Swimming Stroke Research Articles

Hydrodynamics of undulatory underwater swimming: A review

Undulatory underwater swimming (UUS) occurs in the starts and turns of three of the four competitive swimming strokes and plays a significant role in overall swimming performance. The majority of research examining UUS is comparative in nature, dominated by studies comparing aquatic animals' undulatory locomotion with the UUS performance of humans. More recently, research directly examining human forms of UUS have been undertaken, providing further insight into the factors which influence swimming velocity and efficiency. This paper reviews studies which have examined the hydromechanical, biomechanical, and coordination aspects of UUS performance in both animals and humans. The present work provides a comprehensive evaluation of the key factors which combine to influence UUS performance examining (1) the role of end-effector frequency and body amplitudes in the production of a propulsive waveform, (2) the effects of morphology on the wavelength of the propulsive waveform and its subsequent impact on the mode of UUS adopted, and (3) the interactions of the undulatory movements to simultaneously optimise propulsive impulse whilst minimising the active drag experienced. In conclusion, the review recommends that further research is required to fully appreciate the complexity of UUS and examine how humans can further optimise performance.

Comparison of Expert and Nonexpert Swimmers' Opinions about the Value, Potency, and Activity of Four Standard Swimming Strokes and Underwater Undulatory Swimming

Underwater undulatory swimming (UUS) is often perceived to be a nonessential aspect of aquatic propulsion. Given their solid theoretical and practical training in swimming, physical education students should be capable of judging the true value of the "fifth stroke," since it appears to be the most efficient technique in high level, competitive swimming. To compare opinions and connotations associated with the stroke and the four official strokes (butterfly, backstroke, breaststroke, and crawl), 198 students (32 of whom were expert swimmers; M age = 20.6 yr., SD = 1.2), were surveyed using the semantic differential of Osgood, Suci, and Tannenbaum. Although answers of expert and nonexpert swimmers differed significantly (p < .01, except for the breaststroke), participants considered overall that undulatory stroke was less attractive, less powerful, and less rapid than the four surface strokes (d = 2.88 for the expert swimmers). Putting one arm in front of the other and repeating the sequence still remains the most solidly held representation of "the right way" to swim. However, the high observed standard deviations for the underwater undulatory stimulus (SD > or = 1.1 with SD max = 3 for the expert swimmers) attests to the view being less strongly held by swimming specialists.

水中ロボットアームを用いた水泳時の四肢に働く非定常流体力の解明 : 水中ロボットアームの開発と流体力測定実験(流体工学,流体機械)

The objective of this study was to clarify the unsteady characteristics of the fluid force acting on limbs during swimming. For this objective, an underwater robot arm was developed in this paper. The robot arm has five degrees-of-freedom in order to perform the various complicated limb motions during swimming. In addition, by changing the hand model into the foot one, the robot also can perform the lower limb motions. The joint torques and the resultant thrust can be measured by the force sensors attached to the robot. In a circulating water tank, an experiment to measure the fluid force was conducted for four swimming strokes of the upper and lower limbs. From the experiment, it was found that even the slight difference of the fluid forces between slightly different swimming motions can be quantified by the developed experimental system. In addition, it was suggested that 'nipping' the water by both lower limbs during the kick of the breaststroke almost does not affect the thrust generation. The developed experimental system with the robot arm is useful not only for measuring the unsteady fluid force, but also for the flow visualization in the future studies.

Pelvic and thigh musculature in frogs (Anura) and origin of anuran jumping locomotion

Comparative analysis of the anuran pelvic and thigh musculoskeletal system revealed that the thigh extensors, responsible for the initial phase of jump, the propulsive stroke in swimming and, if used asynchronously, also for walking, are least affected by the transformations observed between anurans and their temnospondyl ancestors (as reflected in contemporary caudates). The iliac shaft and urostyle, two of the most important anuran apomorphies, represent skeletal support for muscles that are mostly protractors of the femur or are important in attaining a crouching position, a necessary prerequisite for rapid escape. All of these muscles originate or insert on the iliac shaft. As the orientation of the pubis, ischium and ilium is the same in anurans, caudates and by inference also in their temnospondyl ancestors, it is probable that the pelvis was shifted from the sacral vertebra posteriorly along the reduced and stiffened tail (urostyle) by the elongation of the illiac shaft. Thus, the original vertical orientation of the ilium was maintained (which is also demonstrated by stable origins of the glutaeus maximus, iliofemoralis and iliofibularis on the tuber superius) and the shaft itself is a new structure. A review of functional analysis of anuran locomotion suggests some clear differences from that in caudates, suggesting that terrestrial jumping may have been a primary locomotor activity, from which other types of anuran locomotion are derived.

Rolling rhythms in front crawl swimming with six-beat kick

The purpose of this study was to establish the rhythm characteristics of skilled front crawl swimmers using a six-beat kick. These included the amplitudes of the first three Fourier harmonics (H1, H2, H3) and their percent contributions to power contained in the angular displacement signals of the shoulders, hips, knees, and ankles with respect to the longitudinal axis in line with the swimming direction. Three-dimensional video data of seven national/international level swimmers were collected during simulated 200 m front crawl races in which swimmers maintained six-beat kicking patterns. Swimmers differed in all variables but had small variability across the four 50 m laps. Modest changes occurred during the 200 m, with the exception of shoulder roll, which remained constant and was represented almost entirely by a single sinusoid (H1). Changes across laps reached significance for swimming speed, stroke rate, hip roll, and H3 wave velocity between the knee and ankle. A H3 body wave of moderate and increasing velocity travelled caudally from hip to ankle. In the light of existing knowledge of aquatic locomotion this was compatible with the goal of generating propulsion in an efficient manner.

Kinematic Analysis of Swimmers with Permanent Physical Disabilities

When the movement patterns of persons with permanent physical disabilities are observed from underwater, it is apparent that they have adapted unique variations in their swimming strokes to compensate for existing anatomic and neuromuscular deficits. Using underwater videotaping and subsequent analysis it is now possible to both identify and evaluate the movement mechanics of these swimmers. The purpose of this paper is to describe how motion analysis technology can be used in biomechanical research to examine the stroke mechanics of swimmers with permanent physical disabilities. In addition, we will identify the unique movement patterns of these swimmers, and, when applicable, discuss the limitations to their swimming efficiency. Aquatic exercise has been used extensively in the past 20 years as a rehabilitative and therapeutic modality for individuals with permanent physical disabilities. The freedom of movement in the water and the ability to exercise muscles which, on land, have difficulty overcoming gravitational constraints makes swimming and related aquatic activities invaluable for persons with a wide range of physically disabling conditions (Daly, 1999; Dummer, 1999; Prins, 1988). Since the primary intent of analyzing the swimming stroke mechanics of disabled swimmers is to improve instructional techniques, the first objective is to examine the underwater movement patterns of these swimmers. The methods for teaching and analyzing the swimming stroke mechanics of swimmers with permanent physical disabilities are similar to those used for assisting able-bodied swimmers. Stroke patterns are videotaped from above- and underwater and evaluated using digital video recorders. Slow motion and freeze-frame capabilities of the video recorders allow more detailed analysis; however, these assessments, no matter how detailed, remain somewhat subjective. With the advent of motion capture technology, which is used for research in biomechanics, it is now possible to determine motion more precisely by quantifying the results. Biomechanics is divided into two branches of study. Kinematics deals with the description of spatial and temporal parameters of movement measured as linear and angular displacements, velocities, and accelerations. Kinetics examines the forces that lead to the resulting kinematic changes (Griffiths, 2006; Kreighbaum, 1996). Using underwater videography and motion capture technology, the

The kinematic determinants of anuran swimming performance: an inverse and forward dynamics approach

The aims of this study were to explore the hydrodynamic mechanism of Xenopus laevis swimming and to describe how hind limb kinematics shift to control swimming performance. Kinematics of the joints, feet and body were obtained from high speed video of X. laevis frogs (N=4) during swimming over a range of speeds. A blade element approach was used to estimate thrust produced by both translational and rotational components of foot velocity. Peak thrust from the feet ranged from 0.09 to 0.69 N across speeds ranging from 0.28 to 1.2 m s(-1). Among 23 swimming strokes, net thrust impulse from rotational foot motion was significantly higher than net translational thrust impulse, ranging from 6.1 to 29.3 N ms, compared with a range of -7.0 to 4.1 N ms from foot translation. Additionally, X. laevis kinematics were used as a basis for a forward dynamic anuran swimming model. Input joint kinematics were modulated to independently vary the magnitudes of foot translational and rotational velocity. Simulations predicted that maximum swimming velocity (among all of the kinematics patterns tested) requires that maximal translational and maximal rotational foot velocity act in phase. However, consistent with experimental kinematics, translational and rotational motion contributed unequally to total thrust. The simulation powered purely by foot translation reached a lower peak stroke velocity than the pure rotational case (0.38 vs 0.54 m s(-1)). In all simulations, thrust from the foot was positive for the first half of the power stroke, but negative for the second half. Pure translational foot motion caused greater negative thrust (70% of peak positive thrust) compared with pure rotational simulation (35% peak positive thrust) suggesting that translational motion is propulsive only in the early stages of joint extension. Later in the power stroke, thrust produced by foot rotation overcomes negative thrust (due to translation). Hydrodynamic analysis from X. laevis as well as forward dynamics give insight into the differential roles of translational and rotational foot motion in the aquatic propulsion of anurans, providing a mechanistic link between joint kinematics and swimming performance.

Modelling, Computing and Sport

This article presents a computational model for propulsion generation in front crawl swimming. The obtained results show close agreement with directly measured forces acting on a computer controlled robotic arm that kinematically simulated a planar arm stroke. The model was applied to real-life swimming strokes and demonstrated that the three-dimensionality improves efficiency of the stroke and that contrary to popular belief the arm does not need to be fully extended while swimming.

Modelling spatial–temporal and coordinative parameters in swimming

This study modelled the changes in spatial–temporal and coordinative parameters through race paces in the four swimming strokes. The arm and leg phases in simultaneous strokes (butterfly and breaststroke) and the inter-arm phases in alternating strokes (crawl and backstroke) were identified by video analysis to calculate the time gaps between propulsive phases. The relationships among velocity, stroke rate, stroke length and coordination were modelled by polynomial regression. Twelve elite male swimmers swam at four race paces. Quadratic regression modelled the changes in spatial–temporal and coordinative parameters with velocity increases for all four strokes. First, the quadratic regression between coordination and velocity showed changes common to all four strokes. Notably, the time gaps between the key points defining the beginning and end of the stroke phases decreased with increases in velocity, which led to decreases in glide times and increases in the continuity between propulsive phases. Conjointly, the quadratic regression among stroke rate, stroke length and velocity was similar to the changes in coordination, suggesting that these parameters may influence coordination. The main practical application for coaches and scientists is that ineffective time gaps can be distinguished from those that simply reflect an individual swimmer's profile by monitoring the glide times within a stroke cycle. In the case of ineffective time gaps, targeted training could improve the swimmer's management of glide time.

Shoulder pain in elite swimmers: primarily due to swim-volume-induced supraspinatus tendinopathy

Background/hypothesisShoulder pain in elite swimmers is common, and its pathogenesis is uncertain.Hypothesis/study designThe authors used a crosssectional study design to test Jobe’s hypothesis that repetitive forceful swimming leads to shoulder...

Heart rate regulation and extreme bradycardia in diving emperor penguins

To investigate the diving heart rate (f(H)) response of the emperor penguin (Aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in McMurdo Sound, Antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (TDRs). In contrast to any other freely diving bird, a true bradycardia (f(H) significantly <f(H) at rest) occurred during diving [dive f(H) (total beats/duration)=57+/-2 beats min(-1), f(H) at rest=73+/-2 beats min(-1) (mean +/- s.e.m.)]. For dives less than the aerobic dive limit (ADL; duration beyond which [blood lactate] increases above resting levels), dive f(H)=85+/-3 beats min(-1), whereas f(H) in dives greater than the ADL was significantly lower (41+/-1 beats min(-1)). In dives greater than the ADL, f(H) reached extremely low values: f(H) during the last 5 mins of an 18 min dive was 6 beats min(-1). Dive f(H) and minimum instantaneous f(H) during dives declined significantly with increasing dive duration. Dive f(H) was independent of swim stroke frequency. This suggests that progressive bradycardia and peripheral vasoconstriction (including isolation of muscle) are primary determinants of blood oxygen depletion in diving emperor penguins. Maximum instantaneous surface interval f(H) in this study is the highest ever recorded for emperor penguins (256 beats min(-1)), equivalent to f(H) at V(O(2)) max., presumably facilitating oxygen loading and post-dive metabolism. The classic Scholander-Irving dive response in these emperor penguins contrasts with the absence of true bradycardia in diving ducks, cormorants, and other penguin species.

Flexible paddle sheds new light on speed: a novel method for the remote measurement of swim speed in aquatic animals

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 4:157-164 (2008) - DOI: https://doi.org/10.3354/esr00052 Flexible paddle sheds new light on speed: a novel method for the remote measurement of swim speed in aquatic animals Emily L. C. Shepard1,*, Rory P. Wilson1, Nikolai Liebsch1, Flavio Quintana2,3, Agustina Gómez Laich2, Klaus Lucke4 1Biological Sciences, Institute of Environmental Sustainability, University of Wales, Swansea SA2 8PP, UK 2Centro Nacional Patagónico (CENPAT)-CONICET, (9120) Puerto Madryn, Chubut, Argentina 3Wildlife Conservation Society, 2300 Southern Boulevard, New York, New York 10460, USA 4Forschungs- und Technologiezentrum Westküste, Hafentörn, 25761 Büsum, Germany *Email: 381601@swansea.ac.uk ABSTRACT: Speed is a key determinant of energy expenditure in free-living animals, and particularly in marine vertebrates, where power requirements for swimming increase as a cubed function of the speed. However, current devices used to measure swim speed in free-living animals have limitations, including excessive drag, low resolution, high stall speed (ca. 0.3 m s–1), cost, biofouling and susceptibility to damage. We present a speed sensor system that utilises the reflectance of infrared light against a flexible paddle that bends in relation to the flow of water over the study animal. In laboratory trials, this performed well across a range of speeds (0.1 to 1.75 m s–1), and had a stall speed of 0.1 m s–1. The advantages of this present paddle system are that it is impervious to the presence of matter in the water column, is inexpensive and easily replaceable. Furthermore, the system is able to record speed data at an unparalleled resolution, limited solely by sampling frequency. Data from deployments of devices on free-living imperial cormorants Phalacrocorax atriceps identified changes in speed within and between swim strokes, and also showed that greater speed was generated per kick as the buoyancy decreased with depth. As such, the flexible paddle system holds promise for the measurement of speed in free-living, aquatic animals. KEY WORDS: Speed · Dive behaviour · Electronic tagging · Marine predator · Energy expenditure · Flow meter Full text in pdf format PreviousNextCite this article as: Shepard ELC, Wilson RP, Liebsch N, Quintana F, Gómez Laich A, Lucke K (2008) Flexible paddle sheds new light on speed: a novel method for the remote measurement of swim speed in aquatic animals. Endang Species Res 4:157-164. https://doi.org/10.3354/esr00052 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 4, No. 1-2. Online publication date: January 18, 2008 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2008 Inter-Research.

水泳用全身筋骨格シミュレータによる4泳法の解析

水泳用全身筋骨格シミュレータによる4泳法の解析

Three-sphere low-Reynolds-number swimmer with a cargo container

A recently introduced model for an autonomous swimmer at low Reynolds number that is comprised of three spheres connected by two arms is considered when one of the spheres has a large radius. The Stokes hydrodynamic flow associated with the swimming strokes and net motion of this system can be studied analytically using the Stokes Green's function of a point force in front of a sphere of arbitrary radius R provided by Oseen. The swimming velocity is calculated, and shown to scale as 1/R3 with the radius of the sphere.

A37 慣性センサを用いた平泳ぎの運動解析(ウォータースポーツ)

The aim of this study is to evaluate the breast stroke motion using new measurement system and analysis method. The measurement system consists of 3-axis gyro sensors, 3-axis acceleration sensors, and 3-axis magnetic field sensors and it is attached to the subject's body. The analysis method corrects the drift error of gyro sensor and provides joint angle using sensor fusion and inverse kinematics. The information about swimmer's motion in hydrospace is easily obtained by using this system. The experimental results indicated the breast stroke motion quantitatively. This measurement system and analysis method can analyze the major features of swimming motion in breast stroke. This method may be able to quantitatively evaluate the skill of swimmer, and to apply to other swimming strokes.

Hydrodynamic Interaction between Two Swimmers at Low Reynolds Number

We investigate the hydrodynamic interactions between micro-organisms swimming at low Reynolds number. By considering simple model swimmers, and combining analytic and numerical approaches, we investigate the time-averaged flow field around a swimmer. At short distances the swimmer behaves like a pump. At large distances the velocity field depends on whether the swimming stroke is invariant under a combined time-reversal and parity transformation. We then consider two swimmers and find that the interaction between them consists of two parts: a passive term, independent of the motion of the second swimmer, and an active term resulting from the simultaneous swimming action of both swimmers. The swimmer-swimmer interaction is a complicated function of their relative displacement, orientation, and phase, leading to motion that can be attractive, repulsive, or oscillatory.

Hand Orientation in Hand Paddle Swimming

The aim of this research was to study the effect of hand paddles on the pitch, the sweepback angles and other stroke kinematic characteristics of the hand during front crawl swimming. Ten female competitive swimmers swam without and with small (116 cm (2)) and large (268 cm (2)) paddles. Four cameras (60 Hz) were used to record the underwater strokes and the digitizing was undertaken using the Ariel Performance Analysis System. When the size of the paddles increased, the stroke length, the mean swimming velocity and the total duration of the stroke were significantly increased (p < 0.05), while the average velocity of the hand during the pull and the push phases were significantly decreased (p < 0.05). The stroke rate was decreased significantly (p < 0.05) only when using large paddles. The relative duration of the separate phases of the stroke, the magnitude of the medial-lateral displacements and the pitch and sweepback angles of the hand were not modified, indicating that the use of hand paddles did not caused significant alterations in the orientation and the movement of the hand during the underwater stroke in front crawl swimming.

Lumbar Intervertebral Disk Degeneration in Elite Competitive Swimmers

Background The majority of orthopaedic problems experienced by competitive swimmers are related to pain in the shoulder, low back, and knee. Three of 39 national swim team members were hampered in their performance due to lumbar disk herniation at an international competition in 2001. There has been no previous research into lumbar disk degeneration in elite competitive swimmers. Hypothesis Excessive competitive swimming activities accelerate lumbar disk degeneration. Study Design Case control study; Level of evidence, 3. Methods Fifty-six elite swimmers (high-load group, 35 men and 21 women; mean age, 19.6 years) and a control group of 38 university recreational level swimmers (low-load group, 24 men and 14 women; mean age, 21.1 years) were evaluated for lumbar disk degeneration using magnetic resonance imaging. We compared the prevalence of disk degeneration and the disk level between the 2 groups and further investigated the relationship among their symptoms, swimming styles, and disk degeneration. Results Thirty-eight (68%) elite swimmers and 11 (29%) controls had degenerated disks at various disk levels, and the prevalence was significantly greater in the elite swimmers (P = .0002). Comparison between the 2 groups of the prevalence of disk degeneration at each level revealed that the disk level of L5-S1 was significantly more frequently degenerated in the high-load group (P = .026). There was no significant relationship observed among the variables of low back pain symptoms, swimming strokes, and disk degeneration. Conclusion Excessive competitive swimming activities might exaggerate lumbar intervertebral disk degeneration, especially in the L5-S1 intervertebral segment. Keywords lumbar intervertebral disk; disk degeneration; swimming; sports

Biomechanical Analysis of the Breaststroke Start

The aim of this study was to analyse the kinematics and coordination of the breaststroke start as regards to skill level using a video device. Ten national swimmers were compared with an international swimmer. All swimmers simulated the 100-m pace for 25 m after a grab start. The kinematical analysis assessed the durations of leave block, flight, entry and glide, pull-out, and the swim up to the 15-m mark phases. The coordination analysis assessed the durations of the time spent with the arms close to the thighs after a complete arm pull-push, the time gap between the end of the arm recovery and the beginning of the leg propulsion during the pull-out phase and at the first swim stroke, and the time gap between the end of leg propulsion and the beginning of arm propulsion. The international swimmer had a shorter 15-m start time than the national swimmers due to shorter times in the swim phase, longer times in the underwater phase, longer times spent with the arms close to the thighs and in glide with the body in extension. The whole population showed a negative superposition of leg propulsion with arm recovery at the pull-out phase, which disappeared at the first swim stroke.

Influences of Swimsuit Design on Swimming Performance in Competitive Female Swimmers

Recently, designs for competitive swimsuits have become diversified. The influences of new swimsuit design on drag, buoyancy and physiological responses were measured in the previous studies. However, few studies have evaluated the association between swimsuit and performance during maximal swimming. PURPOSE: To examine the swimming speed, blood lactate, heart rate, perceptual response and stroke technique during freestyle swimming wearing a traditional body suit and a newly designed swimsuit. METHODS: Six competitive female swimmers (age, 19.0±0.6 yr; height, 161.8±5.3 cm; body weight, 52.7±3.5 kg) swam a 200-m maximal freestyle trial in a 25-m indoor pool wearing a traditional body suit (BS) and a suit designed to cover the body from shoulder to ankle (LJ). Blood lactate concentration (BLa), heart rate (HR) and rating of perceived exertion (RPE) were measured after the trial. Stroke counts were determined to calculate the arm stroke index (ASI) during swimming trials. Each subject was informed of the aims, possible risks, and benefits of this investigation both verbally and in writing prior to their signing an informed consent document. RESULTS: Maximal swimming velocity between the BS (1.483 ± 0.006 m/s) and LJ (1.496 ± 0.011 m/s) trial demonstrated no significant difference, but the four swimmers swam faster in the LJ trial (mean time 1.1 sec; range from 0.6 to 3.3 sec) than the BS trial. BLa (BS: 11.32 ± 1.26 mmol/l vs. LJ: 12.95 ± 1.43 mmol/l), HR (BS: 190.2 ± 4.6 bpm vs. LJ: 190.4 ± 4.7 bpm), and RPE (BS: 19.0 ±0.3 vs. LJ: 18.8 ± 0.5) between the two suit conditions at the completion of the maximal trial were not significantly different. ASI (BS: 97.37 ± 3.97 vs. LJ: 97.90 ± 4.85) that was calculated by dividing the number of total strokes by the velocity was also not significantly different between the suits. CONCLUSIONS: These findings indicate that the new type of swimsuit during maximal freestyle swimming does not provide a physiological and technical advantage.