The purpose of this study was to analyze the joint moment on lower extremity during a developpe devant. Data were collected by Kwon3D, KwonGRF program. Two professional modem female dancers were participated in this experiment. Subjects performed a developpe devant in meddle heights. On the axes of X, Y, Z, it was shown that the maximum joint moment was occurred in hip joint. The moments are plotted during developpe devant. The ankle muscles generate a plantar flexion moment and the knee muscles generate a flexion moment and The hip muscles generate a extension moment. So these muscles of joint muscles were known to play a key role in keeping the body balance while doing developpe devant. In addition adduction moment occurred at hip, knee, an ankle in the order of amount, we could assume from this data that him out motion started from the hip joint. There was small active turn out possible below the hip joint. A small amount of extra turn out could be obtained when standing because of flexion between the foot and floor, which could be used to give a passive external rotation force to the whole leg and this could produce a rotation between the knee and foot. This passive external rotation could produce very damaging results. Therefore, lower extremity joint muscles such as hip, knee, and ankle muscle should be trained to keep the body balance and prevent injury during developpe devant performance. And for the safe and perfect turn ort performance, hip joint abduction, the most important external rotating muscle for him out is needed to train and full stretching should be done in advance.