• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.41-48
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• 2008

The purpose of this study was to analyze the lower extremities joint moment pattern by two types of service motion in tennis pinpoint and platform stance. Seven skilled high school tennis players participated, and the kinematics were recorded by the Vicon motion analysis system. For the gathering and analysis of the data Workstation, Bodybuilder and polygon were used. joint moments and Ground Reaction Forces for the phases involved were analyzed with the following results. There was a different moment pattern for the lower extremities between the two serve motions. For the platform stance there was only a large dorsal flexion moment but for the pinpoint stance there were other large moments. The flexion and maximum moment of the lower extremities occurred at the point of change from back swing and to the forward swing motion. Therefore, this data provides evidence that there is a high risk of injury at this point.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.147-158
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• 2008

The purpose of this study was to analyze the kinematical variables involved in two types of service motion in tennis pinpoint and platform stance, to find the fastest serving method. Seven skilled high school tennis players participated, and the kinematics were recorded by the Vicon motion analysis system. For the gathering and analysis of the data workstation, bodybuilder and polygon were used. During the back swing for the pinpoint stance, as the back leg moves forward the COM and the racquet moves more, thus taking 0.04 seconds longer than the platform stance. The body of the subject takes a bow-shape as the subject's foot moves back and their hip moves forward. This movement enables the subject to create more power during the backswing to impact. It also increases the spread of the COM racquet and the serve speed is increase. As there is no forward movement of the foot during the backswing of the platform stance, the COM and the racquet move less and thus the time required is shorter than that for the pinpoint stance by 0.04seconds. Similarly, the time spent creating the power for the serve is shortened, the COM racquet is narrower and the speed is lessened. However, the advantage of this serve is that it increases the stability.

• Korean Journal of Exercise Nutrition
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• v.13 no.2
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• pp.101-107
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• 2009

The objectives of this study were to investigate 1) the nutritional knowledge, 2) the use of nutritional supplements, and 3) nutrient intakes of male elite bodybuilders (n=20). Participants carried out a comprehensive survey, anthropometric assessment, and 1 day food record. Daily nutrient intakes of the subjects were analyzed using Computer Aided Nutritional Analysis Program (Can-pro 3.0). The mean age of the subjects was 23.4 years. The mean duration of exercise was 5.3 years. The average scores of nutritional knowledge were 71.0%. The subjects were gathered nutrition information from nutrition book (65%), mass communication (50%), friends (50%) and coach (30%) in order. Ninety percentage of the subjects reported that they were taking nutritional supplements. Major reasons for taking nutritional supplements were to improve performance and to build-up muscle. The most frequently taken nutritional supplements were protein powder (85%), multivitamin/mineral (75%), BCAA (60%) and glutamine (55%) in order. The average daily energy intakes of the subjects were 4,248.7 kcal. The mean intake of protein was 370.3 g/day (3.93 g/kg BW). The ratio of total energy intake from carbohydrate, protein and lipid was 51 : 34 : 15. The intakes of most vitamin and minerals through food and nutrition supplements were much higher than those of each nutrient of the RDAs. Especially, vitamin B complex and vitamin C intakes were ranged from 500 to 3,000% of KNHNES. More research needs to be conducted to determine the optimal amounts of carbohydrates, protein, lipid and micro-nutrients for the bodybuilders.