Collective movement of schooling fish reduces the costs of locomotion in turbulent conditions.

The ecological and evolutionary benefits of energy-saving in collective behaviors are rooted in the physical principles and physiological mechanisms underpinning animal locomotion. We propose a turbulence sheltering hypothesis that collective movements of fish schools in turbulent flow can reduce the total energetic cost of locomotion by shielding individuals from the perturbation of chaotic turbulent eddies. We test this hypothesis by quantifying energetics and kinematics in schools of giant danio (Devario aequipinnatus) and compared that to solitary individuals swimming under laminar and turbulent conditions over a wide speed range. We discovered that, when swimming at high speeds and high turbulence levels, fish schools reduced their total energy expenditure (TEE, both aerobic and anaerobic energy) by 63% to 79% compared to solitary fish (e.g., 228 versus 48 kj kg-1). Solitary individuals spend approximately 22% more kinematic effort (tail beat amplitude•frequency: 1.7 versus 1.4 BL s-1) to swim in turbulence at higher speeds than in laminar conditions. Fish schools swimming in turbulence reduced their three-dimensional group volume by 41% to 68% (at higher speeds, approximately 103 versus 33 cm3) and did not alter their kinematic effort compared to laminar conditions. This substantial energy saving highlights that schooling behaviors can mitigate turbulent disturbances by sheltering fish (within schools) from the eddies of sufficient kinetic energy that can disrupt locomotor gaits. Therefore, providing a more desirable internal hydrodynamic environment could be one of the ecological drivers underlying collective behaviors in a dense fluid environment.

Creatine and L-carnitine attenuate muscular laminopathy in the LMNA mutation transgenic zebrafish.

Lamin A/C gene (LMNA) mutations contribute to severe striated muscle laminopathies, affecting cardiac and skeletal muscles, with limited treatment options. In this study, we delve into the investigations of five distinct LMNA mutations, including three novel variants and two pathogenic variants identified in patients with muscular laminopathy. Our approach employs zebrafish models to comprehensively study these variants. Transgenic zebrafish expressing wild-type LMNA and each mutation undergo extensive morphological profiling, swimming behavior assessments, muscle endurance evaluations, heartbeat measurement, and histopathological analysis of skeletal muscles. Additionally, these models serve as platform for focused drug screening. We explore the transcriptomic landscape through qPCR and RNAseq to unveil altered gene expression profiles in muscle tissues. Larvae of LMNA(L35P), LMNA(E358K), and LMNA(R453W) transgenic fish exhibit reduced swim speed compared to LMNA(WT) measured by DanioVision. All LMNA transgenic adult fish exhibit reduced swim speed compared to LMNA(WT) in T-maze. Moreover, all LMNA transgenic adult fish, except LMNA(E358K), display weaker muscle endurance than LMNA(WT) measured by swimming tunnel. Histochemical staining reveals decreased fiber size in all LMNA mutations transgenic fish, excluding LMNA(WT) fish. Interestingly, LMNA(A539V) and LMNA(E358K) exhibited elevated heartbeats. We recognize potential limitations with transgene overexpression and conducted association calculations to explore its effects on zebrafish phenotypes. Our results suggest lamin A/C overexpression may not directly impact mutant phenotypes, such as impaired swim speed, increased heart rates, or decreased muscle fiber diameter. Utilizing LMNA zebrafish models for drug screening, we identify L-carnitine treatment rescuing muscle endurance in LMNA(L35P) and creatine treatment reversing muscle endurance in LMNA(R453W) zebrafish models. Creatine activates AMPK and mTOR pathways, improving muscle endurance and swim speed in LMNA(R453W) fish. Transcriptomic profiling reveals upstream regulators and affected genes contributing to motor dysfunction, cardiac anomalies, and ion flux dysregulation in LMNA mutant transgenic fish. These findings faithfully mimic clinical manifestations of muscular laminopathies, including dysmorphism, early mortality, decreased fiber size, and muscle dysfunction in zebrafish. Furthermore, our drug screening results suggest L-carnitine and creatine treatments as potential rescuers of muscle endurance in LMNA(L35P) and LMNA(R453W) zebrafish models. Our study offers valuable insights into the future development of potential treatments for LMNA-related muscular laminopathy.

Universal wing- and fin-beat frequency scaling.

We derive an equation that applies for the wing-beat frequency of flying animals and to the fin-stroke frequency of diving animals like penguins and whales. The equation states that the wing/fin-beat frequency is proportional to the square root of the animal's mass divided by the wing area. Data for birds, insects, bats, and even a robotic bird-supplemented by data for whales and penguins that must swim to stay submerged-show that the constant of proportionality is to a good approximation the same across all species; thus the equation is universal. The wing/fin-beat frequency equation is derived by dimensional analysis, which is a standard method of reasoning in physics. We finally demonstrate that a mathematically even simpler expression without the animal mass does not apply.

Swimming in a school shelters fish from turbulence.

Much has been written about the energetic effects of animals moving in schools or flocks, but experimental results are few and often ambiguous. A new study in PLOS Biology shows that schooling greatly reduces the cost of transport for fish in turbulent flow.

The effect of forced even pacing and an opponent on end-spurt behaviour in freestyle pool swimming.

To investigate the effect of forced even pacing through virtual pacing assistance and an opponent in a competitive setting on end-spurt behaviour in freestyle swimmers, including related physiological underpinnings. Twenty-seven competitive swimmers and triathletes were recruited. There were four 1500 m freestyle trials: (i) familiarisation time trial, (ii) self-paced time trial (STT), (iii) head-to-head competition time trial (CTT) and (iv) forced even pacing through virtual pacing assistance time trial (FET). Eventually, 12 swimmers met the criteria for the CTT and FET to be included in the analysis. Changes in end-spurt behaviour, finishing time and physiological parameters (lactate, cortisol, noradrenaline and heart rate) were analysed using a linear mixed model with fixed effects for trials and a random effect for swimmer identity. A separate linear model was computed for competition outcome. The end-spurt for each race was determined by means of an end-spurt indicator (ESI; ESI > 0 greater end-spurt). Swimmers demonstrated a significantly greater ESI in FET (+2.6; p < 0.001) and CTT (+1.4; p = 0.022) compared to STT. Blood lactate concentration in FET (+1.0 mmol L-1; p < 0.001) and CTT (+1.6 mmol L-1; p < 0.001) was significantly higher than in STT. Winners had a significantly greater ESI than losers in CTT (+1.6 and p = 0.005). Swimmers utilised a greater end-spurt through metabolically optimal forced even pacing by virtual pacing assistance and in a head-to-head competition due a larger mobilisation of anaerobic reserves as indicated by greater blood lactate concentrations. Winners had a significantly greater end-spurt than losers despite similar metabolic disturbances.

Emergency Medical Planning for an Ultramarathon Open Water Swim: A Case Review of "Swim Tuff".

ABSTRACT: Ultramarathon open water swimming (OWS) events are one of the toughest endurance challenges in the world. The sport has gained notoriety with athletes swimming across the English Channel, Diana Nyad swimming from Cuba to Florida, and the 5- and 10-km OWS in the Olympic schedule. The athletes who participate are exposed to dangerous conditions that expose risks inherent to the sport. The optimal time to prepare for an emergency is before it happens. The aim of this paper is to present an emergency action plan (EAP) designed for the "Swim Tuff" event, a record-breaking ultramarathon swim that took place in Rhode Island, United States. This article identifies an overview of Swim Tuff, the challenges experienced, and how the team designed and implemented risk mitigation strategies. The professionals looking over athletes completing an OWS should be educated and aware of the unique circumstances inherent to the sport.

Multiflagellate Swimming Controlled by Hydrodynamic Interactions.

Many eukaryotic microorganisms propelled by multiple flagella can swim very rapidly with distinct gaits. Here, we model a three-dimensional mutiflagellate swimmer, resembling the microalgae. When the flagella are actuated synchronously, the swimming efficiency can be enhanced or reduced by interflagella hydrodynamic interactions (HIs), determined by the intrinsic tilting angle of the flagella. The asynchronous gait with a phase difference between neighboring flagella can reduce oscillatory motion via the basal mechanical coupling. In the presence of a spherical body, simulations taking into account the flagella-body interactions reveal the advantage of anterior configuration compared with posterior configuration, where in the latter case an optimal flagella number arises. Apart from understanding the role of HIs in the multiflagellate microorganisms, this work could also guide laboratory fabrications of novel microswimmers.

Effects of 8 weeks parent-accompanied swimming on physical capacity and intelligence in preschool children.

This study aimed to explore the potential effects of 8-week parents-accompanied swimming on the physical capacity and intelligence of preschool children in China. Thirty-six boys (mean age 3.56 ± 0.27 years) were divided into three groups: the traditional physical exercise group (TP, n = 12), the accompanied swimming group (AS, n = 12) and the independent swimming group (IS, n = 12). Participants' physical capacity was assessed before and after the intervention using the following indicators: height, weight, distance of tennis ball throw, standing long jump distance, time for the 10-meter shuttle run, time for a two-legged continuous jump, sit-and-reach distance, and time on the walking balance beam. Intelligence was assessed at three points: pre-test, mid-test after 4 weeks, and post-test. Data were analyzed using a two-way repeated measures ANOVA, Bonferroni test (p < 0.05) and effect size. The time of the AS and IS groups to walk the balance beam was significantly lower than the TP group, with a difference of 1.81 s (p < 0.01, [95% CI -3.22 to -0.40], ES = 1.53) and 1.25 s (p < 0.05, [95% CI -2.66 to 0.16], ES = 0.81). At the mid-test, the IQ scores of the TP group were lower than the AS group (p < 0.05, [95% CI -12.45 to -0.96], ES = 0.89). Additionally, at post-test, the IQ scores of the TP group were significantly lower than those of both AS (p < 0.01, [95% CI -14.12 to -2.74], ES = 1.15) and IS groups (p < 0.01, [95% CI -12.53 to -3.31], ES = 1.21). Swimming enhances children's balance and IQ scores more than traditional physical exercises. Involving parents in swimming leads to a more significant increase in IQ scores within 4 weeks of initial swimming exercise.

An improved method of local coloring in vertical-slot fishways to enhance the fish migration effect of grass carp.

Vertical-slot fishway (VSF) has been used in many water conservancy projects to restore the river connectivity. A high-quality fishway project should facilitate fish to discovering the exit and passing through, avoiding to long stay in the fishway and delay the migration. Current research on fishway engineering has not yielded an expected passing ratio of fish migration, and it is therefore of great significance to further study the assisting effect of VSF in fish migration. To begin with, we preliminarily determined the attractive and repelling colors of grass carps based on their swimming behavior in a static water pool configured with local colors. Combined with the migration route of the grass carp in a VSF pool without local coloring, four local coloring cases were designed. Based on the camera results of the four experimental local coloring cases, a comparative analysis was conducted with the blank control group frame by frame. This was followed by the statistics of the number of successfully migrated grass carps and their total completion time. On that basis, the assisting effect of VSF in fish migration under the four cases was evaluated in terms of the reduction rate of migration route length, the reduction rate of completion time, and the improvement rate of passing ratio. The research outcomes indicated that green and blue act as attractive colors while yellow and red serve as repelling colors for grass carp. Adding colors to the training wall and dividing wall in the VSF pool, the migration route of grass carp was appropriately adjusted, alongside a shortened completion time and an improved passing ratio. Of the four local coloring cases, the recommended case showed a significant effect on migration route, with more concentrated moving trajectories and shortened route length. Typically, the migration route length decreased by 26%, and the frequency of fish long staying at the junction between the training wall and dividing wall was markedly reduced, as well as the frequency of fish swimming along the water flow from upstream to downstream. The completion time was shortened by 26%, and the passing ratio was enhanced by 44%. The approach of combining local coloring with fish behavior and fishway hydraulics in the pool surpassed the method that optimizes the fishway design only from the fishway hydraulics. The improved method greatly shortened the migration route length, reduced the completion time, and significantly improved the passing ratio of fish passage objects in the VSF. The present research mainly focuses on using model experiments to evaluate the local coloring cases. In the future studies, we will configure local colors to the sidewalls of on-site fishways using environmentally friendly paint or colored organic glass panels. With the monitoring results of the completion time and passing ratio of fish passage objects, the recommended case can be further verified and optimized, thereby providing a more reasonable and feasible local coloring case for assisting fish migration in the VSF project.

Polysaccharides from Artemisia argyi leaves: Environmentally friendly ultrasound-assisted extraction and antifatigue activities.

Artemisia argyi leaf polysaccharide (AALPs) were prepared through ultrasound-assisted extraction (UAE), and their antifatigue activities were evaluated. Extraction was optimized using response surface methodology (RSM), which yielded the following optimal UAE conditions: ultrasonication power of 300 W, extraction temperature of 51 °C, liquid:solid ratio of 20 mL/g, and ultrasonication time of 47 mins. The above optimal conditions resulted in the maximum extraction rate of 10.49 %. Compared with hot water extraction (HWE), UAE supported higher yields and total sugar, uronic acid, and sulfate contents of AALPs. Meanwhile, AALP prepared through UAE (AALP-U) exhibited higher stability due to its smaller particle size and higher absolute value of zeta potential than AALP prepared through HWE (AALP-H). In addition, AALP-U demonstrated stronger antioxidant activity than AALP-H. In forced swimming tests on mice, AALP-U could significantly prolong swimming time with a dose-dependent effect, increase liver and muscle glycogen levels, and improve other biochemical indices, thus showing great potential for application in functional food.

The interplay of group size and flow velocity modulates fish exploratory behaviour.

Social facilitation is a well-known phenomenon where the presence of organisms belonging to the same species enhances an individual organism's performance in a specific task. As far as fishes are concerned, most studies on social facilitation have been conducted in standing-water conditions. However, for riverine species, fish are most commonly located in moving waters, and the effects of hydrodynamics on social facilitation remain largely unknown. To bridge this knowledge gap, we designed and performed flume experiments where the behaviour of wild juvenile Italian riffle dace (Telestes muticellus) in varying group sizes and at different mean flow velocities, was studied. An artificial intelligence (AI) deep learning algorithm was developed and employed to track fish positions in time and subsequently assess their exploration, swimming activity, and space use. Results indicate that energy-saving strategies dictated space use in flowing waters regardless of group size. Instead, exploration and swimming activity increased by increasing group size, but the magnitude of this enhancement (which quantifies social facilitation) was modulated by flow velocity. These results have implications for how future research efforts should be designed to understand the social dynamics of riverine fish populations, which can no longer ignore the contribution of hydrodynamics.

[Water quality and athletes' health: One hundred years on, swimming is once again possible in the Seine]. / La qualité de l'eau et la santé des athlètes : cent ans après, la baignade redevient possible dans la Seine.

A great deal of work has been undertaken to ensure that certain swimming events (open water and triathlon) at the Olympic and Paralympic Games can be held in the Seine under sanitary conditions that respect the health of the athletes. They will be the first to take the plunge in this river, but the aim is to speed up the process of making it possible for the people of Ile-de-France to swim in it too, as well as in the Marne.

The Acute Effects of a Preload Upper-Body Power Exercise on 50-m Freestyle Performance in Youth Swimmers.

ABSTRACT: Hill, V, Patterson, S, Buckthorpe, M, and Legg, HS. The acute effects of a preload upper-body power exercise on 50-m freestyle performance in youth swimmers. J Strength Cond Res 38(7): 1295-1299, 2024-This study aimed to investigate the acute effects of a medicine ball slam and the optimal recovery time required to induce a postactivation performance enhancement (PAPE) response on 50-meter freestyle swimming performance. Twenty-four (13 female, 11 male) competitive, adolescent swimmers (mean ± SD: age, 16.7 ± 1.2 years; height, 173.3 ± 6.7 cm; mass, 63.1 ± 6.4 kg) participated in a randomized crossover study. After the PAPE intervention (3 × 5 medicine ball slams), subjects had 1-minute, 4-minute, and 8-minute recovery periods before a 50-m maximal freestyle swim. A 1-way repeated-measures ANOVA revealed that different recovery times elicited changes in 50-m performance (F = 12.12, p < 0.0005). After 4 minutes of recovery, 50-m performance was 1.6% (0.47 seconds) faster (95% confidence interval [CI] [0.17-0.77], p < 0.001). When the data were split by sex, after 4 minutes of recovery, 50-m performance was 2% (0.64 seconds) faster for women (95% CI [0.279-0.998], p < 0.001). In conclusion, an upper-body power exercise, before performance, can induce a PAPE response and enhance 50-m freestyle performance after a 4-minute recovery period.

Assessing metabolic rates in zebrafish using a 3D-printed intermittent-flow respirometer and swim tunnel system.

Zebrafish have become a widely used vertebrate model in physiology and reliable measures of their metabolic rate are needed. We have developed a 3D-printed respirometer and swim tunnel system and used it for obtaining accurate measurement of standard metabolic rate (SMR) and maximal, aerobic metabolic rate (MMR) in zebrafish under rest and maximal exercise, respectively. We compared a slow (stepwise) protocol to a fast (continuous) protocol for determining MMR. The fast protocol yielded slightly (but not significantly) higher oxygen consumption rates than the slow protocol and the data, in contrast to the slow protocol, followed a normal distribution. These findings point to the fast protocol as a fast and reliable method for obtaining accurate values of MMR in zebrafish. We make the 3D drawings for printing the system available to researchers, to help streamline the field of metabolic research in zebrafish and other smaller fish species.

Neuromuscular Adaptations in Endurance-Trained Male Adolescents Versus Untrained Peers: A 9-Month Longitudinal Study.

BACKGROUND: Neuromuscular function is considered as a determinant factor of endurance performance during adulthood. However, whether endurance training triggers further neuromuscular adaptations exceeding those of growth and maturation alone over the rapid adolescent growth period is yet to be determined. OBJECTIVE: The present study investigated the concurrent role of growth, maturation, and endurance training on neuromuscular function through a 9-month training period in adolescent triathletes. METHODS: Thirty-eight 13- to 15-year-old males (23 triathletes [~6 h/week endurance training] and 15 untrained [<2 h/week endurance activity]) were evaluated before and after a 9-month triathlon training season. Maximal oxygen uptake (V̇O2max) and power at V̇O2max were assessed during incremental cycling. Knee extensor maximal voluntary isometric contraction torque (MVCISO) was measured and the voluntary activation level (VAL) was determined using the twitch interpolation technique. Knee extensor doublet peak torque (T100Hz) and normalized vastus lateralis (VL) electromyographic activity (EMG/M-wave) were also determined. VL and rectus femoris (RF) muscle architecture was assessed using ultrasonography. RESULTS: Absolute V̇O2max increased similarly in both groups but power at V̇O2max only significantly increased in triathletes (+13.8%). MVCISO (+14.4%), VL (+4.4%), and RF (+15.8%) muscle thicknesses and RF pennation angle (+22.1%) increased over the 9-month period in both groups similarly (p < 0.01), although no changes were observed in T100Hz, VAL, or VL EMG/M-wave. No changes were detected in any neuromuscular variables, except for coactivation. CONCLUSION: Endurance training did not induce detectible, additional neuromuscular adaptations. However, the training-specific cycling power improvement in triathletes may reflect continued skill enhancement over the training period.

Effects of physical training on the metabolic profile of rats exposed to chronic restraint stress.

INTRODUCTION: Despite strong evidences supporting the protective role of exercise against stress-induced repercussions, the literature remains inconclusive regarding metabolic aspects. Therefore, this study aimed to evaluate the effect of Physical Training (PT) by swimming on the metabolic parameters of rats subjected to restraint stress. METHODS: Wistar rats (n = 40) were divided into four groups: Control (C), Trained (T), Stressed (S), and Trained/Stressed (TS). The restraint stress protocol involved confining the animals in PVC pipes for 60 minutes/day for 12 weeks. Concurrently, the swimming PT protocol was performed without additional load in entailed sessions of 60 minutes conducted five days a week for the same duration. The following parameters were analyzed: fitness progression assessed by the physical capacity test, body mass, serum level of glucose, triglyceride, cholesterol and corticosterone, as well as glycemic tolerance test, evaluated after glucose administration (2 g/kg, i.p.). RESULTS: Trained groups (T and TS) exhibited enhanced physical capacity (169 ± 21 and 162 ± 22% increase, respectively) compared to untrained groups (C: 9 ± 5 and S: 11 ± 13% increase). Corticosterone levels were significantly higher in the S group (335 ± 9 nmoL/L) compared to C (141 ± 3 nmoL/L), T (174 ± 3 nmoL/L) and TS (231 ± 7 nmoL/L), which did not differ from each other. There were no significant changes in serum glucose, cholesterol, and triglyceride levels among the groups. However, the glycemic curve after glucose loading revealed increased glycemia in the S group (area under curve 913 ± 30 AU) but the TS group exhibited values (673 ± 12 AU) similar to the groups C (644 ± 10 AU) and T (649 ± 9 AU). CONCLUSION: Swimming-based training attenuated stress-induced corticosterone release and prevented glucose intolerance in rats, reinforcing the importance of exercise as a potential strategy to mitigate the pathophysiological effects of stress.

Race Dynamics in Triathlon Mixed-Team-Relay Meaningfully Changes with The New Regulation Towards Paris 2024.

Mixed-Team-Relay (MTR) triathlon is a novel Olympic discipline whose performance determinants and tactical behaviors have barely been studied. Additionally, a regulatory change has been made to the male and female relay order for the Paris 2024 Olympics. Therefore, this study aimed to determine the performance determinants and race dynamics as a function of competitive level on the new regulated MTR triathlon. Results from 129 national teams, (516 elite triathletes) across five MTR World Triathlon Series and two MTR European Championships in 2022 and 2023, were analyzed. Split times, average speeds, time behind the race leader (gap), partial and finishing positions, pack position as well as the rank positions of every segment, relay leg, and overall race were computed. Decision tree analyses were conducted as a predictive method for the overall results, and correspondence analyses were conducted to examine the relationship between the different relay legs and segments and the finishing positions. The performance of the fourth leg was the most relevant for overall result (30%), as well as the fourth running leg (16%) and the female legs performance (7%). Medallist relay teams were characterized by displaying a differential speed lower than 0.5 and 0.83 km/h, respectively, from the best-ranking athletes in the Legs 1 and 4. Furthermore, staying in the front pack after the second swimming leg showed a great relationship with achieving a medal position. New MTR triathlon rules shift race dynamics, emphasizing individual efforts in cycling and swimming, while maintaining the crucial importance of running.

The evolution of olfactory sensitivity, preferences, and behavioral responses in Mexican cavefish is influenced by fish personality.

Animals are adapted to their natural habitats and lifestyles. Their brains perceive the external world via their sensory systems, compute information together with that of internal states and autonomous activity, and generate appropriate behavioral outputs. However, how do these processes evolve across evolution? Here, focusing on the sense of olfaction, we have studied the evolution in olfactory sensitivity, preferences, and behavioral responses to six different food-related amino acid odors in the two eco-morphs of the fish Astyanax mexicanus. To this end, we have developed a high-throughput behavioral setup and pipeline of quantitative and qualitative behavior analysis, and we have tested 489 six-week-old Astyanax larvae. The blind, dark-adapted morphs of the species showed markedly distinct basal swimming patterns and behavioral responses to odors, higher olfactory sensitivity, and a strong preference for alanine, as compared to their river-dwelling eyed conspecifics. In addition, we discovered that fish have an individual 'swimming personality', and that this personality influences their capability to respond efficiently to odors and find the source. Importantly, the personality traits that favored significant responses to odors were different in surface fish and cavefish. Moreover, the responses displayed by second-generation cave × surface F2 hybrids suggested that olfactory-driven behavior and olfactory sensitivity is a quantitative genetic trait. Our findings show that olfactory processing has rapidly evolved in cavefish at several levels: detection threshold, odor preference, and foraging behavior strategy. Cavefish is therefore an outstanding model to understand the genetic, molecular, and neurophysiological basis of sensory specialization in response to environmental change.