Purpose of this study is to evaluate the temperature lowering effects of the local cold air application on the skin surface and the muscle of different depth, and to observe whether the rebound rise of the temperature occurs after the cold air application.

Subjects were prepared in a relaxed prone position. Cold air of CRAis(Kyung-won Century, Korea) was applied to the gluteal area of 20 healthy subjects for 5 minutes. The skin and intramuscular temperatures were measured by a thermogram(Infrared system, Sweden) and digital thermometers(Barnant company, USA). The temperatures were measured before and 30 seconds after the cold air application, and then every 5 minutes for the next 110 minutes. The few variables were considered that might affect the temperature changes. The thermometer-probes were inserted into the outer quadrant of the gluteal muscle below 5 cm from the iliac crest with the depth of 2 cm, 4 cm, and 6 cm respectively. ANOVA was used for the analysis of the data. The resting temperature of the skin surface was 32.6⁑1.2℃, and the lowest temperature was 12.9⁑3.3℃ after 5 minutes of cold air application. The resting intramuscular temperatures with 2 cm, 4 cm, and 6 cm depth were 36.5⁑0.2℃, 36.9⁑0.2℃, and 37.1⁑0.2℃ respectively (p＜0.05). The lowest temperature in 2 cm, 4 cm, and 6 cm depth was 35.1⁑0.7℃, 36.2⁑0.4℃, and 36.9⁑0.3℃ respectively(p＜0.05). The mean duration to reach the lowest temperature was 20, 25, and 45 minutes respectively. The temperatures in the skin and the muscle with the depth of 2 cm, 4 cm, and 6 cm after 2 hours on cold air application were 32.2⁑1.1℃, 36.2⁑0.5℃, 36.6⁑0.3℃, and 36.9⁑0.3℃(p＜0.05) respectively. The temperatures in the skin and the muscle were significantly lower after 2 hours than before the cold air application(p＜0.05).

The change of skin surface temperature was more rapid than that of the muscle and the deeper the muscle was the lesser the temperature change. In conclusion, the effect of cold air application for 5 minutes lasts up to 2 hours and the rebound rise of the temperature due to reactive vasodilatation seems not to occur in the gluteal muscle.