• Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.113-123
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• 2008

We modeled fish school movements as a capture process in relation to the purse seine method using the three steps of the stimulus-response process (i.e., input stimuli, central decision-making and output reaction). Input stimuli of the model were categorized as either physical stimuli such as visual stimulus, sound stimulus, water flow, and weather or as biological stimuli such as species and size, swimming performance, sensual sensitivity, and presence of prey or predators. The output process determining the spatial orientation of the fish school for 3-D movements was based on swimming speed and angular change in the fish response, and these movements were animated as the relative geometry between the fish school and the purse seine. Simulations were carried out for skipjack tuna (Katsuwonus pelamis) schools reacting to a pelagic purse seine in the southwest Pacific Ocean. Simulation results showed that escape ratios varied from 20 to 70% by the relevant ranges in the stimulus-response thresholds, swimming speeds, and angular changes of fish schools were similar to those observed in the field. Therefore, with knowledge of relevant parameters, this model can be used to predict capture and escape probabilities of purse seine operations for different fish species or conditions.

• Journal of the Korea Convergence Society
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• v.7 no.3
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• pp.159-165
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• 2016

The purpose of this study is to investigate the change in the positive psychology movement of capital represented by the performance of physical disabilities to participate in swimming classes for 10 weeks. The study was conducted with 30 to 40-men group participation handicapped total of 21 patients (10 patients) and non-participation group (11 patients), the duration of the experiment was performed three times a week for 10 weeks, 50 minutes. Data processing is a dictionary, post-test data was calculated the mean and standard deviation, experimental design group two won repeated measures analysis of variance for (swimming participating groups, miserable Lady) and time (before and after) using the SPSS 21.0 statistical program It was performed (2-way [2] RM ANOVA), all the statistical significance level was set at .05. Study, classroom participation of the handicapped swimmer can see that has had a positive effect positive psychological capital.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.283-289
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• 2008

Lepidium meyenii, known as Maca, is traditionally employed in the Andean region for its supposed properties to improve energy and fertility. In the present study, we investigated the effects of gelatinized and fermented Maca on improvement of physical stamina and epididymal sperm counts, and on blood biochemical parameters related to fatigue and tissue injury: creatine phosphokinase, aspartate transaminase, lactate dehydrogenase, blood urea nitrogen, glucose, total cholesterol and total proteins. Adult male mice was divided at random into two main groups (resting and excercise groups). The excercise group was separated into three subgroups (exercise only, exercise with gelatinized Maca and fermented Maca-treatment groups). Gelatinized or fermented Maca (800 mg/kg) were orally administered for 30 days. All animals in exercise groups were subjected to daily 30-min swimming for 28 days 30 min after Maca treatment. Daily exercise decreased the body weight gain, and fermented Maca further attenuated the body weight increase. Gelatinized and fermented Maca significantly increased the maximum swimming time on 14 and 28 days of treatment (p<0.05), respectively, suggestive of a long-term stamina-enhancing effect of fermented Maca. Both Maca fully or significantly recovered blood parameters of energy as well as muscular and hepatocytic injuries changed by repeated exercise and maximum swimming performance (p<0.01). Moreover, gelatinized and fermented Maca increased epididymal sperm counts 22.0% and 32.0%, respectively. In conclusion, the results indicate potential benefits of Maca for improving both physical stamina by minimizing muscular and hepatic damage and preserving energy during swimming exercise and male reproductive function by increasing epididymal sperm counts.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.69-74
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• 2020

The fruit, leaves, and roots of Elaeagnus multiflora Thunb. have been used in traditional Chinese medicine to treat cough, diarrhea, and itching. However, the anti-fatigue effects of E. multiflora fruit (EMF) extract have not been studied in detail. The aim of this study was to examine the effect of EMF on fatigue and exercise performance in BALB/c mice. EMF was orally administered to mice at four doses (10, 50, 100, and 200 mg/kg/day) for 2 weeks. The anti-fatigue activity was evaluated by determining the exhaustive swimming time. Blood lactate and glucose levels and serum lactate levels after a 10 min swimming time, as well as ammonia, creatine kinase (CK), blood urea nitrogen (BUN), lactate dehydrogenase (LDH), and glycogen contents after exhaustive swimming time were measured. The exhaustive swimming time of the EMF 200 group was significantly increased (p <0.01). The EMF groups showed significantly low levels of CK, BUN, LDH, and lactate compared with the control group (p <0.05). Increased liver glycogen was observed in the EMF 200 group (p <0.05). These results suggest that EMF can be utilized as an efficacious natural resource for its anti-fatigue effects.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.2
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• pp.37-46
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• 2020

Objectives In this study, we analyzed the effect of Dioscoreae Rhizoma on exercise practice ability and blood fatigue variable factor in the forced swimming test. Methods Male mice were divided into four group. Mice were administrated with saline, Discorae Rhizoma extracted by water (DRW), Discorae Rhizoma extracted by 30% ethanol (DRE), red ginseng (RG), orally once per day, for 1 week. Exercise performance was evaluated by exhaustive swimming time and weights. Glycogen contents of liver and soleus muscle were measured at the end of the experiment. In addition, the biochemical parameters such as asparate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen, creatine, lactate dehydrogenase (LDH), ammonia, triglycerides (TG), total cholesterol (TC) and free fatty acid (FFA) were analyzed. Results Both DRW and DRE showed an improvement of swimming endurance compared with control group. Levels of ALT, ammonia, TG, TC and FFA were significantly decreased in both DRW and DRE compared with control group. Levels of AST, Creatine were significantly reduced in DRE group compared with control group. Moreover LDH showed only a tendency to increase in the DRW and DRE groups. Conclusions In summary, the present study showed that Dioscoreae Rhizoma improved in physical fatigue and exercise practice ability and DRE improved the superior than those of DRW.

• The Korea Journal of Herbology
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• v.35 no.2
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• pp.31-38
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• 2020

Objectives : Jakyakgamcho-tang has been used as analgesic and spasmolytic for muscle pain. It has reported to anti-diabetes, anti-inflammation, and neuro-protective effects. A clinical study of muscle fatigue and pain improvement effect of Jakyakgamcho-tang has been reported with increasing frequency of clinical use. However, the anti-fatigue effect of Jakyakgamcho-tang in animal model has not been studied. In this study, we compared anti-physical fatigue effects of water and 30% ethanol extract of Jakyakgamcho-tang. Methods : The amounts of components contained in water and 30% ethanol extract of Jakyakgamcho-tang were compared by ultra-performance liquid chromatography. Anti-physical fatigue effects were evaluated using weight-loaded forced swimming test. We also investigated the effects of Jakyakgamcho-tang on the change of fatigue parameters by blood biochemical analysis. Results : The relative amount of components of Jakyakgamcho-tang were about 19-53% higher in the 30% ethanol extract than in the water extract. In the swimming test, 30% ethanol extract showed a significantly greater anti-fatigue effects than conventional water extract of Jakyakgamcho-tang. The 30% ethanol extract of Jakyakgamcho-tang improved the exhausted swimming time (54%), and serum lactate dehydrogenase (48%) and lactic acid (60%) levels compared with water extract of Jakyakgamcho-tang. Conclusions : These results showed that differences in the amounts of components by different extraction were associated with differences of anti-fatigue effect of Jakyakgamcho-tang. Thus, the 30% ethanol extraction method could be applied to dose-reducing formulations of traditional herbal medicines.

• Journal of Life Science
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• v.17 no.10
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• pp.1400-1405
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• 2007

The effect of supplementation with docosahexaenoic acid into n-3 fatty acid deficient diet on improvement of loaming related brain function was investigated. On the second day after conception, Sprague Dawley strain dams were subjected to a diet containing either n-3 fatty acid deficient (Def) or n-3 fatty acid deficient + docosahexaenoic acid (Def+DHA). After weaning, male pups were fed on the same diet of their respective dams until adulthood. Motor activity and Morris water maze tests were measured at 10 weeks old. In motor activity test, there were no statistically significant differences in moving time and moving distance between the Def and Def+DHA diet groups. The n-3 fatty acid deficient with DHA (Def+DHA) group exhibited a shorter escape latency, swimming time and swimming distance (P<0.05) compared to the n-3 fatty acid deficient group (Def) but there was no difference in resting time and swimming speed between the experimental diet groups. In memory retention trial, the number of crossing of the platform position (region A) was significantly greater than those of other regions for the Def+DHA group. However, the Def group swam randomly without preference for the provisions platform location, indicating poorer memory retention. From those results, supplementation with DHA into the n-3 fatty acid deficient diet improved the spatial loaming ability in rats as assessed by Morris water maze test.

• Journal of Life Science
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• v.19 no.7
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• pp.917-922
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• 2009

The effect of adding docosahexaenoic acid into an n-3 fatty acid adequate diet on the improvement of learning related brain function was investigated. On the second day after conception, Sprague Dawley strain dams were subjected to a diet containing either n-3 fatty acid adequate (Adq, 3.4% linolenic acid) or n-3 fatty acid adequate+docosahexaenoic acid (Adq+DHA, 3.31%linolenic acid plus 9.65% DHA). After weaning, male pups were fed on the same diet of their respective dams until adulthood. Motor activity and Morris water maze tests were measured at 10 weeks. In the motor activity test, there were no statistically significant differences in moving time and moving distance between the Adq and Adq+DHA diet groups. The n-3 fatty acid adequate with DHA (Adq+DHA) group tended to show a shorter escape latency, swimming time and swimming distance compared to the n-3 fatty acid adequate group (Adq), but the differences were not statistically significant. There was no difference in resting time, but the Adq+DHA group showed a higher swimming speed compared to the Adq group. In memory retention trials, the numbers of crossing of the platform position (region A), in which the hidden platform was placed, were significantly greater than those of other regions for both Adq and Adq+DHA groups. Based on these results, adding DHA into the n-3 fatty acid adequate diet from gestation to adulthood tended to induce better spatial learning performance in Sprague Dawley rats as assessed by the Morris water maze test, although the difference was not significant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.103-110
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• 2020

Bio-inspired underwater robots have been studied to improve the dynamic performance of fins, such as swimming speed and efficiency, which is the most basic performance. Among them, bio-inspired soft robots with a compliant tail fin can have high degrees of freedom. On the other hand, to improve the driving efficiency of the compliant fins, the stiffness of the tail fin should be changed with the driving frequency. Therefore, a new type of variable stiffness mechanism has been developed and verified. This study, which was inspired by the anatomy of a real dolphin, assessed a process of designing and manufacturing a robotic dolphin with a variable stiffness mechanism. By mimicking the vertebrae of a dolphin, the variable stiffness driving part was manufactured using subtractive and additive manufacturing. A driving tendon was placed considering the location of the tendon in the actual dolphin, and the additional tendon was installed to change its stiffness. A robotic dolphin was designed and manufactured in a streamlined shape, and the swimming speed was measured by varying the stiffness. When the stiffness of the tail fin was varied at the same driving frequency, the swimming speed and thrust changed by approximately 1.24 and 1.5 times, respectively.

• Korean Journal of Applied Biomechanics
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• v.33 no.3
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• pp.101-109
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• 2023

Objective: The aim of this study is to verify the differences in muscle characteristics of elite level swimmers before and after a 2-hour practice session. Method: The study was conducted on 15 elite swimmers. Preliminary measurements for each muscle (Anterior Deltoid, Triceps Brachii, Biceps Brachii, Flexor Carpi Ulnaris) were taken using the MyotonPRO device before training. After approximately 2 hours of training, the same muscle areas were measured again. The collected data was analyzed through descriptive statistics and two-way 2×2 RG·RM ANOVA, and all statistical significance levels were set at α=.05. Results: After analyzing the characteristics of the Flexor Carpi Ulnaris (FCU) before and after training in both proficiency level swimmers (excellent, non-excellent), it was found that the interaction effect of group X repetition in muscle tension (F), muscle stiffness (S), and body recovery time (R) was statistically significant. Secondly, in the analysis of the Biceps Brachii (BB), the main effect of repetition in muscle tension (F), muscle stiffness (S), and body recovery time (R) was statistically significant. Furthermore, the interaction effect of group X repetition in muscle stiffness (S) and body recovery time (R) was statistically significant. Conclusion: The efficient use of FCU and BB suggests that it is an important factor distinguishing the performance of excellent and non-excellent swimmers in swimming. Therefore, if we develop and apply measures to efficiently utilize FCU and BB during training, it can help improve the performance of the athletes.