Does the flutter kick increase hand propulsion in front crawl swimming?

This study aimed to investigate the effect of the flutter kick on the propulsive force generated by a stroke. Eight male swimmers performed 20 m front crawl trials under two conditions: the Whole Condition, involving maximum effort (T100%) and stroke frequencies at 70, 80, and 90% of T100%, and the Arm Condition, which excluded the flutter kick and matched stroke frequencies with the Whole Condition. Various parameters, including swimming velocity, stroke frequency, stroke length, three-dimensional (3D) resultant hand speed, and hand propulsion were calculated based on underwater 3D motion analysis and hand pressure distribution measurements.

Effects of Creatine Supplementation on the Performance, Physiological Response, and Body Composition Among Swimmers: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: Although recent studies have increasingly focused on examining the potential benefits of creatine supplementation to improve performance in swimming events, the impact of creatine supplementation on swimming performance remains a topic of debate and controversy. A comprehensive meta-analytical review was undertaken to evaluate the effects of creatine supplementation on the performance, physiological response, and body composition among swimmers.

Methods: The research methodology adhered strictly to the guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Prevalence and Associated Factors of Physical Complaints Among Japanese Esports Players: A Cross-Sectional Study.

Background In the evolving landscape of electronic sports (esports), where economic and social expectations are soaring, a critical concern has emerged in physical complaints among esports players. However, empirical insights into these complaints' prevalence and influencing factors are scarce. This study aimed to determine the prevalence of physical complaints and their association with esports activities among Japanese esports players.

Ultra-High Vacuum Cells Realized by Miniature Ion Pump Using High-Efficiency Plasma Source.

In recent years, there has been significant interest in quantum technology, characterized by the emergence of quantum computers boasting immense processing power, ultra-sensitive quantum sensors, and ultra-precise atomic clocks. Miniaturization of quantum devices using cold atoms necessitates the employment of an ultra-high vacuum miniature cell with a pressure of approximately 10 Pa or even lower. In this study, we developed an ultra-high vacuum cell realized by a miniature ion pump using a high-efficiency plasma source.

Comparison of foot pressure distribution and foot kinematics in undulatory underwater swimming between performance levels.

This study aimed to elucidate the foot kinematics and foot pressure difference characteristics of faster swimmers in undulatory underwater swimming (UUS). In total, eight faster and eight slower swimmers performed UUS in a water flume at a flow velocity set at 80% of the maximal effort swimming velocity. The toe velocity and foot angle of attack were measured using a motion capture system.

Impact of variations in swimming velocity on wake flow dynamics in human underwater undulatory swimming.

Increasing the velocity of the lower-limb movement is crucial for improving underwater undulatory swimming (UUS) velocity. However, the underlying mechanism of how these movements influence swimming velocity have remained unclear. This study aimed to clarify the relationship between changes in swimming movement and the resulting changes in flow field as a result of changes in test flow velocity (U) in a water flume.

Effects of maslinic acid supplementation on exercise-induced inflammation and oxidative stress in water polo athletes: A randomized, double-blind, crossover, and placebo-controlled trial.

Background: Olive fruit is rich in bioactive pentacyclic triterpenoids, primarily maslinic acid (MA). Previous studies have demonstrated that MA exhibits anti-inflammatory and anti-oxidative effects; however, it is unclear whether MA intake during training inhibits perceptual fatigue and muscle soreness in athletes. This study analyzed the effects of MA supplementation during athletic training on perceptual fatigue and muscle soreness.

Choice of and response to treatment in patients with early-diagnosed rheumatoid arthritis: Real-world data from an inception cohort in Japan (NICER-J).

Objective: Various guidelines recommend that patients with early rheumatoid arthritis (RA) try to achieve clinical remission within 6 months, and early therapeutic intervention is important to this end. This study aimed to investigate short-term treatment outcomes of patients with early-diagnosed RA in clinical practice and to examine predictive factors for achieving remission.

Methods: Of the 210 patients enrolled in the multicenter RA inception cohort, 172 patients who were followed up to 6 months after treatment initiation (baseline) were included.

High-Efficiency Plasma Source Using a Magnetic Mirror Trap for Miniature-Ion Pumps.

In this study, we design a highly efficient plasma source using a magnetic mirror trap with two opposing permanent magnets for a miniature high-efficiency ion pump. First, we simulated the distribution of the magnetic field line formed by the proposed magnetic mirror configuration. By optimizing the distance between two opposing permanent magnets and size of these magnets, a magnetic mirror ratio value of 27 could be obtained, which is an electron confinement efficiency of over 90%.

Wafer-Scale Room-Temperature Bonding of Smooth Au/Ti-Based Getter Layer for Vacuum Packaging.

This study demonstrates room-temperature bonding using a getter layer for the vacuum packaging of microsystems. A thick Ti layer covered with an Au layer is utilized as a getter layer because it can absorb gas molecules in the package. Additionally, smooth Au surfaces can form direct bonds for hermetic sealing at room temperature.

An Ultra-Compact MEMS Pirani Sensor for In-Situ Pressure Distribution Monitoring.

In this study, we designed a microelectromechanical system (MEMS) Pirani vacuum sensor with a compact size. Specifically, the sensor was successfully fabricated based on the Pirani principle and using a commercial eight-inch MEMS foundry process. The sensor fabrication process was carried out using only four photomasks and the proposed sensor had an ultra-compact fabricated size (<2.

Changes in Kinematics and Muscle Activity With Increasing Velocity During Underwater Undulatory Swimming.

This study aimed to investigate the changes in kinematics and muscle activity with increasing swimming velocity during underwater undulatory swimming (UUS). In a water flume, 8 male national-level swimmers performed three UUS trials at 70, 80, and 90% of their maximum swimming velocity (70, 80, and 90%V, respectively). A motion capture system was used for three-dimensional kinematic analysis, and surface electromyography (EMG) data were collected from eight muscles in the gluteal region and lower limbs.

Relationship Between Hand Kinematics, Hand Hydrodynamic Pressure Distribution and Hand Propulsive Force in Sprint Front Crawl Swimming.

Purpose: This study investigated the relationship between hand kinematics, hand hydrodynamic pressure distribution and hand propulsive force when swimming the front crawl with maximum effort.

Methods: Twenty-four male swimmers participated in the study, and the competition levels ranged from regional to national finals. The trials consisted of three 20 m front crawl swims with apnea and maximal effort, one of which was selected for analysis.

Bonding formation and gas absorption using Au/Pt/Ti layers for vacuum packaging.

In this study, we developed a metal multilayer that can provide hermetic sealing after degassing the assemblies and absorbing the residual gases in the package. A package without a leak path was obtained by the direct bonding of the Au/Pt/Ti layers. After packaging, annealing at 450 °C caused thermal diffusion of the Ti underlayer atoms to the inner surface, which led to absorption of the residual gas molecules.

How Technique Modifications in Elite 100m Swimmers Might Improve Front Crawl Performances to Podium Levels: Swimming 'Chariots of Fire'.

In this paper ways in which performance in 100 m front crawl might be improved are explored. Researchers were identified as 'primary sources' to provide a rationale for how swimmers might improve their performance and to estimate the potential magnitude of improvement. The researchers selected as the primary sources were identified from an initial search of the Scopus and Web of Science data bases using keywords appropriate for the race phases including start, stroking, turn, and finish and their component sub-phases.

Kinematic and kinetic parameters to identify water polo players' eggbeater kick techniques.

This study aimed to clarify the kinematic and kinetic parameters that identify the technical differences in the eggbeater kick. Twelve water polo players performed the eggbeater kick, and its kinematics were recorded by a motion capture system. Pressure distributions around the feet were measured by sixteen pressure sensors attached to the dorsal and plantar surfaces of the feet, from which the resultant fluid force acting on the feet and the vertical component of the force (i.

Kinetics of four limb joints during kick-start motion in competitive swimming.

The kick-start technique in competitive swimming generates a force acting on the starting platform owing to gravity, muscle contraction and resulting joint torque. To understand optimal body movement on the starting platform for maximising take-off velocity, it is necessary to investigate the joint torque in relation to the joint's rotation effects. Joint torques were calculated by inverse dynamics using kinetic and kinematic data.

How do swimmers control their front crawl swimming velocity? Current knowledge and gaps from hydrodynamic perspectives.

The aim of this study was to review the literature on front crawl swimming biomechanics, focusing on propulsive and resistive forces at different swimming velocities. Recent studies show that the resistive force increases in proportion to the cube of the velocity, which implies that a proficient technique to miminise the resistive (and maximise the propulsive) force is particularly important in sprinters. To increase the velocity in races, swimmers increase their stroke frequency.

Low-temperature direct bonding of InP and diamond substrates under atmospheric conditions.

An InP substrate was directly bonded on a diamond heat spreader for efficient heat dissipation. The InP surface activated by oxygen plasma and the diamond surface cleaned with an NH/HO mixture were contacted under atmospheric conditions. Subsequently, the InP/diamond specimen was annealed at 250 °C to form direct bonding.

Higher doses of methotrexate associated with discontinuation of oral glucocorticoids after initiation of biological DMARDs: A retrospective observational study based on data from a Japanese multicenter registry study.

Objective: Glucocorticoids are important drugs used to treat rheumatoid arthritis. We recommend glucocorticoid discontinuation as soon as possible given the associated side-effects, but many patients continue to take oral glucocorticoids long-term. The present study aimed to explore factors associated with glucocorticoid discontinuation at 52 weeks after initiating biological disease-modifying antirheumatic drugs (bDMARDs).

A retrospective analysis of the relationship between anti-cyclic citrullinated peptide antibody and the effectiveness of abatacept in rheumatoid arthritis patients.

This study aimed to evaluate the effectiveness of abatacept (ABA) by anti-cyclic citrullinated peptide (ACPA) status on disease activity as well as radiographic progression in patients with rheumatoid arthritis (RA) in clinical settings. A retrospective cohort study was conducted using data from a multicenter registry. Data from a total of 553 consecutive RA patients treated with intravenous ABA were included.

Front Crawl Is More Efficient and Has Smaller Active Drag Than Backstroke Swimming: Kinematic and Kinetic Comparison Between the Two Techniques at the Same Swimming Speeds.

The purpose of this study was to investigate differences in Froude efficiency (η ) and active drag ( ) between front crawl and backstroke at the same speed. η was investigated by the three-dimensional (3D) motion analysis using 10 male swimmers. The swimmers performed 50 m swims at four swimming speeds in each technique, and their whole body motion during one upper-limb cycle was quantified by a 3D direct linear transformation algorithm with manually digitized video footage.

Effects of exceeding stroke frequency of maximal effort on hand kinematics and hand propulsive force in front crawl.

This study aimed to assess kinematic and kinetic changes in front crawl with various stroke frequency () conditions to investigate why swimming velocity () does not increase above a certain (). Eight male swimmers performed 20 m front crawl four times. The first trial involved maximal effort, whereas was controlled during the next three trials.

Propulsive forces on water polo players' feet from eggbeater kicking estimated by pressure distribution analysis.

The purpose of this study was to characterise the unsteady propulsive force during eggbeater kicking by a fluid force estimation method based on pressure distribution analysis. The eggbeater kick was performed by six male water polo players. The participants' eggbeater kicking motions were recorded by three cameras, and the kinematic foot variables were analysed.