Journal articles on the topic 'Swimming – Starts and turns'
To see the other types of publications on this topic, follow the link: Swimming – Starts and turns.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Swimming – Starts and turns.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
de Jesus, Karla, Luis Mourão, Hélio Roesler, Nuno Viriato, Kelly de Jesus, Mário Vaz, Ricardo Fernandes, and João Paulo Vilas-Boas. "3D Device for Forces in Swimming Starts and Turns." Applied Sciences 9, no. 17 (August 30, 2019): 3559. http://dx.doi.org/10.3390/app9173559.
Full textAbstract:
Biomechanical tools capable of detecting external forces in swimming starts and turns have been developed since 1970. This study described the development and validation of a three-dimensional (six-degrees of freedom) instrumented block for swimming starts and turns. Seven force plates, a starting block, an underwater structure, one pair of handgrips and feet supports for starts were firstly designed, numerically simulated, manufactured and validated according to the Fédération Internationale de Natation rules. Static and dynamic force plate simulations revealed deformations between 290 to 376 µε and 279 to 545 µε in the anterior-posterior and vertical axis and 182 to 328.6 Hz resonance frequencies. Force plates were instrumented with 24 strain gauges each connected to full Wheatstone bridge circuits. Static and dynamic calibration revealed linearity ( R 2 between 0.97 and 0.99) and non-meaningful cross-talk between orthogonal (1%) axes. Laboratory and ecological validation revealed the similarity between force curve profiles. The need for discriminating each upper and lower limb force responses has implied a final nine-force plates solution with seven above and two underwater platforms. The instrumented block has given an unprecedented contribution to accurate external force measurements in swimming starts and turns.
2
Qiu, Xiao, Blanca De la Fuente, Alberto Lorenzo, and Santiago Veiga. "Comparison of Starts and Turns between Individual and Relay Swimming Races." International Journal of Environmental Research and Public Health 18, no. 9 (April 29, 2021): 4740. http://dx.doi.org/10.3390/ijerph18094740.
Full textAbstract:
The present study investigated swimmers’ performances on the starting and turning segments between individual and relay races. A total number of 72 race performances of the same swimmers in both relay 4 × 100 m finals (freestyle, medley, and mixed freestyle) and individual 100 m finals or semi-finals (butterfly, breaststroke, and freestyle) from the LEN European Swimming Championships were compared with repeated measures MANOVA. Swimmers performed 5–7% faster starts in the relay than in the corresponding individual events, despite no differences in the flight phase and a lower performance (shorter distances and slower velocities) on the underwater start section. The 15 m turn times were slower in the butterfly relay races although no specific differences in the underwater parameters were observed. These results suggest that specific training of the starting and turning segments should be performed under relay conditions to optimise pacing and performance in the underwater sections.
3
Hermosilla, Francisco, Ross Sanders, Fernando González-Mohíno, Inmaculada Yustres, and José M. González-Rave. "Effects of Dry-Land Training Programs on Swimming Turn Performance: A Systematic Review." International Journal of Environmental Research and Public Health 18, no. 17 (September 3, 2021): 9340. http://dx.doi.org/10.3390/ijerph18179340.
Full textAbstract:
Swimming coaches have prescribed dry-land training programs over the years to improve the overall swimming performance (starts, clean swimming, turns and finish). The main aim of the present systematic review was to examine the effects of dry-land strength and conditioning programs on swimming turns. Four online databases were scrutinised, data were extracted using the Preferred PRISMA guidelines and the PEDro scale was applied. A total of 1259 articles were retrieved from database searches. From the 19 studies which were full-text evaluated, six studies were included in the review process. The review indicated that plyometric, strength, ballistic and core training programs were implemented for improving swimming turn performance. Strength, ballistic and plyometric training focusing on neural enhancement seem to be effective for improving swimming turn performance. The data related to training of the core were not conclusive. Coaches should consider incorporating exercises focusing on improving the neuromuscular factor of the leg-extensor muscles into their daily dry-land training programs. More researches are needed to provide a better understanding of the training methods effects and training organisations for improving swimming turn performance.
4
Krause, Daniel. "Effects of additional knowledge of results on modifying highly practiced acyclic swimming techniques with knowledge of performance." International Journal of Sports Science & Coaching 12, no. 6 (November 2, 2017): 737–46. http://dx.doi.org/10.1177/1747954117738894.
Full textAbstract:
The author investigated the effects of additional knowledge of results on modifying swimming starts and turns with video-based knowledge of performance. A total of 18 swimming experts (15–18 years of age) learned modifications of start and turn techniques with knowledge of performance or a combination of knowledge of performance and knowledge of results. The feedback condition was switched between the groups from experiment 1 to experiment 2. Both experiments contained 50 trials with augmented feedback distributed over five sessions. Both experiments revealed no detrimental effects of additional knowledge of results on process-related performance variables. With respect to the result-related variables (start time and turn time), only the groups without knowledge of results exhibited temporary impairment in the immediate retention tests. The results are largely replicated in both experiments. Knowledge of results seems to have positive effects on modifying with knowledge of performance. The presence of knowledge of results might reduce the deautomatizing conscious control processes that are induced by knowledge of performance and might cause temporary performance impairments.
5
Šťastný, Jan. "Porovnání závodní rychlosti plaveckého způsobu kraul a rychlosti dosažené během intervalů bez vlivu startu a obrátek." Studia sportiva 10, no. 1 (July 11, 2016): 110–16. http://dx.doi.org/10.5817/sts2016-1-11.
Full textAbstract:
The race at 50 meters in freestyle swimming technique can be divided into four main phases -start, swimming at the surface, turn, and finish. With the usage of our measuring system called Tachograph, we mainly analyse the speed of swimming at the surface. Measuring principle does not allow accurate measurement of the speed after starts and turns, for that reason we evaluate the particular sections without the influence of the start and finish. We focused on the evaluation of the ratio of the measured mean swimming speed measured by the system Tachograph with the results of the current best racing performance from the 50 metre distance. For comparison we have processed the results of swimmers who participated in the semi-finals of 2010 European Championship. Our goal was to establish which results of the swimmers measured by Tachograph are at a sufficient level. The objective of the work has been accomplished with the help of statistical methods. Furthermore, we have ascertained that our recorded results differ from the results of elite swimmers whose results have been gained from the evaluation of the sections of swimming at the European Championship. We assume that the race results of our measured swimmers will differ as well. The error may be caused not only by the lack of motivation of the swimmers but also due to the constraints that our measurement system causes.
6
Olstad, Bjørn Harald, Henrik Wathne, and Tomohiro Gonjo. "Key Factors Related to Short Course 100 m Breaststroke Performance." International Journal of Environmental Research and Public Health 17, no. 17 (August 27, 2020): 6257. http://dx.doi.org/10.3390/ijerph17176257.
Full textAbstract:
Background and aim: To identify kinematic variables related to short course 100 m breaststroke performance. Methods: An automatic race analysis system was utilized to obtain start (0–15 m), turn (5 m before the wall until 10 m out), finish (95–100 m), and clean swimming (the rest of the race) segment times as well as cycle rate and cycle length during each swimming cycle from 15 male swimmers during a 100 m breaststroke race. A bivariate correlation and a partial correlation were employed to assess the relationship between each variable and swimming time. Results: Turns were the largest time contributor to the finishing time (44.30 ± 0.58%), followed by clean swimming (38.93 ± 0.50%), start (11.39 ± 0.22%), and finish (5.36 ± 0.18%). The finishing time was correlated (p < 0.001) with start segment time (r = 0.979), clean swimming time (r = 0.940), and 10 m turn-out time (r = 0.829). The clean swimming time was associated with the finishing time, but cycle rate and cycle length were not. In both start and turns, the peak velocity (i.e., take-off and push-off velocity) and the transition velocity were related to the segment time (r ≤ −0.673, p ≤ 0.006). Conclusions: Breaststroke training should focus on: (I) 15 m start with generating high take-off velocity, (II) improving clean swimming velocity by finding an optimal balance between cycle length and rate, (III) 10 m turn-out with maintaining a strong wall push-off, and (IV) establishing a high transition velocity from underwater to surface swimming.
7
Li, Gen, Ulrike K. Müller, Johan L. van Leeuwen, and Hao Liu. "Escape trajectories are deflected when fish larvae intercept their own C-start wake." Journal of The Royal Society Interface 11, no. 101 (December 6, 2014): 20140848. http://dx.doi.org/10.1098/rsif.2014.0848.
Full textAbstract:
Fish larvae may intercept their own wake during sharp turns, which might affect their escape performance. We analysed C-starts of larval zebrafish ( Danio rerio , Hamilton, 1822) using a computational fluid dynamics approach that simulates free swimming (swimming trajectory is determined by fluid forces) by coupling hydrodynamics and body dynamics. The simulations show that fish may intercept their own wake when they turn by 100–180°. During stage 1 of a C-start, the fish generates a strong jet at the tail that is shed into the wake. During stage 2, the fish intercepts this wake. Counterfactual simulations showed that wake interception increased the lateral force on the fish and reduced the fish's turning angle by more than 5°. Wake interception caused no significant acceleration tangential to the trajectory of the fish and did not affect total power output. While experimental and simulation evidence suggests that fish larvae can either undershoot or intercept but not overshoot their wake, our simulations show that larger fish might be able to avoid intercepting their wake by either under- or overshooting. As intercepting its own wake modifies the fish's escape trajectory, fish should account for this effect when planning their escape route.
8
Marinho, Daniel, Tiago Barbosa, Abel Rouboa, and António Silva. "The Hydrodynamic Study of the Swimming Gliding: a Two-Dimensional Computational Fluid Dynamics (CFD) Analysis." Journal of Human Kinetics 29, no. 1 (September 1, 2011): 49–57. http://dx.doi.org/10.2478/v10078-011-0039-4.
Full textAbstract:
The Hydrodynamic Study of the Swimming Gliding: a Two-Dimensional Computational Fluid Dynamics (CFD) AnalysisNowadays the underwater gliding after the starts and the turns plays a major role in the overall swimming performance. Hence, minimizing hydrodynamic drag during the underwater phases should be a main aim during swimming. Indeed, there are several postures that swimmers can assume during the underwater gliding, although experimental results were not conclusive concerning the best body position to accomplish this aim. Therefore, the purpose of this study was to analyse the effect in hydrodynamic drag forces of using different body positions during gliding through computational fluid dynamics (CFD) methodology. For this purpose, two-dimensional models of the human body in steady flow conditions were studied. Two-dimensional virtual models had been created: (i) a prone position with the arms extended at the front of the body; (ii) a prone position with the arms placed alongside the trunk; (iii) a lateral position with the arms extended at the front and; (iv) a dorsal position with the arms extended at the front. The drag forces were computed between speeds of 1.6 m/s and 2 m/s in a two-dimensional Fluent® analysis. The positions with the arms extended at the front presented lower drag values than the position with the arms aside the trunk. The lateral position was the one in which the drag was lower and seems to be the one that should be adopted during the gliding after starts and turns.
9
Born, Dennis-Peter, Joris Kuger, Marek Polach, and Michael Romann. "Turn Fast and Win: The Importance of Acyclic Phases in Top-Elite Female Swimmers." Sports 9, no. 9 (August 31, 2021): 122. http://dx.doi.org/10.3390/sports9090122.
Full textAbstract:
The aim of the study was to investigate the effect of start and turn performances on race times in top-elite female swimmers and provide benchmarks for all performance levels, all swimming strokes, and all race distances of the European Short-Course Championships (EC). The individual races (n = 798) of all female competitors (age: 20.6 ± 3.9 years, FINA points: 792 ± 78) were video-monitored for subsequent analysis of start and turn performances. Benchmarks were established across all competitors of each event based on the 10th, 25th, 50th, 75th, and 90th percentiles. Start and turn performances contributed up to 27.43% and 56.37% to total race time, respectively. Mechanistic analysis revealed that the fastest swimmers had the lowest contribution of the acyclic phases to race time. Therefore, relative to their faster race times, these swimmers were even faster during starts and turns. Multiple linear regression analysis showed large effects of turn performance on 50, 100, 200, 400, and 800 m race times (β = 0.616, 0.813, 0.988, 1.004, and 1.011, respectively), while the effect of start performance continuously decreased the longer the race distance. As turn performance may be the distinguishing factor in modern short-course races, benchmarks should be used to set goals and establish training guidelines depending on the targeted race time.
10
Slawson, S. E., P. P. Conway, L. M. Justham, and A. A. West. "The development of an inexpensive passive marker system for the analysis of starts and turns in swimming." Procedia Engineering 2, no. 2 (June 2010): 2727–33. http://dx.doi.org/10.1016/j.proeng.2010.04.058.
Full text
11
Stosic, Jelena, Santiago Veiga, Alfonso Trinidad, and Enrique Navarro. "How Should the Transition from Underwater to Surface Swimming Be Performed by Competitive Swimmers?" Applied Sciences 11, no. 1 (December 24, 2020): 122. http://dx.doi.org/10.3390/app11010122.
Full textAbstract:
Despite the increasing importance of the underwater segment of start and turns in competition and its positive influence on the subsequent surface swimming, there is no evidence on how the transition from underwater to surface swimming should be performed. Therefore, the aim of the present study was to examine the role of segmental, kinematic and coordinative parameters on the swimming velocity during the pre-transition and transition phases. A total of 30 national male swimmers performed 4 × 25 m (one each stroke) from a push start at maximum velocity while recorded from a lateral view by two sequential cameras (50 Hz), and their kinematic and coordinative swimming parameters were calculated by means of two-dimensional direct linear transformation (DLT) algorithms. Unlike pre-transition, backward regression analysis of transition significantly predicted swimming velocity in all strokes except breaststroke (R2 ranging from 0.263 in front crawl to 0.364 in butterfly). The inter-limb coordination was a predictor in butterfly stroke (p = 0.006), whereas the body depth and inclination were predictors in the alternate strokes (front crawl (p = 0.05) and backstroke (p = 0.04)). These results suggest that the body position and coordinative swimming parameters (apart from kicking or stroking rate and length) have an important influence on the transition performance, which depends on the swimming strokes.
12
Marinho, Daniel A., Victor M. Reis, Francisco B. Alves, João P. Vilas-Boas, Leandro Machado, António J. Silva, and Abel I. Rouboa. "Hydrodynamic Drag during Gliding in Swimming." Journal of Applied Biomechanics 25, no. 3 (August 2009): 253–57. http://dx.doi.org/10.1123/jab.25.3.253.
Full textAbstract:
This study used a computational fluid dynamics methodology to analyze the effect of body position on the drag coefficient during submerged gliding in swimming. The k-epsilon turbulent model implemented in the commercial code Fluent and applied to the flow around a three-dimensional model of a male adult swimmer was used. Two common gliding positions were investigated: a ventral position with the arms extended at the front, and a ventral position with the arms placed along side the trunk. The simulations were applied to flow velocities of between 1.6 and 2.0 m·s−1, which are typical of elite swimmers when gliding underwater at the start and in the turns. The gliding position with the arms extended at the front produced lower drag coefficients than with the arms placed along the trunk. We therefore recommend that swimmers adopt the arms in front position rather than the arms beside the trunk position during the underwater gliding.
13
Blanksby, Brian A., Jennifer R. Simpson, Bruce C. Elliott, and Keith McElroy. "Biomechanical Factors Influencing Breaststroke Turns by Age-Group Swimmers." Journal of Applied Biomechanics 14, no. 2 (May 1998): 180–89. http://dx.doi.org/10.1123/jab.14.2.180.
Full textAbstract:
Because turning can account for one-third of breaststroke race time in 25 m pools, it is possible that enhancing turning techniques can improve performance significantly. Underwater video cameras and a force platform were used to analyze turning techniques of 23 age-group breaststrokers during three 50 m push-start, maximum-effort swims. The criterion measure was the time elapsed between passing the 5 m mark on the approach and departure from the wall (5 m round-trip time [RTT]). Correlations revealed significant commonality of variance (p < .01) between the 5 m RTT and the 2.5 m RTT, 50 m time, average single-stroke velocity, peak reaction force, pivot time, impulse, peak horizontal velocity off the wall, arm and leg split-stroke resumption distances, surfacing distance, surfacing time, and horizontal velocity, height, and mass of the subjects. All swimmers achieved a net gain at the turn in that the mean 5 m RTT (20% of the distance) represented 18.26% of the total swimming time. Following stepwise regression, a successful turn was predicted by the equation 17.113 - 0.322 surfacing distance - 0.036 height - 0.723 surfacing horizontal velocity + 0.723 pivot time - 0.65 peak horizontal velocity.
14
Dabiri, John O., Sean P. Colin, Brad J. Gemmell, Kelsey N. Lucas, Megan C. Leftwich, and John H. Costello. "Jellyfish and Fish Solve the Challenges of Turning Dynamics Similarly to Achieve High Maneuverability." Fluids 5, no. 3 (June 30, 2020): 106. http://dx.doi.org/10.3390/fluids5030106.
Full textAbstract:
Turning maneuvers by aquatic animals are essential for fundamental life functions such as finding food or mates while avoiding predation. However, turning requires resolution of a fundamental dilemma based in rotational mechanics: the force powering a turn (torque) is favored by an expanded body configuration that maximizes lever arm length, yet minimizing the resistance to a turn (the moment of inertia) is favored by a contracted body configuration. How do animals balance these opposing demands? Here, we directly measure instantaneous forces along the bodies of two animal models—the radially symmetric Aurelia aurita jellyfish, and the bilaterally symmetric Danio rerio zebrafish—to evaluate their turning dynamics. Both began turns with a small, rapid shift in body kinematics that preceded major axial rotation. Although small in absolute magnitude, the high fluid accelerations achieved by these initial motions generated powerful pressure gradients that maximized torque at the start of a turn. This pattern allows these animals to initially maximize torque production before major body curvature changes. Both animals then subsequently minimized the moment of inertia, and hence resistance to axial rotation, by body bending. This sequential solution provides insight into the advantages of re-arranging mass by bending during routine swimming turns.
15
DOMENICI, PAOLO, and ROBERT W. BLAKE. "The Kinematics and Performance of the Escape Response in the Angelfish (Pterophyllum Eimekei)." Journal of Experimental Biology 156, no. 1 (March 1, 1991): 187–205. http://dx.doi.org/10.1242/jeb.156.1.187.
Full textAbstract:
The kinematics of turning manoeuvres and the distance-time performance in escape responses of startled angelfish (Pterophyllum eimekei) are investigated employing high-speed cinematography (400 Hz). All escape responses observed are C-type fast-starts, in which the fish assumes a C shape at the end of the initial body contraction (stage 1). Kinematic analysis of the subsequent stage (stage 2) allows the response to be classified into two types: single bend (SB), in which the tail does not recoil completely after the formation of the C, and double bend (DB), in which it does. The two types of response have different total escape angles (measured from the subsequent positions of the centre of mass, SB 120.0°; DB 73.3°, P<0.005), different stage 2 turning angles (in the same direction as stage 1 for SB, 11.0°; in the direction opposite to stage 1 for DB, −21.9°: P<0.0005) and different maximum angular velocities in the direction opposite to the initial one (SB −8.08 rad s−1; DB −56.62 rad s−1: P<0.001). There are no significant differences in stage 1 kinematics for the two types of escape. Stage 1 turning angle is linearly correlated to stage 2 turning angle for DB only (P<0.01; r2=0.60) and to total escape angle for both types of response (P<0.0001; r2=0.80). Stage 1 duration is linearly correlated to stage 1 turning angle (P<0.0001; r2=0.83) and to total escape angle (P<0.0001; r2=0.72) for both types of escape. Distance-time performance is also different in the two response types, mainly because of differences in stage 2 (maximum velocity for SB 0.99 ms−1; maximum velocity for DB 1.53 ms−1: maximum acceleration for SB 34.1 ms−2; maximum acceleration for DB 74.7 ms−2: P<0.0001 in both cases). As a result, there are significant differences in the performance throughout the whole response (maximum velocity 1.02 ms−1 and 1.53 ms−1 for SB and DB fast-starts, respectively; maximum acceleration 63.2 ms−2 and 91.9 ms−2 for SB and DB fast-starts, respectively) as well as within a fixed time (0.03 s). Overall, higher distance-time performances associated with smaller angles of turn are found in DB than in SB responses. Comparison with previous studies reveals that angelfish have a good fast-start performance despite specializations for low-speed swimming. In addition, the angelfish turning radius (0.065±0.0063 L, where L is body length; mean±2 S.E.) is lower than that previously reported for any fish.
16
Daly, Daniel J., Laurie A. Malone, David J. Smith, Yves Vanlandewijck, and Robert D. Steadward. "The Contribution of Starting, Turning, and Finishing to Total Race Performance in Male Paralympic Swimmers." Adapted Physical Activity Quarterly 18, no. 3 (July 2001): 316–33. http://dx.doi.org/10.1123/apaq.18.3.316.
Full textAbstract:
A video race analysis was conducted at the Atlanta Paralympic Games swimming competition. The purpose was to describe the contribution of clean swimming speed, as well as start, turn, and finish speed, to the total race performance in the four strokes for the men’s 100 m events. Start, turn, and finish times, as well as clean swimming speed during four race sections, were measured on videotapes during the preliminary heats (329 swims). Information on 1996 Olympic Games finalists (N = 16) was also available. In Paralympic swimmers, next to clean swimming speed, both turning and finishing were highly correlated with the end race result. Paralympic swimmers do start, turn, and finish slower than Olympic swimmers but in direct relation to their slower clean swimming speed. The race pattern of these components is not different between Paralympic and Olympic swimmers.
17
de Jesus, K., K. de Jesus, P. Figueiredo, P. Gonçalves, S. Pereira, J. P. Vilas-Boas, and R. J. Fernandes. "Biomechanical Analysis of Backstroke Swimming Starts." International Journal of Sports Medicine 32, no. 07 (May 11, 2011): 546–51. http://dx.doi.org/10.1055/s-0031-1273688.
Full text
18
Grznár, Ľuboš, Daniel Jurák, and Jana Labudová. "The Relationship Between Swimming Performance and Time Parameters of the Start and Turn." Acta Facultatis Educationis Physicae Universitatis Comenianae 59, no. 2 (November 1, 2019): 111–17. http://dx.doi.org/10.2478/afepuc-2019-0009.
Full textAbstract:
Summary The start and the turn are factors that influence performance in different swimming disciplines. The aim of this study was to find out the relationship of selected time parameters of the start and the turn with sport performance of 100 m and 1 500 m freestyle finalists in the Olympic Games 2016. Monitored parameters of the start were the start reaction, time under water after the start, and time at a distance of 15 m after the start. The monitored parameters of the turn were the time of 5 m before the turn, the duration of the turn, the time under water after the turn, and time reached at a distance of 15 m after the turn. There was any significant correlation of the resulting time to 1 500 m and the observed start indicators. The significant correlation of the resulting time to 1 500 m and the observed turn indicators was time 5 m before the turn r = 0.952 (p = 0.000); the duration of the turn r = 0.830 (p = 0.011); time at a distance of 15 m after the turn r = 0.886 (p = 0.003). The significant correlation of the resulting time to 100 m and the observed start indicators was time under water after the start r = −0.714 (p = 0.047). The significant correlation of the resulting time to 100 m and the observed turn indicators was the duration of the turn was r = 0.905 (p = 0.002). The results point out the existing relations between 100 m freestyle and time under water after start and duration of the turn. And for 1 500 m existing relations with time 5 m before the turn, the duration of the turn and time at a distance of 15 m after the turn. Therefore, our recommendations for sports practice include development of speed, power and coordination skills with technical execution of the start and the turn into regular swimming training.
19
Mills, Brett D., and Gale Gehlsen. "A Multidisciplinary Investigation of the Relation of State Sport Confidence with Preference and Velocity of Swimming Starts." Perceptual and Motor Skills 83, no. 1 (August 1996): 207–10. http://dx.doi.org/10.2466/pms.1996.83.1.207.
Full textAbstract:
This study investigated the relations of state sport confidence with preference of swimming start, i.e., pike or flat, and vertical velocity for male and female NCAA Division I swimmers. Ten male and 10 female swimmers who had a minimum of five years competitive swimming experience participated. Men generated greater vertical velocity on both the pike and flat starts. Analyses of variance indicated a relationship for gender with the most confident swimming start and vertical velocity for the pike and flat starts. In addition, a significant interaction between gender, preferred swimming start, and most confident swimming start was found Discriminant function analysis using gender as the grouping variable and the dependent variables of vertical velocity and state sport confidence indicated that gender was an indicator of swimmers' performance and state sport confidence on the pike and flat starts.
20
Srivastava, Nikhil, Damon A. Clark, and Aravinthan D. T. Samuel. "Temporal Analysis of Stochastic Turning Behavior of Swimming C. elegans." Journal of Neurophysiology 102, no. 2 (August 2009): 1172–79. http://dx.doi.org/10.1152/jn.90952.2008.
Full textAbstract:
Caenorhabditis elegans exhibits spontaneous motility in isotropic environments, characterized by periods of forward movements punctuated at random by turning movements. Here, we study the statistics of turning movements—deep Ω-shaped bends—exhibited by swimming worms. We show that the durations of intervals between successive Ω-turns are uncorrelated with one another and are effectively selected from a probability distribution resembling the sum of two exponentials. The worm initially exhibits frequent Ω-turns on being placed in liquid, and the mean rate of Ω-turns lessens over time. The statistics of Ω-turns is consistent with a phenomenological model involving two behavioral states governed by Poisson kinetics: a “slow” state generates Ω-turns with a low probability per unit time; a “fast” state generates Ω-turns with a high probability per unit time; and the worm randomly transitions between these slow and fast states. Our findings suggest that the statistics of spontaneous Ω-turns exhibited by swimming worms may be described using a small number of parameters, consistent with a two-state phenomenological model for the mechanisms that spontaneously generate Ω-turns.
21
Seamone, S. G., T. M. McCaffrey, and D. A. Syme. "Disc starts: the pectoral disc of stingrays promotes omnidirectional fast starts across the substrate." Canadian Journal of Zoology 97, no. 7 (July 2019): 597–605. http://dx.doi.org/10.1139/cjz-2018-0054.
Full textAbstract:
We explored how the flattened and rounded pectoral disc of the ocellate river stingray (Potamotrygon motoro (Müller and Henle, 1841)) enables them to use the benthic plane during fast-start escape. Escape responses were elicited via prodding different locations around the pectoral disc and were recorded using video. Modulation of pectoral-fin movements that power swimming enabled omnidirectional escape across the substrate, with similar performance in all directions of escape. Hence, translation of the body did not necessarily have to follow the orientation of the head, overcoming the constraint of a rigid body axis. An increase in prod speed was associated with an increase in initial translational speed and acceleration away from the prod. As prod location shifted towards the snout, yaw rotation increased, eventually reorienting the fish into a forward swimming position away from the prod. Furthermore, P. motoro yawed with essentially zero turning radius, allowing reorientation of the head with simultaneous rapid translation away from the prod, and yaw rate during escape was substantially greater than reported during routine swimming for stingrays. We conclude that stingrays employ a distinctive approach to escape along the substrate, which we have termed disc starts, that results in effective manoeuvrability across the benthic environment despite limited longitudinal flexibility of the body and that challenges the concept of manoeuvrability typically used for fishes.
22
Gehlsen, G. M., and J. L. Wingfield. "CHARACTERISTICS OF COMPETITIVE SWIMMING STARTS: INJURY PREVENTION 280." Medicine & Science in Sports & Exercise 28, Supplement (May 1996): 47. http://dx.doi.org/10.1097/00005768-199605001-00280.
Full text
23
Gonjo, Tomohiro, and Bjørn Harald Olstad. "Race Analysis in Competitive Swimming: A Narrative Review." International Journal of Environmental Research and Public Health 18, no. 1 (December 24, 2020): 69. http://dx.doi.org/10.3390/ijerph18010069.
Full textAbstract:
Researchers have quantified swimming races for several decades to provide objective information on race strategy and characteristics. The purpose of the present review was to summarize knowledge established in the literature and current issues in swimming race analysis. A systematic search of the literature for the current narrative review was conducted in September 2020 using Web of Science, SPORTDiscus (via EBSCO), and PubMed. After examining 321 studies, 22 articles were included in the current review. Most studies divided the race into the start, clean swimming, turn, and/or finish segments; however, the definition of each segment varied, especially for the turn. Ideal definitions for the start and turn-out seemed to differ depending on the stroke styles and swimmers’ level. Many studies have focused on either 100 m or 200 m events with the four strokes (butterfly, backstroke, breaststroke, and freestyle). Contrastingly, there were few or no studies for 50 m, long-distance, individual medley, and relay events. The number of studies examining races for short course, junior and Paralympic swimmers were also very limited. Future studies should focus on those with limited evidence as well as race analysis outside competitions in which detailed kinematic and physiological analyses are possible.
24
Polach, Marek, Dan Thiel, and Zbyněk Svozil. "Turns as an important factor of swimming performance." Tělesná kultura 42, no. 1 (November 7, 2019): 9–13. http://dx.doi.org/10.5507/tk.2019.006.
Full text
25
Webster, J. M., A. West, P. Conway, and M. Cain. "Development of a pressure sensor for swimming turns." Procedia Engineering 13 (2011): 126–32. http://dx.doi.org/10.1016/j.proeng.2011.05.062.
Full text
26
McLean, Scott P., Michael J. Holthe, Peter F. Vint, Keith D. Beckett, and Richard N. Hinrichs. "Addition of an Approach to a Swimming Relay Start." Journal of Applied Biomechanics 16, no. 4 (November 2000): 342–55. http://dx.doi.org/10.1123/jab.16.4.342.
Full textAbstract:
Ten male collegiate swimmers (age = 20.2 ± 1.4 years, height = 184.6 ± 5.8 cm, mass = 82.9 ± 9.3 kg) performed 3 swimming relay step starts, which incorporated a one or two-step approach, and a no-step relay start. Time to 10 m was not significantly shorter between step and no-step starts. A double-step start increased horizontal takeoff velocity by 0.2 m/s. A single-step together start decreased vertical takeoff velocity by 0.2 m/s but increased takeoff height by 0.16 m. Subjects were more upright at takeoff by 4°, 2°, and 5° in the double-step, single-step apart, and single-step together starts, respectively, than in the no-step start. Entry angle was steeper by 2°, entry orientation was steeper by 3°, and entry vertical velocity was faster by 0.3 m/s in the single-step together start. Restricting step length by 50% had little effect on step starts with the exceptions that horizontal velocity was significantly reduced by 0.1 m/s in the double-step start and vertical takeoff velocity was increased by 0.2 m/s in the single-step together start. These data suggested that step starts offered some performance improvements over the no-step start, but these improvements were not widespread and, in the case of the double-step start, were dependent on the ability to take longer steps.
27
Rühlemann, Christoph. "Turn structure and inserts." International Journal of Corpus Linguistics 25, no. 2 (August 28, 2020): 185–214. http://dx.doi.org/10.1075/ijcl.19098.ruh.
Full textAbstract:
Abstract Turns-at-talk often do not start with their main business but rather with a pre-start (Sacks et al., 1974). This paper investigates the correlation of pre-starts with inserts, one of three major word classes (Biber et al., 1999). Based on the BNC’s mark-up, I investigate how inserts are positionally distributed in large amounts of turns of varied lengths. The analysis shows that inserts are overwhelmingly attracted to turn-first positions, the likely location of pre-starts. Further, in a subsample of 1,000 ten-word turns manually coded for pre-starts, 86% of all inserts serve a pre-start function. The findings call into question current speech processing models that fail to factor in turn structure. Further, pre-starts have crucial sequential and interactional implications as early indicators whether the new turn “agrees” with the prior turn and are likely key signals aiding listeners’ action ascription.
28
Skorski, Sabrina, Naroa Etxebarria, and Kevin G. Thompson. "Breaking the Myth That Relay Swimming Is Faster Than Individual Swimming." International Journal of Sports Physiology and Performance 11, no. 3 (April 2016): 410–13. http://dx.doi.org/10.1123/ijspp.2014-0577.
Full textAbstract:
Purpose:To investigate if swimming performance is better in a relay race than in the corresponding individual race.Methods:The authors analyzed 166 elite male swimmers from 15 nations in the same competition (downloaded from www.swimrankings.net). Of 778 observed races, 144 were Olympic Games performances (2000, 2004, 2012), with the remaining 634 performed in national or international competitions. The races were 100-m (n = 436) and 200-m (n = 342) freestyle events. Relay performance times for the 2nd–4th swimmers were adjusted (+ 0.73 s) to allow for the “flying start.”Results:Without any adjustment, mean individual relay performances were significantly faster for the first 50 m and overall time in the 100-m events. Furthermore, the first 100 m of the 200-m relay was significantly faster (P > .001). During relays, swimmers competing in 1st position did not show any difference compared with their corresponding individual performance (P > .16). However, swimmers competing in 2nd–4th relay-team positions demonstrated significantly faster times in the 100-m (P < .001) and first half of the 200-m relays than in their individual events (P < .001, ES: 0.28–1.77). However, when finishing times for 2nd–4th relay team positions were adjusted for the flying start no differences were detected between relay and individual race performance for any event or split time (P > .17).Conclusion:Highly trained swimmers do not swim (or turn) faster in relay events than in their individual races. Relay exchange times account for the difference observed in individual vs relay performance.
29
Morais, Jorge E., Daniel A. Marinho, Raul Arellano, and Tiago M. Barbosa. "Start and turn performances of elite sprinters at the 2016 European Championships in swimming." Sports Biomechanics 18, no. 1 (March 26, 2018): 100–114. http://dx.doi.org/10.1080/14763141.2018.1435713.
Full text
30
Webb, Paul W., Doug H. Hardy, and Vicki L. Mehl. "The effect of armored skin on the swimming of longnose gar, Lepisosteus osseus." Canadian Journal of Zoology 70, no. 6 (June 1, 1992): 1173–79. http://dx.doi.org/10.1139/z92-164.
Full textAbstract:
Fast-starts and steady swimming were compared for two piscivorous fishes, the longnose gar (Lepisosteus osseus), which has an integument armored with ganoid scales, and the unarmored tiger musky (Esox sp.). The body was similarly flexed by both species during fast-starts and steady swimming. Therefore, the heavy integument of the gar did not affect flexibility during swimming. Distance traveled in a given elapsed time during fast-starts was lower for the gar, which averaged 65% of the work done by the musky. On the basis of differences in muscle mass, gars would be expected to perform 72% of the work of muskies during a fast-start. The heavier integument of the gar was estimated to contribute about 90% to the reduced fast-start performance. In steady swimming, mechanical power requirements at a given speed were similar for both gar and musky. Therefore, steady swimming costs do not appear to be affected by armor. The critical swimming speed of gars was 1.9 body lengths/s compared with 3.4 body lengths/s for muskies, but the difference could not be attributed to differences in armoring. The slip speed at which gars first began to swim was 1.21 body lengths/s compared with 0.75 body lengths/s for muskies. Higher station-holding performance is probably not important to modern gars and esocids, but may have been advantageous during the early radiation of fishes.
31
Matúš, Ivan. "Biomechanická analýza štartových skokov v plávaní." Studia sportiva 8, no. 1 (July 14, 2014): 109–25. http://dx.doi.org/10.5817/sts2014-1-12.
Full textAbstract:
Presented research comes up with results representing a role of speed-force and timing parameters in four start types at the track of 7.5 m and 10 m distance. Eighteen performance male swimmers (age 23.4±2.1), specialists in sprint event, participated in this study. We noticed the highest measured vertical force in swimming starts with rearward stretch (ZŠSN, AŠSN) in both track distances. For the horizontal force in the tracks of both distances we noticed the highest values of maximum force in grab starts (ZŠS, ZŠSN), but the average values were the highest in the track starts (AŠSN, AŠS). From the timing parameters on the starting block, the shortest reaction time was measured in swimming starts with rearward stretch (ZŠSN, AŠSN). The shortest movement and starting reaction time from the starting block was measured in the swimming start with rearward stretch (ZŠSN, AŠSN) in both track distances. The shortest time of a flight and gliding phase for the track of 7.5 m and 10 m distance we measured in the track start with rearward. Difference between the first and the second fastest time in the track of 7.5 m distance to 0,02 s, but the track of 10 m distance was doubled. On the basis of these results we recommend to swimmer sprinters to use mainly the track start with rearward. The statistical significance of differences in speed-force parameters pointed on the differences between the four types of swimming starts. In all types of the starts were shown close relations between the track time for 7.5 m and 10 m distance, horizontal force parameters and the time of the flight and gliding phase.
32
Jimenez, Yordano E., and Elizabeth L. Brainerd. "Dual function of epaxial musculature for swimming and suction feeding in largemouth bass." Proceedings of the Royal Society B: Biological Sciences 287, no. 1919 (January 22, 2020): 20192631. http://dx.doi.org/10.1098/rspb.2019.2631.
Full textAbstract:
The axial musculature of many fishes generates the power for both swimming and suction feeding. In the case of the epaxial musculature, unilateral activation bends the body laterally for swimming, and bilateral activation bends the body dorsally to elevate the neurocranium for suction feeding. But how does a single muscle group effectively power these two distinct behaviours? Prior electromyographic (EMG) studies have identified fishes' ability to activate dorsal and ventral epaxial regions independently, but no studies have directly compared the intensity and spatial activation patterns between swimming and feeding. We measured EMG activity throughout the epaxial musculature during swimming (turning, sprinting, and fast-starts) and suction feeding (goldfish and pellet strikes) in largemouth bass ( Micropterus salmoides ). We found that swimming involved obligate activation of ventral epaxial regions whereas suction feeding involved obligate activation of dorsal epaxial regions, suggesting regional specialization of the epaxial musculature. However, during fast-starts and suction feeding on live prey, bass routinely activated the whole epaxial musculature, demonstrating the dual function of this musculature in the highest performance behaviours. Activation intensities in suction feeding were substantially lower than fast-starts which, in conjunction with suboptimal shortening velocities, suggests that bass maximize axial muscle performance during locomotion and underuse it for suction feeding.
33
Hui, Clifford A. "Maneuverability of the Humboldt penguin (Spheniscus humboldti) during swimming." Canadian Journal of Zoology 63, no. 9 (September 1, 1985): 2165–67. http://dx.doi.org/10.1139/z85-318.
Full textAbstract:
Analyses of high-speed film of captive Humboldt penguins (Spheniscus humboldti) show that there is no correlation between the radii of submerged turns and swimming speed. The sharpest turns had a mean turn radius (n = 5) of 0.14 m (0.24 body lengths), were powered by beating wings, and used multiple steering structures (beak, tail, feet, wings) and a flexing body. This turn radius is similar to that of fast-swimming fish with rigid bodies and lunate tails but is greater than that of slower fish with flexible bodies. The maximum turning rate was 10.05 radians s−1. Maneuverability is augmented by neck-extending strike behavior and porpoising leaps.
34
Houel, Nicolas, Marc Elipot, Frédéric André, and Philippe Hellard. "Influence of Angles of Attack, Frequency and Kick Amplitude on Swimmer’s Horizontal Velocity During Underwater Phase of a Grab Start." Journal of Applied Biomechanics 29, no. 1 (February 2013): 49–54. http://dx.doi.org/10.1123/jab.29.1.49.
Full textAbstract:
The underwater phase of starts represents an important part of the performance in sprint swimming’s events. Kinematics variables that swimmers have to take into account to improve their underwater phase of starts are unknown. The aim of this study was to determine the kinematics variables that improve performance during the underwater phase of grab starts. A three-dimensional analysis of the underwater phase of ten swimmers of national level was conducted. Stepwise multiple linear regressions identified the main kinematics variables that influence the horizontal velocity of the swimmer each 0.5 m in the range of 5 to 7.5 m. The results show that the kinematics parameters change during the range of 5 to 7.5 m of the underwater phase of the starts. For this population of swimmers, the results enable proposals of four principles to improve the underwater phase: i) to be streamlined at the beginning of the underwater gliding phase, ii) to start the dolphin kicking after 6 m, iii) to generate propulsive forces using only feet and legs during underwater undulatory swimming, iv) to improve the frequency of underwater undulatory swimming.
35
Ekeberg, Örjan, and Sten Grillner. "Simulations of neuromuscular control in lamprey swimming." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 354, no. 1385 (May 29, 1999): 895–902. http://dx.doi.org/10.1098/rstb.1999.0441.
Full textAbstract:
The neuronal generation of vertebrate locomotion has been extensively studied in the lamprey. Models at different levels of abstraction are being used to describe this system, from abstract nonlinear oscillators to interconnected model neurons comprising multiple compartments and a Hodgkin–Huxley representation of the most relevant ion channels. To study the role of sensory feedback by simulation, it eventually also becomes necessary to incorporate the mechanical movements in the models. By using simplifying models of muscle activation, body mechanics, counteracting water forces, and sensory feedback through stretch receptors and vestibular organs, we have been able to close the feedback loop to enable studies of the interaction between the neuronal and the mechanical systems. The neuromechanical simulations reveal that the currently known network is sufficient for generating a whole repertoire of swimming patterns. Swimming at different speeds and with different wavelengths, together with the performance of lateral turns can all be achieved by simply varying the brainstem input. The neuronal mechanisms behind pitch and roll manoeuvres are less clear. We have put forward a ‘crossed–oscillators’ hypothesis where partly separate dorsal and ventral circuits are postulated. Neuromechanical simulations of this system show that it is also capable of generating realistic pitch turns and rolls, and that vestibular signals can stabilize the posture during swimming.
36
Budick, S. A., and D. M. O'Malley. "Locomotor repertoire of the larval zebrafish: swimming, turning and prey capture." Journal of Experimental Biology 203, no. 17 (September 1, 2000): 2565–79. http://dx.doi.org/10.1242/jeb.203.17.2565.
Full textAbstract:
Larval zebrafish (Brachydanio rerio) are a popular model system because of their genetic attributes, transparency and relative simplicity. They have approximately 200 neurons that project from the brainstem into the spinal cord. Many of these neurons can be individually identified and laser-ablated in intact larvae. This should facilitate cellular-level characterization of the descending control of larval behavior patterns. Towards this end, we attempt to describe the range of locomotor behavior patterns exhibited by zebrafish larvae. Using high-speed digital imaging, a variety of swimming and turning behaviors were analyzed in 6- to 9-day-old larval fish. Swimming episodes appeared to fall into two categories, with the point of maximal bending of the larva's body occurring either near the mid-body (burst swims) or closer to the tail (slow swims). Burst swims also involved larger-amplitude bending, faster speeds and greater yaw than slow swims. Turning behaviors clearly fell into two distinct categories: fast, large-angle escape turns characteristic of escape responses, and much slower routine turns lacking the large counterbend that often accompanies escape turns. Prey-capture behaviors were also recorded. They were made up of simpler locomotor components that appeared to be similar to routine turns and slow swims. The different behaviors observed were analyzed with regard to possible underlying neural control systems. Our analysis suggests the existence of discrete sets of controlling neurons and helps to explain the need for the roughly 200 spinal-projecting nerve cells in the brainstem of the larval zebrafish.
37
Karayannidou, A., P. V. Zelenin, G. N. Orlovsky, and T. G. Deliagina. "Responses of Reticulospinal Neurons in the Lamprey to Lateral Turns." Journal of Neurophysiology 97, no. 1 (January 2007): 512–21. http://dx.doi.org/10.1152/jn.00912.2006.
Full textAbstract:
When swimming, the lamprey maintains a definite orientation of its body in the vertical planes, in relation to the gravity vector, as the result of postural vestibular reflexes. Do the vestibular-driven mechanisms also play a role in the control of the direction of swimming in the horizontal (yaw) plane, in which the gravity cannot be used as a reference direction? In the present study, we addressed this question by recording responses to lateral turns in reticulospinal (RS) neurons mediating vestibulospinal reflexes. In intact lampreys, the activity of axons of RS neurons was recorded in the spinal cord by implanted electrodes. Vestibular stimulation was performed by periodical turns of the animal in the yaw plane (60° peak to peak). It was found that the majority of responding RS neurons were activated by the contralateral turn. By removing one labyrinth, we found that yaw responses in RS neurons were driven mainly by input from the contralateral labyrinth. We suggest that these neurons, when activated by the contralateral turn, will elicit the ipsilateral turn and thus will compensate for perturbations of the rectilinear swimming caused by external factors. It is also known that unilateral eye illumination elicits a contralateral turn in the yaw plane (negative phototaxis). We found that a portion of RS neurons were activated by the contralateral eye illumination. By eliciting an ipsilateral turn, these neurons could mediate the negative phototaxis.
38
Mallett, Adam, Phillip Bellinger, Wim Derave, Eline Lievens, Ben Kennedy, Hal Rice, and Clare Minahan. "Muscle Fiber Typology and Its Association With Start and Turn Performance in Elite Swimmers." International Journal of Sports Physiology and Performance 16, no. 6 (June 1, 2021): 834–40. http://dx.doi.org/10.1123/ijspp.2020-0548.
Full textAbstract:
Purpose: To determine the association between estimated muscle fiber typology and the start and turn phases of elite swimmers during competition. Methods: International and national competition racing performance was analyzed from 21 female (FINA points = 894 ± 39: 104.5 ± 1.8% world record ratio [WRR]) and 25 male (FINA points = 885 ± 54: 104.8 ± 2.1% WRR) elite swimmers. The start, turn, and turn out times were determined from each of the swimmers’ career best performance times (FINA points = 889 ± 48: 104.7 ± 2.0% WRR). Muscle carnosine concentration was quantified by proton magnetic resonance spectroscopy in the gastrocnemius and soleus and was expressed as a carnosine aggregate z score relative to an age- and gender-matched nonathlete control group to estimate muscle fiber typology. Linear mixed models were employed to determine the association between muscle fiber typology and the start and turn times. Results: While there was no significant influence of carnosine aggregate z score on the start and turn times when all strokes and distance events were entered into the model, the swimmers with a higher carnosine aggregate z score (ie, faster muscle typology) had a significantly faster start time in 100-m events compared with the swimmers with a lower carnosine aggregate z score (P = .02, F = 5.825). The start and turn times were significantly faster in the male compared with the female swimmers in the 100-m events compared with other distances, and between the 4 different swimming strokes (P < .001). Conclusion: This study suggests that start times in sprint events are partly determined (and limited) by muscle fiber typology, which is highly relevant when ∼12% of the overall performance time is determined from the start time.
39
West, Daniel J., Nick J. Owen, Dan J. Cunningham, Christian J. Cook, and Liam P. Kilduff. "Strength and Power Predictors of Swimming Starts in International Sprint Swimmers." Journal of Strength and Conditioning Research 25, no. 4 (April 2011): 950–55. http://dx.doi.org/10.1519/jsc.0b013e3181c8656f.
Full text
40
Kilduff, Liam P., Dan J. Cunningham, Nick J. Owen, Daniel J. West, Richard M. Bracken, and Christian J. Cook. "Effect of Postactivation Potentiation on Swimming Starts in International Sprint Swimmers." Journal of Strength and Conditioning Research 25, no. 9 (September 2011): 2418–23. http://dx.doi.org/10.1519/jsc.0b013e318201bf7a.
Full text
41
Sakai, Yusuke, Naoyuki Takesue, and Hiromi Mochiyama. "Compact Swimming Robot with Continuum Water Jet Nozzle for Rapid Turns." IFAC-PapersOnLine 53, no. 2 (2020): 9181–88. http://dx.doi.org/10.1016/j.ifacol.2020.12.2179.
Full text
42
Ellerby, D. J., and J. D. Altringham. "Spatial variation in fast muscle function of the rainbow troutOncorhynchus mykissduring fast-starts and sprinting." Journal of Experimental Biology 204, no. 13 (July 1, 2001): 2239–50. http://dx.doi.org/10.1242/jeb.204.13.2239.
Full textAbstract:
SUMMARYFish fast-starts and sprints are rapid kinematic events powered by the lateral myotomal musculature. A distinction can be made between fast-starts and sprint-swimming activity. Fast-starts are kinematic events involving rapid, asymmetrical movements. Sprints involve a series of symmetrical, high-frequency tailbeats that are kinematically similar to lower-frequency, sustained swimming. The patterns of muscle recruitment and strain associated with these swimming behaviours were determined using electromyography and sonomicrometry. Axial patterns of fast muscle recruitment during sprints were similar to those in slow muscle in that the duration of electromyograhic (EMG) activity decreased in a rostro-caudal direction. There was also an axial shift in activity relative to the strain cycle so that activity occurred relatively earlier in the caudal region. This may result in caudal muscle performing a greater proportion of negative work and acting as a power transmitter as well as a power producer. The threshold tailbeat frequency for recruitment of fast muscle differed with location in the myotome. Superficial muscle fibres were recruited at lower tailbeat frequencies and shortening velocities than those deeper in the musculature. During sprints, fast muscle strain ranged from ±3.4%l0 (where l0 is muscle resting length) at 0.35FL (where FL is fork length) to ±6.3%l0 at 0.65FL. Fast-starts involved a prestretch of up to 2.5%l0 followed by shortening of up to 11.3%l0. Stage 1 EMG activity began simultaneously, during muscle lengthening, at all axial locations. Stage 2 EMG activity associated with the major contralateral contraction also commenced during lengthening and proceeded along the body as a wave. Onset of muscle activity during lengthening may enhance muscle power output.
43
Lecheval, Valentin, Li Jiang, Pierre Tichit, Clément Sire, Charlotte K. Hemelrijk, and Guy Theraulaz. "Social conformity and propagation of information in collective U-turns of fish schools." Proceedings of the Royal Society B: Biological Sciences 285, no. 1877 (April 25, 2018): 20180251. http://dx.doi.org/10.1098/rspb.2018.0251.
Full textAbstract:
Moving animal groups such as schools of fishes or flocks of birds often undergo sudden collective changes of their travelling direction as a consequence of stochastic fluctuations in heading of the individuals. However, the mechanisms by which these behavioural fluctuations arise at the individual level and propagate within a group are still unclear. In this study, we combine an experimental and theoretical approach to investigate spontaneous collective U-turns in groups of rummy-nose tetra ( Hemigrammus rhodostomus ) swimming in a ring-shaped tank. U-turns imply that fish switch their heading between the clockwise and anticlockwise direction. We reconstruct trajectories of individuals moving alone and in groups of different sizes. We show that the group decreases its swimming speed before a collective U-turn. This is in agreement with previous theoretical predictions showing that speed decrease facilitates an amplification of fluctuations in heading in the group, which can trigger U-turns. These collective U-turns are mostly initiated by individuals at the front of the group. Once an individual has initiated a U-turn, the new direction propagates through the group from front to back without amplification or dampening, resembling the dynamics of falling dominoes. The mean time between collective U-turns sharply increases as the size of the group increases. We develop an Ising spin model integrating anisotropic and asymmetrical interactions between fish and their tendency to follow the majority of their neighbours nonlinearly (social conformity). The model quantitatively reproduces key features of the dynamics and the frequency of collective U-turns observed in experiments.
44
Worawannotai, Chalermpong, and Watcharintorn Ruksasakchai. "Competition-Independence Game and Domination Game." Mathematics 8, no. 3 (March 5, 2020): 359. http://dx.doi.org/10.3390/math8030359.
Full textAbstract:
The domination game is played on a graph by two players, Dominator and Staller, who alternately choose a vertex of G. Dominator aims to finish the game in as few turns as possible while Staller aims to finish the game in as many turns as possible. The game ends when all vertices are dominated. The game domination number, denoted by γ g ( G ) (respectively γ g ′ ( G ) ), is the total number of turns when both players play optimally and when Dominator (respectively Staller) starts the game. In this paper, we study a version of this game where the set of chosen vertices is always independent. This version turns out to be another game known as the competition-independence game. The competition-independence game is played on a graph by two players, Diminisher and Sweller. They take turns in constructing maximal independent set M, where Diminisher tries to minimize | M | and Sweller tries to maximize | M | . Note that, actually, it is the domination game in which the set of played vertices is independent. The competition-independence number, denoted by I d ( G ) (respectively I s ( G ) ) is the optimal size of the final independent set in the competition-independence game if Diminisher (respectively Sweller) starts the game. In this paper, we check whether some well-known results in the domination game hold for the competition-independence game. We compare the competition-independence numbers to the game domination numbers. Moreover, we provide a family of graphs such that many parameters are equal. Finally, we present a realization result on the competition-independence numbers.
45
Mori, Daichi, and Motomu Nakashima. "Simulation Model of Flip Turn in Swimming." Proceedings 49, no. 1 (June 15, 2020): 165. http://dx.doi.org/10.3390/proceedings2020049165.
Full textAbstract:
The swimming turn is one of the important factors in producing results in a race. Knowing the mechanical quantities in turns is useful to quantify the turning technique. However, experimental measurements often require considerable time and costs. The aim of this study was to construct a simulation model of a flip turn in the crawl stroke by extending the swimming human simulation model SWUM. The joint motion was created based on the standard crawl motion and a turn commentary video on the Internet. Furthermore, the contact with the wall was represented as forces by virtual springs and dampers and the frictional forces. As a result of simulation, a successful turning motion was confirmed. It was also found that the simulated contact time, the maximum force, and the impulse were within the ranges of the previous research.
46
Domenici, P., and R. Blake. "The kinematics and performance of fish fast-start swimming." Journal of Experimental Biology 200, no. 8 (April 1, 1997): 1165–78. http://dx.doi.org/10.1242/jeb.200.8.1165.
Full textAbstract:
Fast-starts are brief, sudden accelerations used by fish during predator­prey encounters. The kinematics and performance of fish during fast-start manoeuvres have received a lot of attention since they may determine the outcome of predator­prey interactions in terms of feeding success or survival. We will discuss recent progress on (1) the kinematics of escape responses and feeding strikes, (2) the fast-start performance of species with different body morphologies and from different habitats, and (3) the functional significance of fast-start kinematics and performance within the context of predator­prey interactions.
47
Carmigniani, R., L. Seifert, D. Chollet, and C. Clanet. "Coordination changes in front-crawl swimming." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2237 (May 2020): 20200071. http://dx.doi.org/10.1098/rspa.2020.0071.
Full textAbstract:
We report the evolution of the coordination with velocity in front-crawl swimming which is used in competitions over a large range of distances (from 50 m up to 25 km in open-water races). Inside this single stroke, top-level swimmers show different patterns of arm organization. At low velocities, swimmers select an alternated stroke with gliding pauses during their propulsion. The relative duration of the gliding pauses on a stroke cycle is independent of the velocity in this first regime. Above a critical velocity, the relative duration of the gliding pauses starts to decrease as speed increases. Above a second critical velocity, the gliding pauses disappear and the swimmers start to superpose their propulsion phases. These three regimes are first revealed experimentally and then studied theoretically. It appears that below the first critical velocity, swimmers use a constant coordination index and vary their speed by varying their propulsive force to minimize their cost of propulsion. For larger velocities, swimmers use their maximum propulsive force and vary their recovery time to increase further their speed. The physical model developed is general and could be applied to understand other modes of locomotion.
48
Gallino, Giacomo, Lailai Zhu, and François Gallaire. "The Hydrodynamics of a Micro-Rocket Propelled by a Deformable Bubble." Fluids 4, no. 1 (March 14, 2019): 48. http://dx.doi.org/10.3390/fluids4010048.
Full textAbstract:
We perform simulations to study the hydrodynamics of a conical-shaped swimming micro-robot that ejects catalytically produced bubbles from its inside. We underline the nontrivial dependency of the swimming velocity on the bubble deformability and on the geometry of the swimmer. We identify three distinct phases during the bubble evolution: immediately after nucleation the bubble is spherical and its inflation barely affects the swimming speed; then the bubble starts to deform due to the confinement gradient generating a force that propels the swimmer; while in the last phase, the bubble exits the cone, resulting in an increase in the swimmer velocity. Our results shed light on the fundamental hydrodynamics of the propulsion of catalytic conical swimmers and may help to improve the efficiency of these micro-machines.
49
Matthews, Roger. "False Starts, Wrong Turns and Dead Ends: Reflections on Recent Developments in Criminology." Critical Criminology 25, no. 4 (September 25, 2017): 577–91. http://dx.doi.org/10.1007/s10612-017-9372-9.
Full text
50
Strzała, Marek, Arkadiusz Stanula, Piotr Krężałek, Wojciech Rejdych, Jakub Karpiński, Marcin Maciejczyk, and Artur Radecki-Pawlik. "Specific and Holistic Predictors of Sprint Front Crawl Swimming Performance." Journal of Human Kinetics 78, no. 1 (March 1, 2021): 197–207. http://dx.doi.org/10.2478/hukin-2021-0058.
Full textAbstract:
Abstract The aim of the study was to examine the impact of selected water- and dry-land predictors of 50-m front crawl performance among 27 male swimmers aged 19.3 ± 2.67 years. The following water tests were performed: front crawl tethered arm stroking in a water flume (flow velocity: 0.9 m·s–1) and leg tethered flutter kicking in a swimming pool. Anaerobic tests on dry land included arm cranking and a set of 10 countermovement jumps. The maximal and average forces generated by legs in tethered swimming (Fl max and Fl ave) turned out to be the strongest predictors of sprint swimming aptitude. These values were strongly correlated with total speed (Vtotal50) (r = 0.49, p < 0.05 and r = 0.54, p < 0.01, respectively), start, turn, and finishing speed (VSTF) (r = 0.60, p < 0.01 and r = 0.67, p < 0.01, respectively). The relationship of Fl max and Fl ave with surface speed (Vsurface) was moderate (r = 0.33, non-significant and r = 0.41, p < 0.05, respectively). The maximal force generated by arms (Fa max) during flume tethered swimming significantly influenced Vsurface and Vtotal50 (0.51, p < 0.01 and 0.47, p < 0.05, respectively). Its relationship with VSTF was close to significant (0.36, p = 0.07). Upper and lower limb dry-land tests showed lower and more holistic relationships with the 50-m front crawl race, however, being a good complement to overall fitness assessment. Specific in-water evaluation, especially the newly prepared flutter kicking test, as well as dry-land tests, can be applied to regularly monitor progress in swimming training, and to identify talented swimmers.