This study was made for the purpose of clarifying the extent to which the intrathoracic pressure, especially the snatch pressure, rose when performed sports skills with explosive power in both straining and exhaling states. Seven healthy male adults were used as subjects and Balloon Method was used to record the rise of intrathoracic pressure while performing totally 19 skills, five in track and field and 14 in ball-games. The results were as follows: 1. When the skills were involved in the upper arm which required an impulsive power were performed under straining state, the rise of intrathoracic pressure was most remarkable; it was found that the snatch pressure rose up to above 200mmHg. 2. There were large individual differences in the extent of the rise of intrathoracic pressure when perfumed skills in both straining and exhaling states, but no difference was found between the skilled and the unskilled or between the experienced and the less experienced. 3. When a subject performed the same skill in both exhaling and straining states, the rise of the intrathoracic pressure in the latter state was 1.2-2.4 times higher than that in the former. It may be possible to prevent, to some extent, the excessive rise of the intrathoracic pressure by performing skills while exhaling or shouting when lifting things or executing instant power. 4. The appearance of more than 200mmHg of snatch pressure obtained in this study was unexpectedly high, which may cause faint following acute circulatory collapse or obstruction in the brain circulation.