[Purpose] The purpose of this study was to examine the intra- and inter-rater reliabilities of lower extremity muscle strength assessment of healthy adults using hand held dynamometer. [Subjects and Methods] A total of 55 students (19 males and 36 females) in Y University in Gyeongsangnam-do, South Korea participated in this study. Lower extremity muscle strength was measured using a hand-held dynamometer (Commander Muscle Tester, JTech, USA). Flexion and extension strengths of the hip joint, the knee joint, and the ankle joint were measured. [Results] The intra-rater reliabilities were excellent (above 0.9) for the flexion and extension strengths of the ankle, knee, and hip joints. The inter-rater reliabilities were also excellent (above 0.8) for the flexion and extension strengths of the ankle, knee, and hip joint. [Conclusion] Lower extremity muscle strength assessment using a hand-held dynamometer provided consistent results when conducted by different examiners and when measured several times. Therefore, this method is a useful way of deriving objective and quantitative measurement values.

[Purpose] The aim of this study was to examine changes in the muscle activity around the neck according to the neck movement angle during neck flexion and extension. [Subjects and Methods] Activities of the sternocleidomastoid muscle (SCM), splenius capitis and splenius cervicis muscles, upper trapezius muscle, and middle trapezius muscle during flexion and extension were assessed in 24 college students. [Results] SCM muscle activation significantly increased at every angle during flexion and extension. The activities of the splenius capitis and splenius cervicis muscles increased significantly during flexion. The activity of the upper trapezius muscle also increased significantly. [Conclusion] The results highlight the need for individuals not to adopt a neck flexion posture for extended periods.

[Purpose] The present study was conducted to investigate whether ankle proprioceptive exercise affects static and dynamic balance in normal adults. [Subjects and Methods] Twenty-eight normal adults were recruited to measure their static and dynamic balancing before and after the proprioceptive exercise. A subject stood with bare feet on the round supporting platform of the device for measuring balance, and the investigator entered the age and the height of the subjects and set his/her feet on the central point of the monitor screen. Training of ankle proprioceptive sense for the movements of plantar-flexion and dorsiflexion was performed. In the training of joint position sense in plantar-flexion and dorsiflexion, the plantar-flexion and the dorsiflexion were set as 15°, respectively. [Results] The static balancing did not show significant differences in average, while the dynamic balancing showed significant differences. [Conclusion] Ankle proprioceptive exercise can affect dynamic balance.

[Purpose] The present study investigated the effects of squat exercises with and without a variety of tools including a gym ball, wedge, and elastic band on the vastus lateralis and vastus medialis oblique muscles. [Subjects and Methods] A total of twenty healthy subjects with no history of neurological, musculoskeletal injury, or pain in the lower extremities were recruited. All subjects performed four types of exercise (conventional squat exercise, squat exercise with a gym ball, squat exercise with a wedge, squat exercise with an elastic band). [Results] There were no significant differences between exercises in comparison of the vastus lateralis muscle activity. In the squat exercise with a wedge, significantly higher activity of the vastus medialis oblique muscle was found compared with in the squat exercise with an elastic band. [Conclusion] The present study suggests that the conventional squat exercise can be one of the useful interventions for patients with patellofemoral pain syndrome.

[Purpose] The aim of the present study is to examine effects of diaphragm breathing exercise and feedback breathing exercise on maximal oxygen uptake and resting metabolic rate. [Participants and Methods] Thirty-eight healthy participants were randomly assigned to two groups; the diaphragm breathing exercise group and the feedback breathing exercise group. The diaphragm breathing exercise group was asked to perform diaphragm respiration, and the feedback breathing exercise group was asked to breathe with feedback breathing device. Maximal oxygen uptake and resting metabolic rate were measured before and after two breathing exercises. [Results] Significant difference was found in maximal oxygen uptake before and after two breathing exercises. There was also significant difference in resting metabolic rate before and after diaphragm breathing exercise. However, significant difference was not found in resting metabolic rate before and after feedback breathing exercise. There were not significant between-group differences in both maximal oxygen uptake and resting metabolic rate. [Conclusion] Diaphragm breathing exercise and feedback breathing exercise could influence maximal oxygen uptake. Diaphragm breathing exercise could influence resting metabolic rate, but feedback breathing exercise could not.