Swimming Stroke Research Articles

Verbal instructions on learning the Front-Crawl: emphasizing a single component or the interaction between components?

PurposeIn Front-Crawl swimming stroke, the interaction between two of its components, i.e. arm stroke and breathing, affects the performance of the motor skill as a whole and therefore can be considered a critical aspect of the skill. The purpose of our study was to investigate if a verbal instruction emphasizing this interaction could lead to learning gains when provided along with video demonstrations.MethodsParticipants (children) were randomly assigned to three experimental groups according to the type of verbal instruction provided. Component and Interaction groups received their specific instructions along with video demonstrations of a model execution of the Front-Crawl. The Control group watched the same video, but received no further instruction concerning the movement pattern. In the Acquisition phase (AQ) all groups performed 160 trials (organized in 4 sessions) of the task that consisted in swimming 8 meters the Front-Crawl at a comfortable velocity. To assess learning gains, a retention test (RT) and a transfer test (TR) were carried out one week after the end of the AQ.ResultsRegarding RT and TR, the one-way ANOVA on the movement pattern score showed a significant difference between groups, with post-hoc tests revealing that the Interaction group achieved higher score than the Control group.ConclusionsThe results reveal that enhancing aspects of a video demonstration with verbal instruction improves learning gains of the Front-Crawl in children. Additionally, the results suggest that providing verbal instructions about the interaction between stroke and breathing might promote learning gains, compared to providing instructions about the stroke component individually.

The Influence of Anthropometric Indices on Execution Technique Specific to Crawl Swimming for Students of Physical Education and Sport Specialization

The aim of the study was to establish the level of learning and performance of the crawl technique, taking into account the hydrodynamic index and the anthropometric characteristics, as a result of practical swimming lessons, with students of first year, specialization physical education and sport. The Experiment was conducted during the academic year 2015-2016 and included a total of 18 students, boys between the ages of 19-22 years, first year, physical education specialization. Motor skills tests which were applied targeted: the length of facial floating with a push from the wall and the length of time performed on 25 metres distance in the crawl swimming stroke. Anthropometric measurements consisted in the determination of the hydrodynamic index taking into account the biacromial and bitrohanterial diameters and the difference between the wingspan of the arms and height. At the end of the study the floating facial test has recorded a progress of 0.29 m and the test concerning the execution technique of the crawl stroke has recorded a progress of 1.65 h, which in correlation with the hydrodynamic and anthropometric indices led to the conclusion that this is due, in particular, to the execution technique corrected by the methodology applied to the classes of practical works at swimming discipline. Performing practical lessons at the swimming subject unfolded over the course of a university semester reaches the goals of improving knowledge of teaching methodology to a great extent but it equally shows a deficit at the level of physical performance of the future specialists. Following the application of the selected means of action and the choice of an efficient teaching strategy in both tests which aimed at the execution technique indices of the crawl stroke a significant progress was made.

VO2 Kinetics in All-out Arm Stroke, Leg Kick and Whole Stroke Front Crawl 100-m Swimming.

The VO2 response to extreme-intensity exercise and its relationship with sports performance are largely unexplored. This study investigated the pulmonary VO2 kinetics during all-out 100-m front crawl whole stroke swimming (S), arm stroke (A) and leg kick (L). 26 male and 10 female competitive swimmers performed an all-out S trial followed by A and L of equal duration in random order. Breath-by-breath VO2 was measured using a snorkel attached to a portable gas analyzer. Mean (±SD) primary component parameters and peak blood lactate (Lapeak) during S, A, and L were, respectively: time delay (s), 14.2 ± 4.7, 14.3 ± 4.5, 15.6 ± 5.1; amplitude (ml·kg(-1)·min(-1)), 46.8 ± 6.1, 37.3 ± 6.9, 41.0 ± 4.7; time constant (τ, s): 9.2 ± 3.2, 12.4 ± 4.7, 10.1 ± 3.2; Lapeak (mmol·l(-1)), 6.8 ± 3.1, 6.3 ± 2.5, 7.9 ± 2.8. During A and L respectively, 80% and 87% of amplitude in S was reached, whereas A+L were 68% greater than in S. 100-m performance was associated to shorter cardiodynamic phase and greater VO2 amplitude and Lapeak (accounting up to 61% of performance variance), but not to τ. We conclude that (i) VO2 gain was proportional to exercise intensity and muscle mass involved, (ii) kicking is metabolically less efficient, and (iii) the main limiting factor of peak VO2 appears to be O2 delivery and not muscle extraction.

Risk factors for shoulder pain and injury in swimmers: A critical systematic review

Swimming is one of the most popular recreational and competitive sporting activities. In the 2013/2014 swimming season, 9630 men and 12,333 women were registered with the National Collegiate Athletics Association in the USA. The repetitive nature of the swimming stroke and demanding training programs of its athletes raises a number of concerns regarding incidence and severity of injuries that a swimmer might experience during a competitive season. A number of risk factors have previously been identified but the level of evidence from individual studies, as well as the level of certainty that these factors predispose a swimmer to pain and injury, to our knowledge has yet to be critically evaluated in a systematic review. Therefore, the primary objective of this review is to conduct a systematic review to critically assess the published evidence for risk factors that may predispose a swimmer to shoulder pain and injury. Three electronic databases, ScienceDirect, PubMed and SpringerLink, were searched using keywords “(Injury OR pain) AND (Swim*)” and “(Shoulder) AND (Swim*)”. Based on the inclusion and exclusion criteria, 2731 unique titles were identified and were analyzed to a final 29 articles. Only articles with a level of evidence of I, II and III were included according to robust study design and data analysis. The level of certainty for each risk factor was determined. No studies were determined to have a high level of certainty, clinical joint laxity and instability, internal/external rotation, previous history of pain and injury and competitive level were determined to have a moderate level of certainty. All other risk factors were evaluated as having a low level of certainty. Although several risk factors were identified from the reviewed studies, prospective cohort studies, larger sample sizes, consistent and robust measures of risk should be employed in future research.

Assessment of three-dimensional joint kinematics of the upper limb during simulated swimming using wearable inertial-magnetic measurement units

ABSTRACTThe analysis of the joint kinematics during swimming plays a fundamental role both in sports conditioning and in clinical contexts. Contrary to the traditional video analysis, wearable inertial-magnetic measurements units (IMMUs) allow to analyse both the underwater and aerial phases of the swimming stroke over the whole length of the swimming pool. Furthermore, the rapid calibration and short data processing required by IMMUs provide coaches and athletes with an immediate feedback on swimming kinematics during training. This study aimed to develop a protocol to assess the three-dimensional kinematics of the upper limbs during swimming using IMMUs. Kinematics were evaluated during simulated dry-land swimming trials performed in the laboratory by eight swimmers. A stereo-photogrammetric system was used as the gold standard. The results showed high coefficient of multiple correlation (CMC) values, with median (first–third quartile) of 0.97 (0.93–0.95) and 0.99 (0.97–0.99) for simulated front-crawl and breaststroke, respectively. Furthermore, the joint angles were estimated with an accuracy increasing from distal to proximal joints, with wrist indices showing median CMC values always higher than 0.90. The present findings represent an important step towards the practical use of technology based on IMMUs for the kinematic analysis of swimming in applied contexts.

Does a land-based compensatory strength-training programme influences the rotator cuff balance of young competitive swimmers?

During the repeated execution of the swimming strokes, the shoulder adductor and internal rotator muscles have a tendency to become proportionally stronger when compared to their antagonist group. This can lead to muscle imbalances. The aim of this study was to examine the effects of a compensatory training programme on the strength and balance of shoulder rotator muscles in young swimmers. A randomized controlled trial design was used. Forty male swimmers took part in the study and were randomly divided into two groups: an experimental group (n = 20) and a training group (n = 20). A control group (n = 16) of young sedentary male students was also evaluated. The experimental group subjects participated in a 16-week shoulder-strength programme with Thera-Band® elastic bands; the training group was restricted to aquatic training. Peak torque of shoulder internal rotator and external rotator (ER) was measured at baseline and after 16 weeks. Concentric action at 1.04 rad s−1 (3 reps) and 3.14 rad s−1 (20 reps) was measured using an isokinetic dynamometer. The strength-training programme led to an improvement of the ER strength and shoulder rotator balance in the experimental group (data from both shoulders at 1.04 rad s−1). Moreover, concentric action at 3.14 rad s−1 presented significant differences only for the dominant shoulder. Findings suggest that the prescribed shoulder-strengthening exercises could be a useful training option for young competitive swimmers. They can produce an increase in absolute strength values and greater muscle balance in shoulder rotators.

Predicting propulsive forces using distributed sensors in a compliant, high DOF, robotic fin

Engineered robotic fins have adapted principles of propulsion from bony-finned fish, using spatially-varying compliance and complex kinematics to produce and control the fin’s propulsive force through time. While methods of force production are well understood, few models exist to predict the propulsive forces of a compliant, high degree of freedom, robotic fin as it moves through fluid. Inspired by evidence that the bluegill sunfish (Lepomis macrochirus) has bending sensation in its pectoral fins, the objective of this study is to understand how sensors distributed within a compliant robotic fin can be used to estimate and predict the fin’s propulsive force. A biorobotic model of a bluegill sunfish pectoral fin was instrumented with pressure and bending sensors at multiple locations. Experiments with the robotic fin were executed that varied the swimming gait, flapping frequency, stroke phase, and fin stiffness to understand the forces and sensory measures that occur during swimming. A convolution-based, multi-input-single-output (MISO) model was selected to model and study the relationships between sensory data and propulsive force. Subsets of sensory data were studied to determine which sensor modalities and sensor placement locations resulted in the best force predictions. The propulsive forces of the fin were accurately predicted using the linear MISO model on intrinsic sensory data. Bending sensation was more effective than pressure sensation for predicting propulsive forces, and the importance of bending sensation was consistent with several results in biology and engineering studies. It was important to have a spatial distribution of sensors and multiple sensory modalities in order to predict forces across large changes to dynamics. The relationship between propulsive forces and intrinsic sensory measures is complex, and good models should allow for temporal lags between forces and sensory data, changes to the model within a fin stroke, and changes to the model through gait transitions.

Measuring kinematic variables in front crawl swimming using accelerometers: a validation study.

Objective data on swimming performance is needed to meet the demands of the swimming coach and athlete. The purpose of this study is to use a multiple inertial measurement units to calculate Lap Time, Velocity, Stroke Count, Stroke Duration, Stroke Rate and Phases of the Stroke (Entry, Pull, Push, Recovery) in front crawl swimming. Using multiple units on the body, an algorithm was developed to calculate the phases of the stroke based on the relative position of the body roll. Twelve swimmers, equipped with these devices on the body, performed fatiguing trials. The calculated factors were compared to the same data derived to video data showing strong positive results for all factors. Four swimmers required individual adaptation to the stroke phase calculation method. The developed algorithm was developed using a search window relative to the body roll (peak/trough). This customization requirement demonstrates that single based devices will not be able to determine these phases of the stroke with sufficient accuracy.

Isokinetic dynamometry on the internal rotator and adductor muscles of the swimmers’ shoulders: no differences between asymmetrical and symmetrical swimming strokes

OBJECTIVE: In this study, we compare muscular strength of the internal rotators and adductors of the shoulder between asymmetrical (backstroke and freestyle) and symmetrical (breaststroke and butterfly) swimming strokes. METHOD: We evaluated: shoulders of (a) asymmetrical swimmers (aged 21.8 ± 3.8 years), (b) symmetrical swimmers (aged 20.3 ± 4.5 years), (c) recreational swimmers (aged 24.5 ± 4.5 years), and (d) control individuals (aged 25.8 ± 3.5 years). All evaluations were performed on a Biodex® isokinetic dynamometer at velocities of 60° and 300°/second. Adduction and internal rotation movements were evaluated. The variables studied were peak torque corrected for body weight (PTQ/BW), total work (TW) and the agonist/antagonist relationship. RESULTS: There were no differences in adductor strength between the symmetrical and asymmetrical swimmers regarding PTQ/BW (symmetrical: 114.4 Newto-meter vs. asymmetrical: 109.4 Newton-meter) and TW (symmetrical: 642.9 Joules; asymmetrical: 641.5 Joules). There was no difference in the abduction/adduction relationship between the symmetrical (67.4%) and asymmetrical (68.3%) swimmers. There was no difference in the internal rotator musculature between the symmetrical and asymmetrical swimmers regarding the variables PTQ/BW (symmetrical = 66.4 Newton-meter and asymmetrical = 63.4 Newton-meterm) and TW (symmetrical = 517.4 J and asymmetrical 526.7 J). There was no difference in the ratio of external to internal rotation of the shoulder between the symmetrical (65.7%) and asymmetrical (61.5%) swimmers. CONCLUSIONS: There were no differences in muscular strength in the adductor and internal rotator muscles of the shoulder between symmetrical and asymmetrical swimming strokes.

Coach-Swimmer Communications Based on Wrist Mounted 2.4GHz Accelerometer Sensor

Two way real time communications during swimming is important for coaches and swimmers in order to reach optimum performance. This paper presents a 2.4GHz wireless communication system to send acceleration data to a coach tablet at the pool side and allow active interactions between swimmers and their coaches. The radio frequency signal does not propagate effectively underwater because of the high attenuation. Therefore the wireless transmitter sends data only when the swimmer's wrist is outside the water. The y-axis acceleration data provides stroke rate SR, stroke length and swim velocity. The experimental results showed that the link is operational 28% per stroke in freestyle swimming. This is more than enough to send important data from the swimmer and reply with the coach's feedback.

The effect of swimming and type of stroke on bone metabolism in competitive adolescent swimmers: a pilot study.

Physical activity plays a key role in increasing and preserving bone mineral density (BMD). Effects on bone development associated with various nonweight-bearing sporting activities, such as swimming, are controversial. Different strokes used in swimming may also present as another factor. The aim of this study was to evaluate the effect of swimming and type of stroke on BMD in competitive adolescent athletes. Seventy-nine swimmers between the ages of 10 and 21 years participated in this study. BMD was measured with dual-energy X-ray absorptiometry at the lumbar vertebrae and left proximal femur. Daily calorie intake and calcium consumption, and measurements of calcium, phosphorus, alkaline phosphates, 25-hydroxyvitamin D (25(OH) D), and osteocalcin were evaluated. Preliminary results revealed that the type of stroke had no effect on BMD (P = 0.79). Additionally competitive swimmers did not have augmented bone mineral accretion, and in 13.9% of athletes low BMD was confirmed. Sixty percent of swimmers had either deficient or insufficient 25(OH) D levels and a low mean calorie (P = 0.542) and calcium (P = 0.038) intake was observed. This was the first study to evaluate the effect of swimming stroke on BMD. Although no effect was statistically shown, further studies with a larger series may determine this effect.

Skin temperature changes of muscle regions in training swimmers

Our aim was to detect changes in infrared radiation, overloaded structures of the musculoskeletal system at the main part of the shoulder girdle and upper body with the help of elite swimmers of Kometa Brno. First measurement was done before training and second 15 minutes after training in water in the swimming pool. The group consisted of seven Czech national swimmers. Athletes participated in testing during six months. Every measurement contains four positions. Front and back side, right and left side. Every athlete went through 13 measurements. We directed infrared thermograph camera FlukeTiR at 10 muscular groups that are most used in swimming. Besides we have form about training with kilometres, other exercise out of water, competitions, illness and be absent at training and other pain muscles, ligaments etc. We have analysed all temperatures only of one swimmer. Here was significant increased temperature after swimming only in deltoideus anterior at right side (from 33,4±1,02°C to 34,0±0,69°C). The other temperature was significant decreased: muscles groups of pectoralis major and minor (right side from 33,6±0,92 to 33,1±0,61°C; left side from 33,8±0,82 to 33,1±0,69°C), latissimus dorsi and erector spinae - pars lumbalis at both sides together. Five of twenty muscle regions have notable tendencies of increased temperatures, including a front part of deltoideus at right side which is very active by spreading arm forward and beginning of swimming stroke. In nine areas, including the main agonist for swimmers movement forward - triceps brachii, we found out only no significant lowering of temperatures. That was caused by cooling of the swimmer in the water. We have next six swimmers to analysis.

Kinematic Analysis of Butterfly Swimming

This study aimed to examine the relative phase of the arm and leg movements and the percentage of each of the 4 arm movement phases at three race paces of the butterfly swimming between two levels of swimmers based on the temporal analysis. Eight elite male swimmers and eight club level college male swimmers participated in the study. Two underwater high-speed cameras (200Hz) were set in the transverse and sagittal plane under the water and synchronized to capture one cycle of butterfly stroke movement. The kinematics data were digitized and calculated with the Kwon 3D software. The continuous relative phase was calculated using the normalized time series of the angular displacement and angular velocity of the shoulder and knee joints angles. Macroscopically, one cycle of the arm-leg coordination pattern can be observed between two levels at three race paces in butterfly stroke: a consistent relationship (2:1) exists between two dolphin kicks and one arm stroke in butterfly swimming. The continuous relative phase analyses showed that, in the beginning of the stroke-catch phase, the continuous relative phase was from anti-phase (-180°) to in-phase (50°). For the pull phase, the in-phase relation (±50°) remained unchanged throughout the stage. During the push phase, the relative phase gradually increased toward anti-phase (180°). The percentage of catch, pull, push, and recovery phases were not evenly distributed across one cycle of the butterfly stroke. Especially in elite group, there is a trend of decreasing the percentage of catch phase. In conclusion, these results provide useful information for swimmers as well as coaches to examine the swimming movement of the butterfly stroke.

Planimetric frontal area in the four swimming strokes: Implications for drag, energetics and speed

The purpose of this study was to use the planimetric method to determine frontal area (Ap) throughout the stroke cycle in the four swimming strokes as well as during “streamlined leg kicking”. The minimum Ap values in all strokes are similar to those assessed during “streamlined leg kicking” (about 0.13m2). Active drag (Da=1/2ρ Cd Ap v2) was then calculated/estimated based on the average Ap values, as calculated for a full cycle in each condition. Da is the lowest in the “streamlined leg kicking” condition (Da=19.5v2, e.g., similar to the values of passive drag reported in the literature), is similar in front crawl (Da=30.0v2), backstroke (Da=26.9v2) and butterfly (Da=28.5v2) and is the largest in the breaststroke (Da=37.5v2).Based on the C vs. v relationships reported in the literature for the four strokes it is then possible to estimate drag efficiency: for a speed of 1.5ms−1, it ranges from 0.035–0.038 (breaststroke and backstroke, respectively) to 0.052–0.058 (butterfly and front crawl, respectively). This study is the first to establish Ap values throughout the swimming cycle for all swimming strokes and these findings have implications for active drag estimates, for the energetics of swimming and for swimming speed.

Pacing and mood changes while crossing the Adriatic Sea from Italy to Albania: a case study.

To evaluate the pacing strategy, rating of perceived exertion (RPE), and mood during a 78.1-km solo ultraendurance open-water swim. Before and after the event, anthropometric parameters, cortisol, and the profile of mood state (POMS) of 1 male athlete (age 48 y, height 172 cm, body mass 68 kg, body fat 7.2%, athletic achievement: Italian record holder of the Channel Swim) were ascertained. Every 3 h during the event, average swimming speed (SS), stroke rate, stroke length (SL), and RPE were recorded. The athlete completed the event in 23:44 h:min. Compared with the first 3 h of swimming, decreases in SS (-33%) and SL (-25%) were observed between 18 h and 21 h. Thereafter, the athlete increased SS (+41%) and SL (+17%) between 21 h and the end. RPE steadily increased from the beginning to the last 6 h of swimming. Cortisol showed a 23-fold increase. After the event, POMS showed a 500% increase in fatigue, 44% decrease in tension, and 77% decrease in vigor. For the first time ever an athlete crossed the Adriatic Sea. This case study shows that the athlete adopted a variable pacing strategy to complete 78 km. Despite the athlete perceiving his effort at maximum during the last 6 h, the observed increases in SS at the end of the event might substantiate his high potential motivation to accomplish this challenging and unique event.

Profile simulation of highly-skilled sportswomen specializing in front crawl swimming stroke

The article considers the issues associated with structure modeling of competitive activity and the specific training of highly-skilled sportswomen, specializing in front crawl swimming stroke at distances of different lengths, psychophysiological, functional and technical - tactical characteristics of sportswomen of different distance specializations are studied, identified factors affecting the effective distance cover of different length in front crawl swimming stroke are determined and their model specifications are developed.

A single-unit design structure and gender differences in the swimming world championships.

Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs) can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012). For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286) showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences.

The movement of the trunk and breast during front crawl and breaststroke swimming

Breast displacement has been investigated in various activities to inform bra design, with the goal of minimising movement; however, breast motion during swimming has yet to be considered. The aim was to investigate trunk and breast kinematics whilst wearing varying levels of breast support during two swimming strokes. Six larger-breasted females swam front crawl and breaststroke (in a swimming flume), in three breast support conditions while three video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated. Greater breast displacement occurred mediolaterally in the swimsuit condition (7.8, s = 1.5 cm) during front crawl and superioinferiorly in the bare-breasted condition (3.7, s = 1.6 cm) during breaststroke, with the sports bra significantly reducing breast displacements. During front crawl, the greatest trunk roll occurred in the sports bra condition (43.1, s = 8.3°) and during breaststroke greater trunk extension occurred in the swimsuit condition (55.4, s = 5.0°); however, no differences were found in trunk kinematics between the three breast support conditions. Results suggest that the swimsuit was ineffective as a means of additional support for larger-breasted women during swimming; incorporating design features of sports bras into swimsuits may improve the breast support provided.

Effect of Specific Endurance Exercises By Divided The Body In to upper and lower Style on a number of Physical variables and achieving in (50) meter Breast stroke swimming of juniors

Effect of Specific Endurance Exercises By Divided The Body In to upper and lower Style on a number of Physical variables and achieving in (50) meter Breast stroke swimming of juniors

Mechanisms of Elastic Enhancement and Hindrance for Finite-Length Undulatory Swimmers in Viscoelastic Fluids

A computational model of finite-length undulatory swimmers is used to examine the physical origin of the effect of elasticity on swimming speed. We explore two distinct target swimming strokes: one derived from the motion of Caenorhabditis elegans, with large head undulations, and a contrasting stroke with large tail undulations. We show that both favorable stroke asymmetry and swimmer elasticity contribute to a speed-up, but a substantial boost results only when these two effects work together. We reproduce conflicting results from the literature simply by changing relevant physical parameters.