• Korean Journal of Exercise Nutrition
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• v.25 no.1
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• pp.1-6
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• 2021

[Purpose] We determined the effect of partial sleep deprivation (PSD) after an exercise session on exercise performance on the following morning. [Methods] Eleven male athletes performed either a normal sleep trial (CON) or a PSD trial. On the first day (day 1), all subjects performed an exercise session consisting of 90 min of running (at 75% ${\dot{V}}O_{2max}$) followed by 100 drop jumps. Maximal strength (MVC) was evaluated before and after exercise. In the CON trial, the sleep duration was 23:00-7:00, while in the PSD trial, the sleep duration was shortened to 40% of the regular sleep duration. On the following morning (day 2), MVC, the metabolic responses during 20 min of running (at 75% ${\dot{V}}O_{2max}$), and time to exhaustion (TTE) at 85% ${\dot{V}}O_{2max}$ were evaluated. [Results] On day 2, neither the MVC nor ${\dot{V}}O_2$ during 20 min of running differed significantly between the two trials. However, the respiratory exchange ratio was significantly lower in the PSD trial than in the CON trial (p = 0.01). Moreover, the TTE was significantly shorter in the PSD trial than in the CON trial (p = 0.01). [Conclusion] A single night of PSD after an exercise session significantly decreased endurance performance without significantly changing muscle strength or cardiopulmonary response.

• Korean Journal of Exercise Nutrition
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• v.23 no.1
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• pp.48-54
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• 2019

[Purpose] The combined effect of different types of post-exercise treatment has not been fully explored. We investigated the effect of combined cold water immersion (CWI) and compression garment (CG) use after maximal eccentric exercise on maximal muscle strength, indirect muscle damage markers in the blood, muscle thickness, and muscle soreness score 24 h after exercise. [Methods] Ten men performed two trials (CWI + CG and CON) in random order. In the CWI + CG trial, the subjects performed 15 min of CWI (15℃), followed by wearing of a lower-body CG for 24 h after exercise. In the CON trial, there was no post-exercise treatment. The exercise consisted of 6 × 10 maximal isokinetic (60°·s^-1) eccentric knee extensions using one lower limb. The maximal voluntary contraction (MVC) and maximal isokinetic (60°·s^-1) strength during knee extension, as well as the indirect muscle damage markers, were evaluated before exercise and 24 h after exercise. [Results] The maximal muscle strength decreased in both trials (p < 0.001), with no difference between them. The exercise-induced elevation in the myoglobin concentration tended to be lower in the CWI + CG trial than in the CON trial (p = 0.060). The difference in the MVC, maximal isokinetic strength, muscle thickness, and muscle soreness score between the trials was not significant. [Conclusion] CWI followed by wearing of a CG after maximal eccentric exercise tended to attenuate the exercise-induced elevation of indirect muscle damage markers in the blood.

• Korean Journal of Exercise Nutrition
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• v.24 no.2
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• pp.30-37
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• 2020

[Purpose] The present study investigated the effect of endurance exercise with blood flow restriction (BFR) performed at either 25% maximal oxygen uptake (${\dot{V}}O_2$ max) or 40% ${\dot{V}}O_2$ max) on muscle oxygenation, energy metabolism, and endocrine responses. [Methods] Ten males were recruited in the present study. The subjects performed three trials: (1) endurance exercise at 40% ${\dot{V}}O_2$ max without BFR (NBFR40), (2) endurance exercise at 25% ${\dot{V}}O_2$ max with BFR (BFR25), and (3) endurance exercise at 40% ${\dot{V}}O_2$ max with BFR (BFR40). The exercises were performed for 15 min during which the pedaling frequency was set at 70 rpm. In BFR25 and BFR40, 2 min of pressure phase (equivalent to 160 mmHg) followed by 1 min of release phase were repeated five times (5 × 3 min) throughout 15 minutes of exercise. During exercise, muscle oxygenation and concentration of respiratory gases were measured. The blood samples were collected before exercise, immediately after 15 min of exercise, and at 15, 30, and 60 minutes after completion of exercise. [Results] Deoxygenated hemoglobin (deoxy-Hb) level during exercise was significantly higher with BFR25 and BFR40 than that with NBFR40. BFR40 showed significantly higher total-hemoglobin (total-Hb) than NBFR40 during 2 min of pressure phase. Moreover, exercise-induced lactate elevation and pH reduction were significantly augmented in BFR40, with concomitant increase in serum cortisol concentration after exercise. Carbohydrate (CHO) oxidation was significantly higher with BFR40 than that with NBFR40 and BFR25, whereas fat oxidation was lower with BFR40. [Conclusion] Deoxy-Hb and total Hb levels were significantly increased during 15 min of pedaling exercise in BFR25 and BFR40, indicating augmented local hypoxia and blood volume (blood perfusion) in the muscle. Moreover, low-and moderate-intensity exercise with BFR facilitated CHO oxidation.

• Korean Journal of Exercise Nutrition
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• v.15 no.4
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• pp.153-161
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• 2011

The maintenance of skeletal muscle mass is very important for the prevention of life style-related diseases and the improvement of quality of life. It is well-known that resistance exercise and nutrition (especially amino acids) are the most effective interventions for maintaining skeletal muscle mass. It has been reported that many molecules are involved in the regulation of protein synthesis in response to resistance exercise and nutrition. Understanding the molecular mechanisms regulating muscle protein synthesis is crucial for the development of appropriate interventions. The role of intracellular signaling pathways through the mammalian target of rapamycin (mTOR), a serine/threonine protein kinase in the regulation of muscle protein synthesis, has been extensively investigated for these years. Control of protein synthesis by mTOR is mediated through phosphorylation of downstream targets that modulate translation initiation and elongation step. In contrast, upstream mediators regulating mTOR and protein synthesis in response to resistance exercise and amino acid still needed to be determined. In this brief review, we discuss the current progress of intracellular mechanisms for exercise- and amino acid-induced activation of mTOR pathways and protein synthesis in skeletal muscle.

• Korean Journal of Exercise Nutrition
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• v.24 no.1
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• pp.37-45
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• 2020

[Purpose] The purpose of this study was to examine the effects of elastic band exercises and nutritional education, as well as to identify the factors influencing frailty, strength, and nutritional intake of elderly women. [Methods] The subjects in this study were 30 elderly women who were divided into four groups. All groups agreed to participate in four programs: health education only (HE), elastic band exercises only (EX), nutritional education only (NU), and elastic band exercises plus nutritional education (EX+NU). Frailty was evaluated by measuring the frailty factors according to Fried et al. Leg strength was measured using a leg-extension machine. Nutritional intake was assessed by the 24-hour recall method and food records. Nutritional intake was analyzed by CAN Pro 5.0 program. [Results] After three months, the prevalence of frailty significantly decreased in the EX+NU group (P=0.013) compared with that of the HE group (P=0.088). There was significant improvement in leg strength in both the EX (P=0.012) and EX+NU groups (P=0.003) compared with that of the HE group (EX, P=0.005; EX+NU, P=0.002). The nutritional intake significantly decreased in the EX group compared with that of the HE group (P<0.05, P<0.05). [Conclusion] The combination of elastic exercises and nutrition education had positive effects on frailty and leg strength, while having negative effects on total calories, carbohydrate, sodium, and iron intake in elderly women. Elastic exercises only had positive effects on leg strength while having negative effects on nutritional intake in elderly women.

• Journal of the Korean Society of Food Culture
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• v.20 no.3
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• pp.323-330
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• 2005

The purpose of this study was to evaluate the effects of the weight control programme through nutrition education on anthropometry, body composition, dietary behavior, and adipocyte-drived protein in obese elementary school children. The subjects were 17 obese children of OI over 120% from the fourth to sixth grades of elementary school. The subjects were given nutrition education for weight control along with physical and behavioral advices once a week, and the program was 12 weeks long. On the completion of 12 week weight control program, significant decreases in waist and hip circumferences were resulted, however, no changes in body mass index (BMI) and obesity index (OI) were found. Hemoglobin was significantly decreased and HDL-cholesterol was significantly increased. Energy intake was decreased significantly along with intakes of Ca, Fe, folic acid, vitamin B1, vitamin B6, and vitamin C. Meal distribution of energy was changed; % energy from snack significantly from 11.9% to 3.3%. Resistin, leptin, and adiponectin level were not changed; Resistin had a negative correlation with vitamin C intake. Leptin had positive correlations with weight and BMI. Adiponectin was negatively correlated with weight and BMI. In conclusion, nutrition education program for weight control for 12 weeks is effective in changing the dietary behavior, serum profile, and anthropometry in obese elementary children, however, no effect was seen in adipocytokine levels.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.890-899
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• 2010

The sport industry has been continuing to grow in the past few decades in the U.S., and it presents significant opportunities for the practitioners to increase the number of patrons. To convert this opportunity to optimum benefits for a sport organization, one of the most significant challenges for the practitioners would be promoting sport attendance and repatronage. So far, many studies have tried to identify variables that affect the level of sports attendance. However, many of these variables are rather uncontrollable due to the nature of the sports and contingencies that are derived from many areas of uncertainties. Thus, to acquire competitive advantage and profit maximization, it would be essential for the managers to focus on understanding controllable elements. This study found that many controllable variables that influence sports attendance coincide with the servicescape elements which have been widely used in the hospitality industry since 1992. In the light of the conceptual framework of servicescape, this study also attempted to isolate the controllable variables that can be utilized to increase the sports attendance. This study presents its significance not only in extending the application of servicescape concept to the sport industry, but also in providing suggestions for future empirical studies that would further identify these variables, gauge the relationship between those variables, and assess its impact on the sports attendance.

• Journal of the Korean Society for Computer Game
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• v.31 no.4
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• pp.9-15
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• 2018

The purpose of this study is to investigate the actual situation of the surrogate games and win trading gameplays in e-sports leagues, and to insist on the creation of new regulations to punish them. The surrogate game surveys was conducted for 40 amateur users and 17 professional users in e-sports leagues. The survey was conducted in-depth interviews with a professional user to learn more about the actual situation of the win trading gameplay. As a result of the study, professional users had a high rate of experience with Gahz'rilla, and they would be able to increase their game rankings through Gahz'rilla. But they did not think Gahz'rilla is a surrogate game. Amateur users had a low rate of experience with Gahz'rilla and did not think they would be able to increase their game rankings through Gahz'rilla relative to professional users. Amature users tend to think of Gahz'rilla as a surrogate game. Both the users agree on the necessity of regulation on Gahz'rilla and surrogate game. Therefore, it is necessary to narrow the gap between the professional users and the amateur users by establishing rules for Gahz'rilla and surrogate game.

• Korean Journal of Exercise Nutrition
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• v.16 no.1
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• pp.27-33
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• 2012

This study was conducted to investigate the effect of a 24-week combined exercise training program in older women with hypertension. Women with hypertension who were 70 years and older were randomized into two groups: combined exercise group (CE; n = 15) and a control group (n = 15). The CE group performed a combined exercise training program four times per week for 24 weeks and the control group did not. Five factors, including body composition (percent body fat and skeletal muscle mass), health-related physical fitness, adipocytokines (interleukin-6 [IL-6] and tumor necrosis factor-alpha [TNF-α]), kidney risk factors (glomerular filtration rate [GFR] and cystatin C), and systolic and diastolic blood pressure were measured before and after the program. The findings showed that total muscle mass, health-related physical fitness factors, and GFR increased significantly in the CE group compared to those in the control. Additionally, systolic and diastolic blood pressure and IL-6, TNF-α, and cystatin C levels in the CE group decreased significantly after the intervention. In contrast, total muscle mass decreased significantly and blood pressure remained unchanged in the control group. These results suggest that CE training may positively impact circulating levels of adipocytokines and cystatin C and improve physical fitness levels in elderly women with hypertension. Therefore, CE training helps to prevent renal disease and improve health-related physical fitness, eventually leading to a better quality of life.

• Clinical Nutrition Research
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• v.13 no.1
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• pp.8-21
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• 2024

In this study, the effects of a 12-month multidisciplinary education program on the health status, dietary quality, and eating habits of children and adolescents attending community childcare centers were investigated. A total of 88 participants aged 7 to 17 years from 7 community childcare centers in Gyeonggi-do were enrolled. The intervention consisted of 12 multidisciplinary education sessions covering topics such as nutrition, exercise, and psychological education. All participants received the same education, and the effectiveness of the program was evaluated by categorizing them into a high participation group (HPG) and a low participation group (LPG) based on their participation rates. After intervention, in physical activities, moderate-intensity exercise was significantly reduced in the LPG, and there was no significant difference in psychological parameters. However, notable differences were observed in nutritional data. After intervention, intakes of calorie, carbohydrate, protein, and fat were significantly increased in both groups, and in particular, the change was found to be greater in HPG. Additionally, dietary fiber intake compared to the 2015 Korean Dietary Reference Intakes was increased in both groups. Daily food intake also increased dietary fiber intake in HPG, and meat and fruit intake was increased in LPG. In the nutrition quotient, there was a significant difference in HPG's pre- and post-scores in the diversity category, and in nutrient adequacy ratio (NAR), the NAR of phosphorus was increased in both groups. The findings of this study suggest that multidisciplinary education implemented at community childcare centers primarily enhanced nutrition-related factors rather than physical activity or psychological aspects.