Electromyography (EMG) was used to examine gluteus medius and maximus activities with the hip in sustained extension and abduction. [Subjects and Methods] Subjects were 10 healthy male persons, mean age of 24.4 years. The gluteus medius and maximus overlap area was confirmed with ultrasonic imaging. EMG activity of each muscle was measured during a change in lower limb weight load on the measurement side with the hip in sustained extension and abduction. [Results] Activities of the gluteus medius posterior fibers, overlap area, and gluteus maximus upper fibers increased with hip extension, and activities of the gluteus medius and overlap area increased with hip abduction. [Conclusion] Gluteus medius posterior fibers were identified in the area extending from the ventral side of the angle between the lines that connect the vertex of the iliac crest and greater trochanter, and the posterior superior iliac spines and greater trochanter. The gluteus maximus upper fibers were not involved in hip abduction.

The viscous flow simulation is carried out around the KVLCC2 tanker model by the simple and effective way using a new body-force distribution model for the propeller-hull and propeller-hull-rudder interaction. The simple body-force model based on quasi-steady blade element theory is coupled with the Reynolds averaged Navier-Stokes (RANS) code CFDSHIP-IOWA. The captive tests in the trimmed condition and even-keel condition are computed with rudder and without rudder. The computational condition is set up according to the experiments in Osaka University towing tank and the output flow fields are analyzed in details especially in the wake field around the rudder and propeller. The computational results are not only validated with the experiments but also compared with the real propeller computation and other body-force models in order to find out the advantage of the current method. Summarizing the results, the present study could provide the complicated wake field patterns behind the tanker hull form which are as close as the experiment by simply using the new body-force distribution model and the current method can predict the wake field superior to the other body-force models.

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