Swimming Group Research Articles

Paternal exercise protects against liver steatosis in the male offspring of mice submitted to high fat diet

Parental lifestyle has been related to alterations in the phenotype of their offspring. Obese sires can induce offspring insulin resistance as well as increase susceptibility to obesity. On the other hand, obese sires submitted to voluntary exercise ameliorate the deleterious metabolic effects on their offspring. However, there are no studies reporting the effect of programmed exercise training of lean sires on offspring metabolism. AimsThis study aimed to investigate the role of swimming training of sires for 6 weeks on the offspring metabolic phenotype. Main methodsMale C57BL/6 mice fed a control diet were divided into sedentary and swimming groups. After the exercise, they were mated with sedentary females, and body weight and molecular parameters of the offspring were subsequently monitored. Key findingsSwimming decreased the gene expression of Fasn and Acaca in the testes and increased the AMPK protein content in the testes and epididymis of the sires. The progeny presented a low weight at P1, which reached a normal level at P60 and at P90 the animals were challenged with HFD for 16 weeks. The male offspring of trained sires presented less body weight gain than the control group. The level of steatosis decreased in the male offspring from trained sires. The gene expression of Prkaa2, Ppar-1α and Cpt-1 was also increased in the liver of male offspring from trained sires. SignificanceTaken together, these findings suggest that paternal exercise training can improve the metabolic profile in the liver of the progeny, thereby ameliorating the effects of obesity.

Exercise and caloric restriction improve cardiovascular and erectile function in rats with metabolic syndrome.

The aim of this study is to examine the possible benefits of exercise and caloric restriction (CR) on cardiovascular hemodynamics, erectile function, and antioxidant system in metabolic syndrome (MS). Sixty male Spraque-Dawley rats were divided into five groups; control, MS, MS + CR, MS + exercise (EXC), and MS + CR + EXC. To induce MS, 10% fructose solution was applied for 3 months. Thereafter, in CR groups calorie was restricted 40% and in EXC groups swimming was performed for 6 weeks. Body weight, blood glucose, and blood pressure (BP) levels were measured before and after MS induction and at the end of the experiment. After decapitation, tumor necrosis factor (TNF)-α, adiponectin (ADP), and plasminogen activator inhibitor (PAI)-1 levels were investigated in blood, oxidative stress parameters were examined in heart, aorta, and corpus cavernosum (CC) tissues. Isometric contraction in isolated tissue bath was studied in aorta and CC tissues. Animals subjected to exercise and CR had decreased BP and blood glucose levels. Impaired contraction-relaxation responses in MS group were improved with exercise and CR. MS-induced increase in TNF-α, PAI-1, malondialdehyde (MDA), and decrease in ADP, glutathione (GSH), and superoxide dismutase (SOD) were normalized with exercise and CR. Exercise and CR may be beneficial against changes in cardiovascular hemodynamics caused by MS.

Role of swimming on muscle PGC-1\u03b1, FNDC5 mRNA, and assessment of serum omentin, adropin, and irisin in high carbohydrate high fat (HCHF) diet induced obesity in rats

BackgroundExercise benefits a variety of organ systems in mammals, and some of the best recognized effects of exercise on muscle are mediated by the transcriptional peroxisome proliferator-activated receptor gamma co-activator 1-α (PGC-1α). The regulatory effect of swimming on muscle PGC-1α, FNDC5 mRNA expression, and subsequently irisin levels is more controversial. This study aimed to investigate the role of swimming as an exercise on the expression of peroxisome proliferator-activated receptor-gamma coactivator1 alpha (PGC-1α) and Fibronectin type III domain containing 5 (FNDC5) mRNA in skeletal muscle and assessment of serum omentin, adropin, irisin, and PGC-1α levels in high carbohydrate high fat (HCHF) diet induced obesity in rats. Sixty male albino rats are randomly divided into 4 groups (15 rats/group). In the first group (control), rats are fed with standard diet. The 2nd group (cont + swim) is fed on standard diet and made swimming exercise. The 3rd group of rats is fed on HCHF, whereas in the 4th group (HCHF + swim) is also fed on HCHF diet and made swimming exercise for 20 weeks. Blood glucose, insulin, HOMA-IR, lipid profile, omentin, irisin, adropin, and PGC-1α were measured. Also, FNDC5 and PGC-1α are extracted and purified from muscle tissue samples measured by PCR test.ResultsOur results showed significant increase in glucose, insulin, insulin resistance, cholesterol, and triglycerides with significant decrease in omentin, irisin, adropin, PGC-1α, and HDL in HCHF group as compared to the control group. These results improved after exercise in all parameter in HCHF + swim group compare to HCHF group. Also, there was inverse correlation between omentin and fasting glucose and HOMA-IR in HCHF + swim group.ConclusionsIt concluded that swimming exercise improved all the above measured parameters in serum and tissues which might have been promising for the prevention of metabolic diseases.

Swimming improves platelet dysfunction in mice fed with a high-fat diet

Background We investigated the effects and mechanism of swimming on platelet function in mice fed with a high-fat diet. Material and Methods Mice were randomly divided into the control group (NC), high-fat group (HF), and high-fat diet combined with swimming group (FE). The FE group swam for 60 min a day, 5 days a week, for 8 weeks. Results Compared with the NC group, the HF group had significant weight gain, dyslipidemia, abbreviated bleeding time after tail breakage, increased clot retraction, increased platelet aggregation rate, increased spread of platelets on fibrinogen, and increased pAKT level in platelets. Compared with the HF group, the FE group had lower body weight, improved dyslipidemia, prolonged bleeding time, reduced clot retraction, reduced platelet aggregation rate, decreased spread of platelets on fibrinogen, and decreased pAKT level in platelets. Conclusions By inhibiting the level of pAKT in platelets, swimming improves platelet dysfunction in mice fed with a high-fat diet.

Angiostrongylus cantonensis causes cognitive impairments in heavily infected BALB/c and C57BL/6 mice

BackgroundParasitic infections may cause significant effects on behavior, learning, and memory of the host. In the brain of mice heavily infected with Angiostrongylus cantonensis, severe damage has been observed in the hippocampus. This component has been considered to have associations with spatial learning and memory in humans and vertebrates. This study was designed to determine the impairments in behavior, learning, and memory in BALB/c and C57BL/6 mice heavily infected with the parasite.MethodsEach mouse was inoculated with 50 third-stage larvae of A. cantonensis. After infection, daily changes in weight and dietary consumption, worm recoveries and survival rates were determined. The forced swimming test, open field test, and Morris water maze test were employed to evaluate depression- and anxiety-like behavior as well as impairments in spatial learning and memory, respectively.ResultsThe worm recovery rate in the BALB/c mice was significantly lower than that of C57BL/6 mice from day 14 post-infection. The survival rate in infected BALB/c mice decreased to 0% by day 25 whereas those with swim-training survived three more days. On day 42, the C57BL/6 mice had a survival rate of 85.7% in the swimming group and 70% in the non-swimming group. Significant differences were found in weight between infected and non-infected BALB/c and C57BL/6 mice from day 13 and day 12, respectively with corresponding changes in their dietary consumption. Depression-like behavior was found in the infected BALB/c mice but not in C57BL/6 mice. However, anxiety-like behavior was found to occur only in C57BL/6 mice. Impaired spatial learning and memory were also found in the two strains of mice which occurred from day 14 post-infection.ConclusionsResults of this study indicate that A. cantonensis causes depression, anxiety, and impairments in spatial learning and memory in heavily infected mice. Moreover, significantly higher severity was observed in the Th-2 dominant BALB/c mice.

Effect Of Astragalus Injection Combined With Aerobic Exercise On Myocardial Renin-angiotensin System In Diabetic Mice

PURPOSE: This investigation aimed at investigating the synergistic effect of Astragalus injection combined with aerobic exercise on myocardial renin-angiotensin system in diabetic mice,and clarify whether the myocardial disease of diabetic mice is improved. METHODS: 32 6-week-aged male db/db mice were randomly divided into 4 groups,Diabetes mellitus group, Astragalus injection group,Swimming group and Astragalus injection + swimming group.Monitor the amount of drinking water,body weight and blood glucose changes.The myocardial tissue was executed after 6 weeks and the ventricular mass index was calculated;detect the angiotensin II (Ang-II),angiotensin-converting enzyme (ACE) and angiotensin converting enzyme 2(ACE2) in each group of myocardium tissues. RESULTS: In addition to diabetic group, the ventricular mass index of each group was elevated (P<0.05).In addition to the diabetic group, the Ang-IIlevels of myocardial tissues were decreased (P<0.05).In addition to the diabetic group, the ACE and ACE2 levels averaged increased (P<0.05). CONCLUSIONS: Myocardial ACE,ACE2 enzyme activity is generally low, Ang-II content is also higher than other groups, and the decrease of enzyme activity will promote the increase of Ang-II content, indicating that renin-angiotensin system is overactivated, resulting in strong vasoconstriction and myocardial ischemia and hypoxia, and eventually lead to all kinds of cardiomyopathy. After the intervention of astragalus membranaceus or aerobic exercise, the activity of ACE,ACE2 enzyme was increased and the level of Ang-II content was also significantly suppressed. Astragalus membranaceus or aerobic exercise had a positive effect on renin-angiotensin system in myocardial tissue of diabetic mice, and played a protective role in the myocardium of diabetic mice. It was speculated that there was a great deal of inhibition on renin-angiotensin system in myocardium of diabetic mice. It may be achieved by increasing the enzyme activity of ACE2 to inhibit the formation of Ang-II in diabetic myocardial tissue. FUNDING: This study was supported by Jiangsu Province Graduate Research and Innovation Program(KYCX18_1719)

A single session of physical activity restores the mitochondrial organization disrupted by obesity in skeletal muscle fibers

BackgroundSeveral studies have proved that physical activity (PA) regulates energetic metabolism associated with mitochondrial dynamics through AMPK activation in healthy subjects. Obesity, a condition that induces oxidative stress, mitochondrial dysfunction, and low AMPK activity leads to mitochondrial fragmentation. However, few studies describe the effect of PA on mitochondrial dynamics regulation in obesity. AimThe present study aimed to evaluate the effect of a single session of PA on mitochondrial dynamics regulation as well as its effect on mitochondrial function and organization in skeletal muscles of obese rats (Zucker fa/fa). Main methodsMale Zucker lean and Zucker fa/fa rats aged 12 to 13 weeks were divided into sedentary and subjected-to-PA (single session swimming) groups. Gastrocnemius muscle was dissected into isolated fibers, mitochondria, mRNA, and total proteins for their evaluation. Key findingsThe results showed that PA increased the Mfn-2 protein level in the lean and obese groups, whereas Drp1 levels decreased in the obese group. OMA1 protease levels increased in the lean group and decreased in the obese group. Additionally, AMPK analysis parameters (expression, protein level, and activity) did not increase in the obese group. These findings correlated with the partial restoration of mitochondrial function in the obese group, increasing the capacity to maintain the membrane potential after adding calcium as a stressor, and increasing the transversal organization level of the mitochondria analyzed in isolated fibers. SignificanceThese results support the notion that obese rats subjected to PA maintain mitochondrial function through mitochondrial fusion activation by an AMPK-independent mechanism.

Sensing Water: Uncovering Health and Well-Being in the Sea and Surf

This article considers how different recreational users engage with and utilize blue spaces as health-enabling. Informed by empirical and participatory fieldwork with surfing and sea swimming groups, we explore embodied and emotional experiences while researching directly within blue space. Given a focus on health and well-being, we identify different dimensions of how surfers and swimmers narrate those experiences while directly immersed in water during a sport/recreational activity. Such questions resonate with geographical thinking around phenomenology, active relational geographies, embodiment, emotion, and sport and leisure practice. We use a broad health promotion or enabling spaces approach to capture different emotional and embodied accounts of immersions in blue space, recognizing that this capture is emergent in and from place.

Swimming With the Bicheno “Coffee Club”: The Textured World of Wild Swimming

Wild swimming is currently experiencing a surge in popularity as people avowedly attempt to reconnect with the natural world. Previous research has positioned wild swimming as a solitary pursuit whereby individuals retreat from society to connect with or overcome nature and better themselves. This article draws on an ethnographic examination of a wild swimming group in Australia and reveals that while being in nature and personal fulfillment are key motivations for these wild swimmers, it is the social interactions that facilitate a deep engagement with their local “bluespace.” We argue that rather than swimming away from the world, by “wayfaring” together these swimmers become connected to their environment, and each other, simultaneously. Such findings indicate potential social, health, and environmental benefits of collective wild swimming.

RISK FACTORS FOR THE DEVELOPMENT OF MALADAPTIVE REACTIONS TO DIFFERENT TYPES OF PHYSICAL LOAD IN MIDDLE-AGED MEN

Aim. The article is aimed at assessing the risks for developing pathological reactions to different types of physical activity in middle-aged men. Materials and methods. A comprehensive study of 34 men was conducted, of which 19 people performed strength exercises and 15 people practiced sport in swimming groups. The following data were studied: official data of the clinical examination, indicators of an electrocardiographic study of the cardiovascular system, data of functional tests, anthropometric indicators, data of magnetic resonance imaging. All participants underwent an annual medical examination. Functional tests were performed on a treadmill (Matrix USA) with parallel ECG recording (Cardiovit AT-101, Schiller, Switzerland). The development of physical qualities was assessed at three control points: at the beginning of the study, at 6 and 9 months of the study. Statistical processing was carried out using standard methods of variation statistics (Statistica 10.0 USA). Result. Almost the entire sample had pathological changes in the cardiovascular and musculoskeletal system, which created a significant risk of maladaptation to physical activity. Strength exercises in some cases provoked an increase in blood pressure (BP) to maximum values, resulted in pain in the vertebral region and injuries of the capsular ligamentous structures. The training sessions in the swimming groups were characterized by the absence of a risk to the regulatory adaptive systems of the body, which allowed to increase the reserves of the cardiorespiratory system. Conclusion. Strength exercises for middle-aged men impose significant risks to health, while swimming is an effective means for developing physical qualities and increasing the functional reserves of the respiratory and cardiovascular systems.

Profil Prestasi Atlet Renang Grup 3 Kota Semarang Tingkat Jawa Tengah Tahun 2019

This study examines the performance profile of Semarang City swimming athletes who are in group 3 (12-13 years). Focus on how the development profile of Semarang City Group 3 athlete swimming achievements in 2019? The purpose of this study was to determine the profile of the achievements of group 3 swimming athletes in Semarang City, Central Java Level 2019. This type of research is descriptive. The population in this study were group 3 swimmers, one male and four female, interview data collection methods and documentation via the JatengFast Web. The data analysis technique uses descriptive qualitative. Conclusions in this study, there was an increase and decrease in the time record of Semarang 3 group swimming athletes starting from KRAP INTANPARI Open in 2019, Central Java Kejurprov - 2019 Batang Regent Cup, Semarang City POPDA, POPDA PROVINCE and in the KRAPPROV race in Jepara Regent 2019 Cup.

Long-Term Exercise Alters the Profiles of Circulating Micro-RNAs in the Plasma of Young Women.

Objective: The objective of this paper was to study the effects of long-term exercise on circulating microRNAs (miRNAs) in human plasma.Methods: Whole blood was collected from 10 female elite athletes with at least 5 years of training experience in a Synchronized Swimming Group (S group) and 15 female college students without regular exercise training (C group). Plasma miRNAs were then isolated, sequenced, and semi-quantified by the second-generation sequencing technology, and the results were analyzed by bioinformatics methods.Results: We found 380 differentially expressed miRNAs in the S group compared with the C group, among which 238 miRNAs were upregulated and 142 were downregulated. The top five abundant miRNAs in the 380 miRNAs of the S group are hsa-miR-451a, hsa-miR-486, hsa-miR-21-5p, hsa-miR-423-5p, and hsa-let-7b-5p. Muscle-specific/enriched miRNAs were not significantly different, except for miR-206 and miR-486. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, a large proportion of the differentially expressed miRNAs are targeted in cancer-related pathways, including proteoglycans in cancer and miRNAs in cancer and basal cell carcinoma. As the levels of circulating miRNAs (ci-miRNAs) are commonly known to be significantly deregulated in cancer patients, we further compared the levels of some well-studied miRNAs in different types of cancer patients with those in the S group and found that long-term exercise regulates the level of ci-miRNAs in an opposite direction to those in cancer patients.Conclusion: Long-term exercise significantly alters the profiles of plasma miRNAs in healthy young women. It may reduce the risk of certain types of cancers by regulating plasma miRNA levels.

Dimethylarginine dimethylaminohydrolase-1 contributes to exercise-induced cardiac angiogenesis in mice.

Dimethylarginine dimethylaminohydrolase-1 (DDAH1) maintains nitric oxide (NO) bioavailability by degrading asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of nitric oxide synthase (NOS). It has been well established that DDAH1 and exercise play crucial roles in promoting cardiac angiogenesis under pathological conditions. However, the role of DDAH1 in exercise-induced cardiac angiogenesis remains unclear. In this study, we focused on the change in DDAH1 in response to moderate exercise and the underlying mechanism of exercise-induced cardiac angiogenesis. Eight-week-old male DDAH1 global knockout (KO) mice and DDAH1flox/flox mice (wild-type) were randomly divided into sedentary groups (control) and swimming groups (exercise). After eight weeks of swimming at five days per week, all the mice were anesthetized and sacrificed. Histological examination and Western blot analysis were performed. There were low levels of myocardial capillaries in DDAH1 KO mice under control and exercise conditions. Notably, exercise elevated DDAH1 protein expression, as observed by Western blot analysis. The common cardiac angiogenesis biomarkers vascular endothelial growth factor (VEGF) and Caveolin-1 were increased during exercise. A significant difference in VEGF was observed between the DDAH1 KO and wild-type groups. Similarly, increased Caveolin-1 expression was abrogated in DDAH1 KO mice. Furthermore, we tested the R-Ras/AKT/GSK3β signaling pathway to study the underlying molecular mechanism. DDAH1 may regulate the R-Ras/AKT/GSK3β pathway due to distinct protein changes in this pathway in the DDAH1 KO and wild-type groups. Our findings suggest that DDAH1 plays an important role in exercise-induced cardiac angiogenesis by regulating the R-Ras/AKT/GSK3βsignaling pathway.

Swimming exercise ameliorates mood disorder and memory impairment by enhancing neurogenesis, serotonin expression, and inhibiting apoptosis in social isolation rats during adolescence.

Social isolation during adolescence is associated with anxiety, depres-sion, and memory impairment. Exercise has been reported as a positive effect on brain function, especially hippocampus. The present study ex-amined the effect of swimming exercise on apoptosis, cell proliferation, and serotonin expression in social isolation rats during adolescence stage. Social isolation started at postnatal day 21 and continued for 6 weeks. The rats in the swimming group were forced to swim for 60 min once daily during 6 days per week for 6 consecutive weeks. The rats in the social isolation during adolescence showed anxiety, depression, short-term memory impairment. Social isolation facilitated apoptosis and inhibited cell proliferation and differentiation. Social isolation sup-pressed expression of serotonin, brain-derived neurotrophic factor, and tyrosine kinase B. Swimming exercise alleviated anxiety, depression, short-term impairment. Swimming exercise suppressed apoptosis, en-hanced neurogenesis, and increased serotonin expression. In our study, swimming exercise ameliorates mood disorder and memory impairment by enhancing neurogenesis and serotonin expression and inhibiting apoptosis in social isolation.

Computational and robotic modeling reveal parsimonious combinations of interactions between individuals in schooling fish.

Coordinated motion and collective decision-making in fish schools result from complex interactions by which individuals integrate information about the behavior of their neighbors. However, little is known about how individuals integrate this information to take decisions and control their motion. Here, we combine experiments with computational and robotic approaches to investigate the impact of different strategies for a fish to interact with its neighbors on collective swimming in groups of rummy-nose tetra (Hemigrammus rhodostomus). By means of a data-based agent model describing the interactions between pairs of H. rhodostomus (Calovi et al., 2018), we show that the simple addition of the pairwise interactions with two neighbors quantitatively reproduces the collective behavior observed in groups of five fish. Increasing the number of interacting neighbors does not significantly improve the simulation results. Remarkably, and even without confinement, we find that groups remain cohesive and polarized when each agent interacts with only one of its neighbors: the one that has the strongest contribution to the heading variation of the focal agent, dubbed as the "most influential neighbor". However, group cohesion is lost when each agent only interacts with its nearest neighbor. We then investigate by means of a robotic platform the collective motion in groups of five robots. Our platform combines the implementation of the fish behavioral model and a control system to deal with real-world physical constraints. A better agreement with experimental results for fish is obtained for groups of robots only interacting with their most influential neighbor, than for robots interacting with one or even two nearest neighbors. Finally, we discuss the biological and cognitive relevance of the notion of "most influential neighbors". Overall, our results suggest that fish have to acquire only a minimal amount of information about their environment to coordinate their movements when swimming in groups.

THE EFFECT OF SINGLE- AND REPEATED- EXCESSIVE SWIMMING EXERCISE ON KIDNEY HISTOPATHOLOGY OF MALE RATS WISTAR STRAIN (Rattus norvegicus)

Background: Physical exercise aims to improve or maintain physical fitness. However, excessive physical exercise may cause increase of oxidative stress which leads to cellular injury, including in the proximal tubules of kidney. This research aims to find out the effect of single- and repeated- excessive swimming exercise to the kidney histopathology of male wistar rats (Rattus norvegicus). Methods: This research was an experimental study with complete random and post test only control group design. Twenty seven male wistar rats were divided into three treatment groups: control group, single- excessive swimming exercise group (45 minutes for one day), and repeated- excessive swimming exercise group (45 minutes/day for seven days). In the end of the treatment, the kidney of the rats were taken to be analyzed by using hematoxylin-eosin stain. The mean of proximal tubules injury of kidneys were counted by two observers using blinded method. Data were analyzed by using one way anova test. Result: The analysis showed there was a significant difference in the mean percentage of proximal tubules injury between control group and single swimming group as well as the repeated swimming group (Anova p=0,000), also there was significant difference between the treatment groups (p=0,020). The highest average of proximal tubules injury was in the single swimming group. Conclusion: Single- and repeated- excessive swimming exercise causes the proximal tubules injury of kidney.

Salidroside protects the cardiac function of exhausted rats by inducing Nrf2 expression.

To investigate whether salidroside (Sal) protected the rat heart from exhaustive exercise-induced injury by inducing nuclear factor erythroid 2-related factor 2 (Nrf2) expression. Forty-eight male Sprague-Dawley rats were divided into four groups (n = 12 rats per group): the control, the exhaustive swimming (ES) group, the low-dose Sal plus acute exhaustive swimming (SLE) group, and the high-dose Sal plus acute exhaustive swimming (SHE) group. In the SLE and SHE groups, 15 and 30 mg/kg Sal were administered, respectively, once a day. The rats in the control and ES groups were administered the same amount of physiological saline, respectively, once a day. On the 14th day, the rats in the ES, SLE and SHE groups underwent exhaustive swimming training once. Then cardiac function parameters and electrocardiograms were recorded. Biomarkers of myocardial injury in the serum and oxidative stress factors in the myocardial tissue were evaluated using ELISA tests. The levels of Nrf2, nuclear Nrf2 and Kelch-like ECH-associated protein 1 (Keap1) messenger RNA and proteins were assessed in the myocardium using q-PCR and Western blotting, respectively. Compared to the control group, the ES group showed remarkable increases in serum brain natriuretic peptide (BNP), cardiac troponin I (cTnI) and reactive oxygen species levels, but significant decreases in catalase and glutathione levels (p < 0.05). Compared to the ES group, the Sal treatment decreased serum BNP and cTnI levels and alleviated the changes in levels of oxidative stress-related factors. After treatment with Sal, nuclear and intracellular levels of Nrf2 protein were increased in the myocardial cells, while the level of Keap1 protein was decreased (p < 0.05). Sal protected the heart from exhaustive exercise induced injury, and it may improve cardiac function and cardiac bioelectricity in exhausted rats by inducing Nrf2 expression.

Group behavior and tolerance of Eurasian minnow (Phoxinus phoxinus) in response to tones of differing pulse repetition rate.

Behavioral guidance systems are commonly used in freshwater fish conservation. The biological relevance of sound to fish and recorded responses to human-generated noise supports the viability of the use of acoustics as an effective stimulus in such technologies. Relatively little information exists on the long-term responses and recovery of fish to repeated acoustic exposures. In a controlled laboratory study, the response and tolerance of Eurasian minnow (Phoxinus phoxinus) shoals to tonal signals (150 Hz of 1 s pulse duration) differing only in temporal characteristics ("continuous," "slow," "intermediate," or "fast" pulse repetition rate) were investigated. In comparison to independent control groups, fish increased their mean group swimming speed, decreased inter-individual distance, and became more aligned in response to the onset of all four acoustic treatments. The magnitude of response, and time taken to develop a tolerance to a treatment differed according to pulse repetition rate. Groups were found to have the greatest and longest lasting response to tone sequences tested in this study when they were pulsed at an intermediate rate of 0.2 s-1. This study illustrates the importance of understanding the response of fish to acoustic signals, and will assist toward the development of longer-term effective acoustic guidance systems.

Impact of changes in fat mass and lean soft tissue on bone mineral density accrual in adolescents engaged in different sports: ABCD Growth Study.

To analyze the impact of changes in lean soft tissue (LST) and fat mass on areal bone mineral density (BMD) accrual in the lower limbs among adolescents engaged in sports with different weight-bearing levels. Longitudinal (12months: measurements at two time points). Adolescents of both sexes (n = 191; 62 girls [32.5%] and 129 boys [67.5%]) were divided into three groups: control group (n = 65), swimming group (n = 25), and weight-bearing sports group (n = 100). Absolute changes in LST (kg) and fat mass (kg) were the independent variables, while BMD accrual (left and right legs) was the dependent variable. Linear regression was used to assess the relationship between dependent and independent variables in a multivariate model adjusted by sex, body weight, somatic maturation, serum osteocalcin, and baseline values of BMD of the lower limbs. For the left leg, LST was positively related to areal BMD accrual in the control (β = 0.021 [95%CI: 0.001 to 0.042]) and weight-bearing sport groups (β = 0.051 [95%CI: 0.037 to 0.065]), but not among swimmers (β = 0.029 [95%CI: - 0.004 to 0.062]). For the right leg, LST was positively related to areal BMD accrual in the swimming group (β = 0.065 [95%CI: 0.031 to 0.100]) and weight-bearing sport groups (β = 0.048 [95%CI: 0.034 to 0.062]), but not in the control group (β = 0.014 [95%CI: - 0.002 to 0.030]). Fat mass was not significantly related to areal BMD in either leg. Changes in LST were the most relevant determinant of BMD accrual in the lower limbs, mainly among adolescents engaged in sports.

Postural control in karate practitioners: Does practice make perfect?

BackgroundKarate training likely leads to enhanced postural control, however, previous studies did not always include a healthy, physically active comparison group and the findings are inconsistent. Research questionWill the postural control of experienced karate practitioners be better than that of experienced swimmers, i.e., athletes with similar characteristics who do not practice under conditions that require upright postural control? MethodsIn this cross-sectional study, 20 experienced, male karate practitioners and 20 experienced, male swimmers, ages 20-50, performed four standing postural control tasks of increasing difficulty: (a) two-legged stance with eyes open; (b) one-legged stance with eyes open; (c) one-legged stance with eyes closed, and (d) a dual-task, one-legged stance with eyes closed and a verbal fluency challenge. The primary outcome measure was a functional, behavioral measure that reflects the loss of balance. Specifically, in tasks that included one-legged stance, every touch of the raised foot to the floor was counted. Center-of-gravity movements were measured using a wearable sensor. ResultsTask-related differences were seen in all of the postural control measures. In the OneLegEyesClosed task, the median number of touches was 0.00 in the karate group and 6.50 in the swimming group (p < 0.001). In the OneLegEyesClosedWords task, the median number of touches was 0.00 in the karate group and 5.00 in the swimming group (p < 0.001). Shannon entropy, a measure of the complexity of the sway of the center-of-gravity, was lower in the karate group (p = 0.002), compared to the swimmers. SignificanceKarate training is associated with a higher level of postural control, even when compared to a physically active age-matched comparison group. In addition to supporting the specificity of exercise training principle, these findings raise the intriguing possibility that karate may be useful as a form of pre-habilitation, potentially aiding in the prevention of age-associated declines in balance control.