共查询到20条相似文献，搜索用时 781 毫秒
1.
Ice friction of flared ice hockey skate blades 总被引：2，自引：0，他引：2
In ice hockey, skating performance depends on the skill and physical conditioning of the players and on the characteristics of their equipment. CT Edge have recently designed a new skate blade that angles outward near the bottom of the blade. The objective of this study was to compare the frictional characteristics of three CT Edge blades (with blade angles of 4 degrees, 60, and 8 degrees, respectively) with the frictional characteristics of a standard skate blade. The friction coefficients of the blades were determined by measuring the deceleration of an aluminium test sled equipped with three test blades. The measurements were conducted with an initial sled speed of 1.8 m s(-1) and with a load of 53 kg on each blade. The friction coefficient of the standard blades was 0.0071 (s = 0.0005). For the CT Edge blades with blade angles of 4 degrees, 6 degrees, and 8 degrees, friction coefficients were lower by about 13%, 21%, and 22%, respectively. Furthermore, the friction coefficients decreased with increasing load. The results of this study show that widely accepted paradigms such as "thinner blades cause less friction" need to be revisited. New blade designs might also be able to reduce friction in speed skating, figure skating, bobsledding, and luge. 相似文献
2.
When sharpening ice hockey blades a hollow is created at the running surface of the blade. This study aimed to quantify the effect of different blade hollows on (a) blade–ice friction, (b) skating performance in an agility course, and (c) players’ perception of blade sharpness, performance, and comfort. Friction was quantified by measuring the deceleration of a sled running on the blades. Skating performance was tested with 15 volunteers performing a total of 9 trials on 3 different hollow radii. Perception was assessed using a questionnaire. Friction increased with decreasing hollow radius. Skating performance was significantly impeded at a hollow radius of 3.18 mm. Within the range of 9.53–22.23 mm performance differences were subject specific and several subjects showed no differences. Players appeared to be not sensitive enough to identify hollow radii, and only half of the subjects ranked their performance correctly. 相似文献
3.
The FAST 2.0i numerical model of ice friction was developed for an inclined speed skate blade. It describes ice friction at sliding velocities sufficiently high to produce a lubricating layer of meltwater, which completely separates the ice and slider surfaces (known as the hydrodynamic friction regime). Friction arises from ploughing a groove in the ice and from the shear stress in the lubricating Couette flow. The model takes into account frictional melting, heat conduction into the ice and the lateral squeeze flow of the lubricating liquid. We use the numerical model to calculate the ice–blade contacts, the parameters of the lubricating liquid layer, and the relative importance of the various contributions to the overall friction coefficient. We also use it to perform sensitivity studies and to predict the variation of ice friction during a typical skating stroke. The model results compare favorably with measurements of the ice friction coefficient during speed skating, made by others. 相似文献
4.
Fluid forces on kayak paddle blades of different design 总被引：1，自引：1，他引：0
Three kayak paddle blades of different design (Conventional, Norwegian, Turbo) were tested in a low-speed wind tunnel at a
maximum chord Reynolds number of Re = 2.2–2.7 × 105 (corresponding to speed through water of ≈1 m/s). The mean drag force and side force acting on each blade were measured,
as the yaw and pitch angles were varied. The results were compared with those recorded for a finite rectangular flat plate
of similar area and aspect ratio. For zero pitch angle of the blades, the results indicate that the drag coefficient was mostly
independent of the blade design as the yaw angle was varied between ± 20°, with only the Norwegian blade design displaying
a marginally higher drag coefficient than either of the other two blades or the flat plate. Increasing the pitch angle to
30°, while maintaining the yaw angle at zero, resulted in a 23% reduction of the drag coefficient for the flat plate, but
only a 15% reduction of the drag coefficients for the three blades. For all designs, the drag coefficient reduction followed
a simple cosine relationship as the pitch angle or yaw angle was increased. The wind tunnel experiments revealed that the
side force coefficients for all three paddle blade designs were entirely independent of the blade design and were indistinguishable
from those recorded for a flat plate. In summary, the study showed that the nondimensional force coefficients are largely
independent of the paddle blade design. 相似文献
5.
Abstract The purpose of this investigation was to examine the fluid dynamic characteristics of the two most commonly used oar blades: the Big Blade and the Macon. Scaled models of each blade, as well as a flat Big Blade, were tested in a water flume using a quasi-static method similar to that used in swimming and kayaking research. Measurement of the normal and tangential blade forces enabled lift and drag forces generated by the oar blades to be calculated over the full range of sweep angles observed during a rowing stroke. Lift and drag force coefficients were then calculated and compared between blades. The results showed that the Big Blade and Macon oar blades exhibited very similar characteristics. Hydraulic blade efficiency was not therefore found to be the reason for claims that the Big Blade could elicit a 2% improvement in performance over the Macon. The Big Blade was also shown to have similar characteristics to the flat plate when the angle of attack was below 90°, despite significant increases in the lift coefficient when the angle of attack increased above 90°. This result suggests that the Big Blade design may not be completely optimized over the whole stroke. 相似文献
6.
7.
Antoine Fortier René A. Turcotte 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(4):341-350
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 < 0.05). 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 < 0.05) were observed, with a trend for left-turn dominance. This study demonstrates the asymmetric dynamic behaviour inherent in skating change-of-direction tasks. 相似文献
8.
Sport-specific resistance training, through limb loading, can be a complimentary training method to traditional resistance training by loading the working muscles during all phases of a specific movement. The purpose of this study was to examine the acute effects of skating with an additional load on the skate, using a skate weight prototype, on kinematics, kinetics, and muscle activation during the acceleration phase while skating on a synthetic ice surface. 10 male hockey skaters accelerated from rest (standing erect with knees slightly bent) under four non-randomized load conditions: baseline 1 (no weight), light (0.9 kg per skate), heavy (1.8 kg per skate), and baseline 2 (no weight). Skating with additional weight caused athletes to skate slower (p < 0.001; η2 = 0.551), and led to few changes in kinematics: hip sagittal range of motion (ROM) decreased (2.2°; p = 0.032; η2 = 0.274), hip transverse ROM decreased (3.4°; p < 0.001; η2 = 0.494), ankle sagittal ROM decreased (2.3°; p = 0.022; η2 = 0.295), and knee sagittal ROM increased (7.8°; p < 0.001, η2 = 0.761). Overall, weighted skates decreased skating velocity, but athletes maintained similar muscle activation profiles (magnitude and trends) with minor changes to their skating kinematics. 相似文献
9.
This work uses numerical methods to investigate the feasibility of modifying an instrument used in speed skating to analyze
blades from four different ice sports. The instrument, a handheld rocker gauge, is adapted to create a device that can effectively
profile other types of skate blades and bobsleigh runners. Since there are significant differences between short and long-track
blades one could expect a difference in the gauges used to study these blades. Despite this expectation, the same gauge is
used in both disciplines. The usefulness of these gauges has been proven in speed skating so it is expected that they should
also be useful to study hockey blades and bobsleigh runners. To optimize the gauge size for different blade types we digitize
the profile of a blade, which we use to simulate gauge data. Then we use that gauge data to reconstruct the profile and compare
it to the original digital profile. The result is compared for various gauge sizes and the gauge size is optimized for each
of the four disciplines. The only commercially available device seems optimal for bobsleigh and long track speed skating.
Smaller gauges are recommended for analyzing short track speed skates and hockey skates.
相似文献
| Louis PoirierEmail: |
10.
G. Wayne Marino 《Research quarterly for exercise and sport》2013,84(3):234-238
Abstract The purpose of this study was to explore the techniques of ice skating acceleration through analysis of specific characteristics of the movement pattern during a “front start” skating task. Two Locam 16 mm cameras operating at 100 frames per second were used to record side and overhead views of the first 6.0m of the skating starts of 69 male subjects. Data were collected on three skating start criteria, three structural variables, and twelve performance variables measured over the first three strides of the start. Summary statistics were generated and Pearson product moment correlation analysis was used to assess relationships between the criteria and performance variables. In addition, stepwise multiple regression analysis was used to predict time to skate 6.0m from a combination of the structural and performance variables. Results revealed that the mean time taken to skate 6.0m was 1.95 sec; the mean instantaneous velocity at the 6.0 mark was 5.75 m/s; and the mean average acceleration over 6.0m was 2.96m/s2. Evaluation of correlation coefficients, the regression model and summary statistics resulted in several conclusions: (1) There is a statistically significant positive relationship between velocity attained and the average rate of acceleration over a 6.0m distance in a front style skating start. (2) There are statistically significant negative relationships between both mean acceleration and final instantaneous velocity, and the time taken to skate 6.0m in a front style skating start. (3) In general, the stride pattern associated with a high rate of acceleration and a minimal skating time in a front style skating start includes: a high stride rate, significant forward lean at the point of touchdown of the recovery skate, short single support periods, and placement of the recovery foot below the hip of the recovery leg at the end of the single support period. 相似文献
11.
P. Morrison D. J. Pearsall R. A. Turcotte K. Lockwood D. L. Montgomery 《Sports Engineering》2005,8(2):91-97
The purpose of this study was to investigate the effect of skate blade hollow on oxygen consumption during forward skating
on a treadmill. Varsity level female hockey players (n = 10, age = 21.7 years) performed skating tests at three blade hollows [0.25 in (6.35 mm), 0.50 in (12.7 mm), and 0.75 in
(19.05 mm)]. The subjects skated for four minutes at three submaximal velocities (12, 14 and 16 km h−1), separated by five minutes of passive recovery. In addition, a VO2max test was performed on the day that the subjects skated at the 0.50 in hollow. The VO2max test commenced at 14 km h−1 and increased by 1 km h−1 each minute until volitional exhaustion was achieved. Four variables were measured for each skating bout, volume of gas expired
(V
E), volume of oxygen consumed (VO
2), heart rate (HR) and rating of perceived exertion (RPE). No significant differences (p < 0.05) were found in any of the four test variables (V
E, VO2, HR, RPE) across the three skate hollows. These results show that when skating on a treadmill at submaximal velocities, skate
blade hollow has no significant effect onV
E, VO2, HR or RPE. 相似文献
12.
Abstract The aim of the present study was to find a more optimal blade design for rowing performance than the Big Blade, which has been shown to be less than optimal for propulsion. As well as the Big Blade, a flat Big Blade, a flat rectangular blade, and a rectangular blade with the same curvature and projected area as the Big Blade were tested in a water flume to determine their fluid dynamic characteristics at the full range of angles at which the oar blade might present itself to the water. Similarities were observed between the flat Big Blade and rectangular blades. However, the curved rectangular blade generated significantly more lift in the angle range 0 – 90° than the curved Big Blade, although it was similar between 90 and 180°. This difference was attributed to the shape of the upper and lower edges of the blade and their influence on the fluid flow around the blade. Although the influence of oar blade design on boat speed was not investigated here, the significant increases in fluid force coefficients for the curved rectangular blade suggest that this new oar blade design could elicit a practically significant improvement in rowing performance. 相似文献
13.
Xavier Robert-Lachaine René A. Turcotte Philippe C. Dixon David J. Pearsall 《Sports Engineering》2012,15(4):197-206
Dynamic forces and range of motion (ROM) were measured during on-ice skating using a standard hockey skate and a modified skate (MS) with an altered tendon guard and eyelet configuration. The objective of this study was to determine if these modifications resulted in biomechanical and performance changes during on-ice skating skills. The right skate of each type was instrumented with a calibrated strain gauge force transducer system to measure medial?Clateral and vertical forces during ice skating. In addition, a goniometer was placed about the ankle and rear foot to measure ROM during skating. Ten subjects executed three skills: forward skating, crossovers inside foot and crossovers outside foot. The MS demonstrated significant gains of 5°?C9° in dorsi-plantarflexion ROM (p?<?0.05). Total peak force occurred later during plantarflexion, suggesting a more prolonged and effective force generation with the MS during a given skating stride. A 14?C20?% increase (p?>?0.05) in mean work and power output was noted with the MS, although no improved times were observed during the skating skills. Potentially, some players may need a period of familiarization to take advantage of the design alterations of the MS. 相似文献
14.
Eline van der Kruk Marco M. Reijne Bjorn de Laat DirkJan Veeger 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(5):527-538
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. 相似文献
15.
Matt R. Cross Farhan Tinwala Seth Lenetsky Pierre Samozino Matt Brughelli Jean-Benoit Morin 《Journal of sports sciences》2017,35(22):2198-2203
Understanding the impact of friction in sled sprinting allows the quantification of kinetic outputs and the effective loading experienced by the athlete. This study assessed changes in the coefficient of friction (µk) of a sled sprint-training device with changing mass and speed to provide a means of quantifying effective loading for athletes. A common sled equipped with a load cell was towed across an athletics track using a motorised winch under variable sled mass (33.1–99.6 kg) with constant speeds (0.1 and 0.3 m · s?1), and with constant sled mass (55.6 kg) and varying speeds (0.1–6.0 m · s?1). Mean force data were analysed, with five trials performed for each condition to assess the reliability of measures. Variables were determined as reliable (ICC > 0.99, CV < 4.3%), with normal-force/friction-force and speed/coefficient of friction relationships well fitted with linear (R2 = 0.994–0.995) and quadratic regressions (R2 = 0.999), respectively (P < 0.001). The linearity of composite friction values determined at two speeds, and the range in values from the quadratic fit (µk = 0.35–0.47) suggested µk and effective loading were dependent on instantaneous speed on athletics track surfaces. This research provides a proof-of-concept for the assessment of friction characteristics during sled towing, with a practical example of its application in determining effective loading and sled-sprinting kinetics. The results clarify effects of friction during sled sprinting and improve the accuracy of loading applications in practice and transparency of reporting in research. 相似文献
16.
E. van der Kruk O. den Braver A. L. Schwab F. C. T. van der Helm H. E. J. Veeger 《Sports Engineering》2016,19(4):273-281
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 push-off force in both the lateral direction and normal direction of the skate and the centre of pressure of these forces. The skate consists of a newly designed rigid bridge (0.6 kg), embedding two three-dimensional force sensors (Kistler 9602, Kistler Group, Winterthur, Switzerland), which fits between most individual skate shoes and Maple skate blades. The instrumented klapskates were calibrated on a tensile testing machine, where they proved to be unaffected to temperature conditions and accurate up to an RMS of 42 N (SEM = 1 N) in normal and up to an RMS of 27 N (SEM = 1 N) in lateral direction. Furthermore, the centre of pressure of these forces on the blade was determined up to a mean error of 10.1 mm (SD = 6.9 mm). On-ice measurements showed the possibility of recording with both skates simultaneously and synchronously, straights as well as curves. The option to send data wirelessly and real-time to other devices makes it possible to eventually provide skaters and coaches with visual real-time feedback during practice. 相似文献
17.
Louis Poirier Edward P. Lozowski Sean Maw Darren J. Stefanyshyn Robert I. Thompson 《Sports Engineering》2011,14(2-4):67-72
We report the first derivation of the coefficient of friction between bobsleigh runners and ice from experimental measurements performed in a controlled environment. In a series of experiments on both horizontal ice and a track sloped at 6.80°, a radar gun was used to sample the speed of a moving sled in the range of (1–10) m/s at a sample rate of 31.25 Hz. The acceleration of the sled, and thus the coefficient of friction, was extracted from these data, with a value of (4.2 ± 0.9) × 10?3 for the coefficient of friction associated with a set of two-man bobsleigh runners. There was no detectable variation in the coefficient of friction with velocity at this range of speeds and experimental accuracy. This result improves our knowledge of this coefficient over currently accepted values determined from indirect measurements, and indicates that the coefficient is lower than the currently accepted range. 相似文献
18.
冰刀结构、冰刀研磨、运动服装等非运动员主体条件的技术创新不仅丰富了速度滑冰训练理论的完善,对速度滑冰技术的改进亦起到决定性作用。短道速滑运动员使用槽刃冰刀可以增大运动员弯道滑行时法线方向冰刀与冰面之间的斜面的支撑力,可以让运动员把身体向圆心方向倾斜的程度加大、产生更大的向心力,以更快的速度滑过弯道。在4轴联动数控磨床基础上设计一台专门加工短道速滑冰刀槽刃的自动磨刀机,技术关键是将冰刀刀片与砂轮轴布置在同一水平面上、使用单斜边砂轮,这样才可以为短道速滑冰刀磨出槽刃。短道速滑冰刀槽刃数控自动磨刀机还包括工件夹具、电源、数控装置、辅助装置等其他功能组件。 相似文献
19.
Abstract 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 < 0.001), which corresponds to a time advantage of 0.41 ± 0.31 s over 100 m. The double-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. 相似文献
20.
Abstract The golf swing has been modelled as a planar movement, but recent findings suggest that the upper limbs and golf club do not move in a single plane. However, the idea that the club alone can be swung in a single inclined plane has not been investigated mathematically. The aims of this study were to determine whether a single plane could be fitted to club motion, and if this plane varied for different clubs. Ten golfers (handicap 1 – 5) performed repeated, consistent swings with three clubs (driver, 5-iron, and pitching wedge). The motion of each club during the downswing was fitted to a single plane. The fit of the plane varied between golfers and clubs (r 2 = 0.871 – 0.995, root mean square residual = 44.9 – 166.2 mm). Mean angles of the plane to the reference horizontal Z axis (driver: 125.5°, s = 3.0; 5-iron: 117.1°, s = 3.0; wedge: 113.6°, s = 2.7) and target line axis (driver: ?7.8°, s = 5.9; 5-iron: ?4.9°, s = 5.7; wedge: ?5.9°, s = 6.0) were significantly (P < 0.05) different. Further analysis revealed a single plane was more appropriate for some participants than others, but that it might be neither desirable nor possible in some cases. 相似文献