Is There Any Effect of Symmetry on Velocity of the Four Swimming Strokes?

The different characteristics of the four swimming strokes affect the interplay between the four limbs, acting as a constraint to the force produced by each hand and foot. The purpose of this study was to analyze the symmetry of force production with a varying number of limbs in action and see its effect on velocity. Fifteen male swimmers performed four all-out bouts of 25-m swims in the four strokes in full-body stroke and segmental actions. A differential pressure system was used to measure the hands/feet propulsive force and a mechanical velocity meter was used to measure swimming velocity. Symmetry index was calculated based on the force values. All strokes and conditions presented contralateral limb asymmetries (ranging from 6.73% to 28% for the peak force and from 9.3% to 35.7% for the mean force). Backstroke was the most asymmetric stroke, followed-up by butterfly, front crawl, and breaststroke. Kicking conditions elicited the higher asymmetries compared with arm-pull conditions. No significant associations were found between asymmetries and velocity. The absence of such association suggests that, to a certain and unknown extent, swimming may benefit from contralateral limb asymmetry.

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The influence of different hand paddle size on 100-m front crawl kinematics

Journal of Human Kinetics ◽

10.2478/v10078-012-0070-0 ◽

2012 ◽

Vol 34 (1) ◽

pp. 112-118 ◽

Cited By ~ 1

Author(s):

Daniel López-Plaza ◽

Fernando Alacid ◽

Pedro A. López-Miñarro ◽

José M. Muyor

Keyword(s):

Swimming Performance ◽

Video Camera ◽

Swimming Velocity ◽

Stroke Rate ◽

Front Crawl ◽

Stroke Length ◽

Elite Swimmers ◽

The Mean

AbstractThe purpose of this study was to determine the influence of different sizes of hand paddles on kinematicparameters during a 100 m freestyle swimming performance in elite swimmers. Nine elite swimmers (19.1 ± 1.9 years)completed three tests of 100 m without paddles, with small paddles (271.27 cm2) and with large paddles (332.67 cm2),respectively. One video camera was used to record the performance during the three trials. The mean swimmingvelocity, stroke rate and stroke length were measured in the central 10 meters of each 50 m length. The results showedthat stroke length tended to increase significantly when wearing hand paddles (p < 0.05) during both the first andsecond 50 m sections whereas the increase in swimming velocity occurred only in the second 50 m (p < 0.05).Conversely, the stroke rate showed a slight decreasing trend with increasing paddle size. During the 100 m freestyletrial the stroke kinematics were changed significantly as a result of the increase in propelling surface size when handpaddles were worn.

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The Relationship Between Selected Load-Velocity Profile Parameters and 50 m Front Crawl Swimming Performance

Frontiers in Physiology ◽

10.3389/fphys.2021.625411 ◽

2021 ◽

Vol 12 ◽

Author(s):

Tomohiro Gonjo ◽

Nikolai Njøs ◽

Ola Eriksrud ◽

Bjørn H. Olstad

Keyword(s):

Velocity Profile ◽

Swimming Performance ◽

Regression Line ◽

National Level ◽

Maximum Velocity ◽

Swimming Velocity ◽

Front Crawl ◽

Mean Velocity ◽

The Mean ◽

The Relationship

The purpose of the present study was to establish relationships between sprint front crawl performance and a swimming load-velocity profile. Fourteen male national-level swimmers performed 50 m front crawl and semi-tethered swimming with three progressive loads. The 50 m performance was recorded with a multi-camera system, with which two-dimensional head displacement and the beginning of each arm-stroke motion were quantified. Forward velocity (V50m), stroke length (SL) and frequency (SF) were quantified for each cycle, and the mean value of all cycles, excluding the first and last cycles, was used for the analysis. From the semi-tethered swimming test, the mean velocity during three stroke cycles in mid-pool was calculated and plotted as a function of the external load, and a linear regression line expressing the relationship between the load and velocity was established for each swimmer. The intercepts between the established line and the axes of the plot were defined as theoretical maximum velocity (V0) and load (L0). Large to very large correlations were observed between V50m and all variables derived from the load-velocity profiling; L0 (R = 0.632, p = 0.015), L0 normalized by body mass (R = 0.743, p = 0.002), V0 (R = 0.698, p = 0.006), and the slope (R = 0.541, p < 0.046). No significant relationships of SL and SL with V50m and the load-velocity variables were observed, suggesting that each swimmer has his own strategy to achieve the highest swimming velocity. The findings suggest that load-velocity profiling can be used to assess swimming-specific strength and velocity capabilities related to sprint front crawl performance.

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Functional implications of supercontracting muscle in the chameleon tongue retractors

Journal of Experimental Biology ◽

10.1242/jeb.204.21.3621 ◽

2001 ◽

Vol 204 (21) ◽

pp. 3621-3627 ◽

Cited By ~ 1

Author(s):

Anthony Herrel ◽

Jay J. Meyers ◽

Peter Aerts ◽

Kiisa C. Nishikawa

Keyword(s):

Prey Capture ◽

Three Dimensional ◽

Force Production ◽

Retractor Muscle ◽

Muscle Physiology ◽

Large Prey ◽

Wide Range ◽

Ambush Predators ◽

Full Body

SUMMARYChameleons capture prey items using a ballistic tongue projection mechanism that is unique among lizards. During prey capture, the tongue can be projected up to two full body lengths and may extend up to 600 % of its resting length. Being ambush predators, chameleons eat infrequently and take relatively large prey. The extreme tongue elongation (sixfold) and the need to be able to retract fairly heavy prey at any given distance from the mouth are likely to place constraints on the tongue retractor muscles. The data examined here show that in vivo retractor force production is almost constant for a wide range of projection distances. An examination of muscle physiology and of the ultrastructure of the tongue retractor muscle shows that this is the result (i) of active hyoid retraction, (ii) of large muscle filament overlap at maximal tongue extension and (iii) of the supercontractile properties of the tongue retractor muscles. We suggest that the chameleon tongue retractor muscles may have evolved supercontractile properties to enable a substantial force to be produced over a wide range of tongue projection distances. This enables chameleons successfully to retract even large prey from a variety of distances in their complex three-dimensional habitat.

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111In-oxine platelet survivals in thrombocytopenic infants

Blood ◽

10.1182/blood.v70.3.652.bloodjournal703652 ◽

1987 ◽

Vol 70 (3) ◽

pp. 652-656

Author(s):

V Castle ◽

G Coates ◽

JG Kelton ◽

M Andrew

Keyword(s):

Life Span ◽

Function Analysis ◽

Screening Tests ◽

Severe Thrombocytopenia ◽

Common Occurrence ◽

Platelet Volume ◽

Platelet Destruction ◽

Percent Recovery ◽

The Mean ◽

Full Body

Thrombocytopenia is a common occurrence (20%) in sick neonates, but the causes have not been well studied. In this report we demonstrate that thrombocytopenia in the neonate is characterized by increased platelet destruction as shown by shortened homologous 111In-oxine-labeled platelet life spans. Thirty-one prospectively studied thrombocytopenic neonates were investigated by measuring the 111In-labeled platelet life span, platelet-associated IgG (PAIgG), and coagulation screening tests. In every infant, the thrombocytopenia was shown to have a destructive component since the mean platelet life span was significantly shortened to 65 +/- 6 (mean +/- SEM) hours with a range of one to 128 hours compared with adult values (212 +/- 8; range, 140 to 260; gamma function analysis). The platelet survival was directly related to the lowest platelet count and inversely related to both the highest mean platelet volume and duration of the thrombocytopenia. In 22 infants the percent recovery of the radiolabeled platelets was less than 50%, which suggested that increased sequestration also contributed to the thrombocytopenia. Infants with laboratory evidence of disseminated intravascular coagulation (n = 8) or immune platelet destruction evidenced by elevated levels of PAIgG (n = 13) had even shorter platelet survivals and a more severe thrombocytopenia compared with the ten infants in whom an underlying cause for the thrombocytopenia was not apparent. Full-body scintigraphic images obtained in 11 infants showed an increased uptake in the spleen and liver, with a spleen-to- liver ratio of 3:1. This study indicates that thrombocytopenia in sick neonates is primarily destructive, with a subgroup having evidence of increased platelet sequestration.

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Effect of three different set-up conditions on the propulsive force measures, reliability, and ecological validity during front crawl tethered-swimming

International Journal of Performance Analysis in Sport ◽

10.1080/24748668.2021.1974182 ◽

2021 ◽

pp. 1-20

Author(s):

Otávio Joaquim Baratto de Azevedo ◽

Clara Knierim Correia ◽

Gustavo Soares Pereira ◽

Luciano Sales Prado ◽

Helio Roesler ◽

...

Keyword(s):

Ecological Validity ◽

Propulsive Force ◽

Front Crawl ◽

Set Up

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Kinetic Analysis of Water Fitness Exercises: Contributions for Strength Development

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16193784 ◽

2019 ◽

Vol 16 (19) ◽

pp. 3784 ◽

Cited By ~ 1

Author(s):

Santos ◽

Rama ◽

Marinho ◽

Barbosa ◽

Costa

Keyword(s):

Upper Limb ◽

Force Production ◽

Peak Force ◽

Strength Development ◽

Isokinetic Dynamometer ◽

Symmetric Motion ◽

Pressure System ◽

Dry Land ◽

Force Variation ◽

Selection Of

The evaluation of propulsive forces in water allows the selection of the most appropriate strategies to develop strength during water fitness sessions. The aim of this study was threefold: (i) to analyze the rate of force production; (ii) to analyze the rate of force variation; and (iii) to compare limbs’ symmetry in two water fitness exercises. Twenty-two young health subjects (age: 21.23 ± 1.51 years old, body mass: 67.04 ± 9.31 kg, and height: 166.36 ± 8.01 cm) performed incremental protocols of horizontal adduction (HA) and rocking horse (RHadd), from 105 until 150 b·min–1. Data acquisition required an isokinetic dynamometer and a differential pressure system that allowed the assessment of (a) isometric peak force of dominant upper limb (IsometricFD); (b) propulsive peak force of dominant upper limb (PropulsiveFD); and (c) propulsive peak force of nondominant upper limb (PropulsiveFND). Significant differences were found in the rate of force production (RateFD) between the majority cadences in both exercises. The RateFD reached ~68% of the force in dry-land conditions, and lower cadences promoted a higher rate of force variation (ΔForce). Most actions were asymmetric, except for the HA at 135 b·min–1. In conclusion, the musical cadence of 135 b·min–1 seems to elicit a desired rate of force production with a symmetric motion in both exercises.

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Clinical characteristics of acute respiratory distress syndrome survived patients at a tertiary hospital in Jakarta

Medical Journal of Indonesia ◽

10.13181/mji.v26i1.1470 ◽

2017 ◽

Vol 26 (1) ◽

pp. 35-9

Author(s):

Zulkifli Amin ◽

Fitriana N. Rahmawati ◽

Chrispian O. Mamudi ◽

Astrid P. Amanda

Keyword(s):

Developing Countries ◽

Descriptive Analysis ◽

Good Deal ◽

Tertiary Hospital ◽

Clinical Profile ◽

Primary Data ◽

Apache Ii Score ◽

Common Causes ◽

The Mean ◽

Different Characteristics

Background: While a good deal of research on characteristic the different characteristics between surviving and dying patient with ARDS has been conducted globally, such research is scarce in developing countries. This study aimed to obtain clinical profile of ARDS survivors during hospitalization.Methods: This was a prospective, observational study conducted at a tertiary hospital in Jakarta from October 2015 to April 2016. Primary data was collected from ARDS patients based on Berlin Definition admitted to emergency room, ICU, HCU, ICCU, and all other wards. The patients were followed until they discharged. We only included survivors on the analysis. Descriptive analysis was done using SPSS 21.0.Results: A total of 43 patients were survived during study period. The majority were below 65 years of age (69.8%) and were male (53.5%). ARDS was mainly mild in severity (62.8%) and early onset (55.8%). Sepsis was the most common causes of ARDS (97.7%). Most of the patients had comorbidities (74.4%). Majority of the patients had APACHE II score <20 (77.3%) with mean 15.6±4.8. The mean of albumin was 2.9±0.6 and the median of procalcitonin was 3 (0.1-252.3.Conclusion: The clinical profile of ARDS survivors in our study were mostly similar with other studies conducted in developed and other developing countries.

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Association between Changes in Swimming Velocity, Vertical Center of Mass Position, and Projected Frontal Area during Maximal 200-m Front Crawl

Proceedings ◽

10.3390/proceedings2020049060 ◽

2020 ◽

Vol 49 (1) ◽

pp. 60

Author(s):

Sohei Washino ◽

Akihiko Murai ◽

Hirotoshi Mankyu ◽

Yasuhide Yoshitake

Keyword(s):

Inverse Kinematics ◽

Center Of Mass ◽

Three Dimensional ◽

Frontal Area ◽

Whole Body ◽

Swimming Velocity ◽

Front Crawl ◽

Motion Data ◽

Mass Position ◽

Shape Data

We examined the association between changes in swimming velocity, vertical center of mass (CoM) position, and projected frontal area (PFA) during maximal 200-m front crawl. Three well-trained male swimmers performed a single maximal 200-m front crawl in an indoor 25-m pool. Three-dimensional (3D) shape data of the whole body were fitted to 3D motion data during swimming by using inverse kinematics computation to estimate PFA accurately. Swimming velocity decreased, the vertical CoM position was lowered, and PFA increased with swimming distance. There were significant correlations between swimming velocity and vertical CoM position (|r| = 0.797–0.982) and between swimming velocity and PFA (|r| = 0.716–0.884) for each swimmer. These results suggest that descent of the swimmer’s body and increasing PFA with swimming distance are associated with decreasing swimming velocity, although the causal factor remains unclear.

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