-cases cast ashore at two sites along the South African coastline were identified and examined for cause of mortality. A total of 574 egg-cases collected from False Bay could be attributed to five species of scyliorhinid shark. two skates and the elephantfish or chimaera, while the 538 ...

Molecular markers reveal spatially segregated cryptic species in a critically endangered fish, the common skate (Dipturus batis).

Science.gov (United States)

Griffiths, Andrew M; Sims, David W; Cotterell, Stephen P; El Nagar, Aliya; Ellis, Jim R; Lynghammar, Arve; McHugh, Matthew; Neat, Francis C; Pade, Nicolas G; Queiroz, Nuno; Serra-Pereira, Bárbara; Rapp, Toby; Wearmouth, Victoria J; Genner, Martin J

2010-05-22

Many sharks and skates are particularly vulnerable to overfishing because of their large size, slow growth, late maturity and low fecundity. In Europe dramatic population declines have taken place in common skate (Dipturus batis L.), one of the largest demersal fish in regional shelf seas, leading to extirpations from substantial parts of its former range. Here we report the discovery of cryptic species in common skate collected from the northeast Atlantic continental shelf. Data from nuclear microsatellite markers indicated two clearly distinct clades and phylogenetic analysis of mitochondrial DNA sequences demonstrated monophyly of each one of them. Capture locations showed evidence of strong spatial segregation, with one taxon occurring mainly in waters off the southern British Isles and around Rockall, while the other was restricted to more northerly shelf waters. These apparently cryptic species showed overlapping substrate and depth preferences, but distributional limits were closely related to temperature gradients, potentially indicating thermal limits to their distributions. This discovery of hidden diversity within a large, critically endangered marine vertebrate demonstrates how marine biodiversity can be underestimated, even in such a relatively well-studied and heavily exploited region.

Molecular markers reveal spatially segregated cryptic species in a critically endangered fish, the common skate (Dipturus batis)

Science.gov (United States)

Griffiths, Andrew M.; Sims, David W.; Cotterell, Stephen P.; El Nagar, Aliya; Ellis, Jim R.; Lynghammar, Arve; McHugh, Matthew; Neat, Francis C.; Pade, Nicolas G.; Queiroz, Nuno; Serra-Pereira, Bárbara; Rapp, Toby; Wearmouth, Victoria J.; Genner, Martin J.

2010-01-01

Many sharks and skates are particularly vulnerable to overfishing because of their large size, slow growth, late maturity and low fecundity. In Europe dramatic population declines have taken place in common skate (Dipturus batis L.), one of the largest demersal fish in regional shelf seas, leading to extirpations from substantial parts of its former range. Here we report the discovery of cryptic species in common skate collected from the northeast Atlantic continental shelf. Data from nuclear microsatellite markers indicated two clearly distinct clades and phylogenetic analysis of mitochondrial DNA sequences demonstrated monophyly of each one of them. Capture locations showed evidence of strong spatial segregation, with one taxon occurring mainly in waters off the southern British Isles and around Rockall, while the other was restricted to more northerly shelf waters. These apparently cryptic species showed overlapping substrate and depth preferences, but distributional limits were closely related to temperature gradients, potentially indicating thermal limits to their distributions. This discovery of hidden diversity within a large, critically endangered marine vertebrate demonstrates how marine biodiversity can be underestimated, even in such a relatively well-studied and heavily exploited region. PMID:20106849

Gastric inhibitory peptide, serotonin, and glucagon are unexpected chloride secretagogues in the rectal gland of the skate (Leucoraja erinacea).

Science.gov (United States)

Kelley, Catherine A; Decker, Sarah E; Silva, Patricio; Forrest, John N

2014-05-01

Since the discovery of the rectal gland of the dogfish shark 50 years ago, experiments with this tissue have greatly aided our understanding of secondary active chloride secretion and the secretagogues responsible for this function. In contrast, very little is known about the rectal gland of skates. In the present experiments, we performed the first studies in the perfused rectal gland of the little skate (Leucoraja erinacea), an organ weighing less than one-tenth of the shark rectal gland. Our results indicate that the skate gland can be studied by modified perfusion techniques and in primary culture monolayers, and that secretion is blocked by the inhibitors of membrane proteins required for secondary active chloride secretion. Our major finding is that three G protein-coupled receptor agonists, the incretin gastric inhibitory polypeptide (GIP), also known as glucose-dependent insulinotropic peptide, as well as glucagon and serotonin, are unexpected potent chloride secretagogues in the skate but not the shark. Glucagon stimulated chloride secretion to a mean value of 1,661 ± 587 μeq·h(-1)·g(-1) and serotonin stimulated to 2,893 ± 699 μeq·h(-1)·g(-1). GIP stimulated chloride secretion to 3,733 ± 679 μeq·h(-1)·g(-1) and significantly increased tissue cAMP content compared with basal conditions. This is the first report of GIP functioning as a chloride secretagogue in any species or tissue.

The impact of ice-skating injuries on orthopaedic admissions in a regional hospital.

LENUS (Irish Health Repository)

Dillon, J P

2012-02-03

Since the opening of a temporary ice-rink in our hospital\\'s catchment area, we have observed an increase in patients requiring in-patient treatment for orthopaedic intervention. The authors performed a prospective analysis of all patients admitted to our unit over a one-month period. Epidemiological data, wearing of protective gear and skater experience were collected. Fracture type, treatment required, average length of hospital stay and number of days missed from work was also recorded. Ice-skating injuries accounted for 7.7% of our total admissions over the study period. There was a significant variation noted in the types of fracture sustained ranging from comminuted fractures of the radial head to spiral fractures of the tibia. The average length of hospital stay was 2.6 days and average time missed from work was 6.1 weeks. This paper highlights the potential serious injuries that can occur in ice-skating and their impact on admissions to our orthopaedic unit.

Development of Automated Tracking System with Active Cameras for Figure Skating

Science.gov (United States)

Haraguchi, Tomohiko; Taki, Tsuyoshi; Hasegawa, Junichi

This paper presents a system based on the control of PTZ cameras for automated real-time tracking of individual figure skaters moving on an ice rink. In the video images of figure skating, irregular trajectories, various postures, rapid movements, and various costume colors are included. Therefore, it is difficult to determine some features useful for image tracking. On the other hand, an ice rink has a limited area and uniform high intensity, and skating is always performed on ice. In the proposed system, an ice rink region is first extracted from a video image by the region growing method, and then, a skater region is extracted using the rink shape information. In the camera control process, each camera is automatically panned and/or tilted so that the skater region is as close to the center of the image as possible; further, the camera is zoomed to maintain the skater image at an appropriate scale. The results of experiments performed for 10 training scenes show that the skater extraction rate is approximately 98%. Thus, it was concluded that tracking with camera control was successful for almost all the cases considered in the study.

Optimal pacing strategy: From theoretical modeling to reality in 1500m speed skating

NARCIS (Netherlands)

Hettinga, F.J.; de Koning, J.J.; Schmidt, L.J.I.; Wind, N.A.C.; McIntosh, B.; Foster, C.

2011-01-01

Purpose: Athletes are trained to choose the pace which is perceived to be correct during a specific effort, such as the 1500-m speed skating competition. The purpose of the present study was to "override" self-paced (SP) performance by instructing athletes to execute a theoretically optimal pacing

Optimal pacing strategy : from theoretical modelling to reality in 1500-m speed skating

NARCIS (Netherlands)

Hettinga, F. J.; De Koning, J. J.; Schmidt, L. J. I.; Wind, N. A. C.; MacIntosh, B. R.; Foster, C.

Purpose Athletes are trained to choose the pace which is perceived to be correct during a specific effort, such as the 1500-m speed skating competition. The purpose of the present study was to "override" self-paced (SP) performance by instructing athletes to execute a theoretically optimal pacing

Food habits of the broad nose skate, Bathyraja brachyurops (Chondrichthyes, Rajidae, in the south-west Atlantic

Directory of Open Access Journals (Sweden)

Mauro Belleggia

2008-12-01

Full Text Available Food habits of Bathyraja brachyurops were studied based on stomach content analyses of 346 specimens collected from research cruises carried out from 2003 to 2005 on the Argentinean continental shelf (36ºS-55ºS. A total of 265 stomachs (76.6% contained food, and thirty-five taxonomic levels of prey were identified. The most important prey were fishes followed by isopods. Trophic level analysis revealed that B. brachyurops is a tertiary consumer throughout its life history. There were no differences between sexes and regions in the diet composition, but dietary shifts with ontogeny were found. The Levins’ standardized index indicated wider niche breadth for small skates, whereas larger skate specimens showed a narrow niche breadth with a specialization in fishes.

An Analysis of US Emergency Department Visits From Falls From Skiing, Snowboarding, Skateboarding, Roller-Skating, and Using Nonmotorized Scooters.

Science.gov (United States)

Nathanson, Brian H; Ribeiro, Kara; Henneman, Philip L

2016-07-01

We analyzed the US incidence of emergency department (ED) visits and hospitalizations for falls from skiing, snowboarding, skateboarding, roller-skating, and nonmotorized scooters in 2011. The outcome was hospital admission from the ED. The primary analysis compared pediatric patients aged 1 to 17 years to adults aged 18 to 44 years. The analysis used ICD-9 E-codes E885.0 to E885.4 using discharge data from the Nationwide Emergency Department Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. Approximately 214 000 ED visits met study criteria. Skiing injuries had the highest percentage of hospitalizations (3.30% in pediatric patients and 6.65% in adults 18-44 years old). Skateboard and snowboard injuries were more likely to require hospitalization than roller skating injuries in pediatric patients (odds ratio = 2.42; 95% CI = 2.14-2.75 and odds ratio = 1.83; 95% CI =1.55-2.15, respectively). In contrast, skateboard and snowboard injuries were less severe than roller-skating injuries in adults. © The Author(s) 2015.

The role of incline, performance level, and gender on the gross mechanical efficiency of roller ski skating

Science.gov (United States)

Sandbakk, Øyvind; Hegge, Ann Magdalen; Ettema, Gertjan

2013-01-01

The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level, and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points [the Federation of International Skiing (FIS) approved scoring system for ski racing] where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r = −0.89 to 0.98 and P < 0.05 in all cases). Gross efficiency was higher at the steeper incline, both for men (17.1 ± 0.4 vs. 15.8 ± 0.5%, P < 0.05) and women (16.9 ± 0.5 vs. 15.7 ± 0.4%, P < 0.05), but without any gender differences being apparent. Significant correlations between gross efficiency and performance level were found for both inclines and genders (r = −0.65 to 0.81 and P < 0.05 in all cases). The current study demonstrated that cross-country skiers of both genders used less metabolic energy to perform the same amount of work at steeper inclines, and that the better ranked elite male and female skiers skied more efficiently. PMID:24155722

Na+-taurocholate cotransporting polypeptide (NTCP/SLC10A1) ortholog in the marine skate Leucoraja erinacea is not a physiological bile salt transporter.

Science.gov (United States)

Yu, Dongke; Zhang, Han; Lionarons, Daniel A; Boyer, James L; Cai, Shi-Ying

2017-04-01

The Na + -dependent taurocholate cotransporting polypeptide (NTCP/SLC10A1) is a hepatocyte-specific solute carrier, which plays an important role in maintaining bile salt homeostasis in mammals. The absence of a hepatic Na + -dependent bile salt transport system in marine skate and rainbow trout raises a question regarding the function of the Slc10a1 gene in these species. Here, we have characterized the Slc10a1 gene in the marine skate, Leucoraja erinacea The transcript of skate Slc10a1 (skSlc10a1) encodes 319 amino acids and shares 46% identity to human NTCP (hNTCP) with similar topology to mammalian NTCP. SkSlc10a1 mRNA was mostly confined to the brain and testes with minimal expression in the liver. An FXR-bile salt reporter assay indicated that skSlc10a1 transported taurocholic acid (TCA) and scymnol sulfate, but not as effectively as hNTCP. An [ 3 H]TCA uptake assay revealed that skSlc10a1 functioned as a Na + -dependent transporter, but with low affinity for TCA ( K m = 92.4 µM) and scymnol sulfate ( K i = 31 µM), compared with hNTCP (TCA, K m = 5.4 µM; Scymnol sulfate, K i = 3.5 µM). In contrast, the bile salt concentration in skate plasma was 2 µM, similar to levels seen in mammals. Interestingly, skSlc10a1 demonstrated transport activity for the neurosteroids dehydroepiandrosterone sulfate and estrone-3-sulfate at physiological concentration, similar to hNTCP. Together, our findings indicate that skSlc10a1 is not a physiological bile salt transporter, providing a molecular explanation for the absence of a hepatic Na + -dependent bile salt uptake system in skate. We speculate that Slc10a1 is a neurosteroid transporter in skate that gained its substrate specificity for bile salts later in vertebrate evolution. Copyright © 2017 the American Physiological Society.

The Vibe of Skating : Design and Testing of a Vibro-Tactile Feedback System

NARCIS (Netherlands)

Jansen, A.J.; Dekker, M.C.; van der Steen, Diederik; Espinosa, Hugo G.; Rowlands, David R.; Shepherd, Jonathan; Thiel, David V.

2018-01-01

Providing athletes with real-time feedback on their performance is becoming common in many sports, also in speed skating. This research-by-design project aims at finding a tool that allows the speed skater to get real-time feedback on his performance. Speed skaters often mention a so-called “good

Lower Leg Anterior and Lateral Intracompartmental Pressure Changes Before and After Classic Versus Skate Nordic Rollerskiing.

Science.gov (United States)

Woods, Katherine M; Petron, David J; Shultz, Barry B; Hicks-Little, Charlie A

2015-08-01

Chronic exertional compartment syndrome (CECS) is a debilitating condition resulting in loss of function and a decrease in athletic performance. Cases of CECS are increasing among Nordic skiers; therefore, analysis of intracompartmental pressures (ICPs) before and after Nordic skiing is warranted. To determine if lower leg anterior and lateral ICPs and subjective lower leg pain levels increased after a 20-minute Nordic rollerskiing time trial and to examine if differences existed between postexercise ICPs for the 2 Nordic rollerskiing techniques, classic and skate. Crossover study. Outdoor paved loop. Seven healthy Division I Nordic skiers (3 men, 4 women; age = 22.71 ± 1.38 y, height = 175.36 ± 6.33 cm, mass = 70.71 ± 6.58 kg). Participants completed two 20-minute rollerskiing time trials using the classic and skate technique in random order. The time trials were completed 7 days apart. Anterior and lateral ICPs and lower leg pain scores were obtained at baseline and at minutes 1 and 5 after rollerskiing. Anterior and lateral ICPs (mm Hg) were measured using a Stryker Quic STIC handheld monitor. Subjective measures of lower leg pain were recorded using the 11-point Numeric Rating Scale. Increases in both anterior (P = .000) and lateral compartment (P = .002) ICPs were observed, regardless of rollerskiing technique used. Subjective lower leg pain increased after the classic technique for the men from baseline to 1 minute postexercise and after the skate technique for the women. Significant 3-way interactions (technique × time × sex) were observed for the anterior (P = .002) and lateral (P = .009) compartment ICPs and lower leg pain (P = .005). Postexercise anterior and lateral ICPs increased compared with preexercise ICPs after both classic and skate rollerskiing techniques. Lower leg pain is a primary symptom of CECS. The subjective lower leg pain 11-point Numeric Rating Scale results indicate that increases in lower leg ICPs sustained during Nordic

Validity of Lactate Thresholds in Inline Speed Skating.

Science.gov (United States)

Hecksteden, Anne; Heinze, Tobias; Faude, Oliver; Kindermann, Wilfried; Meyer, Tim

2015-09-01

Lactate thresholds are commonly used as estimates of the highest workload where lactate production and elimination are in equilibrium (maximum lactate steady state [MLSS]). However, because of the high static load on propulsive muscles, lactate kinetics in inline speed skating may differ significantly from other endurance exercise modes. Therefore, the discipline-specific validity of lactate thresholds has to be verified. Sixteen competitive inline-speed skaters (age: 30 ± 10 years; training per week: 10 ± 4 hours) completed an exhaustive stepwise incremental exercise test (start 24 km·h, step duration 3 minutes, increment 2 km·h) to determine individual anaerobic threshold (IAT) and the workload corresponding to a blood lactate concentration of 4 mmol·L (LT4) and 2-5 continuous load tests of (up to) 30 minutes to determine MLSS. The IAT and LT4 correlated significantly with MLSS, and the mean differences were almost negligible (MLSS 29.5 ± 2.5 km·h; IAT 29.2 ± 2.0 km·h; LT4 29.6 ± 2.3 km·h; p > 0.1 for all differences). However, the variability of differences was considerable resulting in 95% limits of agreement in the upper range of values known from other endurance disciplines (2.6 km·h [8.8%] for IAT and 3.1 km·h [10.3%] for LT4). Consequently, IAT and LT4 may be considered as valid estimates of the MLSS in inline speed skating, but verification by means of a constant load test should be considered in cases of doubt or when optimal accuracy is needed (e.g., in elite athletes or scientific studies).

Surgical Repair of an Impalement Genital Injury from an Inline Skating Accident in a 7-Year-Old Prepubertal Girl: A Case Report.

Science.gov (United States)

Csorba, Roland; Engel, Joerg B; Wieg, Christian

2017-02-01

In girls who present with vaginal trauma, sexual abuse is often the primary diagnosis. The differential diagnosis must include patterns and the mechanism of injury that differentiate accidental injuries from inflicted trauma. A 7-year-old prepubertal girl presented to the emergency department with genital bleeding after a serious accidental impaling injury from inline skating. After rapid abduction of the legs and a fall onto the blade of an inline skate this child incurred an impaling genital injury consistent with an accidental mechanism. The dramatic genital injuries when repaired healed with almost imperceptible residual evidence of previous trauma. To our knowledge, this case report represents the first in the medical literature of an impaling vaginal trauma from an inline skate and describes its clinical and surgical management. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Pacing Behavior and Tactical Positioning in 500-and 1000-m Short-Track Speed Skating

NARCIS (Netherlands)

Noorbergen, Olaf S.; Konings, Marco J.; Micklewright, Dominic; Elferink-Gemser, Marge T.; Hettinga, Florentina J.

Purpose: To explore pacing behavior and tactical positioning during the shorter 500- and 1000-m short-track competitions. Methods: Lap times and intermediate rankings of elite 500- and 1000-m short-track-skating competitors were collected over the 2012-13 season. First, lap times were analyzed using

Gosto musical e hexis corporal: a questão do estilo na prática do skate de rua em Ponta Grossa-PR

Directory of Open Access Journals (Sweden)

Adriano Albuquerque Barreto

2017-04-01

Full Text Available http://dx.doi.org/10.5007/2175-8042.2017v29n50p50 Nosso trabalho é uma análise da estética musical incorporada por um grupo de skatistas e sua relação com do estilo de skate desenvolvido pelos praticantes. A hexis corporal na prática do skate de rua, em nosso espaço de investigação, se mostrou associada com o gosto musical do grupo em questão. Deste modo, nosso propósito foi evidenciar essas referências musicais e seu impacto na formação do estilo do skate praticado. Nossa experiência antropológica com os skatistas e o referencial teórico inspirado pela leitura dos trabalhos de Bourdieu sobre estética musical e a hexis corporal foram nossas fontes de pesquisa. Partindo de uma breve história da skatemusic e da exposição dos skatistas sobre a influência do estilo musical no estilo da prática do skate, exploramos o habitus destes enquanto interdependências dos grupos e parte de um charme ou carisma na conformação dos skaters.

Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.

Science.gov (United States)

Hesford, Catherine Mary; Laing, Stewart J; Cardinale, Marco; Cooper, Chris E

2012-03-01

It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P skating has implications for training and performance.

Mood after various brief exercise and sport modes: aerobics, hip-hop dancing, ice skating, and body conditioning.

Science.gov (United States)

Kim, Sungwoon; Kim, Jingu

2007-06-01

To investigate the potential psychological benefits of brief exercise and sport activities on positive mood alterations, 45 Korean high school and 232 undergraduate students enrolled in physical education and stress management classes voluntarily participated and were randomly assigned to one of four activities: aerobic exercise, body conditioning, hip-hop dancing, and ice skating. Mood changes from before to after exercise (2 pm to 3 pm) were measured based on a Korean translation of the Subjective Exercise Experiences Scale. The findings suggested that the aerobics and hip-hop dancing groups rated positive well-being higher than the body conditioning and ice skating groups. Immediately after exercise, psychological distress was rated lower in the aerobics and hip-hop dancing groups, as was fatigue.

76 FR 53872 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Secretarial...

Science.gov (United States)

2011-08-30

... scientific information indicating significant increases in skate biomass. DATES: Public comments must be... may submit comments, identified by NOAA-NMFS-2011-0197, by any one of the following methods... from the resulting list and click on the ``Submit a Comment'' icon on the right of that line. Fax: (978...

Energy efficient skating rink by heat recovery and CO2 refrigerant; Energiezuinige schaatsbaan door warmteterugwinning en CO2-koudedrager

Energy Technology Data Exchange (ETDEWEB)

Mooi, R. [IBK Compac, Houten (Netherlands)

2009-03-15

In October 2008 a new indoor skating rink was opened in Enschede, Netherlands. The refrigeration plant for this skating rink was designed, delivered and installed by IBK Compac. CO2 was chosen as the secondary refrigerant; CO2 is easily detectable, sustainable and - above all - very energy efficient, since less pumping energy is required and pipes with a smaller diameter can be used. The waste heat of the refrigeration plant is used for the Zamboni (ice resurfacer), for the central heating system and for the unique floor heating system, which is located under the skating rink. [Dutch] In oktober 2008 werd in Enschede de IJsbaan Twente geopend. Het werd een geheel overdekte schaatsbaan, waarvoor IBK Compac de koude-installatie heeft ontworpen, geleverd en geinstalleerd. Gekozen werd voor CO2 als secundaire koudedrager. CO2 is goed detecteerbaar, duurzaam en vooral zeer energie-efficient doordat er minder pompenergie nodig is en er leidingen met een kleinere diameter kunnen worden gebruikt. De restwarmte van de koelinstallatie wordt o.a. benut voor de dweilmachine (Zamboni), voor het cv-blok en voor het unieke vloerverwarmingssysteem dat onder de ijsbaan ligt.

The complete validated mitochondrial genome of the yellownose skate Zearaja chilensis (Guichenot 1848) (Rajiformes, Rajidae).

Science.gov (United States)

Vargas-Caro, Carolina; Bustamante, Carlos; Bennett, Michael B; Ovenden, Jennifer R

2016-01-01

The yellownose skate Zearaja chilensis is endemic to South America. The species is the target of a valuable commercial fishery in Chile, but is highly susceptible to over-exploitation. The complete mitochondrial genome was described from 694,593 sequences obtained using Ion Torrent Next Generation Sequencing. The total length of the mitogenome was 16,909 bp, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Comparison between the proposed mitogenome and one previously described from "raw fish fillets from a skate speciality restaurant in Seoul, Korea" resulted in 97.4% similarity, rather than approaching 100% similarity as might be expected. The 2.6% dissimilarity may indicate the presence of two separate stocks or two different species of, ostensibly, Z. chilensis in South America and highlights the need for caution when using genetic resources without a taxonomic reference or a voucher specimen.

AFSC/REFM: Movement of Alaska skates (Bathyraja parmifera) in the Bering Sea , determined through conventional tagging

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains the results of a tagging study being conducted on the Alaska skate (Bathyraja parmifera) in the eastern Bering Sea. The purpose of the study is...

Common skate (Raja kenojei) secretes pentraxin into the cutaneous secretion: The first skin mucus lectin in cartilaginous fish.

Science.gov (United States)

Tsutsui, Shigeyuki; Yamaguchi, Motoki; Hirasawa, Ai; Nakamura, Osamu; Watanabe, Tasuku

2009-08-01

A lactose-specific lectin with a molecular mass of about 25 kDa was purified from the skin mucus of a cartilaginous fish-the common skate (Raja kenojei). The complementary DNA sequence of the lectin was 1540 bp long and contained a reading frame encoding 226 amino acids, which showed approximately 38% identity to pentraxins of mammals and teleosts. Gene expression was observed in the skin, gill, stomach and intestine in the healthy skate. We also identified an isotype gene from the liver whose deduced amino-acid sequence shared 69.0% identity with the skin type gene. The antiserum detected protein in the skin, where the lectin is localized in the epidermal cells, and in the blood plasma. The lectin genes are multicopied in the common skate genome. Although pentraxins are acute phase proteins, mRNAs of both the isotypes were not upregulated after the in vivo challenge with formalin-killed Escherichia coli, which suggests that they are constantly present in the skin mucus and blood plasma to protect against pathogenic invasion. This lectin is the fifth type of lectin found in the cutaneous secretions of fish, demonstrating that skin mucus lectins have evolved with marked molecular diversity in fish.

Ice skating injuries: can they be reduced or prevented?

Science.gov (United States)

Oakland, C D

1990-01-01

The opening of an ice rink resulted in 469 attendances at the local Accident and Emergency department over the first year. One hundred and eight had a significant injury. Thirty-seven patients were admitted. Thirty-three required an operation under general anaesthesia. Thirty had consumed alcohol at the rink's bar. Nine of these had a fracture. The number of skates attending the Accident and Emergency department per 1000 visits to the rink declined over the study period. Injuries could be reduced if protective clothing was worn. Alcohol should not be sold at the rink. First aid although effective could be improved. PMID:2390159

Progressive hypoxia decouples activity and aerobic performance of skate embryos.

Science.gov (United States)

Di Santo, Valentina; Tran, Anna H; Svendsen, Jon C

2016-01-01

Although fish population size is strongly affected by survival during embryonic stages, our understanding of physiological responses to environmental stressors is based primarily on studies of post-hatch fishes. Embryonic responses to acute exposure to changes in abiotic conditions, including increase in hypoxia, could be particularly important in species exhibiting long developmental time, as embryos are unable to select a different environment behaviourally. Given that oxygen is key to metabolic processes in fishes and aquatic hypoxia is becoming more severe and frequent worldwide, organisms are expected to reduce their aerobic performance. Here, we examined the metabolic and behavioural responses of embryos of a benthic elasmobranch fish, the little skate (Leucoraja erinacea), to acute progressive hypoxia, by measuring oxygen consumption and movement (tail-beat) rates inside the egg case. Oxygen consumption rates were not significantly affected by ambient oxygen levels until reaching 45% air saturation (critical oxygen saturation, S crit). Below S crit, oxygen consumption rates declined rapidly, revealing an oxygen conformity response. Surprisingly, we observed a decoupling of aerobic performance and activity, as tail-beat rates increased, rather than matching the declining metabolic rates, at air saturation levels of 55% and below. These results suggest a significantly divergent response at the physiological and behavioural levels. While skate embryos depressed their metabolic rates in response to progressive hypoxia, they increased water circulation inside the egg case, presumably to restore normoxic conditions, until activity ceased abruptly around 9.8% air saturation.

Práctica del skate, ciudadanía y participación política en jóvenes platenses

Directory of Open Access Journals (Sweden)

Jorge Ricardo Saraví

2015-01-01

Full Text Available La ciudad de La Plata se ha caracterizado en los últimos años por ser un lugar de manifestación y expresión de luchas vinculadas a la práctica del skate. En ese marco, se han puesto en debate temas centrales como la ciudadanía, los derechos de los ciudadanos, el uso de los espacios públicos y el cuidado del patrimonio urbano. Nuestra investigación (Saraví, 2012, tuvo por objeto analizar la práctica del skate llevada adelante por jóvenes, utilizando métodos cualitativos y de corte interpretativo. A través de los relatos de los protagonistas y con la ayuda de documentos escritos, hemos tratado de construir un relato interpretativo de cómo diferentes hechos y sucesos fueron modificando no solamente los escenarios de la práctica del skate en la ciudad, sino también la vida urbana de La Plata. Hechos que fueron constituyéndose en jalones en la búsqueda de afirmación de la ciudadanía de jóvenes skaters platenses.

Pacing Strategy, Muscle Fatigue and Technique in 1500m Speed Skating and Cycling Time-Trials

NARCIS (Netherlands)

Stoter, Inge K; MacIntosh, Brian R; Fletcher, Jared R; Pootz, Spencer; Zijdewind, Inge; Hettinga, Florentina J

2016-01-01

PURPOSE: To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500m speed skating and cycling time-trials, when a faster or slower start is instructed. METHODS: Nine speed skaters and nine cyclists, all competing at regional or national level, performed two 1500m

Structural and Functional Components of the Skate Sensory Organ Ampullae of Lorenzini.

Science.gov (United States)

Zhang, Xing; Xia, Ke; Lin, Lei; Zhang, Fuming; Yu, Yanlei; St Ange, Kalib; Han, Xiaorui; Edsinger, Eric; Sohn, Joel; Linhardt, Robert J

2018-05-09

The skate, a cartilaginous fish related to sharks and rays, possesses a unique electrosensitive sensory organ known as the ampullae of Lorenzini (AoL). This organ is responsible for the detection of weak electric field changes caused by the muscle contractions of their prey. While keratan sulfate (KS) is believed to be a component of a jelly that fills this sensory organ and has been credited with its high proton conductivity, modern analytical methods have not been applied to its characterization. Surprisingly, total glycosaminoglycan (GAG) analysis demonstrates that the KS from skate jelly is extraordinarily pure, containing no other GAGs. This KS had a molecular weight of 20 to 30 kDa, consisting primarily of N-linked KS comprised mostly of a monosulfated disaccharide repeating unit, →3) Gal (1→4) GlcNAc6S (1→. Proteomic analysis of AoL jelly suggests that transferrin, keratin, and mucin serve as KS core proteins. Actin and tropomyosin are responsible for assembling the macrostructure of the jelly, and parvalbumin α-like protein and calreticulin regulate calcium and potassium channels involved in the transduction of the electrical signal, once conducted down the AoL by the jelly, serving as the molecular basis for electroreception.

Age group athletes in inline skating: decrease in overall and increase in master athlete participation in the longest inline skating race in Europe - the Inline One-Eleven.

Science.gov (United States)

Teutsch, Uwe; Knechtle, Beat; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

2013-01-01

Participation and performance trends in age group athletes have been investigated in endurance and ultraendurance races in swimming, cycling, running, and triathlon, but not in long-distance inline skating. The aim of this study was to investigate trends in participation, age, and performance in the longest inline race in Europe, the Inline One-Eleven over 111 km, held between 1998 and 2009. The total number, age distribution, age at the time of the competition, and race times of male and female finishers at the Inline One-Eleven were analyzed. Overall participation increased until 2003 but decreased thereafter. During the 12-year period, the relative participation in skaters younger than 40 years old decreased while relative participation increased for skaters older than 40 years. The mean top ten skating time was 199 ± 9 minutes (range: 189-220 minutes) for men and 234 ± 17 minutes (range: 211-271 minutes) for women, respectively. The gender difference in performance remained stable at 17% ± 5% across years. To summarize, although the participation of master long-distance inline skaters increased, the overall participation decreased across years in the Inline One-Eleven. The race times of the best female and male skaters stabilized across years with a gender difference in performance of 17% ± 5%. Further studies should focus on the participation in the international World Inline Cup races.

Variations in relative age effects in individual sports: skiing, figure skating and gymnastics.

Science.gov (United States)

Baker, Joseph; Janning, Christina; Wong, Harmonie; Cobley, Stephen; Schorer, Jörg

2014-01-01

In many sports, policy-makers and administrators employ annual cohorts to reduce differences between athletes during childhood and youth. Although well-intended, unintended relative age effects (RAEs) usually occur. RAEs refer to the specific selection, participation and attainment disadvantages associated with participants' birthdates relative to an arbitrary 'cutoff' date used to group participants within annual age groups. To date, we have little understanding of RAEs in individual sports. In this article, Study 1 considered the presence of RAEs in 1474 ski jumping, 7501 cross-country skiing, 15,565 alpine skiing, 4179 snowboarders and 713 Nordic combined athletes. Chi-square analyses revealed significant RAEs for most of these contexts across sexes. In Study 2, RAEs in the aesthetic sports of figure skating (n=502) and female gymnastics (n=612) were considered. There was no effect for the figure skaters and an atypical effect for the gymnasts. The significant effects across most ski sports coupled with the null effects in figure skating and atypical effect in gymnastics suggest that sport-specific contextual factors are important elements in understanding the mechanisms of RAEs, although further work is necessary to validate these findings.

Body movements during the off-ice execution of back spins in figure skating.

Science.gov (United States)

Mapelli, Andrea; Rodano, Renato; Fiorentini, Angelo; Giustolisi, Andrea; Sidequersky, Fernanda V; Sforza, Chiarella

2013-10-01

Using an optoelectronic motion capture system, we quantitatively assessed the arrangement of body segments and the displacement of the horizontal projection of the center of mass (CM) in seven skaters performing off-ice back spins on a rotating device (spinner). The position of the CM at the beginning of the spins was not a determining factor, but its rapid stabilization towards the center of the spinner, together with the achievement of a stable arrangement of trunk and limbs, was crucial to get the dynamic equilibrium, necessary for a lasting performance. At full spinning, however, there was an indicative variety of individual body postures. A final deceleration, associable with the loss of body equilibrium, was detected in the last spin of most of skaters. In conclusion, the current investigation demonstrated that the off-ice execution of back spin, a critical movement of ice skating, can be measured in laboratory, thus providing quantitative information to both the skaters and the coaches. The analysis is not invasive, and it may be proposed also for longitudinal evaluations of skating and postural training. Copyright © 2013 Elsevier Ltd. All rights reserved.

Feeding ecology of Bathyraja macloviana (Rajiformes, Arhynchobatidae: a polychaete-feeding skate from the South-west Atlantic

Directory of Open Access Journals (Sweden)

Ezequiel Mabragaña

2005-09-01

Full Text Available The present paper analyses the diet, feeding strategy and niche width of B. macloviana in a sector of the Argentinean Continental Shelf (ACS. Individuals (n = 147 were collected from 43 sampling stations in late summer and autumn 2001. Thirty one alimentary items in the gut contents were found, with a clear dominance of polychaetes. Crustaceans were secondary alimentary items. The polychaete Travisia kerguelensis was the main food item ingested, followed by Nepthyidae, Sabellidae and Lumbrineridae, while Gammaridae and Cirolanidae were the main items among crustaceans. The niche width and feeding strategy displayed by B. macloviana support the specialisation towards polychaetes throughout this study. Slow motile and infaunal species constitute major preys. The results suggest that this skate actively selects worms, reflecting, in some sense, the composition of the polychaete assemblage, and allowing a low dietary overlap with other sympatric skates of the ACS.

Complete Genome Sequence of a Rhodococcus Species Isolated from the Winter Skate Leucoraja ocellata.

Science.gov (United States)

Wiens, Julia; Ho, Ryan; Fernando, Dinesh; Kumar, Ayush; Loewen, Peter C; Brassinga, Ann Karen C; Anderson, W Gary

2016-09-01

We report here a genome sequence for Rhodococcus sp. isolate UM008 isolated from the renal/interrenal tissue of the winter skate Leucoraja ocellata Genome sequence analysis suggests that Rhodococcus bacteria may act in a novel mutualistic relationship with their elasmobranch host, serving as biocatalysts in the steroidogenic pathway of 1α-hydroxycorticosterone. Copyright © 2016 Wiens et al.

Peak incidence of distal radius fractures due to ice skating on natural ice in The Netherlands

NARCIS (Netherlands)

van Lieshout, Arno P. W.; van Manen, Christiaan J.; du Pré, Karel J.; Kleinlugtenbelt, Ydo V.; Poolman, Rudolf W.; Goslings, J. Carel; Kloen, Peter

2010-01-01

An increase of distal radius fractures was seen in 2009 when an extended cold spell allowed natural ice skating in Amsterdam. This resulted in overload of our Emergency Departments and operating rooms. This study reports patient and fracture characteristics of these injuries. We also determined

Gastro-intestinal handling of water and solutes in three species of elasmobranch fish, the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate Raja eglanteria.

Science.gov (United States)

Anderson, W Gary; Dasiewicz, Patricia J; Liban, Suadi; Ryan, Calen; Taylor, Josi R; Grosell, Martin; Weihrauch, Dirk

2010-04-01

The present study reports aspects of GI tract physiology in the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate, Raja eglanteria. Plasma and stomach fluid osmolality and solute values were comparable between species, and stomach pH was low in all species (2.2 to 3.4) suggesting these elasmobranchs may maintain a consistently low stomach pH. Intestinal osmolality, pH and ion values were comparable between species, however, some differences in ion values were observed. In particular Ca(2+) (19.67+/-3.65mM) and Mg(2+) (43.99+/-5.11mM) were high in L. erinacea and Mg(2+) was high (130.0+/-39.8mM) in C. palgiosum which may be an indication of drinking. Furthermore, intestinal fluid HCO(3)(-) values were low (8.19+/-2.42 and 8.63+/-1.48mM) in both skates but very high in C. plagiosum (73.3+/-16.3mM) suggesting ingested seawater may be processed by species-specific mechanisms. Urea values from the intestine to the colon dropped precipitously in all species, with the greatest decrease seen in C. plagiosum (426.0+/-8.1 to 0mM). This led to the examination of the molecular expression of both a urea transporter and a Rhesus like ammonia transporter in the intestine, rectal gland and kidney in L. erinacea. Both these transporters were expressed in all tissues; however, expression levels of the Rhesus like ammonia transporter were orders of magnitude higher than the urea transporter in the same tissue. Intestinal flux rates of solutes in L. erinacea were, for the most part, in an inward direction with the notable exception of urea. Colon flux rates of solutes in L. erinacea were all in an outward direction, although absolute rates were considerably lower than the intestine, suggestive of a much tighter epithelia. Results are discussed in the context of the potential role of the GI tract in salt and water, and nitrogen, homeostasis in elasmobranchs.

Population structure and historical demography of the thorny skate (Amblyraja radiata, Rajidae) in the North Atlantic

NARCIS (Netherlands)

Chevolot, M.; Wolfs, P.H.J.; Palsson, J.; Rijnsdorp, A.D.; Stam, W.T.; Olsen, J.L.

2007-01-01

Population genetic structure of the thorny skate (Amblyraja radiata) was surveyed in >300 individuals sampled from Newfoundland, Iceland, Norway, the Kattegat and the central North Sea. A 290-bp fragment of the mt cytochrome-b gene was first screened by SSCP. Sequences of SSCP haplotypes revealed

Population structure and historical demography of the thorny skate (Amblyraja radiata, Rajidae) in the North Atlantic

NARCIS (Netherlands)

Chevolot, Malia; Wolfs, Peter H. J.; Palsson, Jonbjorn; Rijnsdorp, Adriaan D.; Stam, Wytze T.; Olsen, Jeanine L.; Palson, J.

Population genetic structure of the thorny skate (Amblyraja radiata) was surveyed in > 300 individuals sampled from Newfoundland, Iceland, Norway, the Kattegat and the central North Sea. A 290-bp fragment of the mt cytochrome-b gene was first screened by SSCP. Sequences of SSCP haplotypes revealed

Anticancer Activity of a Hexapeptide from Skate (Raja porosa) Cartilage Protein Hydrolysate in HeLa Cells.

Science.gov (United States)

Pan, Xin; Zhao, Yu-Qin; Hu, Fa-Yuan; Chi, Chang-Feng; Wang, Bin

2016-08-16

In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY), which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa) cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC50 of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB) fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer.

Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

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Carolin Stangier, Thomas Abel, Julia Mierau, Wildor Hollmann, Heiko K. Strüder

2016-03-01

Full Text Available The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour for 8 weeks. Training intensity was determined within non-specific (cycling or running and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m and one non-specific (30s cycling or 200m running all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa and glucose (BGL 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak was significantly increased (+17%; p = 0.01 in both groups and highly correlated with the sprint performance (r = -0.71. BLa values decreased significantly (-18%, p = 0.02 after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04 in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group.

77 FR 10463 - Fisheries of the Northeastern United States; Proposed 2012-2013 Northeast Skate Complex Fishery...

Science.gov (United States)

2012-02-22

... information on skates. The ABC is calculated by multiplying the median catch/biomass ratio by the most recent... readily available, and individual vessel profitability cannot be determined directly; therefore, expected changes in gross revenues were used as a proxy for profitability. This action does not introduce any new...

Seasonal variations in the physiological stress response to discrete bouts of aerial exposure in the little skate, Leucoraja erinacea.

Science.gov (United States)

Cicia, Angela M; Schlenker, Lela S; Sulikowski, James A; Mandelman, John W

2012-06-01

Aerial exposure and acute thermal stress have been shown to elicit profound physiological disruptions in obligate water-breathing teleosts. However, no study has investigated these responses in an elasmobranch. To address this, venous blood samples were collected and evaluated from little skates (Leucoraja erinacea) subjected to discrete aerial exposure durations (0, 15, and 50 min) coupled with differing abrupt thermal changes (gradient between seawater and air; winter: ΔT=-3 °C; summer: ΔT=+9 °C) in two distinct laboratory studies. In general, blood acid-base properties (e.g. decline in pH; elevation in PCO(2)) and select metabolites (elevated whole-blood lactate) and electrolytes (elevated plasma K(+)) were significantly disrupted by aerial exposure, and were most disturbed after skates were exposed to air for 50 min. However, the magnitude of the blood acid-base perturbations, metabolic contribution to the resulting blood acidosis, elevations to ionic and metabolic parameters, and delayed mortality were more extreme during the summer study, suggesting that acute thermal stress exacerbates the physiological impairments associated with aerial exposure in little skates. Conversely, a reduced thermal gradient (from seawater to air) may attenuate the magnitude of metabolic and ionic perturbations, resulting in a high physiological threshold for coping with extended aerial exposure. Copyright © 2011 Elsevier Inc. All rights reserved.

Cardiorespiratory demands during an inline speed skating marathon race: a case report.

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

2016-09-01

This study was designed to investigate the intensity profile during an inline speed skating marathon road race. A highly-trained male athlete (20 y, 73.4 kg, 178 cm, V̇O2 peak: 60.8 mL·kg-1·min-1) participated in a marathon road race. Oxygen uptake (V̇O2), respiratory exchange ratio (RER), heart rate (HR) and speed were measured using a portable gas analysis system with a HR monitor and GPS-Sensor integrated. The athlete´s peak V̇O2, HR and speed at ventilatory thresholds were assessed during an incremental field test (22 km·h-1, increase 2 km·h-1 every 5 min) one week before the race. During the race, the absolute time spent in the "easy intensity zone" (V̇O2 below VT1) was 1 min, 49 min "moderate intensity zone" (V̇O2 between VT1 and VT2), and 26 min in the "hard intensity zone" (V̇O2 above VT2). The average HR was 171±6 bpm, corresponding to 95% of the maximum. This study shows that inline speed skating road races over a marathon are conducted at moderate to high V̇O2 and heart rate levels. The physiological racing pattern is very intermittent, requiring both a high level of aerobic and anaerobic capacity.

Identification of a single sinusoidal bile salt uptake system in skate liver

International Nuclear Information System (INIS)

Fricker, G.; Hugentobler, G.; Meier, P.J.; Kurz, G.; Boyer, J.L.

1987-01-01

To identify the sinusoidal bile acid uptake system(s) of skate liver, photoaffinity labeling and kinetic transport studies were performed in isolated plasma membranes as well as intact hepatocytes. In both preparations photoaffinity labeling with the photolabile bile salt derivative revealed the presence of a predominant bile salt binding polypeptide with an apparent molecular weight of 54,000. The [ 3 H]-labeling of this polypeptide was inhibited by taurocholate and cholate in a concentration-dependent manner and was virtually abolished by 1 mM of the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. Kinetic studies of hepatic uptake with taurocholate, cholate, and the photoreactive bile salt derivative indicated the involvement of a single transport system, and all three substrates mutually competed with the uptake of each other. Finally, irreversible inhibition of the bile salt uptake system of photoaffinity labeling of hepatocytes with high concentrations of photolabile derivative reduced the V max but the K m of taurocholate uptake. These findings strongly indicate that a single polypeptide with an apparent molecular weight of 54,000 is involved in sinusoidal bile salt uptake into skate hepatocytes. These findings contrast with similar studies in rat liver that implicate both a 54,000- and 48,000-K polypeptide in bile salt uptake and are consistent with a single Na + -independent transport mechanism for hepatic bile salt uptake in this primitive vertebrate

Sexual dimorphism in sister species of Leucoraja skate and its relationship to reproductive strategy and life history.

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Martinez, Christopher M; Rohlf, F James; Frisk, Michael G

2016-01-01

Instances of sexual dimorphism occur in a great variety of forms and manifestations. Most skates (Batoidea: Rajoidei) display some level of body shape dimorphism in which the pectoral fins of mature males develop to create a distinct bell-shaped body not found in females. This particular form of dimorphism is present in each of the sister species Leucoraja erinacea and Leucoraja ocellata, but differences between sexes are much greater in the former. In order to understand the nature and potential causes of pectoral dimorphism, we used geometric morphometrics to investigate allometry of fin shape in L. erinacea and L. ocellata and its relationship to the development of reproductive organs, based on previous work on the bonnethead shark, Sphyrna tiburo. We found that allometric trajectories of overall pectoral shape were different in both species of skate, but only L. erinacea varied significantly with respect to endoskeleton development. Male maturation was characterized by a number of sex-specific morphological changes, which appeared concurrently in developmental timing with elongation of cartilage-supported claspers. We suggest that external sexual dimorphism of pectoral fins in skates is a byproduct of skeletal growth needed for clasper development. Further, the magnitude of male shape change appears to be linked to the differential life histories of species. This work reports for the first time that pectoral dimorphism is a persistent feature in rajoid fishes, occurring in varying degrees across several genera. Lastly, our results suggest that pectoral morphology may be useful as a relative indicator of reproductive strategy in some species. © 2016 Wiley Periodicals, Inc.

The impact of orthopaedic injuries sustained at an urban public ice skating rink: is it really free?

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Schwarzkopf, Ran; Nacke, Elliot A; Tejwani, Nirmal C

2014-01-01

Previous reports in the literature from Europe and Asia cite an increased burden on the local emergency departments and orthopaedic services during the operational period of the ice skating rinks. This retrospective observational study was undertaken in order to report the incidence, characteristic, and severity of injuries during a full season at a large urban ice skating rink, as well as to quantify the added burden the ice skating rink places on the local emergency department and the orthopaedic service. All patients seen at our emergency room who sustained an injury at the neighboring "free" ice rink were identified over the 4-month period when it was open. The data collected included type of injury, demographics, and need for surgical treatment. Over this period, 118 patients were seen in our ED (of the 135 referrals from the ice rink logbook); Of these, 43 (38%) required an orthopaedic consult and were evenly divided into upper (22) and lower extremity injuries (21). Sixty-seven percent of the patients were adults, and the most common fractures were ankle and distal radius fractures. There were two open fractures of the distal radius seen in the older patients (both in patients > 50). Overall 32% of patients needed operative treatment. Of the non-orthopaedic injuries, the most common was head injury (25%). An ice-rink may be "free" but adds significant burden to the healthcare system, and these costs should be factored in by both the sponsoring body and the healthcare system for treatment of these additional patients.

Analysis of food habits of skate Rioraja agassizii (Elasmobranchii, Rajidae) from southern Brazil.

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Motta, N S; Della-Fina, N; Souza, C C A; Rodrigues, E S; Amorim, A F

2016-06-01

Catches and exports of skate Rioraja agassizii place this species as "vulnerable to extinction" on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N), weight (%M), frequency of occurrence (% FO), and index of relative importance (IRI). The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.

Analysis of food habits of skate Rioraja agassizii (Elasmobranchii, Rajidae from southern Brazil

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N. S. Motta

Full Text Available Abstract Catches and exports of skate Rioraja agassizii place this species as “vulnerable to extinction” on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N, weight (%M, frequency of occurrence (% FO, and index of relative importance (IRI. The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.

Curvature singularity and film-skating during drop impact

Science.gov (United States)

Duchemin, Laurent; Josserand, Christophe

2011-09-01

We study the influence of the surrounding gas in the dynamics of drop impact on a smooth surface. We use an axisymmetric model for which both the gas and the liquid are incompressible; lubrication regime applies for the gas film dynamics and the liquid viscosity is neglected. In the absence of surface tension a finite time singularity whose properties are analysed is formed and the liquid touches the solid on a circle. When surface tension is taken into account, a thin jet emerges from the zone of impact, skating above a thin gas layer. The thickness of the air film underneath this jet is always smaller than the mean free path in the gas suggesting that the liquid film eventually wets the surface. We finally suggest an aerodynamical instability mechanism for the splash.

Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K.

2016-01-01

The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group. Key points In addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks

Spawning Characteristics and Artificial Hatching of Female Mottled Skate, Beringraja pulchra in the West Coast of Korea.

Science.gov (United States)

Kang, Hee-Woong; Jo, Yeong-Rok; Kang, Duk-Yong; Jeong, Gyeong-Suk; Jo, Hyun-Su

2013-09-01

The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at 8°C, 13°C, 18°C, water temperature (12.8 to 24.2°C), and the best hatching temperature was 18°C. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate.

Age group athletes in inline skating: decrease in overall and increase in master athlete participation in the longest inline skating race in Europe – the Inline One-Eleven

Science.gov (United States)

Teutsch, Uwe; Knechtle, Beat; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

2013-01-01

Background Participation and performance trends in age group athletes have been investigated in endurance and ultraendurance races in swimming, cycling, running, and triathlon, but not in long-distance inline skating. The aim of this study was to investigate trends in participation, age, and performance in the longest inline race in Europe, the Inline One-Eleven over 111 km, held between 1998 and 2009. Methods The total number, age distribution, age at the time of the competition, and race times of male and female finishers at the Inline One-Eleven were analyzed. Results Overall participation increased until 2003 but decreased thereafter. During the 12-year period, the relative participation in skaters younger than 40 years old decreased while relative participation increased for skaters older than 40 years. The mean top ten skating time was 199 ± 9 minutes (range: 189–220 minutes) for men and 234 ± 17 minutes (range: 211–271 minutes) for women, respectively. The gender difference in performance remained stable at 17% ± 5% across years. Conclusion To summarize, although the participation of master long-distance inline skaters increased, the overall participation decreased across years in the Inline One-Eleven. The race times of the best female and male skaters stabilized across years with a gender difference in performance of 17% ± 5%. Further studies should focus on the participation in the international World Inline Cup races. PMID:23690697

Relationship between gene polymorphisms and development of physical qualities in athletes (based on the material of speed skating

Directory of Open Access Journals (Sweden)

Анна Ильютик

2017-09-01

Full Text Available The paper summarizes the results of the studies on the identification of the relationship between the polymorphisms in a number of genes with the manifestation of speed-strength qualities and endurance in speed skaters. The theoretical and experimental substantiation is presented for the algorithm of determining the sports specialization of athletes specializing in speed skating on the basis of the results of polymorphism analysis of the genes ACE, NOS3, BDKRB2, ACTN3, PPARG, and CYP17A1. The algorithm consists of determining both the polymorphism of individual genes and the combinations of gene polymorphisms, thus making it possible to estimate the number of alleles and genotypes associated with endurance and/or speed-strength qualities. The use of this algorithm enables identifying physical qualities, to the development of which there is the greatest genetic predisposition, and choosing on their basis a skating specialization of the athlete.

Nitrogen dioxide exposures inside ice skating rinks.

Science.gov (United States)

Brauer, M; Spengler, J D

1994-01-01

OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

The organic anion transport polypeptide 1d1 (Oatp1d1) mediates hepatocellular uptake of phalloidin and microcystin into skate liver.

Science.gov (United States)

Meier-Abt, F; Hammann-Hänni, A; Stieger, B; Ballatori, N; Boyer, J L

2007-02-01

Organic anion transporting polypeptides (rodent Oatp; human OATP) mediate cellular uptake of numerous organic compounds including xenobiotic toxins into mammalian hepatocytes. In the little skate Leucoraja erinacea a liver-specific Oatp (Oatp1d1, also called sOatp) has been identified and suggested to represent an evolutionarily ancient precursor of the mammalian liver OATP1B1 (human), Oatp1b2 (rat), and OATP1B3 (human). The present study tested whether Oatp1d1 shares functional transport activity of the xenobiotic oligopeptide toxins phalloidin and microcystin with the mammalian liver Oatps/OATPs. The phalloidin analogue [(3)H]-demethylphalloin was taken up into skate hepatocytes with high affinity (Km approximately 0.4 microM), and uptake could be inhibited by phalloidin and a variety of typical Oatp/OATP substrates such as bromosulfophthalein, bile salts, estrone-3-sulfate, cyclosporine A and high concentrations of microcystin-LR (Ki approximately 150 microM). When expressed in Xenopus laevis oocytes Oatp1d1 increased uptake of demethylphalloin (Km approximately 2.2 microM) and microcystin-LR (Km approximately 27 microM) 2- to 3-fold over water-injected oocytes, whereas the alternative skate liver organic anion transporter, the dimeric Ostalpha/beta, exhibited no phalloidin and only minor microcystin-LR transport. Also, the closest mammalian Oatp1d1 orthologue, the human brain and testis OATP1C1, did not show any phalloidin transport activity. These results demonstrate that the evolutionarily ancient Oatp1d1 is able to mediate uptake of cyclic oligopeptide toxins into skate liver. The findings support the notion that Oatp1d1 is a precursor of the liver-specific mammalian Oatps/OATPs and that its transport properties are closely associated with certain forms of toxic liver injury such as for example protein phosphatase inhibition by the water-borne toxin microcystin.

The organic anion transport polypeptide 1d1 (Oatp1d1) mediates hepatocellular uptake of phalloidin and microcystin into skate liver

International Nuclear Information System (INIS)

Meier-Abt, F.; Hammann-Haenni, A.; Stieger, B.; Ballatori, N.; Boyer, J.L.

2007-01-01

Organic anion transporting polypeptides (rodent Oatp; human OATP) mediate cellular uptake of numerous organic compounds including xenobiotic toxins into mammalian hepatocytes. In the little skate Leucoraja erinacea a liver-specific Oatp (Oatp1d1, also called sOatp) has been identified and suggested to represent an evolutionarily ancient precursor of the mammalian liver OATP1B1 (human), Oatp1b2 (rat), and OATP1B3 (human). The present study tested whether Oatp1d1 shares functional transport activity of the xenobiotic oligopeptide toxins phalloidin and microcystin with the mammalian liver Oatps/OATPs. The phalloidin analogue [ 3 H]-demethylphalloin was taken up into skate hepatocytes with high affinity (Km ∼ 0.4 μM), and uptake could be inhibited by phalloidin and a variety of typical Oatp/OATP substrates such as bromosulfophthalein, bile salts, estrone-3-sulfate, cyclosporine A and high concentrations of microcystin-LR (Ki ∼ 150 μM). When expressed in Xenopus laevis oocytes Oatp1d1 increased uptake of demethylphalloin (Km ∼ 2.2 μM) and microcystin-LR (Km ∼ 27 μM) 2- to 3-fold over water-injected oocytes, whereas the alternative skate liver organic anion transporter, the dimeric Ostα/β, exhibited no phalloidin and only minor microcystin-LR transport. Also, the closest mammalian Oatp1d1 orthologue, the human brain and testis OATP1C1, did not show any phalloidin transport activity. These results demonstrate that the evolutionarily ancient Oatp1d1 is able to mediate uptake of cyclic oligopeptide toxins into skate liver. The findings support the notion that Oatp1d1 is a precursor of the liver-specific mammalian Oatps/OATPs and that its transport properties are closely associated with certain forms of toxic liver injury such as for example protein phosphatase inhibition by the water-borne toxin microcystin

Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

Science.gov (United States)

Sakurai, Yoshihisa; Fujita, Zenya; Ishige, Yusuke

2016-01-01

This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions. PMID:27049388

Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

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Yoshihisa Sakurai

2016-04-01

Full Text Available This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions.

Optimal pacing strategy: from theoretical modelling to reality in 1500-m speed skating.

Science.gov (United States)

Hettinga, F J; De Koning, J J; Schmidt, L J I; Wind, N A C; Macintosh, B R; Foster, C

2011-01-01

Athletes are trained to choose the pace which is perceived to be correct during a specific effort, such as the 1500-m speed skating competition. The purpose of the present study was to "override" self-paced (SP) performance by instructing athletes to execute a theoretically optimal pacing profile. Seven national-level speed-skaters performed a SP 1500-m which was analysed by obtaining velocity (every 100 m) and body position (every 200 m) with video to calculate total mechanical power output. Together with gross efficiency and aerobic kinetics, obtained in separate trials, data were used to calculate aerobic and anaerobic power output profiles. An energy flow model was applied to SP, simulating a range of pacing strategies, and a theoretically optimal pacing profile was imposed in a second race (IM). Final time for IM was ∼2 s slower than SP. Total power distribution per lap differed, with a higher power over the first 300 m for IM (637.0 (49.4) vs 612.5 (50.0) W). Anaerobic parameters did not differ. The faster first lap resulted in a higher aerodynamic drag coefficient and perhaps a less effective push-off. Experienced athletes have a well-developed performance template, and changing pacing strategy towards a theoretically optimal fast start protocol had negative consequences on speed-skating technique and did not result in better performance.

Identification guide to skates (Family Rajidae) of the Canadian Atlantic and adjacent regions

Science.gov (United States)

Sulak, Kenneth J.; MacWhirter, P. D.; Luke, K.E.; Norem, A.D.; Miller, J.M.; Cooper, J.A.; Harris, L.E.

2009-01-01

Ecosystem-based management requires sound information on the distribution and abundance of species both common and rare. Therefore, the accurate identification for all marine species has assumed a much greater importance. The identification of many skate species is difficult as several are easily confused and has been found to be problematic in both survey data and fisheries data collection. Identification guides, in combination with training and periodic validation of taxonomic information, improve our accuracy in monitoring data required for ecosystem-based management and monitoring of populations. This guide offers a comparative synthesis of skate species known to occur in Atlantic Canada and adjacent regions. The taxonomic nomenclature and descriptions of key morphological features are based on the most up-to-date understanding of diversity among these species. Although this information will aid the user in accurate identification, some features vary geographically (such as colour) and others with life stage (most notably the proportion of tail length to body length; the presence of spines either sharper in juveniles or in some cases not yet present; and also increases in the number of tooth rows as species grow into maturity). Additional information on juvenile features are needed to facilitate problematic identifications (e.g. L. erinacea vs. L. ocellata). Information on size at maturity is still required for many of these species throughout their geographic distribution.

Chondroitin Sulfate-Rich Extract of Skate Cartilage Attenuates Lipopolysaccharide-Induced Liver Damage in Mice.

Science.gov (United States)

Song, Yeong Ok; Kim, Mijeong; Woo, Minji; Baek, Jang-Mi; Kang, Keon-Hee; Kim, Sang-Ho; Roh, Seong-Soo; Park, Chan Hum; Jeong, Kap-Seop; Noh, Jeong-Sook

2017-06-15

The protective effects of a chondroitin sulfate-rich extract (CSE) from skate cartilage against lipopolysaccharide (LPS)-induced hepatic damage were investigated, and its mechanism of action was compared with that of chondroitin sulfate (CS) from shark cartilage. ICR mice were orally administrated 200 mg/kg body weight (BW) of CS or 400 mg/kg BW of CSE for 3 consecutive days, followed by a one-time intraperitoneal injection of LPS (20 mg/kg BW). The experimental groups were vehicle treatment without LPS injection (NC group), vehicle treatment with LPS injection (LPS group), CS pretreatment with LPS injection (CS group), and CSE pretreatment with LPS injection (CSE group). Hepatic antioxidant enzyme expression levels in the CS and CSE groups were increased relative to those in the LPS group. In LPS-insulted hepatic tissue, inflammatory factors were augmented relative to those in the NC group, but were significantly suppressed by pretreatment with CS or CSE. Moreover, CS and CSE alleviated the LPS-induced apoptotic factors and mitogen-activated protein kinase (MAPK). In addition, CS and CSE effectively decreased the serum lipid concentrations and downregulated hepatic sterol regulatory element-binding proteins expression. In conclusion, the skate CSE could protect against LPS-induced hepatic dyslipidemia, oxidative stress, inflammation, and apoptosis, probably through the regulation of MAPK signaling.

Effects of Cycling vs. Running Training on Endurance Performance in Preparation for Inline Speed Skating.

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Hesse, Clemens; Claen, Stephanie; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

2016-06-01

Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean ± SD 24 ± 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: ∼52% of V[Combining Dot Above]O2peak: 500 kcal per session). Before and after the training intervention, all athletes performed an incremental specific (inline speed skating) and 1 nonspecific (cycling or running) step test according to the group affiliation. In addition to blood lactate concentration, oxygen uptake (V[Combining Dot Above]O2), ventilatory equivalent (VE/V[Combining Dot Above]O2), respiratory exchange ratio (RER), and heart rate were measured. The specific posttest revealed significantly increased absolute V[Combining Dot Above]O2peak values (2.9 ± 0.4, 3.4 ± 0.7, p = 0.01) and submaximal V[Combining Dot Above]O2 values (p ≤ 0.01). VE/V[Combining Dot Above]O2 and RER significantly decreased at maximal (46.6 ± 6.6, 38.5 ± 3.4, p = 0.005; 1.1 ± 0.03, 1.0 ± 0.04, p = 0.001) and submaximal intensities (p ≤ 0.04). None of the analysis revealed a significant group effect (p ≥ 0.15). The results indicate that both cycling vs. running exercise at ∼52% of V[Combining Dot Above]O2peak had a positive effect on the athletes' endurance performance. The increased submaximal V[Combining Dot Above]O2 values indicate a reduction in athletes' inline speed skating technique. Therefore, athletes would benefit from a focus on technique training in the subsequent period.

Angiotensin-I converting enzyme inhibitory peptides from antihypertensive skate (Okamejei kenojei) skin gelatin hydrolysate in spontaneously hypertensive rats.

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Ngo, Dai-Hung; Kang, Kyong-Hwa; Ryu, BoMi; Vo, Thanh-Sang; Jung, Won-Kyo; Byun, Hee-Guk; Kim, Se-Kwon

2015-05-01

The aim of this study was to investigate antihypertensive effect of bioactive peptides from skate (Okamejei kenojei) skin gelatin. The Alcalase/protease gelatin hydrolysate below 1 kDa (SAP) exhibited the highest angiotensin-I converting enzyme (ACE) inhibition compared to other hydrolysates. SAP can decrease systolic blood pressure significantly in spontaneously hypertensive rats. SAP inhibited vasoconstriction via PPAR-γ expression, activation and phosphorylation of eNOS in lungs. Moreover, the expression levels of endothelin-1, RhoA, α-smooth muscle actin, cleaved caspase 3 and MAPK were decreased by SAP in lungs. Vascularity, muscularization and cellular proliferation in lungs were detected by immunohistochemical staining. Finally, two purified peptides (LGPLGHQ, 720Da and MVGSAPGVL, 829Da) showed potent ACE inhibition with IC50 values of 4.22 and 3.09 μM, respectively. These results indicate that bioactive peptides isolated from skate skin gelatin may serve as candidates against hypertension and could be used as functional food ingredients. Copyright © 2014 Elsevier Ltd. All rights reserved.

"Balancing on Skates on the Icy Surface of Work": a metasynthesis of work participation for persons with psychiatric disabilities.

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Kinn, Liv Grethe; Holgersen, Helge; Aas, Randi W; Davidson, Larry

2014-03-01

To explore how persons with psychiatric disabilities experience facilitators of and barriers to participation in paid work in transitional, supported, and open employment settings, in order to provide guidance for efforts to attract and retain these persons in gainful employment as a key dimension of recovery and community life. A metasynthesis was conducted using 16 qualitative studies published between 1990 and 2011. Ten themes, two phases, and an overarching metaphor were identified. The first five themes describe facilitators of and impediments to getting a job (getting off the bench): (1) fighting inertia; (2) taking control; (3) encouraging peers; (4) disruptions related to the illness; (5) lack of opportunities and supports. The next five themes represent facilitators of and impediments to working (skating on the ice); (6) going mainstream; (7) social cohesion; (8) clarity in role and responsibilities; (9) environmental factors; (10) managing self-disclosure. We chose as our overarching metaphor "Balancing on Skates on the Icy Surface of Work," as we view both iceskaters and workers with psychiatric disabilities as needing to achieve and maintain their balance while being "on the edge" between various extremities. We have shown that, for persons with psychiatric disabilities to "get off the bench" and "onto the ice" of employment, they may need to be supported in finding and maintaining their balance in new situations through a combination of learning new skills and competencies (learning how to skate) while receiving in vivo assistance from empathic and knowledgeable supporters (being coached while on the ice).

Neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and cholecystokinin (CCK) in winter skate (Raja ocellata): cDNA cloning, tissue distribution and mRNA expression responses to fasting.

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MacDonald, Erin; Volkoff, Hélène

2009-04-01

cDNAs encoding for neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and cholecystokinin (CCK) were cloned in an elasmobranch fish, the winter skate. mRNA tissue distribution was examined for the three peptides as well as the effects of two weeks of fasting on their expression. Skate NPY, CART and CCK sequences display similarities with sequences for teleost fish but in general the degree of identity is relatively low (50%). All three peptides are present in brain and in several peripheral tissues, including gut and gonads. Within the brain, the three peptides are expressed in the hypothalamus, telencephalon, optic tectum and cerebellum. Two weeks of fasting induced an increase in telencephalon NPY and an increase in CCK in the gut but had no effects on hypothalamic NPY, CART and CCK, or on telencephalon CART. Our results provide basis for further investigation into the regulation of feeding in winter skate.

La cultura skate en las sociedades contemporáneas: una aproximación etnográfica a la ciudad de Madrid

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Rubén Díez García

2015-01-01

Full Text Available This paper offers an approach to the study of skateboarding in the city of Madrid through a multi-sited ethnographic study which combines online and offline research. Based on this methodology, we show an analysis of some of the main characteristics of the skate culture in our society, particularly in the city of Madrid, putting the emphasis on the most intersubjective and cultural aspects of this reality. In recent years skateboarding has experienced a visible increase in Madrid and the analytic frame that we propose for studying its diffusion and escalation, answers to changes in the cultural order of western societies and the skate culture in itself, in dynamic interdependence with the economic sphere, as the order of production and distribution of cultural and sporting services and goods.

Peak effect versus skating in high-temperature nanofriction

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Zykova-Timan, T.; Ceresoli, D.; Tosatti, E.

2007-03-01

The physics of sliding nanofriction at high temperature near the substrate melting point, TM, is so far unexplored. We conducted simulations of hard tips sliding on a prototype non-melting surface, NaCl(100), revealing two distinct and opposite phenomena for ploughing and for grazing friction in this regime. We found a frictional drop close to TM for deep ploughing and wear, but on the contrary a frictional rise for grazing, wearless sliding. For both phenomena, we obtain a fresh microscopic understanding, relating the former to `skating' through a local liquid cloud, and the latter to linear response properties of the free substrate surface. We argue that both phenomena occur more generally on surfaces other than NaCl and should be pursued experimentally. Most metals, in particular those possessing one or more close-packed non-melting surfaces, such as Pb, Al or Au(111), are likely to behave similarly.

Some euryhalinity may be more common than expected in marine elasmobranchs: the example of the South American skate Zapteryx brevirostris (Elasmobranchii, Rajiformes, Rhinobatidae).

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Wosnick, Natascha; Freire, Carolina A

2013-09-01

Elasmobranchs are essentially marine, but ~15% of the species occur in brackish or freshwater. The Brazilian marine coastal skate Zapteryx brevirostris, non-reported in nearby estuaries, was submitted to 35, 25, 15, and 5 psu, for 6 or 12h (n=6). Plasma was assayed for osmolality, urea, and ions (Na(+), Cl(-), K(+), Mg(2+)). Muscle water content was determined, and the rectal gland, kidney and gills were removed for carbonic anhydrase (CA) and Na(+),K(+)-ATPase (NKA) activities. The skate survived to all treatments. Plasma osmolality and urea levels decreased respectively by 27% and 38% after 12h in 5 psu (with respect to levels when in seawater), but plasma Na(+), Cl(-), and Mg(2+) were well regulated. Plasma K(+) showed some conformation after 12h. Muscle hydration was maintained. Branchial CA and NKA did not respond to salinity. Rectal gland NKA decreased upon seawater dilution, while renal NKA increased. This skate was shown to be partially euryhaline. The analysis of plasma urea of elasmobranchs in brackish and freshwater versus salinity and time-allied to the widespread occurrence of some euryhalinity in the group-led us to revisit the hypothesis of a brackish water habitat for elasmobranch ancestors. Copyright © 2013 Elsevier Inc. All rights reserved.

Efficient stratified ventilation - air conditioning of skating rinks; Effiziente Schichtlueftung - Klimatisierung von Eissporthallen

Energy Technology Data Exchange (ETDEWEB)

Fiedler, E. [Fa. Caverion, Aachen (Germany)

2007-07-01

Air conditioning of ice rinks is not just a matter of user comfort. Excessive humidity will cause frosting and poor ice quality while mist formation may interfere with hockey games. Constant condensation in the roof area causes severe damage of the building and is assumed to be a maine cause of the breakdown of the Bad Reichenhall skating hall in January 2006. In the Wolfsburg ice arena, an innovative ventilation concept was implemented which meets complex user demands and is characterized by its high energy efficiency. (orig.)

Puberty and Physical Self-Perceptions of Competitive Female Figure Skaters II: Maturational Timing, Skating Context, and Ability Status

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Monsma, Eva V.

2008-01-01

One study of figure skaters found that menarcheal status was a stronger predictor than age in explaining the variance in their self-perceptions. Postmenarcheal skaters had significantly lower self-esteem and physical self-concept and were less satisfied with their appearance than premenarcheal skaters. Surprisingly, skating context (i.e., skating…

Two novel antioxidant nonapeptides from protein hydrolysate of skate (Raja porosa) muscle.

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Hu, Fa-Yuan; Chi, Chang-Feng; Wang, Bin; Deng, Shang-Gui

2015-04-03

In the current study, the preparation conditions of neutrase hydrolysate (SMH) from skate (Raja porosa) muscle protein were optimized using orthogonal L9(3)4 tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S) 2%, and enzymolysis time 5 h, EC50 of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B) were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A) and NWDMEKIWD (SP-B) with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC50 0.390 and 0.176 mg/mL), DPPH· (EC50 0.614 and 0.289 mg/mL), and O2-· (EC50 0.215 and 0.132 mg/mL) in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp), acidic (2Asp and Glu), and basic (Lys) amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.

Two Novel Antioxidant Nonapeptides from Protein Hydrolysate of Skate (Raja porosa Muscle

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Fa-Yuan Hu

2015-04-01

Full Text Available In the current study, the preparation conditions of neutrase hydrolysate (SMH from skate (Raja porosa muscle protein were optimized using orthogonal L9(34 tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S 2%, and enzymolysis time 5 h, EC50 of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A and NWDMEKIWD (SP-B with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC50 0.390 and 0.176 mg/mL, DPPH· (EC50 0.614 and 0.289 mg/mL, and O2−· (EC50 0.215 and 0.132 mg/mL in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp, acidic (2Asp and Glu, and basic (Lys amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.

Modeling of competitive activity of skilled athletes specialized at 1500 m distance on short-track skating

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O.S. Kholodova

2013-10-01

Full Text Available Background: Models of competitive activity at the 1500 m distance on short-track skating are developed on the basis of defining the relationship between sports results and major characteristics which describe speed of running at different parts of the distance. Material: we analyzed reports of competitions at the European and World Championships, World Cups 2007-2011. The dynamics of the speed finalists of the competition at the 1500 m - in hits (n = 33, quarterfinals (n = 34, semi-finals (n = 32 and finals (n = 39. Results: it was determined that for a distance of 1500 m short track skating is the most appropriate model with factors of influence: the speed of the first to sixth part of distance , the speed difference between the first and second half of the distance, time of the slowest circle, the difference between the time of the slowest and fastest circles. Conclusions: time of overcoming of distance will diminish at the rational change of model indexes. It will allow to increase possibility of output in the next circle of competitions and accordingly improve a place in final protocol.

Evaluation of skate meal and sablefish viscera meal as fish meal replacement in diets for Pacific threadfin (Polydactylus saxfilis)

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The objectives of this study were to investigate the nutritional value of skate meal (SM) and black cod viscera meal (BCVM) from Alaska and to ascertain their suitability as replacements for commercial pollock fishmeal in diets for Pacific threadfin (Polydactylus sexfilis). Test diets were made by r...

Motor unit firing frequency of lower limb muscles during an incremental slide board skating test.

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Piucco, Tatiane; Bini, Rodrigo; Sakaguchi, Masanori; Diefenthaeler, Fernando; Stefanyshyn, Darren

2017-11-01

This study investigated how the combination of workload and fatigue affected the frequency components of muscle activation and possible recruitment priority of motor units during skating to exhaustion. Ten male competitive speed skaters performed an incremental maximal test on a slide board. Activation of six muscles from the right leg was recorded throughout the test. A time-frequency analysis was performed to compute overall, high, and low frequency bands from the whole signal at 10, 40, 70, and 90% of total test time. Overall activation increased for all muscles throughout the test (p  0.80). There was an increase in low frequency (90 vs. 10%, p = 0.035, ES = 1.06) and a decrease in high frequency (90 vs. 10%, p = 0.009, ES = 1.38, and 90 vs. 40%, p = 0.025, ES = 1.12) components of gluteus maximus. Strong correlations were found between the maximal cadence and vastus lateralis, gluteus maximus and gluteus medius activation at the end of the test. In conclusion, the incremental skating test lead to an increase in activation of lower limb muscles, but only gluteus maximus was sensitive to changes in frequency components, probably caused by a pronounced fatigue.

Impact of the initial classic section during a simulated cross-country skiing skiathlon on the cardiopulmonary responses during the subsequent period of skate skiing.

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Mourot, Laurent; Fabre, Nicolas; Andersson, Erik; Willis, Sarah J; Hébert-Losier, Kim; Holmberg, Hans-Christer

2014-08-01

The aim of this study was to assess potential changes in the performance and cardiorespiratory responses of elite cross-country skiers following transition from the classic (CL) to the skating (SK) technique during a simulated skiathlon. Eight elite male skiers performed two 6 km (2 × 3 km) roller-skiing time trials on a treadmill at racing speed: one starting with the classic and switching to the skating technique (CL1-SK2) and another employing the skating technique throughout (SK1-SK2), with continuous monitoring of gas exchanges, heart rates, and kinematics (video). The overall performance times in the CL1-SK2 (21:12 ± 1:24) and SK1-SK2 (20:48 ± 2:00) trials were similar, and during the second section of each performance times and overall cardiopulmonary responses were also comparable. However, in comparison with SK1-SK2, the CL1-SK2 trial involved significantly higher increases in minute ventilation (V̇E, 89.8 ± 26.8 vs. 106.8 ± 17.6 L·min(-1)) and oxygen uptake (V̇O2; 3.1 ± 0.8 vs 3.5 ± 0.5 L·min(-1)) 2 min after the transition as well as longer time constants for V̇E, V̇O2, and heart rate during the first 3 min after the transition. This higher cardiopulmonary exertion was associated with ∼3% faster cycle rates. In conclusion, overall performance during the 2 time trials did not differ. The similar performance times during the second sections were achieved with comparable mean cardiopulmonary responses. However, the observation that during the initial 3-min post-transition following classic skiing cardiopulmonary responses and cycle rates were slightly higher supports the conclusion that an initial section of classic skiing exerts an impact on performance during a subsequent section of skate skiing.

Resistance and Spray Characteristics of a 1/13-Scale Model of the Consolidated Vultee Skate 7 Seaplane, TED No. NACA DE 338

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McKann, Robert E.; Coffee, Claude W.; Arabian, Donald D.

1949-01-01

A model of a Consolidated Vultee Aircraft Corporation Skate 7 sea-plane:was tested in Langley tank no= 2. Resistance data, 'spray photographs, and underwater photographs,are given in this report without discussion.

Active peptides from skate (Okamejei kenojei) skin gelatin diminish angiotensin-I converting enzyme activity and intracellular free radical-mediated oxidation.

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Ngo, Dai-Hung; Ryu, BoMi; Kim, Se-Kwon

2014-01-15

Skin gelatin of skate (Okamejei kenojei) was hydrolyzed using Alcalase, flavourzyme, Neutrase and protamex. It was found that the Alcalase hydrolysate exhibited the highest angiotensin-I converting enzyme (ACE) inhibitory activity. Then, Alcalase hydrolysate was further hydrolyzed with protease and separated by an ultrafiltration membrane system. Finally, two peptides responsible for ACE inhibitory activity were identified to be MVGSAPGVL (829Da) and LGPLGHQ (720Da), with IC50 values of 3.09 and 4.22μM, respectively. Moreover, the free radical-scavenging activity of the purified peptides was determined in human endothelial cells. In addition, the antioxidative mechanism of the purified peptides was evaluated by protein and gene expression levels of antioxidant enzymes. The current study demonstrated that the peptides derived from skate skin gelatin could be used in the food industry as functional ingredients with potent antihypertensive and antioxidant benefits. Copyright © 2013 Elsevier Ltd. All rights reserved.

The first ice skating rink in the world (Glaciarium) and it's remarkable inventor John Gamgee; De allereerste kunstijsbaan ter wereld en de opmerkelijke uitvinder John Gamgee

Energy Technology Data Exchange (ETDEWEB)

Berends, E. [Grenco, Den Bosch (Netherlands)

2005-02-15

Some historical aspects are given of the development of the first ice skating rink (Glaciarium) that was opened in 1876 in Chelsea, London, UK. Also attention is paid to the inventor of the skating rink, professor dr. John Gamgee and some of the other inventions of this remarkable person. [Dutch] De historie van de eerste kunstijsbaan (Glaciarium) die in 1876 in Chelsea in Londen werd geopend, wordt uit de doeken gedaan. Daarnaast wordt aandacht geschonken aan de uitvinder, professor dr. John Gamgee, en worden enkele andere uitvindingen van deze opmerkelijke man belicht.

Take-off Stability Characteristics of a 1/13-scale Model of the Consolidated Vultee Skate 7 Seaplane (TED No. NACA DE 338)

Science.gov (United States)

McKann, Robert; Coffee, Claude W.; Abrabian, Donald D.

1949-01-01

The take-off stability characteristics of a Consolidated Vultee Aircraft Corporation Skate 7 seaplane were determined in the Langley tank no. 2. Trim limits of stability, trim tracks, and elevator limits of stability are presented.

Exposure to 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) impacts multiple organ systems in developing little skate (Leucoraja erinacea).

Science.gov (United States)

Effects of exposure to coplanar polychlorinated biphenyls (PCBs) and other dioxin-like chemicals on developing vertebrates involve many organ systems, including the skeletal and cardiovascular systems. Apex predators, including those from the class Chondrichthyes (sharks, skates,...

Anticancer Activity of a Hexapeptide from Skate (Raja porosa Cartilage Protein Hydrolysate in HeLa Cells

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Xin Pan

2016-08-01

Full Text Available In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY, which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC50 of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p < 0.01. Thus, FIMGPY could induce apoptosis by upregulating the Bax/Bcl-2 ratio and caspase-3 activation. Using a DNA ladder method further confirmed that the anti-proliferation activity of FIMGPY was attributable to its role in inducing apoptosis. These results suggest that FIMGPY from skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer.

Conditioning Methodologies for DanceSport: Lessons from Gymnastics, Figure Skating, and Concert Dance Research.

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Outevsky, David; Martin, Blake Cw

2015-12-01

Dancesport, the competitive branch of ballroom dancing, places high physiological and psychological demands on its practitioners, but pedagogical resources in these areas for this dance form are limited. Dancesport competitors could benefit from strategies used in other aesthetic sports. In this review, we identify conditioning methodologies from gymnastics, figure skating, and contemporary, modern, and ballet dance forms that could have relevance and suitability for dancesport training, and propose several strategies for inclusion in the current dancesport curriculum. We reviewed articles derived from Google Scholar, PubMed, ScienceDirect, Taylor & Francis Online, and Web of Science search engines and databases, with publication dates from 1979 to 2013. The keywords included MeSH terms: dancing, gymnastics, physiology, energy metabolism, physical endurance, and range of motion. Out of 47 papers examined, 41 papers met the inclusion criteria (validity of scientific methods, topic relevance, transferability to dancesport, publication date). Quality and validity of the data were assessed by examining the methodologies in each study and comparing studies on similar populations as well as across time using the PRISMA 2009 checklist and flowchart. The relevant research suggests that macro-cycle periodization planning, aerobic and anaerobic conditioning, range of motion and muscular endurance training, and performance psychology methods have potential for adaptation for dancesport training. Dancesport coaches may help their students fulfill their ambitions as competitive athletes and dance artists by adapting the relevant performance enhancement strategies from gymnastics, figure skating, and concert dance forms presented in this paper.

Reception of low-intensity millimeter-wave electromagnetic radiation by the electroreceptors in skates

International Nuclear Information System (INIS)

Akoev, G.N.; Avelev, V.D.

1995-01-01

Low intensity millimeter-wave electromagnetic radiation of less than 10 mW cm -2 power intensity has a nonthermal effect on the body and it is widely used in medical practice for treatment of various diseases. Nevertheless, the effect of EMR on biological tissues is not understood. The skin and its sensory receptors are considered to be responsible for EMR reception, but this has yet to be confirmed. The present experiments were designed to study the effect of millimeter-wave electromagnetic radiation on the ampullae of Lorenzini in skates, which are very sensitive to weak electrical stimuli at low frequency. (author)

Age group athletes in inline skating: decrease in overall and increase in master athlete participation in the longest inline skating race in Europe – the Inline One-Eleven

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Teutsch U

2013-05-01

Full Text Available Uwe Teutsch,1 Beat Knechtle,1,2 Christoph Alexander Rüst,1 Thomas Rosemann,1 Romuald Lepers31Institute of General Practice and Health Services Research, University of Zurich, Zurich, Switzerland; 2Gesundheitszentrum St Gallen, St Gallen, Switzerland; 3INSERM U1093, Faculty of Sport Sciences, University of Burgundy, Dijon, FranceBackground: Participation and performance trends in age group athletes have been investigated in endurance and ultraendurance races in swimming, cycling, running, and triathlon, but not in long-distance inline skating. The aim of this study was to investigate trends in participation, age, and performance in the longest inline race in Europe, the Inline One-Eleven over 111 km, held between 1998 and 2009.Methods: The total number, age distribution, age at the time of the competition, and race times of male and female finishers at the Inline One-Eleven were analyzed.Results: Overall participation increased until 2003 but decreased thereafter. During the 12-year period, the relative participation in skaters younger than 40 years old decreased while relative participation increased for skaters older than 40 years. The mean top ten skating time was 199 ± 9 minutes (range: 189–220 minutes for men and 234 ± 17 minutes (range: 211–271 minutes for women, respectively. The gender difference in performance remained stable at 17% ± 5% across years.Conclusion: To summarize, although the participation of master long-distance inline skaters increased, the overall participation decreased across years in the Inline One-Eleven. The race times of the best female and male skaters stabilized across years with a gender difference in performance of 17% ± 5%. Further studies should focus on the participation in the international World Inline Cup races.Keywords: endurance, men, women, gender

O que o skate pode dizer sobre o ensino de geografia?

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Luciano Hermes da Silva

2014-07-01

Full Text Available Este artigo pretende problematizar a prática do skate de rua como objeto de reflexão no âmbito do ensino de Geografia. Objetiva demonstrar como os skatistas protagonizam a ressignificação da cidade através de usos originais do mobiliário urbano. Trata-se de reforçar o movimento que articula as práticas espaciais dos jovens aos conteúdos e temas tradicionais da Geografia. A partir da referência ao conceito de espaço público, busca-se demonstrar que o recurso às práticas cotidianas da juventude permite problematizar conflitos, relações identitárias e processos relacionados à produção social do espaço.

In vitro metabolism of the pro-carcinogen aflatoxin B1 by liver preparations of the calf, nurse shark and clearnose skate.

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Bodine, A B; Luer, C A; Gangjee, S A; Walsh, C J

1989-01-01

1. Liver postmitochondrial supernatant preparations of calf, clearnose skate, and nurse shark were able to metabolize the fungal toxin aflatoxin B1 to various metabolites. 2. Calf liver produced aflatoxin M1 and Q1 as the major chloroform soluble metabolites, with small amounts of aflatoxicol formed during incubation. 3. Liver preparations of the elasmobranchs, however, produced aflatoxicol as the major chloroform soluble metabolite with no other metabolite being detected. 4. The water soluble metabolite profiles for the three species were also quite different with the tris diol adduct being produced to a much greater extent in calf liver preparations. 5. Aflatoxicol production by the elasmobranch liver homogenates was reversible with the skate reconverting a large amount (30%) of aflatoxicol to AFB1. The nurse shark, however, appeared to convert a portion of aflatoxicol to an unknown metabolite more polar than AFB1. 6. Calf liver DNA bound approximately 3 x more 3H-AFB1 than shark liver DNA.

GFAP-immunopositive structures in spiny dogfish, Squalus acanthias, and little skate, Raia erinacea, brains: differences have evolutionary implications.

Science.gov (United States)

Kálmán, M; Gould, R M

2001-07-01

GFAP expression patterns were compared between the brains of a spiny dogfish (Squalus acanthias) and a little skate (Raia erinacea). After anesthesia, the animals were perfused with paraformaldehyde. Serial vibratome sections were immunostained against GFAP using the avidin-biotin method. Spiny dogfish brain contained mainly uniformly-distributed, radially arranged ependymoglia. From GFAP distribution, the layered organization in both the telencephalon and the tectum were visible. In the cerebellum, the molecular and granular layers displayed conspicuously different glial structures; in the former a Bergmann glia-like population was found. No true astrocytes (i.e., stellate-shaped cells) were found. Radial glial endfeet lined all meningeal surfaces. Radial fibers also seemed to form endfeet and en passant contacts on the vessels. Plexuses of fine perivascular glial fibers also contributed to the perivascular glia. Compared with spiny dogfish brain, GFAP expression in the little skate brain was confined. Radial glia were limited to a few areas, e.g., segments of the ventricular surface of the telencephalon, and the midline of the diencephalon and mesencephalon. Scarce astrocytes occurred in every brain part, but only the optic chiasm, and the junction of the tegmentum and optic tectum contained large numbers of astrocytes. Astrocytes formed the meningeal glia limitans and the perivascular glia. No GFAP-immunopositive Bergmann glia-like structure was found. Astrocytes seen in the little skate were clearly different from the mammalian and avian ones; they had a different process system - extra large forms were frequently seen, and the meningeal and perivascular cells were spread along the surface instead of forming endfeet by processes. The differences between Squalus and Raia astroglia were much like those found between reptiles versus mammals and birds. It suggests independent and parallel glial evolutionary processes in amniotes and chondrichthyans, seemingly

Surgical outcomes and nipple projection using the modified skate flap for nipple-areolar reconstruction in a series of 422 implant reconstructions.

Science.gov (United States)

Zhong, Toni; Antony, Anu; Cordeiro, Peter

2009-05-01

Numerous techniques have been used in an attempt to achieve long-term nipple projection following nipple-areolar reconstruction (NAR). A common setback, however, is the diminution of projection over time; this phenomenon is particularly evident following implant based breast reconstruction. The purpose of this report was thus to evaluate surgical outcomes and long-term nipple projection with the use of "modified skate flap" technique in exclusively implant based postmastectomy reconstructions. A retrospective review was performed for the period between 1993 and 2007. All consecutive patients with 2-staged tissue expander/implant reconstructions followed by NAR using the modified skate flap technique performed by the senior author (P.C.) were identified in a prospectively maintained breast reconstruction database. Only patients with a minimum of 1-year follow-up were included in the study. Patients with a history of irradiation to the breast were excluded from nipple projection assessment. Clinical outcome measurements included long-term nipple projection as well as incidence of complications from the NAR procedure using the modified skate flap technique. Over the 15-year study period, 475 patients underwent 2-staged tissue expander/implant reconstruction followed by NAR using the modified skate flap technique. Of these, there was a total of 292 patients with the minimum requirement of 1-year follow-up post NAR (61% follow-up rate). The total number of reconstructed nipple areolar complexes evaluated in this series was 422 (130 bilateral and 162 unilateral NAR). Forty patients (28 unilateral and 12 bilateral NAR) who received radiation to their breasts were excluded from nipple projection assessment. At a median follow-up of 44 months (range: 12-84 months), mean nipple projection was 2.5 mm (range: 1-4 mm). Minor complications occurred in 7.2% of the patients (n = 292). Skin graft donor site dehiscence was the most common complication (3.1%) followed by partial skin

Batoid locomotion: effects of speed on pectoral fin deformation in the little skate, Leucoraja erinacea.

Science.gov (United States)

Di Santo, Valentina; Blevins, Erin L; Lauder, George V

2017-02-15

Most batoids have a unique swimming mode in which thrust is generated by either oscillating or undulating expanded pectoral fins that form a disc. Only one previous study of the freshwater stingray has quantified three-dimensional motions of the wing, and no comparable data are available for marine batoid species that may differ considerably in their mode of locomotion. Here, we investigate three-dimensional kinematics of the pectoral wing of the little skate, Leucoraja erinacea , swimming steadily at two speeds [1 and 2 body lengths (BL) s -1 ]. We measured the motion of nine points in three dimensions during wing oscillation and determined that there are significant differences in movement amplitude among wing locations, as well as significant differences as speed increases in body angle, wing beat frequency and speed of the traveling wave on the wing. In addition, we analyzed differences in wing curvature with swimming speed. At 1 BL s -1 , the pectoral wing is convex in shape during the downstroke along the medio-lateral fin midline, but at 2 BL s -1 the pectoral fin at this location cups into the flow, indicating active curvature control and fin stiffening. Wing kinematics of the little skate differed considerably from previous work on the freshwater stingray, which does not show active cupping of the whole fin on the downstroke. © 2017. Published by The Company of Biologists Ltd.

Development of real-time PCR assay for genetic identification of the mottled skate, Beringraja pulchra.

Science.gov (United States)

Hwang, In Kwan; Lee, Hae Young; Kim, Min-Hee; Jo, Hyun-Su; Choi, Dong-Ho; Kang, Pil-Won; Lee, Yang-Han; Cho, Nam-Soo; Park, Ki-Won; Chae, Ho Zoon

2015-10-01

The mottled skate, Beringraja pulchra is one of the commercially important fishes in the market today. However, B. pulchra identification methods have not been well developed. The current study reports a novel real-time PCR method based on TaqMan technology developed for the genetic identification of B. pulchra. The mitochondrial cytochrome oxidase subunit 1 (COI) nucleotide sequences of 29 B. pulchra, 157 skates and rays reported in GenBank DNA database were comparatively analyzed and the COI sequences specific to B. pulchra was identified. Based on this information, a system of specific primers and Minor Groove Binding (MGB) TaqMan probe were designed. The assay successfully discriminated in 29 specimens of B. pulchra and 27 commercial samples with unknown species identity. For B. pulchra DNA, an average Threshold Cycle (Ct) value of 19.1±0.1 was obtained. Among 27 commercial samples, two samples showed average Ct values 19.1±0.0 and 26.7±0.1, respectively and were confirmed to be B. pulchra based on sequencing. The other samples tested showed undetectable or extremely weak signals for the target fragment, which was also consistent with the sequencing results. These results reveal that the method developed is a rapid and efficient tool to identify B. pulchra and might prevent fraud or mislabeling during the distribution of B. pulchra products. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Simulation of the energy consumption of a skating rink using DOE-2.1E software; Simulation de la consommation d'energie d'un arena a l'aide du logiciel DOE-2.1E

Energy Technology Data Exchange (ETDEWEB)

Zmeureanu, R. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Zelaya, E.M.; Giguere, D. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Diversification Laboratory

2002-07-01

The vast majority of skating rinks in Quebec are over 20 years old, and there is a requirement to retrofit their refrigeration systems. In this paper, the authors presented the approach developed to simulate the thermal phenomena that occur within a skating rink in Canada. The simulation tool was designed by the Canada Centre for Mineral and Energy Technology (CANMET) Energy Technology Centre in cooperation with Concordia University to study the sensitivity of various eco energy technologies with a specific application to skating rinks. The originality of this work stems from the use of DOE-2.1E calculation software to simulate heat transfer. The structure of the simulation tool was presented, including a brief description of the calculation algorithms that were developed, as well as some preliminary results obtained during the validation phase. 8 refs., 1 tab., 4 figs.

Establishing the Test-Retest Reliability & Concurrent Validity for the Repeat Ice Skating Test (RIST) in Adolescent Male Ice Hockey Players

Science.gov (United States)

Power, Allan; Faught, Brent E.; Przysucha, Eryk; McPherson, Moira; Montelpare, William

2012-01-01

In this study the authors examine the test-retest reliability and concurrent validity of the Repeat Ice Skating Test (RIST). This was an on-ice field anaerobic test that measured average peak power and was validated with 3 anaerobic lab tests: (a) vertical jump, (b) the Margaria-Kalamen stair test, and (c) the Wingate Anaerobic Test. The…

Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with notes on its biology.

Science.gov (United States)

Bustamante, Carlos; Lamilla, Julio; Concha, Francisco; Ebert, David A; Bennett, Michael B

2012-01-01

Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries.

"Extreme" or tariff sports: their injuries and their prevention (with particular reference to diving, cheerleading, gymnastics, and figure skating).

Science.gov (United States)

Foley, E C; Bird, H A

2013-04-01

The interface between sports medicine and performing arts medicine is closest for "tariff" sports, where the sportsperson can select their own programme of varying difficulty with the more complex skills carrying potential for higher marks. Inevitably, some performers over-reach themselves. Examples of injuries and prevention strategies to avoid such injuries are discussed in a preliminary analysis of four sports: diving, cheerleading, gymnastics, and figure skating.

Vitamin D status and V[combining dot above]O2peak during a skate treadmill graded exercise test in competitive ice hockey players.

Science.gov (United States)

Fitzgerald, John S; Peterson, Ben J; Warpeha, Joseph M; Wilson, Patrick B; Rhodes, Greg S; Ingraham, Stacy J

2014-11-01

Vitamin D status has been associated with cardiorespiratory fitness (CRF) in cross-sectional investigations in the general population. Data characterizing the association between 25-hydroxyvitamin D (25(OH)D) concentration and CRF in athletes are lacking. Junior and collegiate ice hockey players were recruited from the Minneapolis, MN (44.9° N), area during the off-season period (May 16-June 28). The purpose of this study was to examine the cross-sectional association between 25(OH)D concentration and CRF in a sample population of competitive ice hockey players. Circulating 25(OH)D level was assessed from a capillary blood sample analyzed using liquid chromatography-tandem mass spectrometry. V[Combining Dot Above]O2peak during a skate treadmill graded exercise test (GXT) was used to assess CRF. Data on both 25(OH)D concentration and V[Combining Dot Above]O2peak were available for 52 athletes. Insufficient 25(OH)D concentrations were found in 37.7% of the athletes (skate treadmill GXT.

Polarizability of KC60: Evidence for Potassium Skating on the C60 Surface

Science.gov (United States)

Rayane, D.; Antoine, R.; Dugourd, Ph.; Benichou, E.; Allouche, A. R.; Aubert-Frécon, M.; Broyer, M.

2000-02-01

We present the first measurement of the polarizability and the permanent dipole moment of isolated KC60 molecules by molecular beam deflection technique. We have obtained a value of 2506+/-250 Å3 for the polarizability at room temperature. The addition of a potassium atom enhances by more than a factor of 20 the polarizability of a pure C60 molecule. This very high polarizability and the lack of observed permanent dipole show that the apparent polarizability of KC60 is induced by the free skating of the potassium atom on the C60 surface, resulting in a statistical orientation of the dipole. The results are interpreted with a simple model similar to the Langevin theory for paramagnetic systems.

Average number of compressors in operation per day in 25 skating rinks of the City of Montreal; Nombre moyens de compresseurs par jour en fonction dans 25 arenas de la Ville de Montreal

Energy Technology Data Exchange (ETDEWEB)

Dumas, C. [Ville de Montreal, PQ (Canada). Direction des Immeubles Gestion de l' Energie et du Genie Climatique

2002-09-30

Since the summer of 2001, 25 skating rinks from the territory of the old City of Montreal have been linked through a network to the remote management system. This initiative enables the people responsible for the skating rink to easily obtain statistics on the operation of refrigeration systems and to compile this information in the memory of a personal computer (PC). Each compressor system is equipped with a current transformer which acts as proof of monitored operation by the remote management system. Every minute, the compressors are asked in sequence to report on their status. The process by which the data is entered, filtered and analysed was explained and an example provided to better illustrate the concept. As a rule, management believes that it is possible to lower the power of existing refrigeration systems and to select new refrigeration systems according to the data acquired. Based on the results obtained so far, the power of some of the refrigeration systems has already been reduced by letting go one or two of the six refrigeration circuits of a skating rink. 2 tabs.

Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968 (Rajiformes: Rajidae, with notes on its biology.

Directory of Open Access Journals (Sweden)

Carlos Bustamante

Full Text Available Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries.

Morphological Characters of the Thickbody Skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with Notes on Its Biology

Science.gov (United States)

Bustamante, Carlos; Lamilla, Julio; Concha, Francisco; Ebert, David A.; Bennett, Michael B.

2012-01-01

Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries. PMID:22768186

Survey of Antibiotic-producing Bacteria Associated with the Epidermal Mucus Layers of Rays and Skates

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Kim B. Ritchie

2017-07-01

Full Text Available Elasmobranchs represent a distinct group of cartilaginous fishes that harbor a remarkable ability to heal wounds rapidly and without infection. To date very little work has addressed this phenomenon although it is suggested that antibiotic capabilities associated with epidermal surfaces may be a factor. The study of benefits derived from mutualistic interactions between unicellular and multicellular organisms is a rapidly growing area of research. Here we survey and identify bacterial associates of three ray and one skate species in order to assess the potential for antibiotic production from elasmobranch associated bacteria as a novel source for new antibiotics.

Embryonic development of the axial column in the little skate, Leucoraja erinacea.

Science.gov (United States)

Criswell, Katharine E; Coates, Michael I; Gillis, J Andrew

2017-03-01

The morphological patterns and molecular mechanisms of vertebral column development are well understood in bony fishes (osteichthyans). However, vertebral column morphology in elasmobranch chondrichthyans (e.g., sharks and skates) differs from that of osteichthyans, and its development has not been extensively studied. Here, we characterize vertebral development in an elasmobranch fish, the little skate, Leucoraja erinacea, using microCT, paraffin histology, and whole-mount skeletal preparations. Vertebral development begins with the condensation of mesenchyme, first around the notochord, and subsequently around the neural tube and caudal artery and vein. Mesenchyme surrounding the notochord differentiates into a continuous sheath of spindle-shaped cells, which forms the precursor to the mineralized areolar calcification of the centrum. Mesenchyme around the neural tube and caudal artery/vein becomes united by a population of mesenchymal cells that condenses lateral to the sheath of spindle-shaped cells, with this mesenchymal complex eventually differentiating into the hyaline cartilage of the future neural arches, hemal arches, and outer centrum. The initially continuous layers of areolar tissue and outer hyaline cartilage eventually subdivide into discrete centra and arches, with the notochord constricted in the center of each vertebra by a late-forming "inner layer" of hyaline cartilage, and by a ring of areolar calcification located medial to the outer vertebral cartilage. The vertebrae of elasmobranchs are distinct among vertebrates, both in terms of their composition (i.e., with centra consisting of up to three tissues layers-an inner cartilage layer, a calcified areolar ring, and an outer layer of hyaline cartilage), and their mode of development (i.e., the subdivision of arch and outer centrum cartilage from an initially continuous layer of hyaline cartilage). Given the evident variation in patterns of vertebral construction, broad taxon sampling, and

Acanthocotyle gurgesiella n. sp. (Monogenea: Acanthocotylidae) from the deep-sea skate Gurgesiella furvescens (Rajidae) in the south-eastern Pacific.

Science.gov (United States)

Ñacari, L A; Sepulveda, F A; Escribano, R; Oliva, M E

2018-03-01

Little is known about the diversity of parasites of the deep-sea fish of the world's oceans. Here, a new species of monogenean parasite of the deep-sea skate Gurgesiella furvescens is described. Specimens of parasites were obtained from the skin of two specimens of the dusky finless skate, G. furvescens (Rajidae), in the vicinity of Valparaiso (33°S, 72°W), central Chile, from midwater trawl fishing at depths of 350-450 m. Both morphological and molecular analyses were conducted to provide a full description of the new species, named Acanthocotyle gurgesiella. For the molecular analyses, nuclear large subunit (LSU) rDNA and the mitochondrial gene cytochrome c oxidase 1 (COI) were used. From the morphological analysis and a comparison with the known species of the genus, A. gurgesiella can be identified by a combination of morphological characteristics, including the number of testes, number of radial rows of sclerites in the pseudohaptor, aperture of the genital pore and shape of the vitelline follicles. The results from the DNA analysis indicated that A. gurgesiella has a genetic divergence of 3.2-3.7% (LSU rDNA gene) from A. urolophi, the only congener species for which molecular data are available.

Skating on a Film of Air: Drops Impacting on a Surface

Science.gov (United States)

Kolinski, John M.; Rubinstein, Shmuel M.; Mandre, Shreyas; Brenner, Michael P.; Weitz, David A.; Mahadevan, L.

2012-02-01

The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the drop spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate on the air film laterally outward at surprisingly high velocities, consistent with theoretical predictions. Eventually this thin film of air breaks down as the fluid wets the surface via a spinodal-like mechanism. Our results show that the dynamics of impacting drops are much more complex than previously thought, with a rich array of unexpected phenomena that require rethinking classic paradigms.

ALÉM DAS RUAS: IMAGINAÇÃO E ESPAÇOS DA CIDADE PELO SKATE

Directory of Open Access Journals (Sweden)

Guilherme Michelotto Böes

2016-03-01

Full Text Available As cidades metropolitanas estão inscritas nas novas formas de uso público urbano entre as práticas que desafiam as representações culturais e sociais, configurações dos espaços urbanos representados pela arquitetura das cidades que moldam os espaços. Essas modificações apontam a mudança histórica da representação entre os indivíduos sociais. Devemos identificar os desafios com que as codificações dos espaços culturais da cidade se encontram em suas novas propriedades de direito de uso e manifestação social, já que produzem narrativas que alteram a produção dos espaços na inscrição de identidade social. Práticas cotidianas possibilitam situações, essas com que deparamos na forma de organização social da cidade, tanto formalmente ou informalmente administrada, o local da estrutura dos sistemas de valores na referência ao espaço/tempo de ser utilizado. As ruas imaginadas, apropriadas pelos skatistas, como narrativa da prática cotidiana nos espaços públicos urbanos, que cada vez mais são abandonados em detrimento aos espaços privados. Desse modo, pode o skate trazer a discussão sobre o urbano, apontando que as identidades culturais nos espaços públicos estão longe da percepção ilícita de práticas culturais urbanas. Assim o skate pode então encontrar o diálogo entre a imaginação da experiência urbana contemporânea nas ruas das cidades.

Preliminary observations on the effects of selenate on the development of the embryonic skate, Raja eglanteria

Science.gov (United States)

Conrad, G. W.; Luer, C. A.; Paulsen, A. Q.; Funderburgh, J. L.; Spooner, B. S. (Principal Investigator)

1993-01-01

Morphogenesis of the clearnose skate, Raja eglanteria, was not significantly inhibited as a result of 7 days of exposure to 1-2 mM selenate in the sea water during Days 59-69 of embryonic development (hatching would normally have occurred at 82 +/- 4 days of incubation). Although corneal transparency appeared normal in the eye, preliminary measurements of the thickness of Bowman's layer of the cornea suggested that it was significantly thinner in the corneas of embryos exposed to 1-2 mM selenate. Selenate is an ion reported to inhibit sulfation of glycosaminoglycans in connective tissue.

Study on application of single-crystal ice `Kurobe ice column` to high-speed skating rinks. Demonstration test result at Olympic memorial arena `M wave` in Nagano city; Tankesshohyo `Kurobe no hyojun` no kosoku skate link eno tekiyosei kenkyu. Naganoshi olympic kinen arina `Emu Wave` deno jissho shiken kekka

Energy Technology Data Exchange (ETDEWEB)

Iwasaki, M. [Kansai Electric Power Co. Inc., Osaka (Japan)

1999-06-10

For high-speed low-friction skating rinks, research was made on sticking artificial ice columns (ice bamboo shoot). The ice columns were fabricated with the ice column production equipment equipped with 4-line water droplet dropping devices which were installed at intervals of 0.3m on both sides of a pathway of 200m long, 2.6m wide and 1.8m high in the lateral adit of Kurobegawa No.4 hydroelectric power station. The grown ice columns were processed for high-speed skating rinks through cutting, confirmation of single crystal and crystal orientation, slicing for every 7mm thickness and packaging. The ice columns were spread all over the rink while sliding them to prevent mixing of bubbles after spraying distilled water of nearly 25 degreesC onto base ices. In addition, hot water of nearly 40 degreesC was sprayed to produce the final ice rink of 30mm thick by nearly 5mm a day. The dynamic friction coefficient of the ice column rink reduced to 0.0038 by nearly 16% as compared with 0.0045 of conventional rinks. (NEDO)

Pacing Strategy, Muscle Fatigue, and Technique in 1500-m Speed-Skating and Cycling Time Trials.

Science.gov (United States)

Stoter, Inge K; MacIntosh, Brian R; Fletcher, Jared R; Pootz, Spencer; Zijdewind, Inge; Hettinga, Florentina J

2016-04-01

To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500-m speed-skating and cycling time trials when a faster or slower start is instructed. Nine speed skaters and 9 cyclists, all competing at regional or national level, performed two 1500-m time trials in their sport. Athletes were instructed to start faster than usual in 1 trial and slower in the other. Mean velocity was measured per 100 m. Blood lactate concentrations were measured. Maximal voluntary contraction (MVC), voluntary activation (VA), and potentiated twitch (PT) of the quadriceps muscles were measured to estimate central and peripheral contributions to muscle fatigue. In speed skating, knee, hip, and trunk angles were measured to evaluate technique. Cyclists showed a more explosive start than speed skaters in the fast-start time trial (cyclists performed first 300 m in 24.70 ± 1.73 s, speed skaters in 26.18 ± 0.79 s). Both trials resulted in reduced MVC (12.0% ± 14.5%), VA (2.4% ± 5.0%), and PT (25.4% ± 15.2%). Blood lactate concentrations after the time trial and the decrease in PT were greater in the fast-start than in the slow-start trial. Speed skaters showed higher trunk angles in the fast-start than in the slow-start trial, while knee angles remained similar. Despite similar instructions, behavioral adaptations in pacing differed between the 2 sports, resulting in equal central and peripheral contributions to muscle fatigue in both sports. This provides evidence for the importance of neurophysiological aspects in the regulation of pacing. It also stresses the notion that optimal pacing needs to be studied sport specifically, and coaches should be aware of this.

The influence of incline and speed on work rate, gross efficiency and kinematics of roller ski skating.

Science.gov (United States)

Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2012-08-01

During competitions, elite cross-country skiers produce higher external work rates on uphill than on flat terrain. However, it is not presently known whether this reflects solely higher energy expenditure. Furthermore, the kinematic factors associated with these higher rates of uphill work have not yet been examined. Therefore, in the present investigation the work rate and associated kinematic parameters at similar metabolic rates during roller ski skating on flat and uphill terrains have been compared. Seven elite male skiers performed six 5-min sub-maximal exercise bouts at the same low, moderate and high metabolic rates on 2 and 8% inclines, while roller skiing on a treadmill employing the G3 skating technique. The work rate was calculated as work against gravity and friction, whereas the energetic equivalent of VO(2) was taken as the metabolic rate. Gross efficiency was defined as work rate divided by metabolic rate. Kinematic parameters were analyzed in three dimensions. At the same metabolic rate, the work rate, cycle rate, work per cycle and relative duration of propulsive phases during a cycle of movement were all higher on the 8% than on the 2% incline at all speeds (all P < 0.05). At similar work rates, gross efficiency was greater on the 8% incline (P < 0.05). In conclusion, these elite skiers consistently demonstrated higher work rates on the 8% incline. To achieve the higher work rates on the steeper incline, these elite skiers employed higher cycle rates and performed more work per cycle, in association with a longer relative propulsive phase.

Energy pumping analysis of skating motion in a half pipe and on a level surface

Science.gov (United States)

Feng, Z. C.; Xin, Ming

2015-01-01

In this paper, an energy pumping mechanism for locomotion is analysed. The pumping is accomplished by exerting forces perpendicular to the direction of motion. The paper attempts to demonstrate an interesting application of the classical mechanics to two sporting events: a person skating in a half pipe and a person travelling on a level surface on a skateboard. The equations of motion based on simplified mechanical models are derived using the Lagrange mechanics. The energy-pumping phenomenon is revealed through numerical simulations with simple pumping actions. The result presented in this paper can be used as an interesting class project in undergraduate mechanics or physics courses. It also motivates potential new applications of energy pumping in many engineering fields.

The effect of swinging the arms on muscle activation and production of leg force during ski skating at different skiing speeds.

Science.gov (United States)

Göpfert, Caroline; Lindinger, Stefan J; Ohtonen, Olli; Rapp, Walter; Müller, Erich; Linnamo, Vesa

2016-06-01

The study investigated the effects of arm swing during leg push-off in V2-alternate/G4 skating on neuromuscular activation and force production by the leg muscles. Nine skilled cross-country skiers performed V2-alternate skating without poles at moderate, high, and maximal speeds, both with free (SWING) and restricted arm swing (NOSWING). Maximal speed was 5% greater in SWING (P<0.01), while neuromuscular activation and produced forces did not differ between techniques. At both moderate and high speed the maximal (2% and 5%, respectively) and average (both 5%) vertical force and associated impulse (10% and 14%) were greater with SWING (all P<0.05). At high speed range of motion and angular velocity of knee flexion were 24% greater with SWING (both P<0.05), while average EMG of m. biceps femoris was 31% lower (all P<0.05) in SWING. In a similar manner, the average EMG of m. vastus medialis and m. biceps femoris were lower (17% and 32%, P<0.05) during the following knee extension. Thus, swinging the arms while performing V2-alternate can enhance both maximal speed and skiing economy at moderate and, in particularly, high speeds. Copyright © 2016 Elsevier B.V. All rights reserved.

Long-PCR based next generation sequencing of the whole mitochondrial genome of the peacock skate Pavoraja nitida (Elasmobranchii: Arhynchobatidae).

Science.gov (United States)

Yang, Lei; Naylor, Gavin J P

2016-01-01

We determined the complete mitochondrial genome sequence (16,760 bp) of the peacock skate Pavoraja nitida using a long-PCR based next generation sequencing method. It has 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region in the typical vertebrate arrangement. Primers, protocols, and procedures used to obtain this mitogenome are provided. We anticipate that this approach will facilitate rapid collection of mitogenome sequences for studies on phylogenetic relationships, population genetics, and conservation of cartilaginous fishes.

The feeding habits of the eyespot skate Atlantoraja cyclophora (Elasmobranchii: Rajiformes in southeastern Brazil

Directory of Open Access Journals (Sweden)

Alessandra da Fonseca Viana

2014-04-01

Full Text Available The stomach contents of the eyespot skate, Atlantoraja cyclophora (Regan, 1903, were examined with the goal to provide information about the diet of the species. Samples were collected off the southern coast of Rio de Janeiro, Brazil, near Ilha Grande, between January 2006 and August 2007, at a depth of about 60 m. The diet was analyzed by sex, maturity stages and quarterly to verify differences in the importance of food items. The latter were analyzed by: frequency of occurrence, percentage of weight and in the Alimentary Index. The trophic niche width was determined to assess the degree of specialization in the diet. Additionally, the degree of dietary overlap between males and females; juveniles and adults and periods of the year were defined. A total of 59 individuals of A. cyclophora were captured. Females and adults were more abundant. The quarters with the highest concentrations of individuals were in the summer of the Southern Hemisphere: Jan-Feb-Mar 06 and Jan-Feb-Mar 07. Prey items were classed into five main groups: Crustacea, Teleosts, Elasmobranchs, Polychaeta, and Nematoda. The most important groups in the diet of the eyespot skate were Crustacea and Teleosts. The crab Achelous spinicarpus (Stimpson, 1871 was the most important item. The value of the niche width was small, indicating that a few food items are important. The comparison of the diet between males and females and juveniles and adults indicates a significant overlap between the sexes and stages of maturity; and according to quarters, the importance of prey groups differed (crustaceans were more important in the quarters of the summer and teleost in Jul-Aug-Sep and Oct-Nov-Dec 06, indicating seasonal differences in diet composition. Three groups with similar diets were formed in the cluster analysis: (Jan-Feb-Mar 06 and 07; (Apr-May-Jun 06 and Jul-Aug-Sep 07; (Jul-Aug-Sep 06 and Oct-Nov-Dec 06.

Reproductive biology of the Alaska skate Bathyraja parmifera, with comments on an intersexual individual.

Science.gov (United States)

Matta, M E

2015-09-01

A total of 1357 specimens of Alaska skate Bathyraja parmifera were collected in the eastern Bering Sea by fisheries observers and during scientific groundfish surveys from 2003 to 2005. Male and female gonads were examined for maturity stage and seasonal reproductive timing. Based on seasonal reproductive data, including the occurrence of egg cases, ovum size, ovum number, shell-gland width and gonado-somatic index, this species appears to reproduce continually throughout the year. Potential effects of maternal size upon the size and number of mature oocytes were also investigated, with total length having a significant, although weak, influence on both. Morphology of a single intersexual individual encountered during the collection period is also described. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

The complete mitochondrial genome of the Longnose skate: Raja rhina (Rajiformes, Rajidae).

Science.gov (United States)

Jeong, Dageum; Lee, Youn-Ho

2015-02-01

The complete sequence of mitochondrial DNA of a longnose skate, Raja rhina was determined for the first time. It is 16,910 bp in length containing 2 rRNA, 22 tRNA and 13 protein coding genes with the same gene order and structure as those of other Rajidae species. The nucleotide of L-strand is composed of 30.1% A, 27.2% C, 28.5% T and 14.2% G, showing a slight A + T bias. The G is the least used base and markedly lower at the third codon position (5.4%). Twelve of the 13 protein coding genes use ATG as their start codon while the COX1 starts with GTG. As for stop codon, only ND4 shows incomplete stop codon TA. This mitogenome is the first report for a species of the genus Raja, and providing a valuable resource of genetic information for understanding the phylogenetic relationship and the evolution of the genus Raja as well as the family, Rajidae.

Complete mitochondrial genome of the mottled skate: Raja pulchra (Rajiformes, Rajidae).

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Jeong, Dageum; Kim, Sung; Kim, Choong-Gon; Myoung, Jung-Goo; Lee, Youn-Ho

2016-05-01

The complete sequence of mitochondrial DNA of a mottled skate, Raja pulchra was sequenced as being circular molecules of 16,907 bp including 2 rRNA, 22 tRNA, 13 protein-coding genes (PCGs), and an AT-rich control region. The organization of the PCGs is the same as those found in other Rajidae species. The nucleotide of L-strand is composed of 29.8% A, 28.0% C, 27.9% T, and 14.3% G with a bias toward A + T slightly. Twelve of 13 PCGs are initiated by the ATG codon while COX1 starts with GTG. Only ND4 harbors the incomplete termination codon, TA. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA with the exception of [Formula: see text] which has a reduced DHU arm. This mitogenome will provide essential information for better phylogenetic resolution and precision of the family Rajidae and the genus Raja as well as for establishment of a fish stock recovery plan of the species.

Complete mitochondrial genome of the Yellownose skate: Zearaja chilensis (Rajiformes, Rajidae).

Science.gov (United States)

Jeong, Dageum; Lee, Youn-Ho

2016-01-01

The complete sequence of mitochondrial DNA of a Yellownose skate, Zearaja chilensis was determined for the first time. It is 16,909 bp in length covering 2 rRNA, 22 tRNA and 13 protein coding genes with the identical gene order and structure as those of other Rajidae species. The nucleotide of L-strand is composed of low G (14.3%), and slightly high A + T (58.9%) nucleotides. The strong codon usage bias against the use of G (6.0%) is found at the third codon positions. Twelve of the 13 protein coding genes use ATG as the start codon while COX1 starts with GTG. As for the stop codon, only ND4 shows an incomplete stop codon TA. This is the first report of the mitogenome for a species in the genus Zearaja, providing a valuable source of genetic information on the evolution of the family Rajidae and the genus Zearaja as well as for establishment of a sustainble fishery management plan of the species.

Complete mitochondrial genome of the Kwangtung skate: Dipturus kwangtungensis (Rajiformes, Rajidae).

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Jeong, Dageum; Kim, Sung; Kim, Choong-Gon; Lee, Youn-Ho

2015-01-01

The complete sequence of mitochondrial DNA of a Kwangtung skate, Dipturus kwangtungensis, was determined as being circular molecules of 16,912 bp including 2 rRNA, 22 tRNA, 13 protein coding genes (PCGs) and a control region. The arrangement of the PCGs is the same as that found in other Rajidae species. The nucleotide of L-strand which encodes most of the proteins is composed of 30.2% A, 27.4% C, 28.2% T and 14.2% G with a bias toward A+T slightly. Twelve of 13 PCGs are initiated by the ATG codon while COX1 starts with GTG. Only ND4 harbors the incomplete termination codon, TA. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA with the exception of tRNA(Ser)AGY, which has a reduced DHU arm. This mitogenome is the first report for a species of the genus Dipturus, which will become an important source of information on the phylogenetic relationship and the evolution of the genus Dipturus within the family Rajidae.

Energy pumping analysis of skating motion in a half pipe and on a level surface

International Nuclear Information System (INIS)

Feng, Z C; Xin, Ming

2015-01-01

In this paper, an energy pumping mechanism for locomotion is analysed. The pumping is accomplished by exerting forces perpendicular to the direction of motion. The paper attempts to demonstrate an interesting application of the classical mechanics to two sporting events: a person skating in a half pipe and a person travelling on a level surface on a skateboard. The equations of motion based on simplified mechanical models are derived using the Lagrange mechanics. The energy-pumping phenomenon is revealed through numerical simulations with simple pumping actions. The result presented in this paper can be used as an interesting class project in undergraduate mechanics or physics courses. It also motivates potential new applications of energy pumping in many engineering fields. (paper)

Age, growth and length-weight relationship of the rough skate, Raja radula (Linnaeus, 1758 (Chondrichthyans: Rajidae, from the Gulf of Gabes (Tunisia, Central Mediterranean

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Hasna Kadri

2014-05-01

Full Text Available Objective: To investigate the length distribution, sex ratio, length-weight relationship, age and growth of Raja radula in the Gulf of Gabes. Methods: The age and growth characteristic of the rough skate (Raja radula inhabiting in the Gulf of Gabes (Central Mediterranean Sea was determined. A total of 1 250 specimens were sampled. According to the marginal increment band its growth was annual. Results: The growth parameters were derived by using the von-Bertalanffy method and were separately evaluated as follows: TL∞=97.2 cm, K= 0.15 y -1 , to= 0.35, and W∞= 5.28 kg, and TL∞= 76.4 cm, K = 0.22 y -1 , to= 0.16, and W∞= 3.77 kg, for females and males respetively. The maximum age was 12 years for females and 10 years for males. Conclusions: Results from this research will provide a starting point to develop a management plan for the rough skate in the Gulf of Gabes. Further investigations are necessary to quantify the impact of the existing regulations on the population dynamics and recruitment patterns of this species in the region.

O Skate e suas possibilidades educacionais The skateboarding and its educational possibility

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Igor Armbrust

2010-09-01

Full Text Available Os esportes radicais têm sido objetos de discussões, devido ao interesse de aplicabilidade de seus conteúdos relacionados ao lazer, ao esporte e a educação. Todavia, ainda há certo despreparo profissional para empreender essas atividades, o que dificulta implantar tais práticas nos âmbitos educacionais. Este estudo, de natureza qualitativa, teve como objetivo apresentar uma proposta metodológica para organização de um curso de extensão universitária para graduandos e professores de educação física, com a finalidade de promover reflexões sobre os processos de iniciação à prática do skate atrelados ao esporte educacional. O estudo constou de pesquisa bibliográfica, apoiada em levantamentos de artigos, teses, dissertações, livros e sites, em que se relacionavam a prática do skate e sua ação educativa. Além disso, houve uma proposição de implementar uma proposta metodológica, no sentido de complementar os elementos da cultura corporal a ser vivenciada em âmbito escolar e efetivamente contribuir no processo de desenvolvimento do ser humano nos aspectos biológico, psicológico, social e cultural.The radical sports have been discussions' objects due to the interest of applicability of its contents related to leisure, sport, and education. Nevertheless, there is still some professional unprepared to undertake these activities, which makes difficult to introduce these practices in the educational ambit. This study, which has a qualitative character, had the aim to present a methodological proposal of organizing a college extension course for undergraduate students and teachers of physical education with the goal of promoting reflections about the processes of starting in the skateboarding practice coupled to educational sport. The study was consisted of a bibliographic research supported by a survey of articles, thesis, dissertations, books and, websites related to the skateboarding practice and its educative action

Morphology meets molecules: a new genus and two new species of diphyllidean cestodes from the Yellowspotted skate, Leucoraja wallacei, from South Africa.

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Abbott, Lauren McKenna; Caira, Janine N

2014-06-01

Two morphologically disparate undescribed species of diphyllidean cestodes from the Yellowspotted skate, Leucoraja wallacei , from South Africa were included in a recent molecular phylogenetic study aimed at revising diphyllidean classification. From a molecular standpoint, these species were determined to be only distantly related to one another. One (originally referred to as Echinobothrium n. sp. 2) showed affinities with species of the batoid-parasitizing Echinobothrium sensu stricto and is described here as Echinobothrium marquesi n. sp. This species most closely resembles Echinobothrium joshuai, an affinity supported by the previous molecular study, but differs in the form of its "B" hooks and degree of overlap between bothria and cephalic peduncle. The other species (originally referred to as New genus n. sp. 1), although exhibiting the full complement of scolex armature, grouped among primarily shark-hosted genera, most of which lack or exhibit reduced scolex armatures. That unexpected result suggested that erection of a novel genus might be warranted, but morphological grounds supporting the action were not apparent at that time. The present study aimed to explore the morphology of this taxon in more detail. Light and scanning electron microscopy revealed this taxon to be exceptional in that its lateral hooklets, which are arranged in 2 clusters like those of Echinobothrium and Coronocestus, are unique in being arranged in anterior and posterior rows, rather than in a single row. Andocadoncum n. gen. is erected, with Andocadoncum meganae n. sp. as its type, to accommodate this taxon. A minor adjustment to the existing hook formula by presenting counts for the anterior hooklets (a) separately from the posterior hooklets (b) readily accommodates this new form. Leucoraja wallacei is distinctive among skates in hosting 2 different genera of diphyllideans. In the context of the previous molecular phylogenetic analyses, it appears that the presence of

Structure and mechanical implications of the pectoral fin skeleton in the Longnose Skate (Chondrichthyes, Batoidea).

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Huang, Wei; Hongjamrassilp, Watcharapong; Jung, Jae-Young; Hastings, Philip A; Lubarda, Vlado A; McKittrick, Joanna

2017-03-15

Animal propulsion systems are believed to show high energy and mechanical efficiency in assisting movement compared to artificial designs. As an example, batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming via enlarged wing-like pectoral fins. The aim of this work is to illustrate the hierarchical structure of the pectoral fin of a representative batoid, the Longnose Skate (Raja rhina), and explain the mechanical implications of its structural design. At the macro level, the pectoral fins are comprised of radially oriented fin rays, formed by staggered mineralized skeletal elements stacked end-to-end. At the micro level, the midsection of each radial element is composed of three mineralized components, which consist of discrete segments (tesserae) that are mineralized cartilage and embedded in unmineralized cartilage. The radial elements are wrapped with aligned, unmineralized collagen fibers. This is the first report of the detailed structure of the ray elements, including the observation of a 3-chain mineralized tesserae. Structural analyses demonstrate that this configuration enhances stiffness in multiple directions. A two-dimensional numerical model based on the morphological analysis demonstrated that the tessera structure helps distributing shear, tensile and compressive stress more ideally, which can better support both lift and thrust forces when swimming without losing flexibility. Batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming by applying their enlarged wing-like pectoral fins. Previous studies have shown structural features and mechanical properties of the mineralized cartilage skeleton in various batoid fishes. However, the details of the pectoral fin structure at different length scales, as well as the relationship between the mechanical properties and structural design remains unknown. The present work illustrates the hierarchical structure of the pectoral fin of

Smooth-Water Landing Stability and Rough-Water Landing and Take-Off Behavior of a 1/13-Scale Model of the Consolidated Vultee Skate 7 Seaplane, TED No. NACA DE 338

Science.gov (United States)

McKann, Robert F.; Coffee, Claude W.; Arabian, Donald D.

1949-01-01

A model of the Consolidated Vultee Aircraft Corporation Skate 7 seaplane was tested in Langley tank no. 2. Presented without discussion in this paper are landing stability in smooth water, maximum normal accelerations occurring during rough-water landings, and take-off behavior in waves.

Engineering movement of qualified skiers-racers skating style in the current development of ski races

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Sergey Kotliar

2015-08-01

Full Text Available Purpose: analysis of technique of skiing skating style of leading sportsmen of the world. Material and Methods: research was conducted by means of analysis of video data and кинограмм of of skilled racing cross-country ski and biathlon of leading countries of the world. Results: the analysis of dynamic descriptions of technique of the same name ski motions educed the row of factors, from that sportsmen, what applied «Double Push» in the technique of skiing, increase speed of passing of short segments on 4-6%. Conclusions: implementation of «Double Push» can useful for racing cross-country ski and biathlon on competitions on a sprint, on rollers-ski and at implementation of short accelerations on distance, and also on a finish

Dipturus amphispinus sp. nov., a new longsnout skate (Rajoidei: Rajidae) from the Philippines.

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Last, Peter R; Alava, Moonyeen

2013-01-01

A new long-snouted skate, Dipturus amphispinus sp. nov., is formally described based on material caught in the Sulu Sea and later acquired from fish markets of the central and southern Philippines. It differs from its congeners in the western North Pacific, apart from D. wuhanlingi (East and South China Seas), in having a variably-defined, parallel row of posterolaterally directed lumbar thorns, and well-developed scapular thorns on each side of the disc. However, the paired rows of lumbar thorns are better defined in Dipturus amphispinus sp. nov. than in D. wuhanlingi, and these species also differ in some aspects of their morphometrics, meristics and squamation. Dipturus amphispinus sp. nov. displays marked sexual dimorphism with adult males having a relatively broader mouth, much longer teeth, a relatively shorter snout, head and disc, a taller first dorsal fin, and a proportionally longer posterior pelvic-fin lobe and tail, than adult-sized females.

Diet and scavenging habits of the smooth skate Dipturus innominatus.

Science.gov (United States)

Forman, J S; Dunn, M R

2012-04-01

The diet of smooth skate Dipturus innominatus was determined from examination of stomach contents of 321 specimens of 29·3-152·0 cm pelvic length, sampled from research and commercial trawlers at depths of 231-789 m on Chatham Rise, New Zealand. The diet was dominated by the benthic decapods Metanephrops challengeri and Munida gracilis, the natant decapod Campylonotus rathbunae and fishes from 17 families, of which hoki Macruronus novaezelandiae, sea perch Helicolenus barathri, various Macrouridae and a variety of discarded fishes were the most important. Multivariate analyses indicated the best predictors of diet variability were D. innominatus length and a spatial model. The diet of small D. innominatus was predominantly small crustaceans, with larger crustaceans, fishes and then scavenged discarded fishes increasing in importance as D. innominatus got larger. Scavenged discards were obvious as fish heads or tails only, or skeletal remains after filleting, often from pelagic species. Demersal fish prey were most frequent on the south and west Chatham Rise, in areas where commercial fishing was most active. Dipturus innominatus are highly vulnerable to overfishing, but discarding practices by commercial fishing vessels may provide a positive feedback to populations through improved scavenging opportunities. © 2012 NIWA. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Study on application of single-crystal ice 'Kurobe ice column' to high-speed skating rinks. Demonstration test result at Olympic memorial arena 'M wave' in Nagano city. Tankesshohyo 'Kurobe no hyojun' no kosoku skate link eno tekiyosei kenkyu. Naganoshi olympic kinen arina 'Emu Wave' deno jissho shiken kekka

Energy Technology Data Exchange (ETDEWEB)

Iwasaki, M. (Kansai Electric Power Co. Inc., Osaka (Japan))

1999-06-10

For high-speed low-friction skating rinks, research was made on sticking artificial ice columns (ice bamboo shoot). The ice columns were fabricated with the ice column production equipment equipped with 4-line water droplet dropping devices which were installed at intervals of 0.3m on both sides of a pathway of 200m long, 2.6m wide and 1.8m high in the lateral adit of Kurobegawa No.4 hydroelectric power station. The grown ice columns were processed for high-speed skating rinks through cutting, confirmation of single crystal and crystal orientation, slicing for every 7mm thickness and packaging. The ice columns were spread all over the rink while sliding them to prevent mixing of bubbles after spraying distilled water of nearly 25 degreesC onto base ices. In addition, hot water of nearly 40 degreesC was sprayed to produce the final ice rink of 30mm thick by nearly 5mm a day. The dynamic friction coefficient of the ice column rink reduced to 0.0038 by nearly 16% as compared with 0.0045 of conventional rinks. (NEDO)

A new skate genus Orbiraja (Rajiformes: Rajidae) from the Indo-West Pacific.

Science.gov (United States)

Last, Peter R; Weigmann, Simon; Dumale, Don

2016-11-02

Molecular analyses and information gleaned from an examination of the newly available adult male of the North-West Pacific skate, Okamejei jensenae Last & Lim, supported earlier concerns that the species might be mis-assigned. Morphological data based on this specimen supported its placement in a new genus Orbiraja that is assigned to the recently named Rostrorajini based on molecular evidence. This subgroup of the family Rajidae also includes Malacoraja, Neoraja, Rostroraja and an unresolved 'amphi-American Assemblage' (sensu McEachran & Dunn, 1998). Orbiraja is unique within the rajids in having the combination of three, very closely spaced median thorn rows on the tail, no dark-edged ventral pores, and a clasper skeleton with a prominent accessory terminal 3 cartilage formed by a medio-distal extension of the accessory terminal 2 cartilage. Its spiracle appears to be situated posteriorly with respect to the orbit. The group contains two other nominal species, Orbiraja powelli (Alcock) and O. philipi (Lloyd), and an un-named species from Indonesia that needs further investigation. Orbiraja jensenae is rediagnosed based on characteristics of the adult male.

The complete mitochondrial genome of the Korean skate: Hongeo koreana (Rajiformes, Rajidae).

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Jeong, Dageum; Kim, Sung; Kim, Choong-Gon; Lee, Youn-Ho

2014-12-01

The complete mitochondrial genome of the Korean skate, Hongeo koreana, the sole member of its genus, is investigated for the first time. The genome consists of 16,906 bp in length including 2 rRNA, 22 tRNA and 13 protein coding genes with the same gene order and structure of the genome as those of other Rajidae species. The overall nucleotide composition of the L-strand is A = 29.8%, C = 27.9%, T = 27.9% and G = 14.3%, showing a high A + T bias. The anti-G bias (6.0%) is more significant in the third codon position. Twelve of the 13 protein-coding genes use ATG as their start codon while the COX1 gene starts with GTG. For stop codon, ND3 and ND4 genes show incomplete stop codon T. The mitogenome sequence of H. koreana will provide important information on the evolution and the phylogenetic relation of the genus Hongeo in relation to the other genera of the family Rajidae.

Complete mitochondrial genome of the Yellow-spotted skate Okamejei hollandi (Rajiformes: Rajidae).

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Li, Weidong; Chen, Xiao; Liu, Wenai; Sun, Renjie; Zhou, Haolang

2016-07-01

The complete mitochondrial genome of the Yellow-spotted skate Okamejei hollandi was determined in this study. It is 16,974 bp in length and contains 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and one putative control region. The overall base composition is 30.5% A, 27.8% C, 14.0% G, and 27.8% T. There are 28 bp short intergenic spaces located in 12 gene junctions and 31 bp overlaps located in nine gene junctions in the whole mitogenome. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The lengths of 22 tRNA genes range from 68 (tRNA-Ser2) to 75 (tRNA-Leu1) bp. The origin of L-strand replication (OL) sequence (37 bp) was identified between the tRNA-Asn and tRNA-Cys genes. The control region is 1311 bp in length with high A + T and poor G content.

Implementation of an all-ages mandatory helmet policy for ice skating.

Science.gov (United States)

Thibault-Halman, Ginette; Fenerty, Lynne; Wheadon-Hore, Kathie; Walling, Simon; Cusimano, Michael D; Clarke, David B

2015-12-01

Ice skaters sustain a significant number of head injuries each winter. We are the first to implement an all-ages helmet policy at a university-based Canadian arena. We report our experience from a cross-sectional observational study as well as the policy's consequences on helmet use and skating participation. Educational programming was provided prior to policy implementation. Observations of helmet use, falls and skater demographics were conducted prior to education/implementation and after policy implementation. The number of skaters observed was essentially unchanged by the policy; 361 skaters were observed pre-implementation, while 358 were observed post-implementation during the same number of observation-hours. Pre-implementation, helmet use ranged from 97% among children under 12 to 10% among adults; post-implementation use in all skaters was 99%. Falls were observed among all age groups, with preponderance among those aged 4-12. An all-ages helmet policy was successful both in achieving helmet use among all skaters and in maintaining participation rates. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Roof radiation in indoor and covered outdoor skating rinks; Deckenstrahlung in Eishallen und ueberdeckten Ausseneisfeldern

Energy Technology Data Exchange (ETDEWEB)

Gachnang, F. [Eta Energietechnik GmbH, Winterthur (Switzerland); Mayer, H. [Gabathuler AG, Diessenhofen (Switzerland); Schweizer, A. [Baumgartner und Partner AG, Duebendorf (Switzerland); Krieg, J. [Zuercher Hochschule Winterthur, Winterthur (Switzerland)

2005-07-01

This report for the Swiss Federal Office of Energy (SFOE) presents the results of three measurement projects that examined the effect of low-emission materials mounted under the roofing in three different ice rinks on the energy consumption for the refrigeration and air-conditioning installations. In the first object, an indoor ice-hockey rink in Duebendorf, Switzerland, the effect of an aluminium cladding installed and the measurements made concerning the reduction of energy consumption are discussed. Their relevance to further covered ice rinks is examined. The second part takes a look at the effect of soiling and oxidation examined at a further skating rink in Kreuzlingen, Switzerland. The third part of the report examines three different roofing constructions newly installed over an outdoor rink. The findings of the three projects are discussed and recommendations are made.

A new Eastern Central Atlantic skate Raja parva sp. nov. (Rajoidei: Rajidae) belonging to the Raja miraletus species complex.

Science.gov (United States)

Last, Peter R; Séret, Bernard

2016-08-05

An investigation of combined CO1 and NADH2 data for rajid skates referable to Raja miraletus provided evidence that populations ranging from southern Africa to the North-East Atlantic and Mediterranean Sea, once considered to represent a cline, belong to a species complex consisting of at least four valid species. Raja miraletus appears to be confined to the Mediterranean Sea, and the North-East Atlantic from the Bay of Biscay south to Morocco and Madeira. The southernmost species, referable to the resurrected Raja ocellifera, occurs off southern Africa, off Namibia and from False Bay to Durban (South Africa). Two species occur off tropical West Africa, including Raja parva sp. nov. (Senegal, Liberia and Angola but is probably more widespread within the region), and another unidentified species needing further investigation. Raja cf. miraletus, confirmed from Mauritania and Senegal, appears to be a larger skate with a broader disc, more broadly pointed snout, larger spiracles, and a slightly longer and broader tail. Raja parva sp. nov. differs from nominal members of the complex in having an unusually long procaudal tail (exceeding 22% TL), as well as a combination of other external characters. Past investigators observed morphological and anatomical differences between these forms but these were thought to be due to intraspecific variability. They postulated that an upwelling at Cape Blanco (21°N) may have isolated the Mediterranean form (R. miraletus) from Mauritania-Senegal form (now known to be two species). Similarly, the Benguela Current and upwelling off Cape Frio (18°S) were thought to be responsible for separating the Angolan form (R. parva) and South African form (R. ocellifera).

Da Cidade Transfigurada à Cidade Transformada: Culturas Juvenis e a Prática do Skate (1970/1980 * Transfigured city to transformed city: Youth cultures and skateboard practice (1970/1980

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LEONARDO BRANDÃO

2013-03-01

Full Text Available Resumo: Com aproximadamente 4 milhões de praticantes no país, o skate vem se revelando uma das atividades corporais de maior visibilidade entre os jovens. No entanto, sua prática apresenta peculiaridades que merecem ser observadas. Sua relação com os usos da cidade talvez seja a principal delas. Neste artigo, discorremos sobre a constituição histórica do skate de rua a partir do estudo com revistas especializadas nesta atividade que foram publicadas durante as décadas de 1970 e 1980. Concluímos que a cidade, representada pelos skatistas como um paraíso de infindáveis possibilidades de diversão, acabou sendo transformada não somente pelo olhar transfigurativo do skatista, que lhe emprestou novos sentidos e funções, mas ela mesma acabou se modificando para disciplinar os filhos “rebeldes” que seu processo de urbanização ajudou a criar.Palavras-chave: História – Cidade – Skate. Abstract: With approximately 4 million practitioners in the country, skateboarding has been revealing one of the most visible body activities among youth. However, its practice has peculiarities which deserve to be observed. Its relationship with the uses of the city is perhaps the main one of them. In this article, we discuss the historical constitution of the street skateboard from the study of magazines specialized in this activity published during the 1970s and 1980s. We conclude that the city, represented by skateboarders as a paradise of endless possibilities for fun, ended up being transformed not only by the skater’s transfigurative look, which lent it new meanings and functions, but it  ended up itself changing to discipline their "rebellious" children  whcih its urbanization process helped create.Keywords: History – City – Skateboard.

Skating crossovers on a motorized flywheel: a preliminary experimental design to test effect on speed and on crossovers.

Science.gov (United States)

Smith, Aynsley M; Krause, David A; Stuart, Michael J; Montelpare, William J; Sorenson, Matthew C; Link, Andrew A; Gaz, Daniel V; Twardowski, Casey P; Larson, Dirk R; Stuart, Michael B

2013-12-01

Ice hockey requires frequent skater crossovers to execute turns. Our investigation aimed to determine the effectiveness of training crossovers on a motorized, polyethylene high-resistance flywheel. We hypothesized that high school hockey players training on the flywheel would perform as well as their peers training on ice. Participants were 23 male high-school hockey players (age 15-19 years). The study used an experimental prospective design to compare players who trained for 9 sessions on the 22-foot flywheel with players who trained for 9 sessions on a similarly sized on-ice circle. Both groups were compared with control subjects who were randomly selected from the same participant pool as those training on ice. All players were tested before and after their 3-week training regimens, and control subjects were asked to not practice crossovers between testing. Group 1 trained in a hockey training facility housing the flywheel, and group 2 trained in the ice hockey arena where testing occurred. Primary outcome measures tested in both directions were: (a) speed (time in seconds) required to skate crossovers for 3 laps of a marked face-off circle, (b) cadence of skating crossovers on the similarly sized circles, and (c) a repeat interval speed test, which measures anaerobic power. No significant changes were found between groups in on-ice testing before and after training. Among the group 1 players, 7 of 8 believed they benefited from flywheel training. Group 2 players, who trained on ice, did not improve performance significantly over group 1 players. Despite the fact that no significant on-ice changes in performance were observed in objective measures, players who trained on the flywheel subjectively reported that the flywheel is an effective cost-effective alternative to training on ice. This is a relevant finding when placed in context with limited availability of on-ice training.

Exploited but Unevaluated: DNA Barcoding Reveals Skates and Stingrays (Chordata, Chondrichthyes Species Landed in the Indonesian Fish Market

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Hawis Madduppa

2016-06-01

Full Text Available Reliable and precise species identification is important to fisheries management and conservation. However, many rays and skates in Indonesia are currently being exploited and landed into traditional fish market without a proper identification. Therefore, this study was conducted to identify species of skates and stingrays that were landed and traded in three fish markets in Indonesia (Palabuhanratu, Muara Saban, and Lampung using molecular techniques and to determine the conservation status of the identified species based on IUCN (International Union for Conservation of Nature and Natural Resources as well as defined by CITES (Convention on International Trade in Endangered Species. The mitochondrial cytochrome oxidase I (COI gene was amplified by polymerase chain reaction (PCR using a pair of primer, fish-BCL and fish-BCH. Of 29 tissue samples collected from the study sites, a total of five species were successfully identified: Dipturus chilensis (4, Himantura walga (1, Neotrygon kuhlii (11, Taeniura lymma (9 and Rhinoptera javanica (4. The Neighbor Joining phylogeny of mitochondrial lineages, based on partial COI gene sequences, the ingroup haplotypes were clustered into five main clades representing each species. The identified stingrays were being listed as vulnerable (D. chilensis and R. javanica, near threatened (H. walga and T. lymma, and data deficient (N. kuhlii by IUCN, with two species (D. chilensis and H. walga population were indicated decreased. Unfortunately, all of identified species have not been evaluated by CITES regarding their trade status. As a consequences, a valuable effort should be placed to create a scientific network for monitoring programmes not only on a local scale, and to make pressure on governments for adopting molecular techniques as tools for controlling and avoiding misidentification. Keywords: Mitochondrial DNA, Phylogeny, Coral Triangle, Taxonomy, Fisheries

Robust multiple cue fusion-based high-speed and nonrigid object tracking algorithm for short track speed skating

Science.gov (United States)

Liu, Chenguang; Cheng, Heng-Da; Zhang, Yingtao; Wang, Yuxuan; Xian, Min

2016-01-01

This paper presents a methodology for tracking multiple skaters in short track speed skating competitions. Nonrigid skaters move at high speed with severe occlusions happening frequently among them. The camera is panned quickly in order to capture the skaters in a large and dynamic scene. To automatically track the skaters and precisely output their trajectories becomes a challenging task in object tracking. We employ the global rink information to compensate camera motion and obtain the global spatial information of skaters, utilize random forest to fuse multiple cues and predict the blob of each skater, and finally apply a silhouette- and edge-based template-matching and blob-evolving method to labelling pixels to a skater. The effectiveness and robustness of the proposed method are verified through thorough experiments.

Function and Status of Music in Figure Skating%音乐在花样滑冰运动中的作用及地位

Institute of Scientific and Technical Information of China (English)

任玉梅

2011-01-01

花样滑冰运动的伴奏音乐是影响花样滑冰运动艺术表现的关键因素之一。对花样滑冰的伴奏音乐进行研究，认为：音乐可以激发花样滑冰运动员内在情感的表达，音乐可以成为花样滑冰运动员成套动作的编排的导向，音乐与花样滑冰动作完美结合可以有效提高运动员的艺术表现力。提出：鉴赏音乐、感悟音乐、表现音乐等培养花样滑冰运动员乐感的途径和手段。并总结出：形成花样滑冰音乐建设体系、依据项目特点科学选曲和把握项目规律恰当选曲等选取花样滑冰伴奏音乐的方法，为提高我国花样滑冰运动整体运动水平提供理论参考。%The accompanied music is a key influencing factor on a figure skaters＇ artistic expression. By studying the accompanied music of figure skating, the paper thinks that the music may inspire a skater to express his inner emotion and become his guidance of whole motions programming; the perfect combination of music and motions will effectively improve a skater＇s artistic performance. It suggest some means to develop a skater＇s musicality by musical appreciating, inspiring and showing. As a reference for enhancing the whole level of Chinese figure skating, it sums up some methods of choosing the accompanied music as follows ： form a system of figure skating music development, select the music according to the sports specialty.

Falling drops skating on a film of air

Science.gov (United States)

Rubinstein, Shmuel

2012-02-01

When a raindrop hits a window, the surface immediately becomes wet as the water spreads. Indeed, this common observation of a drop impacting a surface is ubiquitous in our everyday experience. I will show that the impact of a drop on a surface is a much richer, more complex phenomenon than our simple experience may suggests: To completely wet the surface the drop must first expel all the air beneath it; however, this does not happened instantaneously. Instead, a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the fluid spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate laterally outward at strikingly high velocities. Simultaneously, the wetting fluid spreads inward at a much slower velocity, trapping a bubble of air within the drop. However, these events occur at diminutive length scales and fleeting time scales; therefore, to visualize them we develop new imaging modalities that are sensitive to the behavior right at the surface and that have time resolution superior to even the very fastest cameras. These imaging techniques reveal that the ultimate wetting of the surface occurs through a completely new mechanism, the breakup of the thin film of air through a spinodal like dewetting process that breaks the cylindrical symmetry of the impact and drives an anomalously rapid spreading of a wetting front. These results are in accord with recent theoretical predictions and challenge the prevailing paradigm in which contact between the liquid and solid occurs immediately, and spreading is dominated by the dynamics of a single contact line.

Redescription and Molecular Assessment of Relationships Among Three Species of Echeneibothrium (Rhinebothriidea: Echeneibothriidae) Parasitizing the Yellownose Skate, Dipturus chilensis, in Chile.

Science.gov (United States)

Bueno, Veronica M; Caira, Janine N

2017-06-01

Much progress has recently been made in revising the taxonomic assignments of genera originally classified in the polyphyletic "Tetraphyllidea." Many of these genera, including Echeneibothrium, were accommodated in the order Rhinebothriidea. However, beyond this larger taxonomic action, little work has been conducted on this genus over the past 50 yr. Consequently, the criteria used for characterizing species of Echeneibothrium have lagged behind those typically used in more modern descriptions of elasmobranch-hosted cestode taxa. A series of collecting trips to Chile to obtain cestodes from the yellownose skate, Dipturus chilensis , provided a unique opportunity to apply modern morphological and molecular methods to investigate the 3 species of Echeneibothrium reported parasitizing this skate, specifically Echeneibothrium megalosoma, Echeneibothrium multiloculatum, and Echeneibothrium williamsi. In addition to redescribing all 3 species, using morphological data from light and scanning electron microscopy, maximum likelihood and bayesian inference phylogenetic analyses of the D1-D3 regions of the 28S rDNA gene were conducted to assess their relationships among other echeneibothriids for which comparable data are available. Sequencing of 59 specimens representing these 3 species of Echeneibothrium allowed us to assess the intra- and interspecific variation in the 28S rDNA gene. The redescriptions use standardized terminology for scolex morphology, proglottid anatomy, and microthrix forms and pattern; they also expand on the original descriptions to include data on scolex size, ovary size, vas deferens and vaginal configurations, testes arrangement, and genital pore position. Our morphological work led to a major reinterpretation of the scolex morphology with the recognition that all 3 species bear an apical bothridial sucker, rather than an apical loculus, prompting emendation of the diagnosis for the family Echeneibothriidae. The presence of a band of spinitriches

Detection of weak electric fields by sharks, rays, and skates.

Science.gov (United States)

Adair, Robert K.; Astumian, R. Dean; Weaver, James C.

1998-09-01

The elasmobranchs-sharks, rays, and skates-can detect very weak electric fields in their aqueous environment through a complex sensory system, the ampullae of Lorenzini. The ampullae are conducting tubes that connect the surface of the animal to its interior. In the presence of an electric field, the potential of the surface of the animal will differ from that of the interior and that potential is applied across the apical membrane of the special sensory cells that line the ampullae. The firing rate of the afferent neurons that transmit signals from the ampullae has been shown to vary with that potential. We show that those firing rates can be described quantitatively in terms of synchronous firing of the sensory cells that feed the neurons. We demonstrate that such synchronism follows naturally from a hypothetical weak cell-to-cell interaction that results in a self-organization of the sensory cells. Moreover, the pulse rates of those cells-and the neurons that service the cells-can be expected to vary with the imposed electric fields in accord with measured values through actions of voltage gated transmembrane proteins in the apical sector of the cell membranes that admit Ca(++) ions. We also present a more conjectural model of signal processing at the neuron level that could exploit small differences in firing rates of nerve fibers servicing different ampullae to send an unambiguous signal to the central nervous system of the animal. (c) 1998 American Institute of Physics.

Life-history traits of the long-nosed skate Dipturus oxyrinchus, from the central western Mediterranean Sea

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Antonello Mulas

2015-11-01

Full Text Available Skates are often considered vulnerable to overfishing because of their peculiar life cycle characteristics rendering them susceptible to overexploitation. In this regard, life-history traits of a by-catch species, the long-nosed skate Dipturus oxyrinchus (Linnaeus, 1758 from Sardinian waters, were investigated. The age, growth and reproduction were studied using 706 specimens sampled during experimental and commercial hauls (depths 76-671 metres. Females (10.4-117.5 cm in total length, TL attained larger sizes than males (14.5-99.5 cm TL. To evaluate the growth, a subsample of 130 individuals (76 females and 54 males was employed. The age was estimated through the annuli counts on sectioned vertebral centra. A high ageing reproducibility and precision was obtained (Index of Average Percent Error=6.56; %CV=8.9. Four models were applied on length at age data: the von Bertalanffy (VBGF, the Exponential, the Gompertz and the Logistic functions. According to the Akaike’s Information Criterion, the Gompertz model (L∞=127.5±4.9 cm; k=0.14±0.009; inflection point=3.97 y-1±0.9 provided the best fitting curve, showing a higher growth rate and a lower L∞ than what obtained with the VBGF (L∞=144.4±11.5 cm; k=0.08±0.001; t0=-1.09±0.23. The oldest female and male were 17 (115.5 cm TL and 15 years (96 cm TL, respectively. Lengths at maturity were 103.5 cm (14 years for females and 91 cm (12.1 years for males corresponding to 88 and 91.5% of the maximum observed length, respectively. The monthly evolution of maturity stages highlighted an extended reproductive cycle with spawning females and active males almost over the year, as confirmed by the Gonado-somatic Index. Ovarian fecundity reached a maximum of 26 yolked follicles. Given the relative abundance in Sardinian seas, we hope that these results will prove useful for the implementation of basic management measures in order to ensure the sustainability of catches of this species, particularly

Description and quantitative analysis of the dentition of the southern thorny skate Amblyraja doellojuradoi.

Science.gov (United States)

Delpiani, G; Spath, M C; Deli Antoni, M; Delpiani, M

2017-06-01

A description of the tooth morphology of 234 jaws from the southern thorny skate Amblyraja doellojuradoi in the south-west Atlantic Ocean is given. Seven rows of teeth were selected and length and width of each tooth in these rows were measured. It was found that functional series corresponds to the third teeth and the average width and length of these teeth were compared among jaws, maturity stages, sexes and rows. Generalized linear models were used to determine the subset of measures that most contribute to explain the variability between groups. It was observed that males have longer teeth than females, but the teeth of females are wider. These differences are attributed to reproductive behaviour, in which males bite females to hold them during copulation. This study provides a description of the teeth of A. doellojuradoi, supplying a valuable tool for identification of species. In addition, the establishment of the main variations observed in the dentition, improves the understanding of the species' biology. © 2017 The Fisheries Society of the British Isles.

Indoor air quality in ice skating rinks in Hong Kong

International Nuclear Information System (INIS)

Guo, H.; Lee, S.C.; Chan, L.Y.

2004-01-01

Indoor air quality in ice skating rinks has become a public concern due to the use of propane- or gasoline-powered ice resurfacers and edgers. In this study, the indoor air quality in three ice rinks with different volumes and resurfacer power sources (propane and gasoline) was monitored during usual operating hours. The measurements included continuous recording of carbon monoxide (CO), carbon dioxide (CO 2 ), total volatile organic compounds (TVOC), particulate matter with a diameter less than 2.5 μm (PM 2.5 ), particulate matter with diameter less than 10 μm (PM 10 ), nitric oxide (NO), nitrogen dioxide (NO 2 ), nitrogen oxide (NO x ), and sulfur dioxide (SO 2 ). The average CO, CO 2 , and TVOC concentrations ranged from 3190 to 6749 μg/m 3 , 851 to 1329 ppm, and 550 to 765 μg/m 3 , respectively. The average NO and NO 2 concentrations ranged from 69 to 1006 μg/m 3 and 58 to 242 μg/m 3 , respectively. The highest CO and TVOC levels were observed in the ice rink which a gasoline-fueled resurfacer was used. The highest NO and NO 2 levels were recorded in the ice rink with propane-fueled ice resurfacers. The air quality parameters of PM 2.5 , PM 10 , and SO 2 were fully acceptable in these ice rinks according to HKIAQO standards. Overall, ice resurfacers with combustion engines cause indoor air pollution in ice rinks in Hong Kong. This conclusion is similar to those of previous studies in Europe and North America

New morphological and molecular evidence confirm the presence of the Norwegian skate Dipturus nidarosiensis (Storm, 1881) in the Mediterranean Sea and extend its distribution to the western basin

OpenAIRE

RAMÍREZ-AMARO, S.; ORDINES, F.; ÁNGEL PUERTO, M.; GARCÍA, C.; RAMON, C.; TERRASA, B.; MASSUTÍ, E.

2017-01-01

The present study confirms the presence of the Norwegian skate Dipturus nidarosiensis (Storm, 1881) in the Mediterranean Sea, by means of morphological traits and molecular markers providing the first record of this species in the Alboran Sea. Cannas et al. (2010) reported D. nidarosiensis for the first time in the Mediterranean from specimens captured in the central western basin, but Ebert & Stehmann (2013) and Stehmann et al. (2015) considered these records "likely refer to the smaller mor...

Descriptions and revised key to the eggcases of the skates (Rajiformes: Rajidae) and catsharks (Carcharhiniformes: Scyliorhinidae) of the British Isles.

Science.gov (United States)

Gordon, Cat A; Hood, Ali R; Ellis, Jim R

2016-08-12

Updated descriptions and measurements for the eggcases of 10 rajiform and three scyliorhinid species occurring in the shelf seas around the British Isles are given, based on museum material, specimens collected during the 'Great Eggcase Hunt' (a Shark Trust recording project), and specimens obtained from fishery surveys. Quantitative data are given for Amblyraja radiata (n = 94), Dipturus batis (n = 24), D. cf. intermedia (n = 33), Leucoraja naevus (n = 94), Raja brachyura (n = 53), R. clavata (n = 52), R. microocellata (n = 57), R. montagui (n = 52), R. undulata (n = 52), Rostroraja alba (n = 5), Galeus melastomus (n = 7), Scyliorhinus canicula (n = 52) and S. stellaris (n = 58). An updated key for the identification of elasmobranch eggcases is provided, incorporating recent changes in skate taxonomy.

THE CORRELATION BETWEEN THE PHYSICAL TRAINING AND THE SPORT PERFORMANCES IN SPEED SKATING AT CHILDREN

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VAIDA Marius

2010-04-01

Full Text Available Sport practice at an early age is a problem of high actuality, this being debated intensely by specialists,the solving of the problem in cause being appreciated as a highly important factor in the general conception ofthe complex process of sport practice, in this process a very important role being held by the physical training.The present paper approaches the complex problem of the connection between the physical training andthe sport performances at children through an experiment realized on 6 speed skaters, 4 boys and 2 girls, withages of 8-9, experiment that had as purpose the demonstration of the importance of the multilateral physical training at skaters of an early age, of course without excluding the importance of the other factors necessary for superior results.Through the obtained results we proved that there is a direct connection between the physical training and the sport performances at children, knowing that the superior results in speed skating, on a long period, depend also by the training quality at an early age

Stomach contents and notes on the reproduction of the Onefin Skate Gurgesiella dorsalifera (Chondrichthyes: Rajidae off Southern Brazil

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Getulio Rincon

Full Text Available The Brazilian endemic deep-water onefin skate (Gurgesiella dorsalifera is a rare small species recently described in the 80's. No biological information is available on this species and its extremely restricted geographic distribution has been used to classify it as a vulnerable species under IUCN red list criteria. Twenty four specimens (115 to 207 mm disc width were captured off southern Brazilian coast at the region of Cape Santa Marta Grande (State of Santa Catarina by deep-water otter trawl (430-524 m. The analysis of stomach contents revealed an apparent opportunistic predation on juveniles of Urophycis brasiliensis (IRI = 6944, with an average total length of 21 mm, followed by mysidaceans (IRI = 2938, unidentified teleosts (IRI = 1969, the copepod Bradyidius plinioi (IRI = 393, and decapod crustaceans (IRI = 297. One mature female with 207 mm DW had two egg cases in its uteri.

Okamejei ornata n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the northwestern Indian Ocean off Socotra Islands

Science.gov (United States)

Weigmann, Simon; Stehmann, Matthias F. W.; Thiel, Ralf

2015-05-01

A new species of the Indo-Pacific skate genus Okamejei is described based on 10 specimens caught around the Socotra Islands (northwestern Indian Ocean). The type series of Okamejei ornata n. sp. was sampled during cruise 17 of RV 'Vityaz' along the deep western Indian Ocean in 1988/89. The new species represents the fifth species of Okamejei in the western Indian Ocean and differs from its congeners in having a unique dorsal pattern of variable dark brown spots encircled with beige pigment and arranged into rosettes. The dorsal ground color is ocher, but the anterior snout is dusky. Compared to congeners in the western Indian Ocean, the new species has a shorter preorbital snout length, a greater orbit diameter, fewer pectoral radials, an intermediate distance between first gill slits, and an intermediate number of upper jaw tooth rows.

Notoraja martinezi sp. nov., a new species of deepwater skate and the first record of the genus Notoraja Ishiyama, 1958 (Rajiformes: Arhynchobatidae) from the eastern Pacific Ocean.

Science.gov (United States)

Concha, Francisco J; Ebert, David A; Long, Douglas J

2016-04-05

A new arhynchobatid skate, Notoraja martinezi, sp. nov., is described from four specimens collected from the eastern Central Pacific from Costa Rica to Ecuador and between depths of 1256-1472 m. The new species is placed in the genus Notoraja based on the long and flexible rostrum and its proportionally long tail with respect to total length. This species is distinct from its congeners in the Western Pacific by the straight margins of its rostrum, long anterior lobes of pelvic fins, and its abundant and very well developed caudal thorns.

Nitric oxide production by nurse shark (Ginglymostoma cirratum) and clearnose skate (Raja eglanteria) peripheral blood leucocytes.

Science.gov (United States)

Walsh, Cathy J; Toranto, Jason D; Gilliland, C Taylor; Noyes, David R; Bodine, Ashby B; Luer, Carl A

2006-01-01

Reactive nitrogen intermediates, such as nitric oxide (NO), are important immunomodulators in vertebrate immune systems, but have yet to be identified as mediators of host defence in any member of class Chondrichthyes, the cartilaginous fishes. In the present study, production of NO by nurse shark (Ginglymostoma cirratum) peripheral blood leucocytes (PBL) stimulated with bacterial cell wall lipopolysaccharide (LPS) was investigated. PBL were cultured for 24 to 96 h following stimulation with LPS at concentrations ranging from 0 to 25 microg ml(-1), in both serum-supplemented and serum-free culture conditions. Production of NO was measured indirectly using the Griess reaction, with maximal NO production occurring after 72 h using 10% FBS and 10 microg LPS ml(-1). Application of these culture conditions to PBL from another cartilaginous fish (clearnose skate, Raja eglanteria) resulted in a similar NO response. Addition of a specific inhibitor of inducible nitric oxide synthase (iNOS), L-N(6)-(1-iminoethyl)lysine (L-NIL), resulted in a significant decrease in the production of NO by PBL from both species.

From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae? De la coexistencia a la exclusión competitiva: ¿Puede la sobrepesca cambiar el resultado de la competencia en rayas (Chondrichthyes, Rajidae?

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Natalia L Ruocco

2012-03-01

Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.La competencia por el alimento podría ser una fuerza importante detrás de los cambios en la estructura de las comunidades de rayas (Rajidae bajo explotación pesquera. Según esta hipótesis, las rayas pequeñas son liberadas de la competencia por las rayas de mayor tama

Life-history traits of the long-nosed skate Dipturus oxyrinchus.

Science.gov (United States)

Bellodi, A; Porcu, C; Cannas, R; Cau, Al; Marongiu, M F; Mulas, A; Vittori, S; Follesa, M C

2017-03-01

This work investigates life-history traits of the long-nosed skate Dipturus oxyrinchus, which is a common by-catch in Sardinian waters. The reproductive variables were analysed from 979 specimens sampled during scientific and commercial hauls. Females (10·4-117·5 cm total length, L T ) attained larger sizes than males (14·5-99·5 cm L T ). To evaluate age and growth, a sub-sample of 130 individuals (76 females and 54 males) were used. The age was estimated by annuli counts of sectioned vertebral centra. Four models were used for the length-at-age data: the von Bertalanffy, the exponential, the Gompertz and the logistic functions. According to the Akaike's information criterion, the Gompertz model seemed to provide the best fitting curve (L ∞ mean ± s.e.: 127·55 ± 4·90 cm, k: 0·14 ± 0·09, IP: 3·97 ± 0·90 years). The oldest female and male were aged 17 (115·5 cm L T ) and 15 years (96·0 cm L T ), respectively. Lengths at maturity were 103·5 cm for females and 91·0 cm for males, corresponding to 90% of the maximum observed length in both sexes. The monthly distribution of maturity stages highlighted an extended reproductive cycle, with spawning females and active males being present almost throughout the year, as confirmed by the gonado-somatic index. Ovarian fecundity reached a maximum of 26 yolked follicles with a mean ± s.e. size of 19·7 ± 6·5 mm. © 2016 The Fisheries Society of the British Isles.

The Jaap Eden ice skating rink was ahead of its time; Jubilerende Jaap Eden kunstijsbaan was tijd ver vooruit

Energy Technology Data Exchange (ETDEWEB)

Berends, E. [GEA Grenco, Den Bosch (Netherlands); Knipscheer, H.J.M. [Ingenieursbureau Knipscheer, Soest (Netherlands)

2012-01-15

In 1959, interest in a 400 meter track arose in the Netherlands as a result of the success of the Dutch skaters. The design and realization of the ice rink in Amsterdam was conducted by Grasso. On 22 December 2011, it was fifty years ago that the Jaap Eden ice skating rink was officially opened. A short overview is given of the construction, the cooling installation, safety and other special aspects and the renovation that took place in 1994. [Dutch] In 1959 ontstond er in Nederland als gevolg van de successen van de Nederlandse schaatsers interesse in een 400-meterbaan. Het ontwerp en de realisatie van een ijsbaan in Amsterdam werden uitgevoerd door Grasso. Op 22 december 2011 was het vijftig jaar geleden dat de Jaap Edenbaan officieel geopend werd. Een kort overzicht van de bouw, koelinstallatie, veiligheid, andere bijzondere aspecten en de renovatie in 1994.

Diel feeding chronology of the skate raja Agassizii (Müller & Henle (Pisces, Elasmobranchii on the continental shelf off Ubatuba, Southeastern Brazil

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Lucy Satiko Hashimoto Soares

1999-03-01

Full Text Available The diet and diel feeding pattern of the skate Raja agassizii were investigated through analysis of stomach contents. A total of 280 stomachs were collected by a series of hauls during a daily cycle in three periods, 8-10 January 1987, 22-24 July and 2-4 December 1988, from the inner continental shelf of the coastal ecosystem of Ubatuba, São Paulo State, Brazil (25º35'S; 45º00'W. According to the results of the stomach fullness and of the number of fresh prey, it is suggested that this species presents continuity in the feeding activity during a day. The stomach contents were mainly composed of crustaceans. Nematodes, polychaetes and fishes also occurred. No changes were observed in dietary composition between day and night.

Diet and feeding behaviour of longnosed skate Dipturus oxyrinchus.

Science.gov (United States)

Mulas, A; Bellodi, A; Cannas, R; Cau, Al; Cuccu, D; Marongiu, M F; Porcu, C; Follesa, M C

2015-01-01

A total of 255 longnosed skate Dipturus oxyrinchus caught in Sardinian waters (central-western Mediterranean Sea), was analysed with respect to fish total length (LT ), season and depth, in order to provide information on diet and feeding behaviour. Specimens ranging from 93 to 1153 mm LT , were collected at depths between 121 and 671 m, during experimental trawl surveys carried out from 2005 to 2010. The diet comprised crustaceans [prey specific index of relative importance (%IPSRI ) = 72·69], teleosts (%IPSRI  = 10·28) and molluscs (%IPSRI  = 10·94). Levins' index (Bi ) showed a narrow niche breadth (Bi  = 0·35). The mean ± s.e. trophic level (TL ) was 3·63 ± 0·50. The analysis showed major ontogenetic changes in the feeding behaviour. Early life stages were characterized by a benthic diet, which changed to benthopelagic during growth. Mysids, particularly Lophogaster typicus (%IPSRI  = 34·51), were the main prey items of immature individuals, replaced by euphausiids, mainly Meganyctiphanes norvegica (%IPSRI  = 13·19), in maturing fish. Crustaceans became less important in mature specimens, being replaced by molluscs (%IPSRI  = 28·99) and teleosts (%IPSRI  = 24·56). A concomitant increase of the TL was recorded (mean ± s.e. = 3·41 ± 0·44, 3·75 ± 0·54 and 4·28 ± 0·61 for immature, maturing and mature individuals). These feeding patterns ensured low levels of intraspecific competition. This study provides new information about the role that the D. oxyrinchus plays in the marine food chain and data now essential to formulate new and effective management plans for this species. © 2014 The Fisheries Society of the British Isles.

Veřejné bruslařské školy

OpenAIRE

Vejpravová, Dominika

2014-01-01

Title of the thesis: Public skating schools Aim: Mapping of teaching in public skating schools in the selected region. Comparison of methods of teaching skating at these schools on the base of observations and interviews with the coaches. The proposal optimal model of teaching skating suitable for use in public skating schools. The work covers the fundamentals of skating. Key words: Ice - skating, child, school.

30% of abatement of coldness needs + free re-heating at the skating rink of Chalons-en-Champagne; 30% de reduction des besoins de froid + rechauffage gratuit a la patinoire de Chalon-en-Champagne

Energy Technology Data Exchange (ETDEWEB)

Anon.

2005-12-01

The skating rink of Chalons-en-Champagne (France) is equipped with a air treatment system based on the use of a sensible energy transfer battery which reduces by 30% the coldness needs for dehumidification. This process uses part of the heat released by the condensers to generate ice. The result is a 30% reduction of the installed power and a 40% reduction of energy consumptions with respect to standard air treatment solutions. (J.S.)

Trends and Variability of the Outdoor Skating Season in Canada during 1951-2005

Science.gov (United States)

Damyanov, Nikolay Nikolaev

Climate change affects a range of human activities, including one of Canada's prime sources of entertainment: ice skating. Whether done recreationally or as hockey, its outdoor component is heavily dependent on weather and climate. Based on information obtained from public works officials from various Canadian cities, I have established a meteorological criterion for the initiation of an outdoor skating season (OSS) as the last day in a sequence of the first three consecutive fall/winter days with a maximum temperature below -5 °C. In addition, I derive a proxy of the OSS length, defined as the total number of days with a maximum temperature below -5 °C after the OSS start date and before the start of March. Using these filters, I have extracted the start dates and the lengths of the OSS for each year during the fifty-five year period 1951-2005 from a comprehensive daily temperature dataset (Vincent et al., 2002). For each station, I created time series of both the OSS start dates and OSS lengths, and calculated the magnitude, sign and statistical significance of the slopes of the best-fit lines to each time series. In order to establish a relationship of the OSS with large-scale climate patterns, I grouped stations into six climatic regions. Depending on location, I then tested each region for correlation with the Pacific North-American teleconnection pattern (PNA) or the North Atlantic Oscillation (NAO), using a composite analysis method. Lastly, I removed the signal due to these climate fluctuations from the OSS start date and length trends in order to determine how much of the variability was caused by these interannual climate oscillations. The results of the study indicate that most stations in British Columbia and southwest Alberta, as well as these in the southern Ontario/Quebc region have witnessed a progressively later onset of the OSS over time. The Prairies, northwest Canada, and some Maritime locales show the opposite trend, although the magnitudes

Race Factors Affecting Performance Times in Elite Long-Track Speed Skating.

Science.gov (United States)

Noordhof, Dionne A; Mulder, Roy C; de Koning, Jos J; Hopkins, Will G

2016-05-01

Analysis of sport performance can provide effects of environmental and other venue-specific factors in addition to estimates of within-athlete variability between competitions, which determines smallest worthwhile effects. To analyze elite long-track speed-skating events. Log-transformed performance times were analyzed with a mixed linear model that estimated percentage mean effects for altitude, barometric pressure, type of rink, and competition importance. In addition, coefficients of variation representing residual venue-related differences and within-athlete variability between races within clusters spanning ~8 d were determined. Effects and variability were assessed with magnitude-based inference. A 1000-m increase in altitude resulted in very large mean performance improvements of 2.8% in juniors and 2.1% in seniors. An increase in barometric pressure of 100 hPa resulted in a moderate reduction in performance of 1.1% for juniors but an unclear effect for seniors. Only juniors competed at open rinks, resulting in a very large reduction in performance of 3.4%. Juniors and seniors showed small performance improvements (0.4% and 0.3%) at the more important competitions. After accounting for these effects, residual venue-related variability was still moderate to large. The within-athlete within-cluster race-to-race variability was 0.3-1.3%, with a small difference in variability between male (0.8%) and female juniors (1.0%) and no difference between male and female seniors (both 0.6%). The variability in performance times of skaters is similar to that of athletes in other sports in which air or water resistance limits speed. A performance enhancement of 0.1-0.4% by top-10 athletes is necessary to increase medal-winning chances by 10%.

Prochristianella mattisi sp. n. (Trypanorhyncha: Eutetrarhynchidae) from the wedgenose skate, Dipturus whitleyi (Rajiformes: Rajidae), from Tasmania (Australia).

Science.gov (United States)

Schaeffner, Bjoern C; Beveridge, Ian

2013-07-01

A new species of Prochristianella Dollfus, 1946 is described from the spiral intestine of the wedgenose skate, Dipturus whitleyi (Iredale) (Rajiformes: Rajidae), off the north-western coast of Tasmania (Australia). Prochristianella mattisi sp. n. is characterised by an acraspedote scolex, two oval bothria, elongate, bent bulbs, a retractor muscle inserting at the base of each bulb and the presence of gland-cells within the bulbs and prebulbar organs. The tentacular armature is typical heteroacanthous, heteromorphous, with a characteristic basal oncotaxy and a metabasal armature with hooks first increasing and then decreasing in size along each principle row. It can be differentiated from other species of Prochristianella by a combination of morphological characters, such as the metabasal tentacular armature with eight hooks per principle row, a unique basal armature without enlarged hooks on the basal swelling and genital pores slightly posterior to the mid-line of the segment. The description of P. mattisi sp. n. increases the number of known species within Prochristianella to 20, eight of which occur in Australian waters. A key for the identification to species within Prochristianella is provided.

New tentacled leech Ceratobdella quadricornuta n. g., n. sp. (Hirudinida: Piscicolidae) parasitic on the starry skate Raja georgiana Norman from the Scotia Sea, Antarctica.

Science.gov (United States)

Utevsky, Andrei; Gordeev, Ilya

2015-07-01

A new fish leech Ceratobdella quadricornuta n. g., n. sp. (Hirudinida: Piscicolidae), a parasite of the Antarctic skate Raja georgiana Norman (Rajiformes: Rajidae) collected between the Falkland Islands and South Georgia Island in the Scotia Sea, is described and compared with related genera. Ceratobdella quadricornuta is characterised by an uncommon appearance of its anterior sucker bearing four well-developed tentacles and a unique combination of features of the reproductive and digestive systems: crop and intestine equally developed, posterior crop caeca separated; accessory glands, conductive tissue and external copulatory area lacking; common part of ejaculatory ducts (common atrium) voluminous and muscular, male copulatory bursa short, small ovisacs opening into female copulatory bursa (vagina).

Odlišnosti a identita in-line bruslení a bruslení na ledě

OpenAIRE

Rampich, Lukáš

2010-01-01

The main aim of the present study was to compare two types of skating - in-line skating and ice skating. An experiment method was used to evaluate an impact of in-line skating lessons on ice-skating skills in 12 and 13 years old children. We tried to find out which skills were transferable and which were not. The secondary aim was to suggest teaching methods of both above mentioned types of skating, point out uniquenesses of in-line skating, and apply them to improve the ice skating skills. T...

A building technical management system optimizes the energy recovery in a swimming pool-skating rink complex; Une GTB optimise la recuperation d'energie d'un complexe piscine-patinoire

Energy Technology Data Exchange (ETDEWEB)

Anon.

2003-04-01

The municipal skating rink of La Roche-sur-Yon (France) is supplied by a direct expansion refrigerating system. The energy recovered from this system allows to heat the sport complex made of a 25 m swimming pool and of a ludic pool. A technical management system ensures the control and management of the overall technical equipments. The automation of the system has permitted to optimize the energy costs which have remained practically unchanged since 20 years, even after the extension of the main pool and the increase of the number of visitors. (J.S.)

Reproductive biology of the spotback skate Atlantoraja castelnaui in the south-west Atlantic Ocean.

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Colonello, J C; García, M L; Lasta, C A; Menni, R C

2012-06-01

This study provides information on the reproduction of spotback skate Atlantoraja castelnaui. A total of 232 individuals (119 females and 113 males) were obtained from surveys carried out between 2003 and 2006, from the south-west Atlantic Ocean, between 34 and 42° S and <50 m deep; another 514 specimens (241 females and 273 males) were obtained between 2005 and 2007 from commercial fishery operations carried out in the same area and landings in the port of Mar del Plata, Argentina. Males ranged from 185 to 1250 mm total length (L(T) ) and females from 243 to 1368 mm L(T) . Length at maturity was estimated to be 980 mm for males and 1089 mm L(T) for females. Lack of variation of testis mass together with the continuous production of mature spermatocyst and spermatozoa in deferent ducts suggested that males can reproduce throughout the year. Females reproduced year-round with peaks of reproductive activity an integral part of a continuous cycle. This conclusion is corroborated by the seasonal variation of ovaries, oviducal gland and the occurrence of females with eggs in the uterus throughout the year. Results from this study indicate that A. castelnaui is very susceptible to fishery pressure. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Pacing and sprint performance in speed skating during a competitive season.

Science.gov (United States)

Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

2010-06-01

This study assessed the effect of time spent in several race sectors (S) on finishing time and determined the variance in distribution of skating time and in total race time for official 1000-m sprint races conducted during a competitive season. Total race and sector times for the first 200 m (S1) and the following two 400-m laps (S2 and S3) of 34 female and 31 male elite speed skaters performed during a series of World Cup Meetings were analyzed. Overall, skaters started fast, reached their peak in S2, and slowed down in S3, irrespective of race category considered (eg, rank of athlete, number of race, altitude of rink, starting lane). Regression analyses revealed that spending a shorter fraction of time in the last (women in S3: B = 239.1; P < .0001; men in S3: B = 201.5; P < .0001) but not in the first (women in S1: B = -313.1; P < .0001; men in S1: B = -345.6; P < .0001) race sector is associated with a short total race time. Upper- compared with lower-ranked skaters varied less in competition-to-competition sector and total race times (women: 0.02 to 0.33 vs 0.02 to 0.51; men: 0.01 to 0.15 vs 0.02 to 0.57). This study confirmed that skaters adopted a fast start pacing strategy during official 1000-m sprint races. However, analyses indicate that shortening time in the closing but not in the starting sector is beneficial for finishing fast. In addition, findings suggest that lower-ranked skaters should concentrate training on lowering their competition-to-competition variability in sector times.

Intraindividuální komparace vybraných koordinačních ukazatelů bruslařského kroku na ledě a při in-line

OpenAIRE

Hospůdka, Jakub

2010-01-01

4 Summary: Title: Intraindividual comparison of selected indicators of coordinating steps on the ice skating and in-line. Objective: Assessment of coordination relationship rate of the skating forward during ice hockey and inline skating. Methods: Surface electromyography combinated with kinematography analysis used synchronized video recording. Results: Kinesiological content of movement during ice skating and inline skating is not the same. The general stereotype of the skating step is sign...

Glutamate modulation of GABA transport in retinal horizontal cells of the skate

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Kreitzer, Matthew A; Andersen, Kristen A; Malchow, Robert Paul

2003-01-01

Transport of the amino acid GABA into neurons and glia plays a key role in regulating the effects of GABA in the vertebrate retina. We have examined the modulation of GABA-elicited transport currents of retinal horizontal cells by glutamate, the likely neurotransmitter of vertebrate photoreceptors. Enzymatically isolated external horizontal cells of skate were examined using whole-cell voltage-clamp techniques. GABA (1 mm) elicited an inward current that was completely suppressed by the GABA transport inhibitors tiagabine (10 μm) and SKF89976-A (100 μm), but was unaffected by 100 μm picrotoxin. Prior application of 100 μm glutamate significantly reduced the GABA-elicited current. Glutamate depressed the GABA dose-response curve without shifting the curve laterally or altering the voltage dependence of the current. The ionotropic glutamate receptor agonists kainate and AMPA also reduced the GABA-elicited current, and the effects of glutamate and kainate were abolished by the ionotropic glutamate receptor antagonist 6-cyano-7-nitroquinoxaline. NMDA neither elicited a current nor modified the GABA-induced current, and metabotropic glutamate analogues were also without effect. Inhibition of the GABA-elicited current by glutamate and kainate was reduced when extracellular calcium was removed and when recording pipettes contained high concentrations of the calcium chelator BAPTA. Caffeine (5 mm) and thapsigargin (2 nm), agents known to alter intracellular calcium levels, also reduced the GABA-elicited current, but increases in calcium induced by depolarization alone did not. Our data suggest that glutamate regulates GABA transport in retinal horizontal cells through a calcium-dependent process, and imply a close physical relationship between calcium-permeable glutamate receptors and GABA transporters in these cells. PMID:12562999

Application of environmental DNA to detect an endangered marine skate species in the wild.

Science.gov (United States)

Weltz, Kay; Lyle, Jeremy M; Ovenden, Jennifer; Morgan, Jessica A T; Moreno, David A; Semmens, Jayson M

2017-01-01

Environmental DNA (eDNA) techniques have only recently been applied in the marine environment to detect the presence of marine species. Species-specific primers and probes were designed to detect the eDNA of the endangered Maugean skate (Zearaja maugeana) from as little as 1 L of water collected at depth (10-15 m) in Macquarie Harbour (MH), Tasmania. The identity of the eDNA was confirmed as Z. maugeana by sequencing the qPCR products and aligning these with the target sequence for a 100% match. This result has validated the use of this eDNA technique for detecting a rare species, Z. maugeana, in the wild. Being able to investigate the presence, and possibly the abundance, of Z. maugeana in MH and Bathurst harbour (BH), would be addressing a conservation imperative for the endangered Z. maugeana. For future application of this technique in the field, the rate of decay was determined for Z. maugeana eDNA under ambient dissolved oxygen (DO) levels (55% saturation) and lower DO (20% saturation) levels, revealing that the eDNA can be detected for 4 and 16 hours respectively, after which eDNA concentration drops below the detection threshold of the assay. With the rate of decay being influenced by starting eDNA concentrations, it is recommended that samples be filtered as soon as possible after collection to minimize further loss of eDNA prior to and during sample processing.

Application of environmental DNA to detect an endangered marine skate species in the wild.

Directory of Open Access Journals (Sweden)

Kay Weltz

Full Text Available Environmental DNA (eDNA techniques have only recently been applied in the marine environment to detect the presence of marine species. Species-specific primers and probes were designed to detect the eDNA of the endangered Maugean skate (Zearaja maugeana from as little as 1 L of water collected at depth (10-15 m in Macquarie Harbour (MH, Tasmania. The identity of the eDNA was confirmed as Z. maugeana by sequencing the qPCR products and aligning these with the target sequence for a 100% match. This result has validated the use of this eDNA technique for detecting a rare species, Z. maugeana, in the wild. Being able to investigate the presence, and possibly the abundance, of Z. maugeana in MH and Bathurst harbour (BH, would be addressing a conservation imperative for the endangered Z. maugeana. For future application of this technique in the field, the rate of decay was determined for Z. maugeana eDNA under ambient dissolved oxygen (DO levels (55% saturation and lower DO (20% saturation levels, revealing that the eDNA can be detected for 4 and 16 hours respectively, after which eDNA concentration drops below the detection threshold of the assay. With the rate of decay being influenced by starting eDNA concentrations, it is recommended that samples be filtered as soon as possible after collection to minimize further loss of eDNA prior to and during sample processing.

The impact of dry-land sprint start training on the short track speed skating start.

Science.gov (United States)

Haug, William B; Drinkwater, Eric J; Cicero, Nicholas J; Barthell, J Anthony; Chapman, Dale W

2017-05-05

This investigation sought to determine the effects of dry-land sprint start training on short track speed skating (STSS) start performance. Nine highly trained short track athletes completed a control period of normal STSS training followed by a four-week training intervention. Before and after the control and intervention periods, athletes performed three electronically timed dry-land and on-ice 14.43 m maximal sprint start efforts. The intervention consisted of two sprint sessions per week consisting of nine electronically timed 14.43 m dry-land sprint starts in addition to normal STSS training. The control period resulted in no substantial change in on-ice start performance (Mean Δ: -0.01 s, 95% Confidence Limits (CL): -0.08 to 0.05 s; Effect Size (ES): -0.05; Trivial) however, a small change was observed in dry-land start performance (Mean Δ: -0.07 s, 95% CL: -0.13 to -0.02 s; ES: -0.49). Following brief specific dry-land sprint start training a small improvement was observed in both on-ice (Mean Δ: -0.07 s, 95% CL: -0.13 to -0.01 s; ES: -0.33) and dry-land (Mean Δ: -0.04 s, 95% CL: -0.09 to 0.00 s; ES: -0.29) start performance. This investigation suggests STSS start performance can be improved through a brief dry-land sprint start training program.

Objectifying Tactics: Athlete and Race Variability in Elite Short-Track Speed Skating.

Science.gov (United States)

Konings, Marco J; Hettinga, Florentina J

2018-02-01

To objectively capture and understand tactical considerations in a race, the authors explored whether race-to-race variation of an athlete and the variation of competitors within a race could provide insight into how and when athletes modify their pacing decisions in response to other competitors. Lap times of elite 500-, 1000-, and 1500-m short-track speed-skating competitions from 2011 to 2016 (N = 6965 races) were collected. Log-transformed lap and finishing times were analyzed with mixed linear models. To determine within-athlete race-to-race variability, athlete identity (between-athletes differences) and the residual (within-athlete race-to-race variation) were added as random effects. To determine race variability, race identity (between-races differences) and the residual (within-race variation) were added as random effects. Separate analyses were performed for each event. Within-athlete race-to-race variability of the finishing times increased with prolonged distance of the event (500-m, CV = 1.6%; 1000-m, CV = 2.8%; 1500-m, CV = 4.1%), mainly due to higher within-athlete race-to-race variability in the initial phase of 1000-m (3.3-6.9%) and 1500-m competitions (8.7-12.2%). During these early stages, within-race variability is relatively low in 1000-m (1.1-1.4%) and 1500-m (1.3-2.8%) competitions. The present study demonstrated how analyses of athlete and race variability could provide insight into tactical pacing decisions in sports where finishing position is emphasized over finishing time. The high variability of short-track skaters is a result of the decision to alter initial pacing behavior based on the behavior of other competitors in their race, emphasizing the importance of athlete-environment interactions in the context of pacing.

Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae, off Uruguay and northern Argentina

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Santiago A. Barbini

Full Text Available ABSTRACT The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS and crabs in the north region (38º - 41ºS. Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.

Metodika pro rozvoj techniky bruslení na bruslařském trenažeru

OpenAIRE

Soukup, Jan

2016-01-01

Title: Methodology for development of skating technique on a skatemill Goals: The objective of the present study is to compile available methodology knowledge re-garding the improvement of skating technique using a skatemill, and to analyse the pro-gress of skating technique in selected ice-hockey players during a comprehensive train-ing programme, where a skating simulator is used. Keywords: Ice Hockey, skatemill, kinematic analysis, hockey skills, motoric skills, ska-ting, modern aids. Powe...

Pacing Behavior and Tactical Positioning in 500- and 1000-m Short-Track Speed Skating.

Science.gov (United States)

Noorbergen, Olaf S; Konings, Marco J; Micklewright, Dominic; Elferink-Gemser, Marije T; Hettinga, Florentina J

2016-09-01

To explore pacing behavior and tactical positioning during the shorter 500- and 1000-m short-track competitions. Lap times and intermediate rankings of elite 500- and 1000-m short-track-skating competitors were collected over the 2012-13 season. First, lap times were analyzed using a MANOVA, and for each lap, differences between sex, race type, final ranking, and stage of competition were determined. Second, Kendall tau-b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined. Top-placed athletes appeared faster than bottom-placed athletes in every lap in the 500-m, while in the 1000-m no differences were found until the final 4 laps (P < .05). Correlations between intermediate and final rankings were already high at the beginning stages of the 50-m (lap 1: r = .59) but not for the 1000-m (lap 1: r = .21). Although 500- and 1000-m short-track races are both relatively short, fundamental differences in pacing behavior and tactical positioning were found. A fast-start strategy seems to be optimal for 500-m races, while the crucial segment in 1000-m races seems to be from the 6th lap to the finish line (ie, after ± 650 m). These findings provide evidence to suggest that athletes balance between choosing an energetically optimal profile and the tactical and positional benefits that play a role when riding against an opponent, as well as contributing to developing novel insights in exploring athletic behavior when racing against opponents.

Comparison of sport-specific and non-specific exercise testing in inline speed skating.

Science.gov (United States)

Stangier, Carolin; Abel, Thomas; Mierau, Julia; Gutmann, Boris; Hollmann, Wildor; Struder, Heiko K

2016-04-01

The most effective way to measure exercise performance in inline speed skating (ISS) has yet to be established. Generally most athletes are examined by means of traditional but unspecific cycling (CYC) or running (RUN) testing. The present study investigates whether a sport-specific incremental test in ISS reveals different results. Eight male top level inline speed skaters (age: 30±4 years; 65.4±6.3 mL∙kg-1∙min-1, training: 12-14 h/week) performed three incremental exhaustive tests in a randomized order (ergometer CYC, field RUN, field ISS). During the tests, heart rate (HR), oxygen uptake (V̇O2, energy expenditure (EE) and blood lactate concentration (BLC) were measured. Analysis of variance revealed no significant differences for peak HR (187±9, 191±9, 190±9; P=0.75), BLC (10.9±2.3, 10.8±2.4, 8.5±3.2; P=0.25), V̇O2 (65.4±6.3, 66.8±3.5, 66.4±6.5; P=0.91) and EE (1371±165, 1335±93, 1439±196; P=0.51) between ISS and CYC or RUN test. Similar results appeared for HR and V̇O2 at submaximal intensities (2 and 4 mmol·L-1 BLC; P≥0.05). Small to moderate effect sizes 0.3-0.87 and considerable variability of differences between the exercise modes (mean bias range between 1% and 17% with 95% limits of agreement between 3% and 33%) among submaximal and maximal results limit the comparability of the three tests. Consequently, CYC and RUN tests may be considered as qualified alternatives for a challenging ISS test. However a sport-specific test should be conducted in cases of doubt, or when precision is required (e.g. for elite athletes or scientific studies).

Characterization of the functional and anatomical differences in the atrial and ventricular myocardium from three species of elasmobranch fishes: smooth dogfish (Mustelus canis), sandbar shark (Carcharhinus plumbeus), and clearnose skate (Raja eglanteria).

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Larsen, Julie; Bushnell, Peter; Steffensen, John; Pedersen, Morten; Qvortrup, Klaus; Brill, Richard

2017-02-01

We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca 2+ release from the sarcoplasmic reticulum (SR) with ryanodine and thapsigargin and measuring the resultant changes in contraction-relaxation parameters and the force-frequency relationship at 20 °C and 30 °C. We also examined ultrastructural differences with electron microscopy. In tissues from smooth dogfish, net force (per cross-sectional area) and measures of the speeds of contraction and relaxation were all higher in atrial than ventricular myocardium at both temperatures. Atrial-ventricular differences were evident in the other two species primarily in measures of the rates of contraction and relaxation. Ryanodine-thapsigargin treatment reduced net force and its maximum positive first derivative (i.e., contractility), and increased time to 50 % relaxation in atrial tissue from smooth dogfish at 30 °C. It also increased times to peak force and half relaxation in clearnose skate atrial and ventricular tissue at both temperatures, but only in atrial tissue from sandbar shark at 30 °C; indicating that SR involvement in excitation-contraction (EC) coupling is species- and temperature-specific in elasmobranch fishes, as it is in teleost fishes. Atrial and ventricular myocardium from all three species displayed a negative force-frequency relationship, but there was no evidence that SR involvement in EC coupling was influenced by heart rate. SR was evident in electron micrographs, generally located in proximity to mitochondria and intercalated discs, and to a lesser extent between the myofibrils; with mitochondria being more numerous in ventricular than atrial myocardium in all three species.

A Case Study Of Applying Infrared Thermography To Identify A Coolant Leak In A Municipal Ice Skating Rink

Science.gov (United States)

Wallace, Jay R.

1989-03-01

This paper deals with the application of infrared imaging radiometry as a diagnostic inspection tool for locating a concealed leak in the refrigeration system supplying glycol coolant to the arena floor of an ice skating rink in a municipal coliseum facility. Scanning approximately 10 miles of black iron tubing embedded in the arena floor resulted in locating a leak within the supply/return side of the system. A secondary disclosure was a restriction to normal coolant flow in some delivery loops caused by sludge build-up. Specific inspection procedures were established to enhance temperature differentials suitable for good thermal imaging. One procedure utilized the temperature and pressure of the city water supply; a second the availability of 130F hot water from the facility's boiler system; and a third the building's own internal ambient temperature. Destructive testing and other data collection equipment confirmed the thermographic findings revealing a section of corrosion damaged pipe. Repair and flushing of the system was quickly completed with a minimum of construction costs and inconvenience. No financial losses were incurred due to the interruption of scheduled revenue events. Probable cause for the shutdown condition was attributed to a flawed installation decision made 15 years earlier during the initial construction stage.

Rapid Development of Microsatellite Markers with 454 Pyrosequencing in a Vulnerable Fish, the Mottled Skate, Raja pulchra

Science.gov (United States)

Kang, Jung-Ha; Park, Jung-Youn; Jo, Hyun-Su

2012-01-01

The mottled skate, Raja pulchra, is an economically valuable fish. However, due to a severe population decline, it is listed as a vulnerable species by the International Union for Conservation of Nature. To analyze its genetic structure and diversity, microsatellite markers were developed using 454 pyrosequencing. A total of 17,033 reads containing dinucleotide microsatellite repeat units (mean, 487 base pairs) were identified from 453,549 reads. Among 32 loci containing more than nine repeat units, 20 primer sets (62%) produced strong PCR products, of which 14 were polymorphic. In an analysis of 60 individuals from two R. pulchra populations, the number of alleles per locus ranged from 1–10, and the mean allelic richness was 4.7. No linkage disequilibrium was found between any pair of loci, indicating that the markers were independent. The Hardy–Weinberg equilibrium test showed significant deviation in two of the 28 single-loci after sequential Bonferroni’s correction. Using 11 primer sets, cross-species amplification was demonstrated in nine related species from four families within two classes. Among the 11 loci amplified from three other Rajidae family species; three loci were polymorphic. A monomorphic locus was amplified in all three Rajidae family species and the Dasyatidae family. Two Rajidae polymorphic loci amplified monomorphic target DNAs in four species belonging to the Carcharhiniformes class, and another was polymorphic in two Carcharhiniformes species. PMID:22837688

Rapid development of microsatellite markers with 454 pyrosequencing in a vulnerable fish, the mottled skate, Raja pulchra.

Science.gov (United States)

Kang, Jung-Ha; Park, Jung-Youn; Jo, Hyun-Su

2012-01-01

The mottled skate, Raja pulchra, is an economically valuable fish. However, due to a severe population decline, it is listed as a vulnerable species by the International Union for Conservation of Nature. To analyze its genetic structure and diversity, microsatellite markers were developed using 454 pyrosequencing. A total of 17,033 reads containing dinucleotide microsatellite repeat units (mean, 487 base pairs) were identified from 453,549 reads. Among 32 loci containing more than nine repeat units, 20 primer sets (62%) produced strong PCR products, of which 14 were polymorphic. In an analysis of 60 individuals from two R. pulchra populations, the number of alleles per locus ranged from 1-10, and the mean allelic richness was 4.7. No linkage disequilibrium was found between any pair of loci, indicating that the markers were independent. The Hardy-Weinberg equilibrium test showed significant deviation in two of the 28 single-loci after sequential Bonferroni's correction. Using 11 primer sets, cross-species amplification was demonstrated in nine related species from four families within two classes. Among the 11 loci amplified from three other Rajidae family species; three loci were polymorphic. A monomorphic locus was amplified in all three Rajidae family species and the Dasyatidae family. Two Rajidae polymorphic loci amplified monomorphic target DNAs in four species belonging to the Carcharhiniformes class, and another was polymorphic in two Carcharhiniformes species.

Trophic ecology of yellownose skate Zearaja chilensis, a top predator in the south-western Atlantic Ocean.

Science.gov (United States)

Belleggia, M; Andrada, N; Paglieri, S; Cortés, F; Massa, A M; Figueroa, D E; Bremec, C

2016-03-01

The diet and trophic level (TL ) of the yellownose skate Zearaja chilensis in the south-western Atlantic Ocean (35°-54° S), and how these varied in relation to body size, sex, maturity stage, depth and region were determined by analysis of stomach contents. From 776 specimens analysed, 671 (86·5%) ranging from 180 to 1190 mm total length (LT ) had prey in their stomachs. The diet was dominated by fishes, mainly the notothenioid Patagonotothen ramsayi and the Argentine hake Merluccius hubbsi. The consumption of fishes and crabs increased with increasing predator size, and these preys were more important in the north than in the south. Isopods and other crustaceans were consumed more in the south and their consumption decreased as the size of Z. chilensis increased. The TL of Z. chilensis increased with LT from 4·29 to 4·59 (mean 4·53), confirming their ecological role as a top predator. The small and large size classes exhibited a low diet overlap and the highest spatial segregation, whereas medium and large specimens had higher co-occurrence and dietary overlap indices. A clear distinction in tooth shape was noted between sexes in adult specimens, with males having longer cusps. This sexual heterodonty may be related to reproductive behaviour, increasing the grasping ability of males during courtship, because there were no differences in diet between the sexes. © 2016 The Fisheries Society of the British Isles.

Distribution of the species of Dipturus Rafinesque (Rajidae, Rajinae, Rajini off Brazil and first record of the Caribbean skate D. teevani (Bigelow & Schroeder, in the Western South Atlantic

Directory of Open Access Journals (Sweden)

Ulisses Leite Gomes

2001-03-01

Full Text Available The Caribbean skate Dipturus teevani (Bigelow & Schroeder, 1951 is recorded for the first time from Brazilian waters. The specimen was collected in the continental slope off Bahia State. With this record, four species of Dipturus Rafinesque, 1810 are known from Brazil: D. chilensis (Guichenot, 1848, D. leptocauda (Kreft & Stehmann, 1975, D. trachyderma (Krefft & Stehmann, 1975 and D. teevani (Bigelow & Schroeder, 1951. They are typical inhabitants of deep waters between the outer shelf edge (195-200m and the slope (more than 500m. Although morphologically conservative, the species of Dipturus can be distinguished from each other by the number of dorsal and nuchal thorns, the number of caudal thorns, dorsal and ventral spinulation and specific total length. An identification key for the species of Dipturus recorded from Brazil is presented.

Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate

Science.gov (United States)

Molina, Anthony J A; Verzi, Michael P; Birnbaum, Andrea D; Yamoah, Ebenezer N; Hammar, Katherine; Smith, Peter J S; Malchow, Robert Paul

2004-01-01

Self-referencing H+-selective microelectrodes were used to measure extracellular H+ fluxes from horizontal cells isolated from the skate retina. A standing H+ flux was detected from quiescent cells, indicating a higher concentration of free hydrogen ions near the extracellular surface of the cell as compared to the surrounding solution. The standing H+ flux was reduced by removal of extracellular sodium or application of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), suggesting activity of a Na+–H+ exchanger. Glutamate decreased H+ flux, lowering the concentration of free hydrogen ions around the cell. AMPA/kainate receptor agonists mimicked the response, and the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) eliminated the effects of glutamate and kainate. Metabotropic glutamate agonists were without effect. Glutamate-induced alterations in H+ flux required extracellular calcium, and were abolished when cells were bathed in an alkaline Ringer solution. Increasing intracellular calcium by photolysis of the caged calcium compound NP-EGTA also altered extracellular H+ flux. Immunocytochemical localization of the plasmalemma Ca2+–H+-ATPase (PMCA pump) revealed intense labelling within the outer plexiform layer and on isolated horizontal cells. Our results suggest that glutamate modulation of H+ flux arises from calcium entry into cells with subsequent activation of the plasmalemma Ca2+–H+-ATPase. These neurotransmitter-induced changes in extracellular pH have the potential to play a modulatory role in synaptic processing in the outer retina. However, our findings argue against the hypothesis that hydrogen ions released by horizontal cells normally act as the inhibitory feedback neurotransmitter onto photoreceptor synaptic terminals to create the surround portion of the centre-surround receptive fields of retinal neurones. PMID:15272044

The relationship between start performance and race outcome in elite 500-m short-track speed skating.

Science.gov (United States)

Haug, William B; Drinkwater, Eric J; Mitchell, Lachlan J; Chapman, Dale W

2015-10-01

Initial short-track speed-skating 14-m start performance has substantial influence on 500-m race outcome at the international level, yet the relationship has not been systematically quantified. The purpose of this investigation was to examine the relationship between rank position entering first corner (RPEFC) and race outcome and to understand how this relationship changes with competition round and absolute race intensity. Data were compiled from 2011-2014 World Cup seasons and 2010 and 2014 Olympic Winter Games. Association between RPEFC and race outcome was determined through Kendall tau-rank correlations. A visual comparison was made of how the relationship changes with relative competition level (race tau correlations were sorted by competition round) and with race intensity (race tau correlations were sorted by within-event winning time). A very large relationship between RPEFC and race outcome was observed (correlations for cohort, τ = .60; men, τ = .53; women, τ = .67). When examined by competition round (quarter- to A-finals), no substantial change in relationship was observed (men, τ = .57-.46; women, τ = .73-.53). However, when the start-performance relationship was considered by within-event winning time, the relationship strength increased with decreasing time (men, τ = .61 to .46; women, τ = .76 to .57; fastest to 7th- and 8th-fastest combined, respectively). These results establish and quantify RPEFC as an important aspect of elite short-track 500-m race outcome. RPEFC as an indicator of race outcome becomes increasingly important with absolute race intensity, suggesting that RPEFC capability is a discriminating factor for competitors of similar top speed and speed endurance.

Skader ved brug af løbehjul

DEFF Research Database (Denmark)

Larsen, Michael Hareskov; Nielsen, Henrik Toft; Larsen, Søren Erik

2002-01-01

Since the beginning of the nineties, skate-boards, in-liners, roller skates, and during the past years non-powered scooters have gained increasing popularity. This surge of enthusiasm has resulted in an increasing number of injuries involving scooters.......Since the beginning of the nineties, skate-boards, in-liners, roller skates, and during the past years non-powered scooters have gained increasing popularity. This surge of enthusiasm has resulted in an increasing number of injuries involving scooters....

Performance Characteristics of Long-Track Speed Skaters : A Literature Review

NARCIS (Netherlands)

Konings, Marco J.; Elferink-Gemser, Marije T.; Stoter, Inge K.; van der Meer, Dirk; Otten, Egbert; Hettinga, Florentina J.

Speed skating is an intriguing sport to study from different perspectives due to the peculiar way of motion and the multiple determinants for performance. This review aimed to identify what is known on (long-track) speed skating, and which individual characteristics determine speed skating

Giving the force direction: Analysis of speed skater push off forces with respect to an inertial coordinate system

OpenAIRE

van der Kruk, E.; van der Helm, F.C.T.; Schwab, A.L.; Veeger, H.E.J.

2016-01-01

Pushoff in speed skating requires an extensive motion strategy. During speed skating the skater continuously changes the lean and steering angle of the skate and therewith the direction of push-off, The forces in an inertial coordinate system can give insight into what amount of the push-off force is directed into the forward motion. In this paper we present the preliminary results of a study on the global forces in speed skating. From a mechanical viewpoint, increasing the lean angle of the ...

The effect of klapskate hinge position on push-off performance: a simulation study

OpenAIRE

Houdijk, J.H.P.; Bobbert, M.F.; de Koning, J.J.; de Groot, G.

2003-01-01

Purpose: The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. Method: For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this m...

From biomechanical theory to application in top sports: The Klapskate story

NARCIS (Netherlands)

de Koning, J.J.; Houdijk, J.H.P.; de Groot, G.; Bobbert, M.F.

2000-01-01

The development of the new skate design specifically the klapskate in a historical and scientific perspective is described. Reasons why it took so long for top athletes to use the new skate design is explained. The klapskate demonstrated its advantage over conventional skates and proved its

Giving the force direction : Analysis of speed skater push off forces with respect to an inertial coordinate system

NARCIS (Netherlands)

van der Kruk, E.; van der Helm, F.C.T.; Schwab, A.L.; Veeger, H.E.J.

2016-01-01

Pushoff in speed skating requires an extensive motion strategy. During speed skating the skater continuously changes the lean and steering angle of the skate and therewith the direction of push-off, The forces in an inertial coordinate system can give insight into what amount of the push-off force

Development and Validation of a Method for Determining Tridimensional Angular Displacements with Special Applications to Ice Hockey Motions.

Science.gov (United States)

Gagnon, Micheline; And Others

1983-01-01

A method for determining the tridimensional angular displacement of skates during the two-legged stop in ice hockey was developed and validated. The angles were measured by geometry, using a cinecamera and specially equipped skates. The method provides a new tool for kinetic analyses of skating movements. (Authors/PP)

In-line bruslení jako tréninkový prostředek letní přípravy v ledním hokeji

OpenAIRE

Gebhart, Martin

2014-01-01

TITLE: In-line skating as a training tool for summer preparation in ice hockey AUTHOR: Martin Gebhart DEPARTMENT: Department of Physical Education SUPERVISOR: PaedDr. Ladislav Pokorný ABSTRACT: Bachelor thesis surveys the use of in-line skating in the summer preparing for ice hockey. Mapping the use of in-line skating is based on a survey questionnaire. The aim is to determine for what purpose is in-line skating used in summer training. The paper focuses on the development of motor skills in ...

76 FR 53840 - Fisheries of the Exclusive Economic Zone Off Alaska; Other Rockfish, Other Flatfish, Sharks, and...

Science.gov (United States)

2011-08-30

... Flatfish, Sharks, and Skates in the Bering Sea and Aleutian Islands Management Area AGENCY: National Marine...-specified reserve to the initial total allowable catch of other rockfish, other flatfish, sharks, and skates..., BSAI other flatfish, BSAI sharks, and BSAI skates was established as 425 metric tons (mt), 2,550 mt, 43...

Biosynthesis of 1α-hydroxycorticosterone in the winter skate Leucoraja ocellata: evidence to suggest a novel steroidogenic route.

Science.gov (United States)

Wiens, J; Ho, R; Brassinga, A K; Deck, C A; Walsh, P J; Ben, R N; Mcclymont, K; Charlton, T; Evans, A N; Anderson, W G

2017-07-01

The present study explores the ability of intracellular bacteria within the renal-inter-renal tissue of the winter skate Leucoraja ocellata to metabolize steroids and contribute to the synthesis of the novel elasmobranch corticosteroid, 1α-hydroxycorticosterone (1α-OH-B). Despite the rarity of C1 hydroxylation noted in the original identification of 1α-OH-B, literature provides evidence for steroid C1 hydroxylation by micro-organisms. Eight ureolytic bacterial isolates were identified in the renal-inter-renal tissue of L. ocellata, the latter being the site of 1α-OH-B synthesis. From incubations of bacterial isolates with known amounts of potential 1α-OH-B precursors, one isolate UM008 of the genus Rhodococcus was seen to metabolize corticosteroids and produce novel products via HPLC analysis. Cations Zn 2+ and Fe 3+ altered metabolism of certain steroid precursors, suggesting inhibition of Rhodococcus steroid catabolism. Genome sequencing of UM008 identified strong sequence and structural homology to that of Rhodococcus erythropolis PR4. A complete enzymatic pathway for steroid-ring oxidation as documented within other Actinobacteria was identified within the UM008 genome. This study highlights the potential role of Rhodococcus bacteria in steroid metabolism and proposes a novel alternative pathway for 1α-OH-B synthesis, suggesting a unique form of mutualism between intracellular bacteria and their elasmobranch host. © 2017 The Fisheries Society of the British Isles.

New African species of Echinobothrium (Cestoda: Diphyllidea) and implications for the identities of their skate hosts.

Science.gov (United States)

Caira, J N; Rodriguez, N; Pickering, M

2013-10-01

Two new species of diphyllidean cestodes of the genus Echinobothrium, each hosted by a different skate species in the Raja miraletus complex, are described. Echinobothrium mercedesae n. sp. is described from R. cf. miraletus 2 off Senegal. Echinobothrium yiae n. sp. is described from R. cf. miraletus 1 off South Africa. Both species are small worms that differ from their 29 described congeners in the combination of number of cephalic peduncle spines per column, hook formula, number and arrangement of testes, and arrangement of vitelline follicles. They are easily distinguished from one another in that whereas the vitelline follicles of E. yiae n. sp. are circumcortical, they are lateral in E. mercedesae n. sp., and also in number of cephalic peduncle spines per column (14-17 vs. 10-12). Echinobothrium yiae n. sp. is also unusual in that the cephalic peduncle spines stop short of the anterior margin of the peduncle. In addition, although the paucity of available material precluded their formal description, evidence of 2 additional new species parasitizing R. miraletus also from Senegal is presented. In combination these worms provide support for the interpretation that what is currently recognized as Raja miraletus actually consists of a complex of geographically restricted species, rather than a polymorphic species of multiple parapatric or allopatrically distributed populations. This interpretation is not only supported by previously published molecular data, but also by newly collected morphological data involving differences in the color patterns of disc ocelli among host specimens of the 3 forms available as a result of digital efforts to ensure the accuracy of host identifications, which are also presented here.

Longevity of men capable of prolonged vigorous physical exercise: a 32 year follow up of 2259 participants in the Dutch eleven cities ice skating tour.

Science.gov (United States)

van Saase, J L; Noteboom, W M; Vandenbroucke, J P

1990-01-01

OBJECTIVE--To compare the long term survival of a group of athletes taking prolonged vigorous physical exercise to that of the general population. DESIGN--Follow up of a cohort of participants in the Dutch eleven cities ice skating tour (a race and recreational tour) over a distance of 200 kilometers. SETTING--Data on participation from the organising committee and data on mortality from all municipalities in The Netherlands. SUBJECTS--2259 Male athletes. MAIN OUTCOME MEASURES--Comparison of all cause mortality in male participants in the tour with that in the general population of The Netherlands. RESULTS--The standardised mortality ratio for all participants during 32 years of follow up was 0.76 (95% confidence interval 0.68 to 0.85), and 0.90 (0.48 to 1.44) for participants in the race, and 0.72 (0.60 to 0.86) for participants in the recreational tour who finished within the time limit. CONCLUSIONS--The capacity for prolonged and vigorous physical exercise, particularly if the exercise is recreational, is a strong indicator of longevity. Images p1409-a p1411-a PMID:2279154

Maturity, size at age and predator-prey relationships of winter skate Leucoraja ocellata in the southern Gulf of St Lawrence: potentially an undescribed endemic facing extirpation.

Science.gov (United States)

Kelly, J T; Hanson, J M

2013-03-01

The goals of this study were to document the size and age structure, size at maturity, ovarian fecundity and diet of the endangered population of winter skate Leucoraja ocellata that resides in the southern Gulf of St Lawrence (SGSL). The maximum size observed for SGSL L. ocellata was 68 cm total length (LT ) but >99% of animals caught were 10 mm diameter were ever observed. At 40 cm LT , the diet changed from one dominated by shrimp Crangon septemspinosa and gammarid amphipods to one dominated by fishes (mainly sand lance Ammodytes spp. and rainbow smelt Osmerus mordax) and Atlantic rock crab Cancer irroratus. Sufficient differences were observed between SGSL L. ocellata and other populations in their size-at-maturity pattern and maximum size to propose the taxonomic re-evaluation of the population. © Her Majesty the Queen in Right of Canada 2013. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

Composición de especies, tasas de captura y estructura de tamaño de peces capturados en la pesquería espinelera artesanal de rayas en la zona sur-austral de Chile Species composition, catch rates, and size structures of fishes caught in the small-scale longline skate fishery off southern Chile

Directory of Open Access Journals (Sweden)

Juan Carlos Quiroz

2008-01-01

Full Text Available En los últimos diez años los desembarques de rayas en la pesquería espinelera artesanal se han incrementado aceleradamente en la zona sur-austral de Chile y actualmente se desconocen características fundamentales para la descripción de la dinámica poblacional, como es la composición de especies, tasas de capturas y estructura de tamaño. En este estudio se exploraron estas características mediante información biológico-pesquera obtenida en un programa de moni toreo experimental desarrollado entre febrero 2003 y agosto 2004. Se analizaron 403 lances de pesca donde se registró información operational (fecha, profundidad, tiempo de reposo, número de anzuelos, captura total y zona de pesca y biológica (identificación de especies, número de especies, peso, sexo y longitud total. Se examinó por zona de pesca la composición de un grupo de 16 especies correspondientes al 98% de la captura total. Las capturas estuvieron constituidas principalmente por raya volantín (Dipturus chilensis y congrio dorado (Genypterus blacodes, que en conjunto representaron el 87,8% de la captura total, mientras que la importancia del resto de las especies de elasmobranquios incidentales no superó el 9%. Adicionalmente, se obtuvo la estructura de tamaño y tasas de captura de congrio dorado y de las únicas dos especies de rajiformes reportadas en las capturas, raya volantín y raya espinuda (Dipturus trachyderma. En estas tres especies, la estructura de tamaño evidenció cambios significativos (p Landings of the small-scale longline skate fishery have increased rapidly off southern Chile during the last ten years. At present, the fundamental characteristics for describing the population dynamics (e.g., species composition, catch rates, size structures are not known. The present study explored these characteristics using biological-fishery information coming from an experimental sampling program carried out between February 2003 and August 2004. A total

Rajella paucispinosa n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the western Indian Ocean off South Mozambique, and a revised generic diagnosis.

Science.gov (United States)

Weigmann, Simon; Stehmann, Matthias F W; Thiel, Ralf

2014-08-08

A new species of the widely in temperate and tropical latitudes distributed skate genus Rajella is described based on an almost adult male specimen from the western Indian Ocean off South Mozambique. The holotype of R. paucispinosa n. sp. was caught during cruise 17 of RV 'Vityaz' along the deep western Indian Ocean in 1988/89. It is the northernmost record of a Rajella specimen in the western Indian Ocean. The new species is the 18th valid species of the genus and the fifth species in the western Indian Ocean. It differs from its congeners in the small maximal total length of about 50 cm and only few thorns on the dorsal surface. The new species has only two thorns on each orbit, one nuchal thorn, one right scapular thorn (left one not detectable, abraded), and one median row of tail thorns. Other species of Rajella typically have half rings of thorns on orbital rims, a triangle of thorns on nape-shoulder region, and at least three rows of tail thorns. Another conspicuous feature of the new species is the almost completely white dorsal and ventral coloration. 

Evaluating judge performance in sport.

Science.gov (United States)

Looney, Marilyn A

2004-01-01

Many sports, such as, gymnastics, diving, ski jumping, and figure skating, use judges' scores to determine the winner of a competition. These judges use some type of rating scale when judging performances (e.g., figure skating: 0.0 - 6.0). Sport governing bodies have the responsibility of setting and enforcing quality control parameters for judge performance. Given the judging scandals in figure skating at the 1998 and 2002 Olympics, judge performance in sport is receiving greater scrutiny. The purpose of this article is to illustrate how results from Rasch analyses can be used to provide in-depth feedback to judges about their scoring patterns. Nine judges' scores for 20 pairs of figure skaters who competed at the 2002 Winter Olympics were analyzed using a four-faceted (skater pair ability, skating aspect difficulty, program difficulty, and judge severity) Rasch rating scale model that was not common to all judges. Fit statistics, the logical ordering of skating aspects, skating programs, and separation indices all indicated a good fit of the data to the model. The type of feedback that can be given to judges about their scoring pattern was illustrated for one judge (USA) whose performance was flagged as being unpredictable. Feedback included a detailed description of how the rating scale was used; for example, 10% of all marks given by the American judge were unexpected by the model (Z > |2|). Three figures illustrated differences between the judge's observed and expected marks arranged according to the pairs' skating order and final placement in the competition. Scores which may represent "nationalistic bias" or a skating order influence were flagged by looking at these figures. If sport governing bodies wish to improve the performance of their judges, they need to employ methods that monitor the internal consistency of each judge as a many-facet Rasch analysis does.

Automatic Classification of the Sub-Techniques (Gears Used in Cross-Country Ski Skating Employing a Mobile Phone

Directory of Open Access Journals (Sweden)

Thomas Stöggl

2014-10-01

Full Text Available The purpose of the current study was to develop and validate an automatic algorithm for classification of cross-country (XC ski-skating gears (G using Smartphone accelerometer data. Eleven XC skiers (seven men, four women with regional-to-international levels of performance carried out roller skiing trials on a treadmill using fixed gears (G2left, G2right, G3, G4left, G4right and a 950-m trial using different speeds and inclines, applying gears and sides as they normally would. Gear classification by the Smartphone (on the chest and based on video recordings were compared. Formachine-learning, a collective database was compared to individual data. The Smartphone application identified the trials with fixed gears correctly in all cases. In the 950-m trial, participants executed 140 ± 22 cycles as assessed by video analysis, with the automatic Smartphone application giving a similar value. Based on collective data, gears were identified correctly 86.0% ± 8.9% of the time, a value that rose to 90.3% ± 4.1% (P < 0.01 with machine learning from individual data. Classification was most often incorrect during transition between gears, especially to or from G3. Identification was most often correct for skiers who made relatively few transitions between gears. The accuracy of the automatic procedure for identifying G2left, G2right, G3, G4left and G4right was 96%, 90%, 81%, 88% and 94%, respectively. The algorithm identified gears correctly 100% of the time when a single gear was used and 90% of the time when different gears were employed during a variable protocol. This algorithm could be improved with respect to identification of transitions between gears or the side employed within a given gear.

Automatic Classification of the Sub-Techniques (Gears) Used in Cross-Country Ski Skating Employing a Mobile Phone

Science.gov (United States)

Stöggl, Thomas; Holst, Anders; Jonasson, Arndt; Andersson, Erik; Wunsch, Tobias; Norström, Christer; Holmberg, Hans-Christer

2014-01-01

The purpose of the current study was to develop and validate an automatic algorithm for classification of cross-country (XC) ski-skating gears (G) using Smartphone accelerometer data. Eleven XC skiers (seven men, four women) with regional-to-international levels of performance carried out roller skiing trials on a treadmill using fixed gears (G2left, G2right, G3, G4left, G4right) and a 950-m trial using different speeds and inclines, applying gears and sides as they normally would. Gear classification by the Smartphone (on the chest) and based on video recordings were compared. Formachine-learning, a collective database was compared to individual data. The Smartphone application identified the trials with fixed gears correctly in all cases. In the 950-m trial, participants executed 140 ± 22 cycles as assessed by video analysis, with the automatic Smartphone application giving a similar value. Based on collective data, gears were identified correctly 86.0% ± 8.9% of the time, a value that rose to 90.3% ± 4.1% (P < 0.01) with machine learning from individual data. Classification was most often incorrect during transition between gears, especially to or from G3. Identification was most often correct for skiers who made relatively few transitions between gears. The accuracy of the automatic procedure for identifying G2left, G2right, G3, G4left and G4right was 96%, 90%, 81%, 88% and 94%, respectively. The algorithm identified gears correctly 100% of the time when a single gear was used and 90% of the time when different gears were employed during a variable protocol. This algorithm could be improved with respect to identification of transitions between gears or the side employed within a given gear. PMID:25365459

Apolo Ohno: Breathing Easier | NIH MedlinePlus the Magazine

Science.gov (United States)

... just recently announced your retirement from competitive speed skating. What does the future hold for Apolo Ohno? Even though I'm no longer skating competitively, I'm still staying active every day ...

Mercury bioaccumulation in cartilaginous fishes from Southern New England coastal waters: Contamination from a trophic ecology and human health perspective

Science.gov (United States)

Taylor, David L.; Kutil, Nicholas J.; Malek, Anna J.; Collie, Jeremy S.

2014-01-01

This study examined total mercury (Hg) concentrations in cartilaginous fishes from Southern New England coastal waters, including smooth dogfish (Mustelus canis), spiny dogfish (Squalus acanthias), little skate (Leucoraja erinacea), and winter skate (L. ocellata). Total Hg in dogfish and skates were positively related to their respective body size and age, indicating Hg bioaccumulation in muscle tissue. There were also significant inter-species differences in Hg levels (mean ± 1 SD, mg Hg/kg dry weight, ppm): smooth dogfish (3.3 ± 2.1 ppm; n = 54) > spiny dogfish (1.1 ± 0.7 ppm; n = 124) > little skate (0.4 ± 0.3 ppm; n = 173) ~ winter skate (0.3 ± 0.2 ppm; n = 148). The increased Hg content of smooth dogfish was attributed to its upper trophic level status, determined by stable nitrogen (δ15N) isotope analysis (mean δ15N = 13.2 ± 0.7‰), and the consumption of high Hg prey, most notably cancer crabs (0.10 ppm). Spiny dogfish had depleted δ15N signatures (11.6 ± 0.8‰), yet demonstrated a moderate level of contamination by foraging on pelagic prey with a range of Hg concentrations, e.g., in order of dietary importance, butterfish (Hg = 0.06 ppm), longfin squid (0.17 ppm), and scup (0.11 ppm). Skates were low trophic level consumers (δ15N = 11.9-12.0‰) and fed mainly on amphipods, small decapods, and polychaetes with low Hg concentrations (0.05-0.09 ppm). Intra-specific Hg concentrations were directly related to δ15N and carbon (δ13C) isotope signatures, suggesting that Hg biomagnifies across successive trophic levels and foraging in the benthic trophic pathway increases Hg exposure. From a human health perspective, 87% of smooth dogfish, 32% of spiny dogfish, and < 2% of skates had Hg concentrations exceeding the US Environmental Protection Agency threshold level (0.3 ppm wet weight). These results indicate that frequent consumption of smooth dogfish and spiny dogfish may adversely affect human health, whereas skates present minimal risk. PMID

Your Guide to Physical Activity and Your Heart

Science.gov (United States)

... flat ground) Horseback riding Roller skating/ice skating Softball Swimming Tennis (doubles) Walking moderately (3.5 mph) ... such as dancing; or group sports, such as softball or doubles tennis? If you like to be ...

Determinants of a simulated cross-country skiing sprint competition using V2 skating technique on roller skis.

Science.gov (United States)

Mikkola, Jussi; Laaksonen, Marko; Holmberg, Hans-Christer; Vesterinen, Ville; Nummela, Ari

2010-04-01

The present study investigated the performance-predicting factors of a simulated cross-country (XC) skiing sprint competition on roller skis, on a slow surface. Sixteen elite male XC skiers performed a simulated sprint competition (4 x 850 m heat with a 20-minute recovery) using V2 skating technique on an indoor tartan track. Heat velocities, oxygen consumption, and peak lactate were measured during or after the heats. Maximal skiing velocity was measured by performing a 30-m speed test. Explosive and maximal force production in the upper body was determined by bench press (BP). Subjects also performed maximal anaerobic skiing test (MAST) and the 2 x 2-km double poling (DP) test. The maximal velocity of MAST (VMAST) and velocities at 3 (V3), 5 (V5), 7 (V7) mmol.L lactate levels in MAST were determined. In the 2 x 2-km test, DP economy (VO2SUBDP) and maximal 2-km DP velocity (VDP2KM) were determined. The best single performance-predicting factors for the sprint performance were VDP2KM (r = 0.73, p < 0.01), V7 (r = 0.70, p < 0.01), and VO2SUBDP (r = -0.70, p < 0.01). Faster skiers in sprint simulation had a higher absolute VO2 (L.min) (p < 0.05-0.01) during sprint heats, and higher anaerobic skiing power (VMAST, p < 0.05) and better anaerobic skiing economy (V3, V5, V7, p < 0.05-0.001) than slower skiers. Faster skiers were also stronger in BP, with regard to both absolute (p < 0.01) and relative (p < 0.05) values. In addition, anaerobic characteristics seem to be of importance at the beginning of the XC skiing sprint competition, whereas the aerobic characteristics become more important as the XC skiing sprint competition progressed. This study indicates that sprint skiers should emphasize sport-specific upper body training, and training skiing economy at high speeds.

Age, growth and length-weight relationship of the white skate, Rostroraja alba (Linnaeus, 1758 (Chondrichthyans: Rajidae, from the Gulf of Gabes (Tunisia, Central Mediterranean

Directory of Open Access Journals (Sweden)

Hasna Kadri

2014-06-01

Full Text Available Objective: To investigate the length distribution, sex ratio, length-weight relationship, age and growth of Rostroraja alba in the Gulf of Gabes. Methods: This study estimated age and growth of the white skate, Rostroraja alba by counting vertebral band pairs from 112 specimens taken by commercial fisheries during 2006-2009 from the Gulf of Gabes (Southern Tunisia, Central Mediterranean Sea. Results: This is the first and only known information in regards to the age and growth of this species in Tunisia. Vertebra diameter was strongly correlated with total length and age, which were expressed by linear or cubic regression equations. The oldest female in this study was 35 years and 160 cm, whereas the oldest male was 32 years and 150 cm. The von Bertalanffy growth parameters were TL∞=(202.26±3.40 cm, K=(0.040±0.038/year and t0=(1.84±0.01 10 -1 /year for females and TL∞=(198.60±3.61 cm, K=(0.060±0.076/year and t0=(1.28±0.04/year for males. Conclusions: This study would be an effective tool for fishery biologists, managers and conservationists to initiate management strategies and regulations for the sustainable conservation of the remaining stocks of this species in the Gulf of Gabes (Southern Tunisia ecosystem

Performance characteristics of long-track speed skaters: a literature review.

Science.gov (United States)

Konings, Marco J; Elferink-Gemser, Marije T; Stoter, Inge K; van der Meer, Dirk; Otten, Egbert; Hettinga, Florentina J

2015-04-01

Speed skating is an intriguing sport to study from different perspectives due to the peculiar way of motion and the multiple determinants for performance. This review aimed to identify what is known on (long-track) speed skating, and which individual characteristics determine speed skating performance. A total of 49 studies were included. Based on a multidimensional performance model, person-related performance characteristics were categorized in anthropometrical, technical, physiological, tactical, and psychological characteristics. Literature was found on anthropometry, technique, physiology, and tactics. However, psychological studies were clearly under-represented. In particular, the role of self-regulation might deserve more attention to further understand mechanisms relevant for optimal performance and for instance pacing. Another remarkable finding was that the technically/biomechanically favourable crouched skating technique (i.e. small knee and trunk angle) leads to a physiological disadvantage: a smaller knee angle may increase the deoxygenation of the working muscles. This is an important underlying aspect for the pacing tactics in speed skating. Elite speed skaters need to find the optimal balance between obtaining a fast start and preventing negative technical adaptations later on in the race by distributing their available energy over the race in an optimal way. More research is required to gain more insight into how this impacts on the processes of fatigue and coordination during speed skating races. This can lead to a better understanding on how elite speed skaters can maintain the optimal technical characteristics throughout the entire race, and how they can adapt their pacing to optimize all identified aspects that determine performance.

Embodying complexity through movement sonification : case study on empowering the speed-skater

NARCIS (Netherlands)

Stienstra, J.T.; Overbeeke, C.J.; Wensveen, S.A.G.

2011-01-01

In this paper, we describe the Augmented Speed-skate Experience (ASE), a case of movement sonification in professional speed-skating. We designed and developed a system that provides feedback on technique to a professional speed-skater through an extra sense-modality, i.e. sound. Complexity is

75 FR 34049 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

Science.gov (United States)

2010-06-16

... as another product form due to processing and/or marketing reasons. The Council further states that... Sec. 648.322(b) of the proposed regulations would have exempted vessels targeting skate that also... sector vessels could increase targeting of skates by these vessels. Response: The Council's Amendment 3...

50 CFR 648.323 - Accountability measures.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Accountability measures. 648.323 Section 648.323 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Skate Complex Fisheries § 648.323 Accountability measures. (a) TAL overages. If the skate wing fishery...

Cell and molecular biology of the spiny dogfish Squalus acanthias and little skate Leucoraja erinacea: insights from in vitro cultured cells.

Science.gov (United States)

Barnes, D W

2012-04-01

Two of the most commonly used elasmobranch experimental model species are the spiny dogfish Squalus acanthias and the little skate Leucoraja erinacea. Comparative biology and genomics with these species have provided useful information in physiology, pharmacology, toxicology, immunology, evolutionary developmental biology and genetics. A wealth of information has been obtained using in vitro approaches to study isolated cells and tissues from these organisms under circumstances in which the extracellular environment can be controlled. In addition to classical work with primary cell cultures, continuously proliferating cell lines have been derived recently, representing the first cell lines from cartilaginous fishes. These lines have proved to be valuable tools with which to explore functional genomic and biological questions and to test hypotheses at the molecular level. In genomic experiments, complementary (c)DNA libraries have been constructed, and c. 8000 unique transcripts identified, with over 3000 representing previously unknown gene sequences. A sub-set of messenger (m)RNAs has been detected for which the 3' untranslated regions show elements that are remarkably well conserved evolutionarily, representing novel, potentially regulatory gene sequences. The cell culture systems provide physiologically valid tools to study functional roles of these sequences and other aspects of elasmobranch molecular cell biology and physiology. Information derived from the use of in vitro cell cultures is valuable in revealing gene diversity and information for genomic sequence assembly, as well as for identification of new genes and molecular markers, construction of gene-array probes and acquisition of full-length cDNA sequences. © 2012 The Author. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Comparative genomics of chondrichthyan Hoxa clusters

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Zhong Ying-Fu

2009-09-01

Full Text Available Abstract Background The chondrichthyan or cartilaginous fish (chimeras, sharks, skates and rays occupy an important phylogenetic position as the sister group to all other jawed vertebrates and as an early lineage to diverge from the vertebrate lineage following two whole genome duplication events in vertebrate evolution. There have been few comparative genomic analyses incorporating data from chondrichthyan fish and none comparing genomic information from within the group. We have sequenced the complete Hoxa cluster of the Little Skate (Leucoraja erinacea and compared to the published Hoxa cluster of the Horn Shark (Heterodontus francisci and to available data from the Elephant Shark (Callorhinchus milii genome project. Results A BAC clone containing the full Little Skate Hoxa cluster was fully sequenced and assembled. Analyses of coding sequences and conserved non-coding elements reveal a strikingly high level of conservation across the cartilaginous fish, with twenty ultraconserved elements (100%,100 bp found between Skate and Horn Shark, compared to three between human and marsupials. We have also identified novel potential non-coding RNAs in the Skate BAC clone, some of which are conserved to other species. Conclusion We find that the Little Skate Hoxa cluster is remarkably similar to the previously published Horn Shark Hoxa cluster with respect to sequence identity, gene size and intergenic distance despite over 180 million years of separation between the two lineages. We suggest that the genomes of cartilaginous fish are more highly conserved than those of tetrapods or teleost fish and so are more likely to have retained ancestral non-coding elements. While useful for isolating homologous DNA, this complicates bioinformatic approaches to identify chondrichthyan-specific non-coding DNA elements

The effects of klapskate hinge position on push-off performance: a simulation study.

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Houdijk, Han; Bobbert, Maarten F; De Koning, Jos J; De Groot, Gert

2003-12-01

The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this model performed a one-leg vertical jump, from a frictionless surface, while keeping its trunk horizontally. In this model, klapskate hinge position was varied by varying the length of the foot segment between 115 and 300 mm. With each foot length, an optimal control solution was found that resulted in the maximal amount of vertical kinetic and potential energy of the body's center of mass at take off (Weff). Foot length was shown to considerably affect push-off performance. Maximal Weff was obtained with a foot length of 185 mm and decreased by approximately 25% at either foot length of 115 mm and 300 mm. The reason for this decrease was that foot length affected the onset and control of foot rotation. This resulted in a distortion of the pattern of leg segment rotations and affected muscle work (Wmus) and the efficacy ratio (Weff/Wmus) of the entire leg system. Despite its simplicity, the model very well described and explained the effects of klapskate hinge position on push off performance that have been observed in speed-skating experiments. The simplicity of the model, however, does not allow quantitative analyses of optimal klapskate hinge position for speed-skating practice.

Life histories of two deep-water Australian endemic elasmobranchs: Argus skate Dipturus polyommata and eastern spotted gummy shark Mustelus walkeri.

Science.gov (United States)

Rigby, C L; White, W T; Smart, J J; Simpfendorfer, C A

2016-03-01

Two Australian endemic elasmobranchs, the Argus skate Dipturus polyommata and the eastern spotted gummy shark Mustelus walkeri, were collected from the by-catch of a prawn Melicertus plebejus trawl fishery off Queensland. Age and growth parameters were estimated from growth band counts in vertebral sections of 220 D. polyommata and 44 M. walkeri. Dipturus polyommata males and females had an observed maximum age of 10 years and reached maximum sizes of 369 and 371 mm total length (LT ), respectively. Mustelus walkeri lived longer, with the oldest female aged 16 years and measuring 1050 mm stretched total length (LST ), and oldest male aged 9 years and 805 mm LST . Dipturus polyommata grew relatively fast with a von Bertalanffy growth completion parameter of k = 0·208 year(-1) with males reaching maturity at 4·0 years (c. 278 mm LT ) and females at 5·1 years (c. 305 mm LT ). Mustelus walkeri grew more slowly with k = 0·033 year(-1) with males estimated to mature at 7-9 years (670-805 mm LST ) and females at 10-14 years (833-1012 mm LST ). Length at birth inferred from neonate D. polyommata was 89-111 mm LT while for M. walkeri it was estimated to be 273 LST based on the value of L0 from the von Bertalanffy growth model. Both species appeared to have continuous reproductive cycles and low fecundity with an average ovarian fecundity of eight follicles for D. polyommata and a litter size of five to seven pups for M. walkeri. Based on these life-history traits, D. polyommata is more resilient to fishing pressure than M. walkeri. © 2016 The Fisheries Society of the British Isles.

75 FR 82296 - Fisheries Off West Coast States; Pacific Coast Groundfish Fishery Management Plan; Amendments 20...

Science.gov (United States)

2010-12-30

... analysis of available observer data may provide additional information on the management [[Page 82299... longnose skate in 2009 was well below the ABC (only 48 percent of the ABC), therefore the risk of... landing allowance for longnose skate at ``Not limited'' for the start of 2011 and continuing analysis of...

The 'appropriate technology' explanation of productivity growth differentials : an empirical approach

NARCIS (Netherlands)

Los, Bart; Timmer, Marcel P.

2001-01-01

We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

Rent seeking with efforts and bids

NARCIS (Netherlands)

Haan, Marco; Schoonbeek, Lambert

2001-01-01

Abstract We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali in the southeast Pacific Ocean

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Carlos Bustamante

2014-05-01

Full Text Available The abundance and species richness of the cartilaginous fish community of the continental shelf and slope off central Chile is described, based on fishery-independent trawl tows made in 2006 and 2007. A total of 194,705 specimens comprising 20 species (9 sharks, 10 skates, 1 chimaera were caught at depths of 100–500 m along a 1,000 km transect between 29.5°S and 39°S. Sample site locations were grouped to represent eight geographical zones within this latitudinal range. Species richness fluctuated from 1 to 6 species per zone. There was no significant latitudinal trend for sharks, but skates showed an increased species richness with latitude. Standardised catch per unit effort (CPUE increased with increasing depth for sharks, but not for skates, but the observed trend for increasing CPUE with latitude was not significant for either sharks or skates. A change in community composition occurred along the depth gradient with the skates, Psammobatis rudis, Zearaja chilensis and Dipturus trachyderma dominating communities between 100 and 300 m, but small-sized, deep-water dogfishes, such as Centroscyllium spp. dominated the catch between 300 and 500 m. Cluster and ordination analysis identified one widespread assemblage, grouping 58% of sites, and three shallow-water assemblages. Assemblages with low diversity (coldspots coincided with highly productive fishing grounds for demersal crustaceans and bony fishes. The community distribution suggested that the differences between assemblages may be due to compensatory changes in mesopredator species abundance, as a consequence of continuous and unselective species removal. Distribution patterns and the quantitative assessment of sharks, skates and chimaeras presented here complement extant biogeographic knowledge and further the understanding of deep-water ecosystem dynamics in relation to fishing activity in the south-east Pacific Ocean.

Rideudstyr og skøjter

DEFF Research Database (Denmark)

Roesdahl, Else; Pedersen, Anne

2014-01-01

Finds from Aggersborg: snaffle-bit, buckles, strap-slides, strap-mounts, iron loop, strap-pendants, bell, enamelled roundel, spurs, animal-head - fragment of a spur?, calkin, ice-skates......Finds from Aggersborg: snaffle-bit, buckles, strap-slides, strap-mounts, iron loop, strap-pendants, bell, enamelled roundel, spurs, animal-head - fragment of a spur?, calkin, ice-skates...

The young skater.

Science.gov (United States)

Smith, A D

2000-10-01

Figure skating is one of the best lifetime sports. Participants may skate alone or with a group, recreationally or competitively, at all ages and at all skill levels. As a sport that improves physical fitness, skating builds strength, flexibility, and cardiopulmonary endurance. As a weight-bearing or high-impact activity, it is one of the best sports for increasing bone mineral density and perhaps for preventing osteoporosis. At least half of all competitive figure skating injuries appear preventable. Boots should be as flexible as the skater can control and should be carefully fitted. Normal flexibility of lower extremity muscles, especially in the growing athlete, markedly decreases the incidence of overuse symptoms of the knee. Core body strength is critical for controlling high-impact jump landings and decreasing injuries to the spine, pelvis, and hip girdle. Adequate shoulder strength is required for pair skaters and ice dancers. A well-designed off-ice training program decreases injury incidence and enhances performance. Assisting these dedicated athletes is truly rewarding as they train and compete at their highest potential, with passion for their sport.

[Sports injuries in children. Epidemiologic study].

Science.gov (United States)

Du Boullay, C T; Bardier, M; Cheneau, J; Bortolasso, J; Gaubert, J

1984-01-01

Among 49 000 cases of infantile emergencies which were received in the BUCI (Bloc d'urgence chirurgical infantile: surgical infantile emergency unit), 5 546 were sport traumas. At an early age, they were caused by outdoor plays; during adolescence, the main cases were caused by team sports. Males are predominant. The number of cases has been regularly progressing, particularly since 1976. The fashion in sports is influenced by médias (i.e. skate board), and can be opposed to the continuous practice of popular sports (swimming, ball games, bycicle. There are winter, summer, school timed sports (the latter being influenced by the sportive scholar associations). The most frequent sports are cycling, football playing, swimming and horse riding, athleticism skating, Other are occasionnal. Changes in sport fashions, female increasing participation, such as horse riding and skating, democratisation (skiing, riding), the worsening of traumas; the pathology concerning bystanders, are described. Cranial and peripheric pathology are dominant. Trunk traumas are scarce but severe. Each sport has an elective pathologic localisation. Injury mechanisms are found, such as stirrup, saddle, ski baton pathology. There is traumatologic similarities; skate board and roller skating; judo and atheleticism; cycling and horse riding. Sport in children is not a replica of the one among adults. Riding a bike is not cycling. Some sports are dangerous: cycling, horse riding, rugby. A traumatological outline is revealed. Preventive measures should be taken. The socio-economical cost is heavy.

Podnikatelský plán

OpenAIRE

Štefančík, Jozef

2007-01-01

Práce se zabývá podstatnými skutečnostmi, které mají vliv na založení internetového obchodu se skate doplňky v ČR. Zmiňuje legislativní, technologické, marktetingové, finanční a jiné aspekty. Praktická část používá zjištěné poznatky k navržení podoby hypotetického internetového obchodu se skate doplňky Skate stuff, s.r.o. a je tak podnikatelským plánem pro potřeby případného začínajícího podnikatele.

Rapid Development of Microsatellite Markers with 454 Pyrosequencing in a Vulnerable Fish, the Mottled Skate, Raja pulchra

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Jung-Ha Kang

2012-06-01

Full Text Available The mottled skate, Raja pulchra, is an economically valuable fish. However, due to a severe population decline, it is listed as a vulnerable species by the International Union for Conservation of Nature. To analyze its genetic structure and diversity, microsatellite markers were developed using 454 pyrosequencing. A total of 17,033 reads containing dinucleotide microsatellite repeat units (mean, 487 base pairs were identified from 453,549 reads. Among 32 loci containing more than nine repeat units, 20 primer sets (62% produced strong PCR products, of which 14 were polymorphic. In an analysis of 60 individuals from two R. pulchra populations, the number of alleles per locus ranged from 1–10, and the mean allelic richness was 4.7. No linkage disequilibrium was found between any pair of loci, indicating that the markers were independent. The Hardy–Weinberg equilibrium test showed significant deviation in two of the 28 single-loci after sequential Bonferroni’s correction. Using 11 primer sets, cross-species amplification was demonstrated in nine related species from four families within two classes. Among the 11 loci amplified from three other Rajidae family species; three loci were polymorphic. A monomorphic locus was amplified in all three Rajidae family species and the Dasyatidae family. Two Rajidae polymorphic loci amplified monomorphic target DNAs in four species belonging to the Carcharhiniformes class, and another was polymorphic in two Carcharhiniformes species.

Improvement of Ice Hockey Players' On-Ice Sprint With Combined Plyometric and Strength Training.

Science.gov (United States)

Dæhlin, Torstein E; Haugen, Ole C; Haugerud, Simen; Hollan, Ivana; Raastad, Truls; Rønnestad, Bent R

2017-08-01

Combined plyometric and strength training has previously been suggested as a strategy to improve skating performance in ice hockey players. However, the effects of combined plyometric and strength training have not previously been compared with the effects of strength training only. To compare the effects of combined plyometric and strength training on ice hockey players' skating sprint performance with those of strength training only. Eighteen participants were randomly assigned to 2 groups that completed 5 strength-training sessions/wk for 8 wk. One group included plyometric exercises at the start of 3 sessions/wk (PLY+ST), and the other group included core exercises in the same sessions (ST). Tests of 10- and 35-m skating sprints, horizontal jumping, 1-repetition-maximum (1 RM) squat, skating multistage aerobic test (SMAT), maximal oxygen consumption, repeated cycle sprints, and body composition were performed before and after the intervention. The participants increased their 1RM squat, lean mass, and body mass (P plyometric and strength training for 8 wk was superior to strength training alone at improving 10-m on-ice sprint performance in high-level ice hockey players.

The brain sizes of living elasmobranchii as their organization level indicator. I. General analysis.

Science.gov (United States)

Myagkov, N A

1991-01-01

The relationship between brain and body masses of 64 species and subspecies of modern sharks and skates was investigated. It was established that the level of their encephalization in terms of the polygons of encephalization and the allometry coefficient (alpha), shows quite obviously the general organization level of one or another taxon of sharks and skates. Alpha = 0.56 for the class of cartilaginous fishes, and for the superorder of sharks and skates alpha = 0.54 and 0.61, accordingly. For several orders alpha constitutes: sharks--common for relict Hexanchiformes and Heterodontiformes 0.44, Squaliformes 0.43 and Carcharhiniformes 0.52 and skates--Rajiformes 0.44 and Dasyatiformes 0.52. All values are similar to those of other vertebrates and the theoretically calculated value of alpha (0.67). It was established the "place" of present-day Elasmobranchii and all cartilaginous fishes in the evolutionary row of Gnathostomata and Craniata on the developing and relative sizes of CNS, and the corrected alpha value for this particular vertebrate class was specified which was found to be sensationally high also in the works of foreign and native authors (Bauchot et al., 1976; Northcutt, 1978; Ebbesson, 1980; Kreps, 1980).

"Skating" and "Skiing" on Special "Skates" and "Skis"

Science.gov (United States)

Torbert, Marianne; Stork, Steve

2006-01-01

It's become commonplace for concerned physical educators and parents to reminisce about the good old days when children played outside. What receives less attention is that for many children, there is too little physical activity outside of physical education class. Too few schools provide daily physical education, and those that do, don't always…

Intraspecific variation in physiological performance of a benthic elasmobranch challenged by ocean acidification and warming.

Science.gov (United States)

Di Santo, Valentina

2016-06-01

Elucidating the combined effects of increasing temperature and ocean acidification on performance of fishes is central to our understanding of how species will respond to global climate change. Measuring the metabolic costs associated with intense and short activities, such as those required to escape predators, is key to quantifying changes in performance and estimating the potential effects of environmental stressors on survival. In this study, juvenile little skate Leucoraja erinacea from two neighboring locations (Gulf of Maine, or northern location, and Georges Bank, or southern location) were developmentally acclimatized and reared at current and projected temperatures (15, 18 or 20°C) and acidification conditions (pH 8.1 or 7.7), and their escape performance was tested by employing a chasing protocol. The results from this study suggest countergradient variation in growth between skates from the two locations, while the optimum for escape performance was at a lower temperature in individuals from the northern latitudes, which could be related to adaptation to the local thermal environment. Aerobic performance and scope declined in skates from the northern latitudes under simulated ocean warming and acidification conditions. Overall, the southern skates showed lower sensitivity to these climatic stressors. This study demonstrates that even mobile organisms from neighboring locations can exhibit substantial differences in energetic costs of exercise and that skates from the northern part of the geographic range may be more sensitive to the directional increase in temperature and acidification expected by the end of the century. © 2016. Published by The Company of Biologists Ltd.

PENGALIAN, KENEGARIAN KOTO RAJO, KECAMATAN KUANTAN HILIR, KABUPATEN KUANTAN SINGINGI

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Evizariza Evizariza

2017-04-01

Full Text Available AbstractThis study aims to examine the religious values   and economic values   of the people on the game Skate “in the village of Multiplication, Kenegarian Kotorajo,.Kuantan Hilir Subdistrict, District Singingi. This study used a descriptive method, a method that is used describe skating in the village folk games Multiplication, Kenegerian Koto tengah Seberang Hilir District of Kuantan, Kuantan District Singingi. Correctly, so that the values   contained in the folk games of skating it can be seen clearly. There are several data collection techniques that I use to understand a descriptive study with interview techniques, observation. The results of this study are yamg religious values   contained in each game is started skating people skating games basmalah always reading and praying, besides instilling honesty, and mutual work sama. Nilai-economic values   contained in the folk games of skating, in the execution of the game can boost the economy of society with digalakkannya social economy. Keywords: religious values   and economic valuesAbstrakPenelitian ini bertujuan untuk meneliti nilai nilai Agama dan nilai ekonomi pada permainan rakyat Seluncur” di Desa Pengalian, Kenegarian Kotorajo. Kecamatan Kuantan Hilir, Kabupaten Singingi. Penelitian ini menggunakan metode  deskriptif, yaitu metode yang digunakan menggambarkan permainan rakyat seluncur di Desa Pengalian, Kenegerian Koto Tengah Kecamatan Kuantan Hilir Seberang, Kabupaten Kuantan Singingi. Secara benar, sehingga nilai-nilai yang terkandung dalam dalam permainan rakyat seluncur itu dapat diketahui dengan jelas. Ada beberapa teknik pengumpulan data yang penulis pakai untuk memahami sebuah penelitian yang bersifat deskriptif dengan teknik wawancara, observasi. Hasil Penelitian ini adalah nilai-nilai agama yang terdapat pada permainan rakyat  seluncur adalah setiap mengawali permainan seluncur selalu membaca basmalah dan berdoa,  selain itu menanamkan sikap jujur, dan

[The role of intense physical activity in the formation of body shape - research based on female figure skaters].

Science.gov (United States)

Paluchowska, Monika

2015-01-01

The article concerns figure skating competitors. Figure skating is a very demanding discipline. It requires a combination of endurance, strength and flexibility. The training ground is ice, which puts strain on the muscles and skeleton. Young children often train more than is healthy for a young and growing body. The aim of the study was to determine the effect of training on the height and weight of female skaters. 181 measurements were taken from three skating clubs, and a survey was conducted among skaters' parents about skaters' siblings. Female skaters are relatively shorter and lighter than their peers, but the differences were not statistically significant. Significant differences were noted between girls whose sisters do not do sports. The results suggest the influence of genetic factors and selection processes on the morphology of the skaters' body.

Novel Compounds From Shark and Stingray Epidermal Mucus With Antimicrobial Activity Against Wound Infection Pathogens

Science.gov (United States)

2014-03-01

consistency compared to mucus from any of the ray species. While this difference is difficult to describe, the terms “ gelatinous ” or “sticky” are...visualized using silver stain (Figure 3). As observed with the ray species, protein patterns for clearnose skates are consistent among individuals of the...three clearnose skates, Raja eglanteria, visualized with silver stain. Molecular weights of standard proteins are in kilodaltons (kD). 9

Anthropometry, Physical Fitness and Coordination of Young Figure Skaters of Different Levels.

Science.gov (United States)

Mostaert, M; Deconinck, F; Pion, J; Lenoir, M

2016-06-01

The aim of the present study was to identify anthropometric, physical, coordinative and ice-skating specific characteristics that discriminate young elite ice skaters from non-elite skaters and their non-skating peers. 32 skaters aged 9-12 years old (11 elites and 21 non-elites) voluntarily participated in the study. They were submitted to 5 anthropometric, 7 physical, 3 coordination and 5 ice-skating specific tests. Reference values of a representative healthy non-skating sample were taken from the Flemish Sports Compass dataset. Figure skaters appeared to be predominantly average mature (93.8%), were lighter and leaner than the reference sample, and demonstrated better physical characteristics and motor coordination. There was no difference between the elite and non-elite group regarding maturity status and anthropometric or physical parameters. Still, elite skaters scored better than non-elites on the coordination tests jumping sideways and tended to do so on the moving sideways test. Profiles of figure skaters differ clearly from a reference population, while non-sport-specific motor coordination tests allow discrimination between elite and non-elite skaters. The relevance of these findings with respect to talent detection and identification in young ice skaters are discussed. © Georg Thieme Verlag KG Stuttgart · New York.

Analysis and functional annotation of expressed sequence tags from in vitro cell lines of elasmobranchs: Spiny dogfish shark (Squalus acanthias) and little skate (Leucoraja erinacea).

Science.gov (United States)

Parton, Angela; Bayne, Christopher J; Barnes, David W

2010-09-01

Elasmobranchs are the most commonly used experimental models among the jawed, cartilaginous fish (Chondrichthyes). Previously we developed cell lines from embryos of two elasmobranchs, Squalus acanthias the spiny dogfish shark (SAE line), and Leucoraja erinacea the little skate (LEE-1 line). From these lines cDNA libraries were derived and expressed sequence tags (ESTs) generated. From the SAE cell line 4303 unique transcripts were identified, with 1848 of these representing unknown sequences (showing no BLASTX identification). From the LEE-1 cell line, 3660 unique transcripts were identified, and unknown, unique sequences totaled 1333. Gene Ontology (GO) annotation showed that GO assignments for the two cell lines were in general similar. These results suggest that the procedures used to derive the cell lines led to isolation of cell types of the same general embryonic origin from both species. The LEE-1 transcripts included GO categories "envelope" and "oxidoreductase activity" but the SAE transcripts did not. GO analysis of SAE transcripts identified the category "anatomical structure formation" that was not present in LEE-1 cells. Increased organelle compartments may exist within LEE-1 cells compared to SAE cells, and the higher oxidoreductase activity in LEE-1 cells may indicate a role for these cells in responses associated with innate immunity or in steroidogenesis. These EST libraries from elasmobranch cell lines provide information for assembly of genomic sequences and are useful in revealing gene diversity, new genes and molecular markers, as well as in providing means for elucidation of full-length cDNAs and probes for gene array analyses. This is the first study of this type with members of the Chondrichthyes. Copyright 2010 Elsevier Inc. All rights reserved.

Towards sustainable fishery management for skates in South America: The genetic population structure of Zearaja chilensis and Dipturus trachyderma (Chondrichthyes, Rajiformes in the south-east Pacific Ocean.

Directory of Open Access Journals (Sweden)

Carolina Vargas-Caro

Full Text Available The longnose skates (Zearaja chilensis and Dipturus trachyderma are the main component of the elasmobranch fisheries in the south-east Pacific Ocean. Both species are considered to be a single stock by the fishery management in Chile however, little is known about the level of demographic connectivity within the fishery. In this study, we used a genetic variation (560 bp of the control region of the mitochondrial genome and ten microsatellite loci to explore population connectivity at five locations along the Chilean coast. Analysis of Z. chilensis populations revealed significant genetic structure among off-shore locations (San Antonio, Valdivia, two locations in the Chiloé Interior Sea (Puerto Montt and Aysén and Punta Arenas in southern Chile. For example, mtDNA haplotype diversity was similar across off-shore locations and Punta Arenas (h = 0.46-0.50, it was significantly different to those in the Chiloé Interior Sea (h = 0.08. These results raise concerns about the long-term survival of the species within the interior sea, as population resilience will rely almost exclusively on self-recruitment. In contrast, little evidence of genetic structure was found for D. trachyderma. Our results provide evidence for three management units for Z. chilensis, and we recommend that separate management arrangements are required for each of these units. However, there is no evidence to discriminate the extant population of Dipturus trachyderma as separate management units. The lack of genetic population subdivision for D. trachyderma appears to correspond with their higher dispersal ability and more offshore habitat preference.

Biología de la raya Psammobatis extenta (Garman, 1913 (Batoidea: Rajidae Biology of the skate Psammobatis extenta (Garman, 1913 (Batoidea: Rajidae

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JUAN M. BRACCINI

2002-03-01

Full Text Available Psammobatis extenta es un miembro común de la fauna de rayas de las costas de Sudamérica y su biología ha sido poco estudiada. Se investigaron aspectos de la biología de P. extenta a partir de datos obtenidos del descarte de arrastres comerciales de la flota pesquera de Puerto Quequén, Argentina, en febrero de 2000. La talla máxima alcanzada por las hembras fue 313 mm L T y 295 mm L T, por los machos. Las proporciones que presentaron menor variación y relación isométrica fueron: distancia narina-boca, distancia interorbital, longitud ojo+espiráculo, largo de disco y ancho de disco. La relación L T-Peso total presentó diferencias significativas (P Psammobatis extenta is a common off-shore member of the South American skate fauna and its biology is poorly known. Aspects of the biology of P. extenta were investigated using data collected from bycatch of commercial trawls in February 2000 off the coast of Puerto Quequén, Argentina. The maximum size attained by females was 313 mm T L and 295 mm T L, by males. Measurements that presented less variation and isometric relation were: nare to mouth length, distance between orbits, orbit and spiracle length, disc length and disc width. There were significant differences (P < 0.05 in the T L -Total weight relation between females and males, the former attaining a greater weight for the same T L. Males reach maturity between 260 and 266 mm in length, about 89 % of their maximum size. Females reach maturity at a length of 236-255 mm, about 79 % of their maximum size. Gravid females (13 % of the mature females presented one egg case per oviduct (single oviparity. There is sexual dimorphism in dentition and alar spines: mature males have pointed conical cusps and possess alar spines along the outer margins of the upper disc, whereas female and immature males have grinding blunt teeth

System planning of Nagano Olympic Memorial Arena; Naganoshi Olympic kinen arena

Energy Technology Data Exchange (ETDEWEB)

Omae, Y.; Nakamura, M. [Kume Sekkei Co. Ltd., Tokyo (Japan); Hayakawa, M.; Kondo, J. [Kajima Corp., Tokyo (Japan); Ito, T. [Daidan Co. Ltd., Osaka (Japan); Yosoyama, Y. [Suga Engineering Co. Ltd., Tokyo (Japan)

1999-11-05

Nagano Olympic Memorial Arena, well known as hosting the Speed Skate Competition in 1998 Winter Olympic Game, is the first multi-purpose facility with 400 m long ice-skate rink in Japan. The superior system for saving energy and resources is the main concept of the arena. This system covers not only the Olympic Game but also multi-functional general usage. The world records and the variety of use are the proof of the accomplishment. (author)

Prey handling using whole-body fluid dynamics in batoids.

Science.gov (United States)

Wilga, Cheryl D; Maia, Anabela; Nauwelaerts, Sandra; Lauder, George V

2012-02-01

Fluid flow generated by body movements is a foraging tactic that has been exploited by many benthic species. In this study, the kinematics and hydrodynamics of prey handling behavior in little skates, Leucoraja erinacea, and round stingrays, Urobatis halleri, are compared using kinematics and particle image velocimetry. Both species use the body to form a tent to constrain the prey with the pectoral fin edges pressed against the substrate. Stingrays then elevate the head, which increases the volume between the body and the substrate to generate suction, while maintaining pectoral fin contact with the substrate. Meanwhile, the tip of the rostrum is curled upwards to create an opening where fluid is drawn under the body, functionally analogous to suction-feeding fishes. Skates also rotate the rostrum upwards although with the open rostral sides and the smaller fin area weaker fluid flow is generated. However, skates also use a rostral strike behavior in which the rostrum is rapidly rotated downwards pushing fluid towards the substrate to potentially stun or uncover prey. Thus, both species use the anterior portion of the body to direct fluid flow to handle prey albeit in different ways, which may be explained by differences in morphology. Rostral stiffness and pectoral fin insertion onto the rostrum differ between skates and rays and this corresponds to behavioral differences in prey handling resulting in distinct fluid flow patterns. The flexible muscular rostrum and greater fin area of stingrays allow more extensive use of suction to handle prey while the stiff cartilaginous rostrum of skates lacking extensive fin insertion is used as a paddle to strike prey as well as to clear away sand cover. Copyright © 2011 Elsevier GmbH. All rights reserved.

Environmental Loads of a Finnish indoor training iceskating rink in the Context of LCA; Jaeaehallirakennuksen aiheuttamat ympaeristoekuormitukset

Energy Technology Data Exchange (ETDEWEB)

Vaahterus, T.; Saari, A.

2001-07-01

In this study the environmental burdens generated by its essential building elements and systems of a typical new indoor training ice-skating rink during entire life cycle were calculated. The calculations were made by using a calculation method developed at Helsinki University of Technology at the department of Civil and Environmental Engineering, Construction Economics and Management. The developed method is based on LCA -methodology and follows the principle of the ISO 14040 Environmental Management standard. In the calculations the life cycle of the indoor training iceskating rink was divided in four main phases: new construction, maintenance and energy, repair, and demolition. In each life cycle phase all the material and energy flows and emissions were calculated. Almost all (99 %) of the building elements in the indoor training ice skating rink were made of non-renewable materials. Also the energy, consumed during the life cycle, was mainly (81 %) produced with non-renewable energy sources. The life cycle phases causing the most environmental loads were energy and new construction. The energy phase consumed 92 % of the total energy and produced 91 of the CO{sub 2} equivalents and 74 % of the SO{sub 2} equivalents. In the new-construction phase 6 % of the life cycle energy was consumed, and 64 % of the ethene equivalents were produced. In addition to these 79 % of the building materials were used in the new- construction phase. The calculations were also tested against the sensitivity to different presumption changes. Two kinds of presumptions were made: ones that could be influenced by project control and others which refer to the future of the building and could not be influenced by project control. The calculations of the environmental loads of the indoor training ice skating rink were most sensitive to changes in the usage profiles and indoor temperature. For example one of the usage profile increased the environmental loads of the indoor training ice

Environmental Loads of a Finnish indoor training iceskating rink in the Context of LCA

International Nuclear Information System (INIS)

Vaahterus, T.; Saari, A.

2001-01-01

In this study the environmental burdens generated by its essential building elements and systems of a typical new indoor training ice-skating rink during entire life cycle were calculated. The calculations were made by using a calculation method developed at Helsinki University of Technology at the department of Civil and Environmental Engineering, Construction Economics and Management. The developed method is based on LCA -methodology and follows the principle of the ISO 14040 Environmental Management standard. In the calculations the life cycle of the indoor training iceskating rink was divided in four main phases: new construction, maintenance and energy, repair, and demolition. In each life cycle phase all the material and energy flows and emissions were calculated. Almost all (99 %) of the building elements in the indoor training ice skating rink were made of non-renewable materials. Also the energy, consumed during the life cycle, was mainly (81 %) produced with non-renewable energy sources. The life cycle phases causing the most environmental loads were energy and new construction. The energy phase consumed 92 % of the total energy and produced 91 of the CO 2 equivalents and 74 % of the SO 2 equivalents. In the new-construction phase 6 % of the life cycle energy was consumed, and 64 % of the ethene equivalents were produced. In addition to these 79 % of the building materials were used in the new- construction phase. The calculations were also tested against the sensitivity to different presumption changes. Two kinds of presumptions were made: ones that could be influenced by project control and others which refer to the future of the building and could not be influenced by project control. The calculations of the environmental loads of the indoor training ice skating rink were most sensitive to changes in the usage profiles and indoor temperature. For example one of the usage profile increased the environmental loads of the indoor training ice skating rink

Exercise economy in skiing and running

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Thomas eLosnegard

2014-01-01

Full Text Available Substantial inter-individual variations in exercise economy exist even in highly trained endurance athletes. The variation is believed to be determined partly by intrinsic factors. Therefore, in the present study, we compared exercise economy in V2-skating, double poling and uphill running. Ten highly trained male cross-country skiers (23 ± 3 years, 180 ± 6 cm, 75 ± 8 kg, VO2peak running: 76.3 ± 5.6 mL•kg-1•min-1 participated in the study. Exercise economy and VO2peak during treadmill running, ski skating (V2 technique and double poling were compared based on correlation analysis with subsequent criteria for interpreting the magnitude of correlation (r. There was a very large correlation in exercise economy between V2-skating and double poling (r = 0.81 and a large correlation between V2-skating and running (r = 0.53 and double poling and running (r = 0.58. There were trivial to moderate correlations between exercise economy and VO2peak (r = 0.00-0.23, cycle rate (r = 0.03-0.46, body mass (r = -0.09-0.46 and body height (r = 0.11-0.36. In conclusion, the inter-individual variation in exercise economy could only moderately be explained by differences in VO2peak, body mass and body height and therefore we suggest that other intrinsic factors contribute to the variation in exercise economy between highly trained subjects.

Lang Lang: From child prodigy to Carregie Hall

Institute of Scientific and Technical Information of China (English)

Tricia Carswell

2004-01-01

<正>As a child, I had three wishes: to have my own bicycle, to take figure-skating lessons, and to play piano. As a young mother of 26,I finally bought a bicycle which I happily rode up and down our farm laneway. At 34, my first lesson with a professional skating teacher was also my last when I fell on the ice and popped an instant bump the size of an egg on the back of my head. To my chagrin, the only keyboard I ever mastered was that of the typewriter/computer.

After swimming one goes on the ice. Multifunctional complex of sports and leisure uses energetic synergies; Nach dem Schwimmen geht's aufs Eis. Multifunktionaler Sport- und Freizeitkomplex nutzt energetische Synergien

Energy Technology Data Exchange (ETDEWEB)

Jaeger, Frank Peter [Redaktionbuero Archikontext, Berlin (Germany); Vonseelen, Tanja

2012-11-01

In Lentpark (Cologne, Federal Republic of Germany) skating and swimming are combined in one building - an unusual combination of use with tradition in Cologne. Recently the bureau Schulitz Architecture + Technology (Braunschweig, Federal Republic of Germany) designed the completed new building of the ice ring and swimming hall. The new building develops the energetic synergies of the coexistence of ice preparation and water heating. The new building was commissioned by KoelnBaeder GmbH (Cologne, Federal Republic of Germany) and is a unique of modern skating arena with spectacular ice overhead way, swimming pool and sauna in Europe.

The impact of a temporary ice-rink on an emergency department service.

LENUS (Irish Health Repository)

Clarke, Heather J

2012-02-03

BACKGROUND: A temporary ice-rink opened close to Cork city for 6 weeks from 30 November 2003. During this time, a number of patients presented to the local emergency departments with ice-skating-related injuries. We documented these injuries. METHODS: All patients presenting to emergency departments in Cork city with ice-skating-related complaints were included. Information on age and sex, mechanism of injury, diagnosis, follow-up\\/disposition and ambulance service utilization was recorded. RESULTS: One hundred and twenty-five ice-rink-related attendances were reported at Cork emergency departments, representing 1.25% of total attendances. One hundred and twenty-three patients presented with skating-related injuries and two with medical complaints occurring at the ice-rink: 70.8% were female patients and 29.2% were male patients. In the 4-14-year age group, however, 48.5% were girls and 51.5% were boys. Most injuries were directly due to falls; 5.6% were due to skate blades. The commonest site of injury was the upper limb. Fractures and dislocations accounted for 53.9% of injuries, with 20.5% of these requiring orthopaedic admission. Lacerations and digital injuries accounted for 7.1%, with 11% of these required admission for surgery. One minor head injury was reported. 38.1% had soft tissue injuries. Fifteen patients were transported by ambulance. These attendances represented a minimum overall cost of 77,510 euro to the local health service. CONCLUSIONS: A temporary ice-rink had a significant impact on local emergency departments. Currently, there is no specific legislation in Ireland relating to public health and safety in ice-rinks. We recommend consultation with local public bodies before opening such facilities, and appropriate regulation.

Records of new and rare elasmobranchs from Taiwan.

Science.gov (United States)

Hsu, Hua Hsun; Joung, Shoou Jeng; Ebert, David A; Lin, Chia Yen

2013-01-01

Five new records of elasmobranchs collected from eastern Taiwan fish markets, Da-xi and Cheng-gong, are presented. Samples were caught by deepsea longliners and bottom trawlers which operate in northeastern waters off Taiwan between 2004 and 2012. These five new species records include the smalltooth sandtiger, Odontaspis ferox (Risso, 1810) (Lamniformes: Odontaspididae), salamander shark, Parmaturus pilosus Garman, 1906 (Carcharhiniformes: Scyliorhinidae), leadhued skate Notoraja tobitukai (Hiyama, 1940) (Rajiformes: Arhynchobatidae), giant skate Dipturus gigas (Ishiyama, 1958) (Rajiformes: Rajidae), and the pelagic stingray Pteroplatytrygon violacea (Bonaparte, 1832) (Myliobatiformes: Dasyatidae), Diagnostic characteristics for each species are given and a key to the genera Parmaturus and Dipturus from Taiwan is presented.

STRESS FRACTURE PREVALENCE IN ELITE FIGURE SKATERS

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Sanda Dubravcic-Simunjak

2008-09-01

Full Text Available Figure skating is a physically demanding sport that requires a unique combination of artistic ability, speed, agility, flexibility and power. During the last decades not only the competitive schedule has become tougher, but after introduction of the new judging system in 2003, also more emphasis is put on difficult technical elements, jumps, steps and spins (ISU Rules, 2006. More studies about possible increasing prevalence of stress fractures in figure skaters and contributing factors are lacking (Dubravcic-Simunjak et al., 2003; Moran, 2000; Pecina et al., 1990. Therefore the aim of this study was to obtain data about the current stress fracture cumulative risk among elite junior and senior figure skaters, as well as possible factors that may contribute to stress fracture incidence. An anonymous questionnaire, divided into 5 sections, inquired about the prevalence of stress fracture were mailed and distributed to all 62 International Skating Union (ISU members by the ISU headquarters in Lausanne, Switzerland. The guidelines of the Helsinki declaration 2004 were followed. From the 644 skaters who received the questionnaire, 412 completed ones were returned from 110 female juniors (78 single skaters, 12 pair skaters and 20 ice dancers and 135 female seniors (97 single skaters, 16 pair skaters and 22 ice dancers and from 79 male juniors (47 single skaters, 12 pair skaters and 20 ice dancers and 88 male seniors (50 single skaters, 16 pair skaters and 22 ice dancers, coming from different ISU members. The response rate was 62% in females and 67% in males. The median age for female skaters was 16 years and for males 18 years (range 12-25 years. All participants started to skate between 3 and 6 years of age and started to compete in national and international competitions when they were between 5 and 7 years old. At the time of this analysis, they had been skating between 9 and 20 years.In females 41 (16.7%, and in males 25 (13.8% figure skaters

The role of HoxA11 and HoxA13 in the evolution of novel fin morphologies in a representative batoid (Leucoraja erinacea

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Shannon N. Barry

2017-12-01

Full Text Available Abstract Background Batoids exhibit unique body plans with derived fin morphologies, such as the anteriorly expanded pectoral fins that fuse to the head, or distally extended anterior pelvic fin lobes used for a modified swimming technique utilized by skates (Rajidae. The little skate (Leucoraja erinacea, exhibits both of these unique fin morphologies. These fin modifications are not present in a typical shark body plan, and little is known regarding the mechanisms underlying their development. A recent study identified a novel apical ectodermal ridge (AER associated with the development of the anterior pectoral fin in the little skate, but the role of the posterior HoxA genes was not featured during skate fin development. Results We present the first evidence for HoxA expression (HoxA11 and HoxA13 in novel AER domains associated with the development of three novel fin morphologies in a representative batoid, L. erinacea. We found HoxA13 expression associated with the recently described novel AER in the anterior pectoral fin, and HoxA11 expression in a novel AER domain in the anterior pelvic fin that we describe here. We find that both HoxA11 and HoxA13 are expressed in claspers, and while HoxA11 is expressed in pelvic fins and claspers, HoxA13 is expressed exclusively in developing claspers of males. Finally, HoxA11 expression is associated with the developing fin rays in paired fins. Conclusion Overall, these results indicate that the posterior HoxA genes play an important role in the morphological evolution of paired fins in a representative batoid. These data suggest that the batoids utilize a unique Hox code, where the posterior HoxA genes exhibit distinct expression patterns that are likely associated with specification of novel fin morphologies.

How Hinge Positioning in Cross-Country Ski Bindings Affect Exercise Efficiency, Cycle Characteristics and Muscle Coordination during Submaximal Roller Skiing

Science.gov (United States)

Bolger, Conor M.; Sandbakk, Øyvind; Ettema, Gertjan; Federolf, Peter

2016-01-01

The purposes of the current study were to 1) test if the hinge position in the binding of skating skis has an effect on gross efficiency or cycle characteristics and 2) investigate whether hinge positioning affects synergistic components of the muscle activation in six lower leg muscles. Eleven male skiers performed three 4-min sessions at moderate intensity while cross-country ski-skating and using a klapskate binding. Three different positions were tested for the binding’s hinge, ranging from the front of the first distal phalange to the metatarsal-phalangeal joint. Gross efficiency and cycle characteristics were determined, and the electromyographic (EMG) signals of six lower limb muscles were collected. EMG signals were wavelet transformed, normalized, joined into a multi-dimensional vector, and submitted to a principle component analysis (PCA). Our results did not reveal any changes to gross efficiency or cycle characteristics when altering the hinge position. However, our EMG analysis found small but significant effects of hinge positioning on muscle coordinative patterns (P skating klapskates. Finally, the within-subject results of the EMG analysis suggested that in addition to the between-subject effects, further forms of muscle coordination patterns appear to be employed by some, but not all participants. PMID:27203597

Characterisation of the energy use of arenas in the province of Quebec : Synthesis report; Caracterisation energetique des arenas du Quebec : Rapport synthese

Energy Technology Data Exchange (ETDEWEB)

Dussault, F.; Chalifour, A.

2000-10-24

Arenas, or skating rinks, represent a type of building with physical characteristics and uses which are relatively homogeneous throughout the country. This study revealed that the time is ripe to improve the energy efficiency of skating rinks in Quebec, and thereby gain environmental benefits through the more efficient use of refrigerants can cause damage to the environment. The aim of the study was to better define the technologies in use and the operating strategies and retrofitting techniques currently applied in the industry in order to provide guidance for an eventual Intervention Program in Refrigeration in Skating Rinks in Quebec. Background information was provided by the authors in section 1, followed by the mandate in section 2. The methodology used to carry out the study was described in section 3. The report examined four broad areas: the market, technical assistance, training, and partnerships. Each of these topics was reviewed in detail in section 4. A synthesis of the interventions was provided in section 5. The authors indicate that this project should be considered while Canada is attempting to meet its environmental commitments in the wake of increases in energy prices. Plans should be focused on measurable results within reasonable financial constraints. 13 figs.

Mouthguard

Science.gov (United States)

... softball, football, wrestling, soccer, lacrosse, rugby, in-line skating and martial arts, as well as recreational sports such as skateboarding and bicycling, should wear mouthguards while competing. Why ...

36 CFR 1002.19 - Winter activities.

Science.gov (United States)

2010-07-01

... RECREATION § 1002.19 Winter activities. (a) Skiing, snowshoeing, ice skating, sledding, innertubing, tobogganing and similar winter sports are prohibited on Presidio Trust roads and in parking areas open to...

Why Exercise Is Wise

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... dancing, in-line skating, tennis , cross-country skiing, hiking, and walking quickly. Strength Training The heart isn't the only muscle to benefit from regular exercise. The other muscles in your ...

78 FR 3346 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

Science.gov (United States)

2013-01-16

..., and 715,830 lb (324,695 kg) of bluefish. The research projects preliminary selected include the... bluefish, and assessment- quality data for weakfish, Atlantic croaker, spot, several skate and ray species...

Home advantage in the Winter Olympics (1908-1998).

Science.gov (United States)

Balmer, N J; Nevill, A M; Williams, A M

2001-02-01

We obtained indices of home advantage, based on the medals won by competing nations, for each event held at the Winter Olympics from 1908 to 1998. These indices were designed to assess home advantage while controlling for nation strength, changes in the number of medals on offer and the performance of 'non-hosting' nations. Some evidence of home advantage was found in figure skating, freestyle skiing, ski jumping, alpine skiing and short track speed skating. In contrast, little or no home advantage was observed in ice hockey, Nordic combined, Nordic skiing, bobsled, luge, biathlon or speed skating. When all events were combined, a significant home advantage was observed (P = 0.029), although no significant differences in the extent of home advantage were found between events (P > 0.05). When events were grouped according to whether they were subjectively assessed by judges, significantly greater home advantage was observed in the subjectively assessed events (P = 0.037). This was a reflection of better home performances, suggesting that judges were scoring home competitors disproportionately higher than away competitors. Familiarity with local conditions was shown to have some effect, particularly in alpine skiing, although the bobsled and luge showed little or no advantage over other events. Regression analysis showed that the number of time zones and direction of travel produced no discernible trends or differences in performance.

How Hinge Positioning in Cross-Country Ski Bindings Affect Exercise Efficiency, Cycle Characteristics and Muscle Coordination during Submaximal Roller Skiing.

Directory of Open Access Journals (Sweden)

Conor M Bolger

Full Text Available The purposes of the current study were to 1 test if the hinge position in the binding of skating skis has an effect on gross efficiency or cycle characteristics and 2 investigate whether hinge positioning affects synergistic components of the muscle activation in six lower leg muscles. Eleven male skiers performed three 4-min sessions at moderate intensity while cross-country ski-skating and using a klapskate binding. Three different positions were tested for the binding's hinge, ranging from the front of the first distal phalange to the metatarsal-phalangeal joint. Gross efficiency and cycle characteristics were determined, and the electromyographic (EMG signals of six lower limb muscles were collected. EMG signals were wavelet transformed, normalized, joined into a multi-dimensional vector, and submitted to a principle component analysis (PCA. Our results did not reveal any changes to gross efficiency or cycle characteristics when altering the hinge position. However, our EMG analysis found small but significant effects of hinge positioning on muscle coordinative patterns (P < 0.05. The changed patterns in muscle activation are in alignment with previously described mechanisms that explain the effects of hinge positioning in speed-skating klapskates. Finally, the within-subject results of the EMG analysis suggested that in addition to the between-subject effects, further forms of muscle coordination patterns appear to be employed by some, but not all participants.

Do Maximal Roller Skiing Speed and Double Poling Performance Predict Youth Cross-Country Skiing Performance?

Directory of Open Access Journals (Sweden)

Roland Stöggl, Erich Müller, Thomas Stöggl

2017-09-01

Full Text Available The aims of the current study were to analyze whether specific roller skiing tests and cycle length are determinants of youth cross-country (XC skiing performance, and to evaluate sex specific differences by applying non-invasive diagnostics. Forty-nine young XC skiers (33 boys; 13.8 ± 0.6 yrs and 16 girls; 13.4 ± 0.9 yrs performed roller skiing tests consisting of both shorter (50 m and longer durations (575 m. Test results were correlated with on snow XC skiing performance (PXC based on 3 skating and 3 classical distance competitions (3 to 6 km. The main findings of the current study were: 1 Anthropometrics and maturity status were related to boys’, but not to girls’ PXC; 2 Significant moderate to acceptable correlations between girls’ and boys’ short duration maximal roller skiing speed (double poling, V2 skating, leg skating and PXC were found; 3 Boys’ PXC was best predicted by double poling test performance on flat and uphill, while girls’ performance was mainly predicted by uphill double poling test performance; 4 When controlling for maturity offset, boys’ PXC was still highly associated with the roller skiing tests. The use of simple non-invasive roller skiing tests for determination of PXC represents practicable support for ski clubs, schools or skiing federations in the guidance and evaluation of young talent.

Description of a new species of skate of the genus Malacoraja Stehmann, 1970: the first species from the southwestern Atlantic Ocean, with notes on generic monophyly and composition (Chondrichthyes: Rajidae

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Marcelo R. de Carvalho

Full Text Available The first report of a western South Atlantic soft skate, genus Malacoraja Stehmann, 1970, is described as Malacoraja obscura, new species, from the southeastern Brazilian continental slope off the states of Espírito Santo and Rio de Janeiro, in depths ranging from 808-1105 m. The new species is known from five specimens and is distinguished from congeners by its unique dorsal coloration with small, faded white spots on disc and pelvic fins, by retaining in larger specimens an irregular row of thorns along dorsal midline of tail (extending from tail base to two-thirds of tail length in 680 mm total length female, and by presenting a ventral tail midline devoid of small denticles only at base (naked region not extending posterior to pelvic fin rear margin. Further diagnostic characters in combination include the lack of scapular thorns in larger specimens, elevated number of tooth rows (64/62 tooth rows in subadult male of 505 mm TL, and 76/74 in large female of 680 mm TL and vertebrae (27-28 Vtr, 68-75 Vprd, ventral disc and tail with a uniform dark brown coloration, paired postventral fenestrae on scapulocoracoid, enlarged posterior postventral fenestra, circular foramen magnum and paired internal carotid foramina on braincase floor. Adult males were unavailable for study, but an anatomical description of M. obscura, n. sp., is provided. Comparisons are made with all known material of M. kreffti, literature accounts of M. senta, and with abundant material of South African M. spinacidermis; M. obscura, n. sp., most closely resembles M. spinacidermis from the eastern South Atlantic in squamation, coloration and size. Malacoraja is monophyletic due to its unique squamation and rostral appendices, and apparently comprises two species-groups, one for M. obscura and M. spinacidermis, and the other for M. kreffti and M. senta, but clarification of species-level relationships must await more anatomical information, particularly of the latter two

50 CFR 648.321 - Framework adjustment process.

Science.gov (United States)

2010-10-01

... actions over the span of at least two Council meetings (the initial meeting agenda must include... bait fisheries; (21) Changes to seasonal quotas in the skate bait or wing fisheries; (22) Reduction of...

75 FR 5541 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands; Final 2009...

Science.gov (United States)

2010-02-03

...\\ BSAI trawl limited access fisheries Red king crab C. opilio C. bairdi (animals) Halibut mortality (mt..., skates, and octopus. Classification This action is authorized under 50 CFR 679.20 and is exempt from...

Movement Characteristics and Heart Rate Profiles Displayed by Female University Ice Hockey Players

Directory of Open Access Journals (Sweden)

Joel Jackson

2016-01-01

Full Text Available Background: Women’s ice hockey is widely popular but the various movement patterns, heart rate responses and work to rest ratios during competitive games has not been adequately investigated.  Objectives: This study determined the frequency and duration of movements that female players perform in ice hockey games using time-motion analysis. The intensity of the game activities were also assessed by heart rate (HR responses and work to rest ratios (W:R. Methods: Twenty-two university female ice hockey players were filmed performing a number of movements during three regular season league games. Results: The following movement patterns were categorized in percent of time performed during the games: forward gliding on ice (36.3 ± 6.2%, forward skating at a moderate intensity (31.2 ± 6.2%, backward glide (9.5 ± 4.1%, standing (7.1 ± 5.9%, struggling (6.3 ± 2.6%, forward skating at maximal intensity (5.3 ± 3.3%, backwards skating at moderate intensity (3.1 ± 3.3%. Defense stood and glided backward more than forwards but skated less at a high or maximal intensity. Positional differences were also observed during different game play situations. The highest HR (±SD achieved during shifts was 182 ± 10 and HR averaged 174 ± 9 bpm for the whole duration of the shifts. The shift and game W:R ratios for all players were 1:1.6 and 1: 3.7, respectively. Conclusions: The findings of this study indicate that female ice hockey games are played at a low to moderate intensity most of the time (~84% of the time spent and are interspersed with brief, intermittent high intensity activities that vary according to player position and game play situation. It was also apparent that female players display markedly high HR responses during game-play indicative of a substantial cardiovascular demand in ice hockey. Keywords: game analysis, work to rest ratios, exercise intensity

Altitude training considerations for the winter sport athlete.

Science.gov (United States)

Chapman, Robert F; Stickford, Jonathon L; Levine, Benjamin D

2010-03-01

Winter sports events routinely take place at low to moderate altitudes, and nearly all Winter Olympic Games have had at least one venue at an altitude >1000 m. The acute and chronic effects of altitude can have a substantial effect on performance outcomes. Acutely, the decline in oxygen delivery to working muscle decreases maximal oxygen uptake, negatively affecting performance in endurance events, such as cross-country skiing and biathlon. The reduction in air resistance at altitude can dramatically affect sports involving high velocities and technical skill components, such as ski jumping, speed skating, figure skating and ice hockey. Dissociation between velocity and sensations usually associated with work intensity (ventilation, metabolic signals in skeletal muscle and heart rate) may impair pacing strategy and make it difficult to determine optimal race pace. For competitions taking place at altitude, a number of strategies may be useful, depending on the altitude of residence of the athlete and ultimate competition altitude, as follows. First, allow extra time and practice (how much is yet undetermined) for athletes to adjust to the changes in projectile motion; hockey, shooting, figure skating and ski jumping may be particularly affected. These considerations apply equally in the reverse direction; that is, for athletes practising at altitude but competing at sea level. Second, allow time for acclimatization for endurance sports: 3-5 days if possible, especially for low altitude (500-2000 m); 1-2 weeks for moderate altitude (2000-3000 m); and at least 2 weeks if possible for high altitude (>3000 m). Third, increase exercise-recovery ratios as much as possible, with 1:3 ratio probably optimal, and consider more frequent substitutions for sports where this is allowed, such as ice hockey. Fourth, consider the use of supplemental O(2) on the sideline (ice hockey) or in between heats (skating and Alpine skiing) to facilitate recovery. For competitions at sea

Preventing head injuries in children

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... Playing contact sports, such as lacrosse, ice hockey, football Riding a skateboard, scooter, or in-line skates ... herein should not be used during any medical emergency or for the diagnosis or treatment of any ...

Why Exercise Is Cool

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... these: swimming basketball hockey running or walking skating soccer cross-country skiing riding your bike jumping rope ... My Body? Can Kids With Asthma Play Sports? Nutrition & Fitness Center Sports, Exercise, and Diabetes Getting Muscles ...

Tips for Healthy Children and Families

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... singles tennis Vacuuming Moving furniture Playing basketball or soccer Playing with children Weight lifting In-line skating ... Crisis Situations Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight Loss and Diet Plans ...

Importance of ice for the «White Olympics»

Directory of Open Access Journals (Sweden)

A. F. Renkel

2016-01-01

Full Text Available Organization of any winter Olympic game, often called as «White Olympics», requires interfacing between sports, technology and glaciology. History of the Olympic winter games and the Norwegian figure skater Sonia Henie, first and the only three-time Olympic champion (1928, 1932, 1936 in ladies figure skating, is presented in the article. Leaving the amateurish sport, Henie became a Hollywood star of the ballet on ice. She was introduced to the inventor Frank Zamboni, who created the ice re-surfacer (the ice-cleaning combine to restore the ice on skating rinks. Using the combine by Henie during her tours in the United States served to advertise this machine, and the name Zamboni had become a trademark for machines «Zamboni».

Features of construction of the training process skiers aged 17-18 years to compete in different styles of skiing

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T.V. Sidorova

2013-05-01

Full Text Available The work is devoted to the improvement of precompetitive preparation of skiers, taking into account the need to participate in competitions of different styles of skiing. The experiment included 20 athletes aged 17-18 years. Isolated model characteristics of athletes who successfully perform classic and skating style of movement. The range of indicators of physical fitness of athletes, which is the norm for this level of qualification. The technique of constructing precompetitive preparation of athletes on the basis of a combination of style of movement. It was established experimentally that the combination of training sessions during the day improves athletic performance in racing classic and skating style. In this case, primary and secondary occupation to carry out a different style of skiing with a change of their rotation on the next day.

Sports and Exercise Safety

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... re important for sports such as football , hockey, baseball, softball, biking, skateboarding, inline skating, skiing , and snowboarding — to ... in sports such as football, ice hockey , and softball and baseball when batting. Goggles are often worn ...

Broken Arm

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... of falling — including football, soccer, gymnastics, skiing and skateboarding — also increases the risk of a broken arm. ... for high-risk activities, such as in-line skating, snowboarding, rugby and football. Don't smoke. Smoking ...

Exercise and Cystic Fibrosis (CF)

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... Gymnastics G Downhill skiing DS Team sports T (soccer, volleyball, basketball, etc.) Ice skating I Rowing, canoeing ... PhD Professor Emeritus of Pediatrics and Exercise and Nutrition Sciences Woman’s and Children’s Hospital of Buffalo and ...

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Gravity-supported exercise with computer gaming improves arm function in chronic stroke.

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Jordan, Kimberlee; Sampson, Michael; King, Marcus

2014-08-01

To investigate the effect of 4 to 6 weeks of exergaming with a computer mouse embedded within an arm skate on upper limb function in survivors of chronic stroke. Intervention study with a 4-week postintervention follow-up. In home. Survivors (N=13) of chronic (≥6 mo) stroke with hemiparesis of the upper limb with stable baseline Fugl-Meyer assessment scores received the intervention. One participant withdrew, and 2 participants were not reassessed at the 4-week follow-up. No participants withdrew as a result of adverse effects. Four to 6 weeks of exergaming using the arm skate where participants received either 9 (n=5) or 16 (n=7) hours of game play. Upper limb component of the Fugl-Meyer assessment. There was an average increase in the Fugl-Meyer upper limb assessment score from the beginning to end of the intervention of 4.9 points. At the end of the 4-week period after the intervention, the increase was 4.4 points. A 4- to 6-week intervention using the arm skate significantly improved arm function in survivors of chronic stroke by an average of 4.9 Fugl-Meyer upper limb assessment points. This research shows that a larger-scale randomized trial of this device is warranted and highlights the potential value of using virtual reality technology (eg, computer games) in a rehabilitation setting. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.