Swimming Group Research Articles

The Impact of Puzzle Feeders, Ice-Pops and Artificial Seaweed on Captive Harbour Seals (Phoca vitulina) Behaviour

Environmental enrichment is used in zoos and aquaria to improve animal welfare through the stimulation of naturalistic behaviours and reduction of stereotypic behaviours. This study investigated the impact of new enrichment items on the behaviour of a group of captive adult harbour seals. Data were collected in summer-autumn 2023 using continuous scan sampling and all behaviours one-zero recording method for 1-minute intervals (4 hours/day, 8 days). Under standard enrichment conditions, more than 90% of the seals’ behavioural budget was represented by naturalistic behaviours, with low levels of pattern group swimming, which occurred mainly before the two daily shows. Group swimming decreased and random swimming increased before the seal shows on days with new enrichment, but these differences were not statistically significant. The presence of new enrichment items led to a significant increase in exploration and a significant decrease in group swimming only during the morning periods when the new items were actually present in the enclosure (p<0.05, Kruskal Wallis test). During these periods the seals interacted most frequently with the submersed fish-filled puzzle feeders and least frequently with the floating artificial seaweed. This study concluded that new environmental enrichment may be beneficial even for seals displaying low levels of stereotypic behaviours as it provides more behavioural choices and helps promote active naturalistic exploratory behaviours which may alleviate captivity induced stress and improve welfare.

Effect of sacubitril/valsartan and dapagliflozin on athletic performance; can the popular cardiac medications of recent years be used as doping agents?

Abstract Background/Introduction Recent guidelines have highlighted the positive impacts of sacubitril/valsartan and dapagliflozin on heart failure management [1]. Given their potential misuse as doping agents in professional sports, this study evaluates their effects on athletic performance. Purpose To investigate the effects of sacubitril/valsartan and dapagliflozin on athletic performance and cardiac functions in a rodent model. Methods The study had a randomized double-blind design. 24 Sprague-Dawley male rats aged 4 months, divided into control, sacubitril/valsartan, and dapagliflozin groups. The rats were weighed at the start of the experiment. The medications (dapagliflozin 1,5 mg/kg/1 ml/once a day, sacubitril/valsartan 60 mg/kg/1 ml/once a day to their respective groups, and normal saline for control group) were administered via gastric gavage for 30 days. The rats were weighed, examined with transthoracic echocardiography and put on rotarod at the start of the experiment, and on 15th and 30th days. The rats were put on forced swimming tests for 20 days. Exhaustion, loss of coordinated movements and failure to surface for 3 seconds after submersion in the water were defined as indications for ending the test as per the guidelines regarding rat exercise testing [2]. M-mode and Doppler measurements, forced swimming test durations, rotarod durations and weight were recorded on 0th, 15th and 30th days. Results Initial performance metrics, including echocardiography, weight, and rotarod tests, showed no significant differences among the groups at baseline. The distributions in data were non-normal. Over the course of the study, median swimming times significantly differed from the 9th session, with dapagliflozin-treated rats exhibiting a substantial increase in endurance. Specifically, dapagliflozin group's swimming times increased to a median of 3580 seconds by the 20th session, compared to 2382 seconds in the control group and 2591 seconds in the sacubitril/valsartan group, indicating a pronounced improvement in exercise capacity (P<0.0001)(Figure-1). Echocardiographic assessments revealed enhanced cardiac output and ejection fraction, particularly in the sacubitril/valsartan group, suggesting increased cardiac efficiency and potential athletic performance enhancement. Conclusion(s) The study demonstrates a significant improvement in athletic performance with dapagliflozin compared to sacubitril/valsartan. These findings suggest a potential for misuse in sports doping, emphasizing the need for stringent regulation and monitoring within competitive athletics.Figure-1

Swim, Strength, or Combined Programs: Effect on Health-Related Physical Fitness in Adolescents With Down Syndrome.

The adolescent population with Down syndrome (DS) appears to show higher levels of body fat and lower levels of cardiorespiratory fitness or muscle strength than their peers without disabilities. There is a need to create physical activity programs to improve these data. The aim of this research was to determine the effects of a 16-week swimming program, strength program, and combined program (swimming and strength training) on body composition and health-related physical fitness on adolescents with DS and to assess whether there are differences in the results of the different training programs. Forty-five adolescents (17 female and 28 male; average age 15.5 [1.53] years) with DS were recruited and randomized to three groups (swim [n = 15], strength [n = 15], and combined [n = 15]). Results showed that the swim group had significant improvements in all health-related physical fitness variables and there was an improvement in some body-composition variables (p < .05). The strength and combined groups obtained minor improvements in the variables analyzed. In summary, a 16-week swim program consisting of three sessions of 60min is able to improve levels of body composition and health-related physical fitness in adolescents with DS. The swim training program seems to be more effective in improving body composition and health-related physical fitness than the strength or combined program. These findings could be useful in different special-education centers due to the predisposition shown by the population with DS to this sportmodality.

Acoustic Target Strengths and Swimbladder Morphology of Chub Mackerel Scomber japonicus in the Northwest Pacific Ocean

The Northwest Pacific chub mackerel (Scomber japonicus) is one of the most productive, economically important fishery resources worldwide. Accurately assessing this species and ensuring adherence to total allowable catch limits are crucial owing to fluctuations in their abundance and distribution. Acoustic target strength measurements of S. japonicus were conducted at 38, 70, and 120 kHz using a split-beam echosounder of individuals from nine size groups (mean fork length, 10.8–28.3 cm) swimming freely in a net cage within a seawater tank. An underwater camera was utilized to simultaneously measure swimming angle. Least-squares regression analysis revealed that when the slope was constrained to 20, as per the generally applicable morphometric equation, the resulting values for the constant term (b20) were −67.7, −66.6, and −67.3 dB at 38, 70, and 120 kHz, respectively. S. japonicus mean swimming angle across the groups was −10.5–9.6° (standard deviation [SD], 16.3–33.3°). Furthermore, the ratio of swimbladder height to swimbladder length, the ratio of swimbladder length to fork length, and the tilt angle of the swimbladder (mean ± SD) were 0.191 ± 0.060, 0.245 ± 0.055, and 9.6 ± 3.0°, respectively. These results can be used for the acoustic stock assessment of S. japonicus in the Northwest Pacific Ocean.

Pile driving noise impacts behavioral patterns of important East Asian juvenile marine fishes

The surge in renewable energy demand, particularly from offshore wind farm (OWF), raises concerns about underwater noise pollution during their construction. Despite extensive studies on underwater noise impacts in European and Western countries, local species targeted investigations are crucial for global application. We assessed how pile driving noise during OWF construction affected the behavior of three juvenile Korean fishes (Lateolabrax japonicus, Acanthopagrus schlegelii, and Platichthys stellatus) prevalent in East Asian seas. Pile driving noise playback induced rapid changes in L. japonicus and A. schlegelii swimming speed and group cohesion, with 40 % remaining un-habituated after 5 min. Notably, L. japonicus showed clear avoidance of the noise source, while P. stellatus behavior remained unchanged at all. Our findings confirm that even relatively low-intensity impulsive noise can alter fish behavior, potentially due to species-specific characteristics. Accumulated data will inform the development of strategies for smart OWF establishment, advancing sustainable energy practices.

Swimming exercise alleviates pathological bone features in curdlan-injected SKG mice by inducing irisin expression

This study assessed the therapeutic potential of swimming exercise in the curdlan-injected SKG mouse model and investigated the modulatory effects of irisin on inflammation. Curdlan-injected SKG were randomly assigned to either a home-cage group or a swimming group for 6 weeks. Changes in clinical arthritis scores and ankle thickness were measured weekly. Post-swimming program, mice were anesthetized for collection of vastus lateralis muscle and blood, which was followed by histological analysis, micro-CT imaging of the ankle joints, and the measurement of pro-inflammatory cytokines and irisin levels. Additionally, curdlan-injected SKG mice were intravenously injected with recombinant irisin protein and observed. Finally, serum levels of irisin in healthy control and ankylosing spondylitis (AS) patient groups were measured by ELISA. The swimming group of curdlan-injected SKG mice exhibited significant improvements in arthritis and enthesitis compared to the home-cage group. In particular, micro-CT and histological analyses revealed a notable reduction in pathological bone features in the swimming group compared to the home-cage group. Muscle endurance was also enhanced in the swimming group compared to the home-cage group, as determined by the wire-hanging test. Intriguingly, irisin levels not only were statistically increased in the swimming group but, also, TNF-α, IL-1β, and IL-6 levels were decreased. Additionally, injection of irisin protein slightly attenuated both arthritis and enthesitis in curdlan-injected SKG mice. Meanwhile, irisin serum levels were declined in AS patients. Overall, we found that swimming exercise attenuated pathological bone features in an AS animal model, potentially mediated by increased irisin serum levels with associated anti-inflammatory effects.

Boosting physical performance in SD rats through brain-targeted delivery of caffeine-loaded transferrin liposomes

This study aimed to explore the impact of caffeine (CAF) encapsulated in transferrin-modified, sterically-stabilized liposomes (Tf-SSL) on the physical performance of rats, specifically forelimb grip strength, running, and swimming. The brain-targeted drug delivery system, Tf-SSL, was used for the administration of caffeine. 168 male Sprague-Dawley (SD) rats were randomly assigned to different groups, including swimming, running, running wheel, and strength groups. Each group was further subdivided into high, medium, and low dose free caffeine (HCAF, MCAF, LCAF) and Tf-SSL CAF groups, along with a control group (CON). The strength, swimming, and running groups underwent training for four weeks, three times per week. The running wheel group was placed in rearing cages for a one-week adaptation period. After the final training session, the resistance, swimming, running, and running wheel exercise capacities of the rats were tested. The rats were administered treatment via tail vein injection, while the blank CON group received 0.9 % saline solution without treatment throughout the entire process. The results demonstrated a Tf-SSL CAF group encapsulation rate of 70.58 ± 5.14 %. Increasing the concentration of supplemented caffeine led to enhanced forelimb grip strength in rats, with significant differences observed in HCAF alone group, medium-dose Tf-SSL CAF (MTf-SSL CAF), and high-dose Tf-SSL CAF (HTf-SSL CAF) groups compared to the CON group. In the running and swimming experiments, higher caffeine supplementation concentrations correlated with increased running and swimming time to exhaustion, and the MTf-SSL CAF group showed longer running and swimming time compared to the HCAF alone group. The results of rat striatal dopamine levels indicated that increased caffeine supplementation concentrations led to higher dopamine secretion, with significantly different striatal concentrations in the HCAF group, MTf-SSL CAF group, and HTf-SSL CAF group compared to the CON group. The running wheel experiment revealed that rats in the medium- and high-dose Tf-SSL CAF groups exhibited greater 6-h running distances than the HCAF group and CON group. In conclusion, caffeine supplementation improved the physical performance of rats, with the high concentration CAF group outperforming the low and medium concentration groups. Furthermore, Tf-SSL CAF demonstrated superior physical enhancement compared to caffeine supplementation alone.

Resistance training presents beneficial effects on bone development of adolescents engaged in swimming but not in impact sports: ABCD Growth Study

BackgroundSports practice during adolescence is important to enhance bone development, although it may provide different effects depending on the mechanical impact present in the sport. Besides, resistance training (RT) may also induce bone changes directly (via muscle contractions) and indirectly (via myokines). However, there have been no studies analyzing the longitudinal influence of engaging in sport with and without added mechanical load. Thus, this study aims to analyze the combined effects of sports participation and resistance training on areal bone mineral density (aBMD) accrual in adolescent athletes participating in swimming and impact sports for 12-months.MethodsThis was a 12-month longitudinal study. The sample comprised 91 adolescents (21 females) aged 10 to 18 years, engaged in impact sports (basketball, tennis, track & field, baseball and gymnastics, n = 66) and non-impact sport (swimming, n = 25). The sample was divided according to resistance training participation: impact sports only (n = 45), impact sports + resistance training (n = 21), swimming-only (n = 17) and swimming + resistance training (n = 8). aBMD and soft tissues were measured using dual-energy X-ray absorptiometry. Generalized linear models analysis was used for the resistance training (RT) x type of sport interaction in predicting aBMD changes overtime, adjusting for maturation, sex and baseline aBMD.ResultsAfter 12-months, all groups showed a significant increase in aBMD, except for the swimming groups (regardless of resistant training), which showed a significant loss in spine aBMD (-0.045 [-0.085 to -0.004] g/cm2 in swimming-only and − 0.047 [-0.073 to -0.021] g/cm2 in swimming + RT). In comparisons between groups, only swimming + RT group, compared with swimming-only group presented higher upper limbs aBMD (0.096 g/cm2 [0.074 to 0.118] in swimming + RT vs. 0.046 [0.032 to 0.060] g/cm2 in swimming only; p < 0.05) and whole body less head (WBLH) aBMD (0.039 [0.024 to 0.054] g/cm2 in swimming + RT vs. 0.017 [0.007 to 0.027] g/cm2 swimming-only; p < 0.05).ConclusionDespite the significant gain in aBMD in all groups and body sites after 12-months, except for the spine site of swimmers, the results indicate that participation in RT seems to improve aBMD accrual in swimmers at the upper limbs and WBLH.

Impact of 8-week cold-and warm water swimming training combined with cinnamon consumption on serum METRNL, HDAC5, and insulin resistance levels in diabetic male rats

ObjectiveNumerous studies have reported the beneficial effects of exercise and the use of herbal supplements in improving type 2 diabetes and insulin resistance. However, there are still many unanswered questions about the effects of cold and hot water, exercise, and herbal supplements on meteorine-like protein (METRNL), which is considered one of the key factors influencing insulin resistance improvement in this condition. Hence, the current study aimed to address these knowledge gaps and investigate the effects of 8 weeks of warm and cold-water swimming exercise with cinnamon consumption on serum levels of METRNL, histone deacetylase-5 (HDAC5), and insulin resistance in diabetic male rats. MethodsFor this purpose, 70 diabetic male rats were randomly divided into seven groups (10 rats in each group) H ealthy control (HC) , Diabetic control , swimming training in cold water (temperature 5 °C) , swimming training at 5‌‌ °C + cinnamon consumption (200 mg/kg body weight) , swimming training in warm water (temperature 36-35 °C) , swimming training in warm water (temperature 36-35 °C) + consumption of cinnamon, and consumption of cinnamon only. ResultsThe present study revealed a significant increase in serum METRNL concentration in the cold-water swimming + cinnamon consumption group (p < 0.05). However, no significant changes were observed in insulin levels and HOMA-IR across the different groups (p > 0.05). Additionally, noteworthy findings included a significant reduction in HDAC5 levels in both the cold-water swimming group and the cold-water swimming + cinnamon consumption group, as well as a significant decrease in fasting blood sugar (FBS) levels in all groups compared to the HC group (p < 0.05). ConclusionsThe results of the present study demonstrate that the combination of cold-water swimming exercises and cinnamon extract consumption led to notable increases in serum METRNL concentration. Additionally, significant reductions were observed in HDAC5 and FBS levels. These findings highlight the potential effectiveness and benefits of the combination of cold-water swimming exercises and cinnamon extract consumption as an approach to improve diabetes-related indices.

Dynamics of physical status indicators under the influence of healthy swimming classes, constructed taking into assount the age characterristics of women's development

The work examines the dynamics of indicators of the physical condition of women aged 20-25 under the influence of recreational swimming classes, built taking into account the age characteristics of women. The purpose of the study was to investigate the dynamics of indicators of physical development, functional state and physical fitness of women aged 20-25 under the influence of recreational swimming classes according to a program that takes into account their age characteristics. The research was carried out in the physical culture and health groups of the "Pioneer" swimming pool in Kharkiv (KZ MSDYUSSHOR on water sports of Yana Klochkova). The study lasted for 10 months. The study involved 30 women aged 20 to 25, randomly selected from among those who attend recreational swimming groups. Two groups were formed for the study: experimental and control. Initially, both groups used the same exercises on the water (low-intensity exercises for familiarization with water, breathing, special exercises, for relaxation; the technique of the chosen method of swimming was consolidated and improved). Later, swimming took on the character of training, and the exercises offered to individuals of both groups began to differ. This difference consisted in the fact that in the experimental group, the duration, number of exercises and repetitions, dose of load, complexity of exercises and amplitude of their movements were proposed according to the age characteristics of the state of the female body. Classes in both groups were held three times a week - the duration of one class was 60 minutes. The following methods were used during data collection: analysis of literary sources; test method; pedagogical experiment; pedagogical observation; method of mathematical processing of research data. The work presents materials that show that the research conducted to study the effectiveness of the program developed and applied by us for women 20-25 years old has confirmed data and a reliable advantage in comparison with the generally accepted program. Eleven out of twelve indicators of physical development and physical fitness improved statistically significantly in the subjects of the experimental group (p &lt;0.01). \The developed health swimming program for women aged 20-25 can be recommended in the health groups of the city's swimming pools.

Phenotype‐dependent downstream dispersal under ordinary flow conditions in juvenile white‐spotted char

AbstractAnimal dispersal is often phenotype‐dependent and can exert evolutionary pressures on populations in which it occurs. The evolutionary pressure arising from phenotype‐dependent dispersal is called spatial sorting. We examined the evolutionary pressure arising from spatial sorting (sorting pressure) caused by downstream dispersal in juvenile white‐spotted char Salvelinus leucomaenis under ordinary flow conditions. We conducted outdoor experiments using an artificial channel with 10 steps to investigate the relationship between phenotypic characteristics and the occurrence or distance of downstream dispersal during five daytime hours. Six experiments were conducted using young‐of‐the‐year juveniles collected early in the morning of each experimental day. We focused on two phenotypes, fork length (body size) and station‐holding (SH) behavior, where juveniles remain sedentary on the substrate. Juveniles were assigned to the “SH group” if they exhibited SH behavior for more than 10 s during a 540‐s observation period, and to the “swimming group” if they exhibited SH behavior for less than 10 s. Juveniles in the swimming group had a higher occurrence of downstream dispersal than in the SH group. In addition, large juveniles in the SH group and small juveniles in the swimming group tended to show long dispersal distances. These results suggest an effective sorting pressure against juveniles with active swimming behavior. This sorting pressure may accumulate in isolated char populations located above a tall migration barrier and contribute to the creation and maintenance of the reported interpopulation variation in SH behavior.

Spawning, larval morphological ontogeny and first feeding of yellow-striped cardinalfish Ostorhinchus cyanosoma (Bleeker, 1853)

The yellow-striped cardinalfish (Ostorhinchus cyanosoma) can be found in the Indo-West Pacific region. It possesses great potential for the ornamental aquarium market due to its vibrant body coloration and tendency of group swimming. This study aims to investigate the spawning frequency and larval morphological ontogeny, and develop first feeding techniques of O. cyanosoma reared in capacity. From April 2021 to August 2022, a total of 70 spawning events were documented for the broodstock. These spawning events did not exhibit specific patterns related to seasonal or lunar cycles. The effects of four live prey treatments (mono-feeding and co-feeding of SS-type rotifer Brachionus sp. and nauplii of copepod Bestiolina coreana) on the mouth opening rate, prey ingestion rate, and prey selectivity of the 0 day-post-hatch (dph) larvae were investigated. The O. cyanosoma larvae displayed significantly higher mouth opening rate, ingestion rate and prey selectivity on the copepod nauplii over the rotifer. In the 7-d larviculture experiment, the larvae showed significant higher survival rate in the copepod feeding treatment (68%) than the rotifer feeding treatment (0%). For ontogeny, O. cyanosoma larvae appeared to be altricial (at pre-flexion stage with no gas bladder and poor-developed fins) and small-mouthed (235.94 μm) when leaving the mouthbrood. The standard length increased from 2.64 to 6.51 mm during 0 to 21dph. Ntochord flexion initiated at 12 dph, and the metamorphosis was completed by 21 dph. This study is the first attempt to document the broodstock management, first feeding protocol and larval ontogeny of O. cyanosoma. The findings could have implications for larviculture of cardinalfishes.

Effectiveness of use of sports and healthy swimming eguipment in increase of physical fitness of girls 17-21 years old

In the course of the study, the peculiarities of physical fitness and changes in indicators of physical performance of young women aged 17-21 under the influence of systematic sports and recreational swimming were studied. The purpose of our study was to assess the effectiveness of using sports and recreational swimming to improve the physical fitness of young women aged 17-21. 38 young women who attend the ZFP groups and health swimming groups of the "Akvarena" pool in Kharkiv took part in the study. The studied women were divided into control (CG, n = 20) and experimental (EG, n = 18) groups. Specialized classes in groups of general physical training and classes in recreational swimming groups were held for nine months, 2-3 times a week, the duration of one class was 45 minutes. The following methods were used during data collection: analysis of literary sources; test method; pedagogical experiment; pedagogical observation; method of mathematical processing of research data. The work presents materials that show that the use of sports and health swimming facilities contributed to the significant optimization of the main indicators of physical fitness of young women who attend sports and health swimming classes (speed, strength, agility, speed and strength abilities), the growth of their aerobic capabilities and level general physical capacity. After the formative experiment, all the indicators used in the study in the women of the experimental group, who were engaged in recreational swimming, were reliable and better than in the young women of the control group, who practiced according to the traditional program for the ZFP groups on land. The obtained results provide grounds for the use of recreational swimming to increase the effectiveness of the process of physical education of young people and young women in particular.

Modeling fish group swimming to optimize underwater vehicle performance

Investigating the hydrodynamic performance of manta rays under staggered propulsion provides insight into the group formation setting of bionic underwater vehicles.

Musculoskeletal Pain in Adolescents Engaged in Impact and Nonimpact Sports-ABCD Growth Study.

This study aimed to identify, through a 28-week follow-up, the association between pain and engagement in different sports among adolescents. In total, 63 adolescents reported the occurrence of pain, which was tracked weekly. Participants were categorized into 2 groups based on their sports participation: "swimming group" and "other sports group." Researchers directly measured the time spent in different intensities during sports participation for 1 week using a heart rate monitor. For the covariates, body mass, body fatness, and whole-body lean soft tissue were assessed using a dual-energy X-ray absorptiometry scanner. Kaplan-Meier plots and risk of pain were calculated for the absence of pain during the follow-up. The association between the sport type and pain occurrence remained significant even after adjusting the models for potential confounders, showing that swimmers had an increased risk of reporting pain in the neck (HR = 3.33; 95% CI, 1.53-7.25), shoulders (HR = 2.21; 95% CI, 1.17-4.21), and trunk (HR = 5.60; 95% CI, 2.28-13.70). The association between the sport type and pain occurrence is evident even when controlling for confounding factors.

Research on the swimming performance of two manta rays under staggered propulsion on the same frequency: When the follower is above the leader

To investigate the hydrodynamic performance of two manta rays swimming in groups under staggered formation, first, a computational model and motion equations of manta rays were established based on biological observations, and then numerical simulations were carried out based on immersed boundary method to simulate the group swimming of manta rays with the same vertical spacing but with a changing streamwise spacing. The results showed that when the streamwise spacing is small between the two manta rays, the hydrodynamic performance decreases dramatically compared to individual swimming. As the streamwise spacing increases, the hydrodynamic performance of the leader is always better than that of individual swimming, and the thrust enhancement is maximized to 10.984% and the efficiency enhancement is maximized to 3.369% when the spacing is 0.4BL. As the streamwise spacing increases, the hydrodynamic performance of the follower shows greater volatility, with a maximum thrust enhancement of 47.923% when the spacing is 0.4BL, and a maximum efficiency enhancement of 14.017% when the spacing is 0.5BL. The system's average thrust gain is maximized at 29.454% when the spacing is 0.4BL, and the system's average efficiency gain is maximized at 7.689% when the spacing is 0.5BL.

Effect of Neurofeedback Training Along With Swimming Exercise on the Stress, Anxiety, Depression, Severity of Dependence, and Craving in Methamphetamine-Dependent Patients

This study investigated whether neurofeedback (NFB) training and swimming exercise (Swim) would reduce the stress, anxiety, depression, severity of dependence, and cravings in patients addicted to methamphetamines. Participants were allocated randomly to four groups: control group, NFB, Swim, and NFB/Swim. All groups completed the study questionnaire before and after treatment. The NFB, Swim, and NFB/Swim groups reported significantly less stress, cravings, and severity of dependence than the control group. The Swim and NFB/Swim groups had significantly lower depression scores than the control group. Also, the NFB/Swim group experienced less anxiety than the control group. However, the NFB/Swim group had lower levels of stress than the Swim group, and lower levels of anxiety and severity of dependence than the NFB group. These findings suggest that NFB training along with swimming exercise was effective in managing methamphetamine-related behavioral disturbances, which may help patients to manage their cravings.

The Effect of Exercise Volume on Depressive-Related Behaviors and Levels of Brain-Derived Neurotrophic Factor and Serum Testosterone Levels

Objective: The aim of the present study was to investigate the effect of training volume on depression-related behaviors and serum levels of brain-derived neurotrophic factor (BDNF) and testosterone in mice. Male NMRI mice, approximately 80 days old and weighing 20 to 23 grams, were used in this study. Methods and Materials: They were kept under a 12-hour light/12-hour dark cycle at a temperature of 23±1°C, with adequate food and water provided. The male NMRI mice, approximately 80 days old and weighing 20 to 23 grams, were kept under a 12-hour light/12-hour dark cycle at a temperature of 23±1°C, with adequate food and water provided. From 90 days old to 118 days old, the animals underwent swimming exercise for 4 weeks. They were divided into two groups: long-term training volume and short-term training volume. The short-term swimming group included one session of short-term training, while the long-term group included three sessions of long-term training with 10-minute swimming periods and 15-minute rest intervals between each session. The water depth and swimming duration gradually increased from 5 to 15 centimeters (second to fourth week) and from 20 (second to third week) to 30 (fourth week) minutes per day. The non-exercised animals were placed in a round tank without water for a duration similar to that of the exercised animals. Results: The results showed a significant difference in immobility duration between the control group and the two training groups, as well as between the two training groups (P ≤ 0.05). There was also a significant difference in depression levels between the two training groups and between the long-term training group and the control group (P ≤ 0.05). However, there was no significant difference between the short-term training group and the control group (P ≥ 0.05). Post hoc test results indicated a significant difference in BDNF levels between the control group and the long-term training group (P ≤ 0.05). Furthermore, there was a significant difference in testosterone levels between the control group and both the short-term and long-term training groups (P ≤ 0.05), but no difference between the two training groups (P ≥ 0.05). Conclusion: Based on the overall results of the study, different training volumes have varying effects on depression and BDNF levels, with long-term training producing greater effects.

Hydrodynamic performance of manta rays swimming in staggered arranged group

To investigate the hydrodynamic performance of manta rays swimming in staggered arranged group, a morphological and kinematic model of manta rays is developed based on biological observations, and then a numerical calculation method is established for group swimming of manta rays based on the Immersed Boundary Method and the Sphere function-based Gas Kinetic Scheme (IB-SGKS). The group swimming of two manta rays with a fixed vertical spacing of 0.1 times the body thickness, and a flow direction spacing of 0—1.5 times the body length is systematically investigated. The average thrust/efficiency of the group system and each individual in the group are analyzed by combining the global three-dimensional (3D) vortex structure and the characteristic cross-section two-dimensional (2D) vortex structure. The numerical results are shown below. When the streamwise spacing between individuals is small, the propulsive performance decreases sharply compared with swimming alone; as the streamwise spacing increases, the propulsive performance of the leader manta ray is consistently better than that of swimming alone, with the maximum thrust enhanced up to 11.24% when &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; = 0.4BL, and the maximum efficiency is enhanced up to 3.58% when &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; = 0.3BL; with the increase of the streamwise spacing, in the thrust/efficiency curves of the follower manta ray appears volatility, with the maximum thrust enhanced to 48.14% when &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; = 0.4BL and the maximum efficiency reached to 12.39% when &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; = 0.5BL; the system average thrust and efficiency enhancement both reach their corresponding maximum values, specifically, 29.69% and 6.77%, when &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; = 0.4BL, which is because the tail vortex of the leading manta ray just passes through the front edge of the follower manta ray and directly acts on the tip vortex that initially falls off from the follower manta rays, thus substantially increasing their vortex energy.

Effects of sports experience on children's gross motor coordination level.

Gross motor coordination (GMC) development could be influenced by age, gender, weight status, geographical area, living setting, home environment, socio-economic status, sports practice. To verify whether practicing sports and practicing different sports could influence children's GMC level. A total of 295 children aged 8-11 years were involved in the study and divided into 5 groups in relation to the sport they practiced: gymnastics group (n = 67; 51F, 16M), cycling group (n = 64; 15F, 49M), athletics group (n = 47; 22F, 25M), swimming group (n = 35; 20F, 15M), control group (n = 82; 42F, 40M). The four subtests of the Körperkoordinations Test für Kinder (KTK) assessed children's GMC level. The scores from each of the four subtests were summed into the KTK total raw score (RS) and then converted into a gender- and age-specific motor quotient (MQ). Children practicing sports showed significantly higher RS and MQ score than children of control group (203.14 ± 38.55 vs. 163.63 ± 43.50 and 98.56 ± 15.79 vs. 83.01 ± 16.71, respectively; p < 0.001). Children practicing gymnastics had a significantly higher RS and MQ than children of cycling, swimming, and control groups (p < 0.05), children of control group had a significantly lower RS and MQ than children of all other groups (p < 0.05). Children practicing gymnastics performed better walking backwards subtest than all other children's groups (p < 0.001). Children of control group performed worse jumping sideways subtest than children of gymnastics, athletics and swimming groups (p < 0.01). Children practicing gymnastics performed better moving sideways subtest than children of athletics, cycling and control groups (p < 0.01); children of control group performed worse than children of all other groups (p < 0.01). Children of control group performed worse hopping for height subtest than children of gymnastics, athletics and cycling groups (p < 0.05); children practicing gymnastics performed better than children of swimming and control groups (p < 0.05). The performance model and therefore the specialized training that each sport discipline required, could justified the differences in children's GMC level among sports groups. Thus, coaches should plan individualized interventions and choose activity contents to support children's GMC development.