Swimming Performance Research Articles

Impact of a Three-Month Training Break on Swimming Performance in Athletes with Intellectual Disability

This study aimed to ascertain whether there were any differences in anthropometrics, heart rate, and swimming performance parameters in athletes with intellectual disabilities (ID) before and after a three-month training break. A total of 21 athletes participated in the study, comprising 16 males and 5 females, with a mean age of 28.3 ± 8.7 years. All participants had ID, and six of them had Down syndrome. The study participants were classified as S14 athletes from a local swimming club. All participants had a minimum of four years of swimming experience and attended two to three one-hour sessions per week for eight consecutive months. All athletes completed two trials of 25 m freestyle swimming, one at the end of a training session and the other at the beginning of a new session. The measurements included weight, body mass index (BMI), handgrip strength (HGS), heart rate (pre- and post-trial), performance (T25), stroke count (SC), stroke length (SL), stroke rate, and the SWOLF efficiency index. The results demonstrated statistically significant elevations in weight (80.2 ± 16.1 to 81.7 ± 15.9), BMI (26.8 ± 5.5 to 27.2 ± 5.5), T25 (33.1 ± 17.1 to 35.6 ± 18), SC (19.3 ± 6.1 to 20.7 ± 7.2), and SWOLF (52.4 ± 22.0 to 56.3 ± 25.2) and a reduction in SL (1.39 ± 0.48 to 1.27 ± 0.42). However, no significant differences were observed in the remaining parameters. Significant correlations were found for body weight, BMI, HGS, and SWOLF with T25 throughout the study. It was concluded that individuals with ID experienced a decline in 25 m swimming performance due to technical rather than physiological factors after three months of detraining.

Genetic basis analysis and genome prediction of swimming performance traits in juvenile spotted sea bass (Lateolabrax maculatus)

The swimming performance of fish is crucial for their survival, playing a significant role in enhancing disease resistance and facilitating stress recovery, particularly in aquaculture fish. Understanding the genetic basis of fish swimming performance is essential for its integration as a key trait in selection breeding programs, especially for deeper offshore aquaculture. Spotted sea bass, an economically important aquaculture fish species in China, exhibits euryhaline and eurythermic characteristics and has demonstrated substantial potential for deep-sea aquaculture. Therefore, in our study, the absolute critical swimming speed (a.Ucrit) of juvenile spotted sea bass were assessed, ranging form 24.50 cm s−1 to 65.00 cm s−1, and this range enabled the identification of individuals with superior and inferior swimming abilities within the test population. Based on whole-genome resequencing, genome-wide association studies (GWAS) were conducted for three phenotypes of swimming performance, identifying 25 associated SNPs and 85 candidate genes, indicating that it is a polygenetic trait influenced by multiple biological processes. The heritability estimates for a.Ucrit and relative critical swimming speed (r.Ucrit) were 0.21 ± 0.08 and 0.22 ± 0.08, respectively. Furthermore, the impact of various genomic selection (GS) models and SNP densities on prediction accuracy of swimming performance was evaluated using genomic prediction (GP). The SVM model is recommended for continuous trait prediction of swimming performance, especially when SNP densities ranges between 500 and 50 K, as it provides more accurate, efficient and stable predictions. Our research further enhances the understanding of the genetic basis of fish swimming performance and holds promise for improving productivity in deep-sea aquaculture through genomic selection.

Impact of green and black tea extracts on swimming performance and caudal fin regeneration in adult zebrafish (Danio rerio) following amputation

This study investigates the effects of green tea and black tea extracts on swimming performance and caudal fin regeneration in adult zebrafish (Danio rerio) following caudal fin amputation. Zebrafish were treated with either tea extract for 14 days, with applications administered three times daily. Swimming performance was assessed against water currents. Results indicated that green tea-treated fish exhibited the greatest resistance to water flow, primarily occupying the high-force zone during a 15-minute exercise session, while black tea-treated fish were mostly found in middle and lower zones. Cumulative distribution analysis showed that green tea-treated fish maintained their positions in stronger current zones significantly longer than both black tea and control groups (p < 0.0001). Conversely, control fish displayed the highest area of caudal fin regeneration, significantly surpassing both tea-treated groups. Green tea-treated fish showed the least regeneration area, though differences from black tea were not statistically significant. These findings challenge previous studies suggesting that green tea enhances tissue regeneration. The pro-apoptotic effects of green tea's primary component, epigallocatechin gallate (EGCG), may have limited its regenerative potential despite its antioxidant properties. This research highlights the complex relationship between tea polyphenols, swimming performance, and tissue regeneration, suggesting that while both green and black tea can enhance physiological performance, their effects vary based on the interplay between antioxidative benefits and apoptosis-inducing mechanisms.

Effects of maximum thickness position on hydrodynamic performance for fish-like swimmers

When designing the internals of robotic fish, variations in the internal arrangements of power and control systems cause differences in external morphological structures, particularly the positions of maximum thickness. These differences considerably affect swimming performance. This study examines the impact of the topological structure of self-propelled fish-like swimmers on hydrodynamic performance using fluid-structure interaction techniques. Fish-like swimmers with maximum thickness closest to the head exhibit optimal swimming performance, characterized by modest energy consumption for fast-response acceleration during the starting phase and higher swimming velocity for high-speed travel during steady swimming. As the maximum thickness moves toward the middle, acceleration performance significantly weakens and swimming speed decreases, although maximum energy consumption is relatively reduced. This study will provide a notable reference for the morphological design of underwater robotic fish.

Instrumented swim test for quantifying motor impairment in rodents.

Swim tests are highly effective for identifying vestibular deficits in rodents by offering significant vestibular motor challenges with reduced proprioceptive input, unlike rotarod and balance beam tests. Traditional swim tests rely on subjective assessments, limiting objective quantification and reproducibility. We present a novel instrumented swim test using a miniature motion sensor with a 3D accelerometer and 3D gyroscope affixed to the rodent's head. This setup robustly quantifies six-dimensional motion-three translational and three rotational axes-during swimming with high temporal resolution. We demonstrate the test's capabilities by comparing head movements of Gpr156-/- mutant mice, which have impaired otolith organ development, to their heterozygous littermates. Our results show axis-specific differences in head movement probability distribution functions and dynamics that identify mice with the Gpr156 mutation. Axis-specific power spectrum analyses reveal selective movement alterations within distinct frequency ranges. Additionally, our spherical visualization and 3D analysis quantifies swimming performance based on head vector distance from upright. We use this analysis to generate a single classifier metric-a weighted average of an animal's head deviation from upright during swimming. This metric effectively distinguishes animals with vestibular dysfunction from those with normal vestibular function. Overall, this instrumented swim test provides quantitative metrics for assessing performance and identifying subtle, axis- and frequency-specific deficits not captured by existing systems. This novel quantitative approach can enhance understanding of rodent sensorimotor function including enabling more selective and reproducible studies of vestibular-motor deficits.

Dynamic changes in gut microbiota and production phenotypes driven by host genetic background in large yellow croaker

The gut microbiota is becoming increasingly important in enhancing aquaculture productivity. However, there are fewer studies on the effect of host genetic background on the gut microbiota of cultured fish. In the current study, we aimed to determine whether the genetic background of large yellow croaker influences differences in gut microbial composition and growth. To address this objective, we conducted a comparative experiment involving the nearshore cage culture of a selected line (SL) of large yellow croaker, which was subjected to genetic selection for swimming performance, alongside a control line (CL). Both lines were reared under identical environmental and dietary conditions for a duration of six weeks. We employed 16S rRNA gene sequencing technology to analyze the gut microbial composition of the large yellow croaker, and utilized bioinformatics methods to assess the abundance and diversity of the gut microbiota. The findings revealed that the core gut microbiota of both lines primarily comprised Proteobacteria, Firmicutes, and Bacteroidetes. However, a significant disparity in gut microbiota abundance was observed between SL and CL following nearshore cage culture. Additionally, the survival rate of SL reached 64.8 %, significantly higher than the 37.3 % observed in CL. The feed conversion efficiency of SL reached 47.7 %, significantly higher than that of CL (28.6 %). These results underscore the influence of host genetic background on driving differences in gut microbial community composition and production phenotypes. This research offers intriguing insights into the interconnectedness of gut microbiota, fish genetics, and production phenotypes.

Optimization of a passive roll absorber for robotic fish based on tune mass damper

The robotic fish utilizes a bio-inspired undulatory propulsion system to achieve high swimming performance. However, significant roll motion has been observed at the head when the tail oscillates at certain frequencies, adversely affecting both perception accuracy and propulsion efficiency. In this paper, the roll torque acting on the robotic fish is theoretically analyzed and decomposed into gravitational, inertial, and hydrodynamic components. Resonance is identified as a key factor amplifying the roll response. To mitigate this roll and enhance stability, a passive roll absorber based on tuned mass damper is designed. A simplified rolling structure is dynamically modeled to optimize absorber parameters. Experiments are conducted to quantify the roll torque experienced by the robotic fish, with the effectiveness of the absorber verified on both the simplified model and the robotic fish. Results show that the maximum roll angle of the simplified system under harmonic load decreases from 98° to29∘, representing a reduction of over 70%, while a 25.1% reduction is achieved on the robotic fish.

The effects of warm thermal variability on metabolism and swimming performance in wild Atlantic salmon (Salmo salar).

Warmer and more variable temperatures have been implicated in the recent decline of Atlantic salmon (Salmo salar) in Eastern Canada. To date, we know little on how ecologically relevant thermal fluctuations affect swimming performance in fishes. The goal of this study is to determine the effects of warm versus cool diel thermal variability on swimming efficiency and the speed limit for sustainable aerobically fueled swimming. We acclimated wild S. salar juveniles to a cool and a warm ecologically realistic diel thermal profile (16-21 and 19-24°C), and then tested individuals over a common acute change in temperature (16-24°C). We measured metabolic rate and swimming kinematics at a range of swimming speeds, at five temperatures (16, 18, 20, 22, and 24°C) and calculated swimming efficiency. Our temperature acclimation did not appear to significantly affect energetic and kinematic swimming efficiency, but acute exposure to high temperature did increase overall metabolic rate. It appears that wild S. salar can swim efficiently and sustainably during both acute cool and warm exposures, and after acclimation to diel thermal variation of 16-21 or 19-24°C.

Sensitivity of larval Dendropsophus haddadi (Bastos and Pombal 1996), an anuran species from the Brazilian Atlantic Forest, to acute exposure to nitrate.

Nitrogenous pollution has been reported to be a major threat to biodiversity and, therefore, it may be related to the decline of amphibians, the most threatened group of vertebrates in the world. In spite of this, and the widespread release of nitrogenous compounds into the environment, research on the impact of this pollution on Neotropical species remains limited. The aim of this study was to assess the sensitivity of one anuran species inhabiting in the Brazilian Atlantic Forest (Dendropsophus haddadi) to NaNO3 by an acute exposure laboratory experiment, addressing also whether carryover effects exist. Larval mortality increased as time went on in the case of the highly polluted treatments, which also affected swimming performance. Mean lethal concentration (LC50) values revealed that the sensitivity of the study species to NaNO3 was similar to that described for other amphibians, both tropical and temperate species. Additionally, larvae exposed to moderate levels of pollution significantly increased final mass. In spite of this, once larvae were transfered into clean water, no further mortality was recorded, and swimming performance improved. These results indicate that tropical species may not be more vulnerable to chemical pollution than temperate ones, and suggest that they are able to recover from acute short exposure to nitrogenous compounds, all of which represent a new addition to the knowledge of the vulnerability of Dendropsophus haddadi to pollution and, thus, to Neotropical ecotoxicology.

Endurance in Long-Distance Swimming and the Use of Nutritional Aids.

Long-distance swimmers exert energetic, physiological, and neuromuscular demands that must be matched with adequate body composition to improve their performance in long-distance swimming. This review aims to compile all available information on energetic and physiological demands, optimal body composition, nutrition, and ergogenic supplements in long-distance swimming. This will provide an understanding of the specific challenges and needs of this sport and will help swimmers and coaches design more effective training and nutrition plans to optimise performance and achieve their goals. Databases such as Web of Science, SciELO Citation Index, MEDLINE (PubMed), Current Contents Connect, KCI-Korean Journal Database, and Scopus were searched for publications in English using keywords such as swimming, endurance, energy demands, physiological demands, nutrition, body composition, and ergogenic aids, individually or in combination. There is convincing evidence that several physical indicators, such as propulsive surface area, technical, such as stroke rate, and functional, such as hydration strategies, are related to swimming performance and body composition. Each athlete may have a specific optimal body fat level that is associated with improved sporting performance. The nutritional needs of open water swimmers during competition are quite different from those of pool swimmers. Swimmers with an adequate physique have a high body muscle mass and moderately related anaerobic strength both on land and in the water. These general and specific strength capacities, which are given by certain anthropometric and physiological characteristics, are seen throughout the work, as well as ergogenic and nutritional strategies, which have an important impact on long-distance swimming performance.

Axial muscle‐fibre orientations in larval zebrafish

AbstractMost teleost fish propel themselves with lateral body waves powered by their axial muscles. These muscles also power suction feeding through rapid expansion of the mouth cavity. They consist of muscle segments (myomeres), separated by connective tissue sheets (myosepts). In adult teleosts, the fast axial muscle fibres follow pseudo‐helical trajectories, which are thought to distribute strain (relative fibre length change) approximately evenly across transverse sections during swimming, thereby optimizing power generation. To achieve strain equalization, a significant angle to the longitudinal axis on the frontal plane (azimuth) is necessary near the medial plane, increasing strain. Additionally, a deviation from longitudinal orientation on the sagittal plane (elevation) is required laterally to decrease strain. Despite several detailed morphological studies, our understanding of muscle‐fibre orientations in the entire axial musculature of fish remains incomplete. Furthermore, most research has been done in post‐larval stages, leaving a knowledge gap regarding the changing axial muscle architecture during larval development. Larval fish exhibit different body size, body shape and swimming kinematics compared to adults. They experience relatively high viscous forces, requiring higher tail‐beat amplitudes to overcome increased drag. Additionally, larval fish swim with higher tail‐beat frequencies. Histological studies have shown that in larval fish, muscle fibres in the anal region transition from an almost longitudinal orientation to a pseudo‐helical pattern by 3 dpf (days post‐fertilization). However, these studies were limited to a few sections of the body and were prone to shrinkage and tissue damage. Here, we introduce a novel methodology for quantifying muscle‐fibre orientations along the entire axial muscles. We selected 4 dpf larval zebrafish for our analyses, a stage where larvae are actively swimming but not yet free‐feeding. High‐resolution confocal 3D scans were obtained from four genetically modified zebrafish expressing green fluorescent protein in fast muscle fibres. Fluorescence variation allowed segmentation of individual muscle fibres, which were then converted to fish‐bound coordinates by correcting for the fish's position and orientation in the scan, and normalized to pool results across individuals. We show that at 4 dpf, muscle‐fibre trajectories exhibit a helical pattern tapering towards the tail. Average fibre angles decrease from anterior to posterior, with azimuth varying over the dorsoventral axis and elevation varying over the mediolateral axis. Notably, only the anteriormost 20% of the body displayed higher azimuth angles near the medial plane. Angles between neighbouring fibres were substantial, particularly at the rim of the epaxial and hypaxial muscles. The revealed muscle‐fibre architecture at this age presumably contributes to the swimming performance of these larvae, but that swimming performance is probably not the only driving factor for the fibre pattern. Our methodology offers a promising avenue for exploring muscle‐fibre orientations across ontogenetic series and provides a foundation for in‐depth functional studies on the role of muscle architecture in facilitating swimming performance of larval fish.

Changes in Race Performance During the Underwater Phases of a 200 m Bi-Fins Race Simulation After Application of Respiratory Muscle Training-A Case Study in the Current World Record Holder.

Maximal athletic performance can be limited by various factors, including restricted respiratory function. These limitations can be mitigated through targeted respiratory muscle training, as supported by numerous studies. However, the full potential of respiratory training in competitive finswimming has not been fully investigated. This case study aims to evaluate the effects of eight-week respiratory muscle training (RMT) on performance variability during the underwater phases of a 200 m bi-fins race simulation in an elite finswimmer (current world record holder and multiple world championship medalist). Performance variability was assessed based on pre-test, inter-test, and post-test data. Each measurement included pulmonary function and swim performance evaluations. In this study, underwater performance parameters, such as distance, time, velocity, and number of kicks, were assessed using video analysis synchronized with race timing and evaluated using the Dartfish software. The swimmer followed a 28-day training program with an Airofit PRO™ respiratory trainer between tests, with daily sessions targeting both inspiratory and expiratory muscles. The training involved 6-10 min of targeted exercises per day. Significant improvements were observed in Wilcoxon's paired-sample test between the pre-test and post-test results in terms of underwater distance (p = 0.012; d = 1.26), underwater time (p = 0.012; d = 1.26), and number of underwater kicks (p = 0.043; d = 1.01), resulting in a 14.23% longer underwater distance, 14.08% longer underwater time, and 14.94% increase in underwater kicks. Despite the increased distance and time, underwater velocity remained stable, indicating improved underwater performance efficiency. Despite some improvements, it is not possible to conclude that respiratory muscle training (RMT) can contribute to improved finswimming performance during the underwater phases of a 200 m bi-fins race simulation in this particular athlete's case. Further research with a larger sample size is necessary to fully understand the impact of RMT on finswimming performance.

Endurance of leg muscle strength and endurance of arm muscle strength to the ability of swimming speed 200 meters breaststroke

The lack of breaststroke swimming ability among athletes has led to a decline in breaststroke swimming performance in the Solok city swimming association. This problem is thought to be related to the low endurance of leg and arm muscles to the swimming speed of 200 meters breaststroke. This correlational study aims to reveal the contribution of leg muscle endurance, arm muscles, and the joint contribution of both to swimming speed 200 meters breaststroke in athletes coaching achievements in the Solok city swimming association. This study involved 25 swimming athletes in Solok city, with total sampling technique. Data on leg muscle strength endurance was measured through the squat jump test, arm muscle strength endurance through the push up test, and swimming speed through the 200 meter breaststroke swimming test. Data were analyzed using simple and multiple correlations with a significant level of α = 0.05, and the contribution was calculated by the formula r² x 100%. The results of data analysis showed that leg muscle strength endurance contributed 74.65%, while arm muscle strength endurance contributed 70.06%. The combination of both contributed 74.99% to the ability of 200 meters breaststroke swimming speed of athletes coaching achievements in swimming associations in Solok city.

Determining Validity and Reliability of an In-Field Performance Analysis System for Swimming.

To permit the collection of quantitative data on start, turn and clean swimming performances in any swimming pool, the aims of the present study were to (1) validate a mobile in-field performance analysis system (PAS) against the Kistler starting block equipped with force plates and synchronized to a 2D camera system (KiSwim, Kistler, Winterthur, Switzerland), (2) assess the PAS's interrater reliability and (3) provide percentiles as reference values for elite junior and adult swimmers. Members of the Swiss junior and adult national swimming teams including medalists at Olympic Games, World and European Championships volunteered for the present study (n = 47; age: 17 ± 4 [range: 13-29] years; World Aquatics Points: 747 ± 100 [range: 527-994]). All start and turn trials were video-recorded and analyzed using two methods: PAS and KiSwim. The PAS involves one fixed view camera recording overwater start footage and a sport action camera that is moved underwater along the side of the pool perpendicular to the swimming lane on a 1.55 m long monostand. From a total of 25 parameters determined with the PAS, 16 are also measurable with the KiSwim, of which 7 parameters showed satisfactory validity (r = 0.95-1.00, p < 0.001, %-difference < 1%). Interrater reliability was determined for all 25 parameters of the PAS and reliability was accepted for 21 of those start, turn and swimming parameters (ICC = 0.78-1.00). The percentiles for all valid and reliable parameters provide reference values for assessment of start, turn and swimming performance for junior and adult national team swimmers. The in-field PAS provides a mobile method to assess start, turn and clean swimming performance with high validity and reliability. The analysis template and manual included in the present article aid the practical application of the PAS in research and development projects as well as academic works.

Study on the Hydrodynamics of a Cownose Ray’s Flapping Pectoral Fin Model near the Ground

Cownose rays typically swim close to the ocean floor, and the nearby substrate inevitably influences their swimming performance. In this research, we numerically investigate the propulsive capability of cownose rays swimming near the ground by resolving three-dimensional viscous unsteady Navier–Stokes equations. The ground effect generally has a favorable impact on swimming. The thrust and lift increase as the near-substrate distance decreases. Nevertheless, a body length is the recommended distance from the ground, at which the flapping efficiency and swimming stability obtain a good trade-off. The increase in lift is due to the pressure difference between the dorsal and ventral surfaces of the ray, and the thrust boost is due to the enhanced shear vortex at the fin’s leading edge when swimming near the substrate. Our results indicate that the ground effect is more noticeable when the fin flaps are symmetrical compared to asymmetrical. In asymmetric flapping, the hydrodynamic performance improves at a smaller value than the half-amplitude ratio (HAR). The frequency of flapping also significantly affects swimming performance. We find that a superior flapping frequency, at which maximum efficiency is reached, occurs when flapping close to the substrate, and this superior frequency is consistent with the behavior of our model’s biological counterpart.

Carangiform‐Like Magnetic Milliswimmer With Negative Buoyancy for Agile 3D Navigation in Confined Fluid Environments

AbstractMiniature soft robots designed with magnetoelastic materials have the potential for noninvasive navigation in narrow spaces and innovative clinical therapies. However, the complex environment inside the body imposes stringent requirements on the motility and environmental adaptability of robots. Inspired by carangiform fish morphology and kinematics, a 3D free‐swimming magnetic milliswimmer with enhanced controllability, maneuverability, and environmental adaptability is developed. This milliswimmer is negatively buoyant like most fishes and employs magnetic torque to actuate its body. It mimics fish muscle contractions and generates a carangiform‐like body curvature distribution that results in comparable swimming behavior and performance. Compared with previous designs, it achieves over six times the equivalent motion performance and enables gravity‐resisting free‐swimming, with fish‐like maneuverability (a minimum turning radius of just 0.05 body length and a maximum turning rate of up to 4737 deg s−1). Its ability to transport and release cargo precisely while navigating three‐dimensionally in an ex vivo porcine urinary system is demonstrated. The designed bionic magnetic soft robot is expected to advance biomedical applications of magnetoelastic materials, particularly in urinary and other clinical treatments.

Somatotype and Swimming Performance of National Level Male Swimmers in India

Somatotype and Swimming Performance of National Level Male Swimmers in India

An adverse outcome pathway approach linking retinoid signaling disruption to teratogenicity and population-level outcomes

Recent research efforts in endocrine disruption have focused on evaluating non-EATS (estrogen, androgen, thyroid, and steroidogenesis) pathways. Retinoid signaling disruption is noteworthy because of its teratogenic effects and environmental relevance. However, current environmental risk assessments are limited in their ability to evaluate impacts on individuals and populations. This study characterizes an Adverse Outcome Pathway (AOP) network linking retinoid signaling disruption to teratogenicity and survival in zebrafish. We identified Retinoic Acid Receptor (RAR) overactivation as the molecular initiating event leading to key events including craniofacial (CFM) and tail (TM) malformations, posterior swim bladder (SB) non-inflation, impaired swimming performance, and reduced feeding, ultimately resulting in decreased survival. Our study (1) determines critical sensitivity windows for CFM, posterior SB non-inflation, and TM, (2) provides quantitative measurements for CFM and TM, and (3) defines impacts on higher biological levels including food ingestion, swimming, and survival. Results show that all-trans retinoic acid (ATRA) induces strong teratogenic effects with sensitivity windows between 4 and 48 h post fertilization (hpf) for CFM, TM, and posterior SB non-inflation. TM is the most sensitive indicator, with EC50 of 0.2 - 0.26 µg/L across exposure windows 4–48, 4–72, 4–96, and 4–120 hpf. Besides inducing known malformations, ATRA impaired posterior SB inflation with EC50 of 1 - 1.21 µg/L across the same exposure windows. ATRA exposure (1 µg/L) resulted in 50 % food ingestion inhibition at 7 days post fertilization (dpf) and 10 % survival at 14 dpf. This study provides a regulatory-relevant framework linking developmental effects to population outcomes, highlighting ecological risks and needs for improved risk assessments.

Optimizing light environments in aquatics center to enhance the performance of Olympic champions and other elite swimmers: An experimental study

Several major international sports events in the next five years require new sports venues, with lighting environments being a crucial factor. Typically, the lighting systems in sports venues are primarily for illumination. However, since light has been indicated to affect human psychology and physiology, we investigated whether the light environments in sports buildings impact athletic performance. Additionally, swimming is the indoor sport with the most gold medals in the Olympics. Therefore, we conducted a within-subject, randomized crossover study in an aquatics center with fourteen elite swimmers, including the Olympic champions and Asian champions (6 female and 8 male; 19.3 ± 3.4 years of age). During the experiment, the elite swimmers were exposed to either a common correlated color temperature (CCT) light environment (controlled condition: 5780 K) or an experimental light environment (8512 K) in the aquatics center, with both having the same illuminance (1020 lx). The neurobehavioral and swimming test results showed that the Olympic champions and other elite swimmers had significantly faster responses, fewer lapses, greater arousal, less visual fatigue, quicker reactions at start, and higher swimming speeds in the experimental condition compared to the controlled condition (p < 0.05). Our findings suggest that the light environment in the aquatics center affects swimmers' non-visual performance and enhancing the CCT of the light environment could improve swimmers' performance. We propose the concepts of Sports Lighting Beyond Illumination and Sports Human-Centric Lighting to enhance athletes’ health and performance, and to improve the sports environment for a better experience for all participants.

Parasite-Driven host manipulation: The case of trematodes in Neotropical tadpoles

Parasites can impact tadpole survival in both lethal and sublethal ways. Sublethal effects include alterations in morphology and behavior, reduced competitive ability, and increased vulnerability to predation, while lethal effects result in direct mortality. These impacts can have significant consequences at both individual and population levels, especially given that amphibians host various parasites and pathogens, which may contribute to population declines. This study investigated the influence of digenetic trematodes, specifically Lophosicyadiplostomum sp. and Echinostomatidae metacercariae – larval stages found in second intermediate hosts, on the development and behavior of Physalaemus cuvieri tadpoles. Behavioral experiments assessed tadpole activity (time and movement number), water column use, and food consumption rates using video recordings and image analysis. Swimming performance was evaluated through predation simulations, and tadpole morphology (i.e. body size and mass) was measured post-experimentally. Infections by these digenetic trematodes resulted in a notable reduction in tadpole activity. A negative correlation was observed between Lophosicyadiplostomum sp. parasite load and both tadpole activity duration and movement frequency, indicating a common response to trematode infection. This study underscores the need for further research on digenetic trematodes to determine whether these behavioral modifications represent host manipulation by the parasites, potentially optimizing their transmission to the final host.