Orthogonal test on local temperature influenced by different parameters and manipulation types of An-pressing Xinshu (BL 15)

Objective To explore the optimal thermal effect parameter combination of An-pressing manipulation based on the pressing force, time and frequency, and to compare the thermal effect differences between the rhythmic and the continuous An-pressing manipulations. Methods Three levels of light, moderate and heavy pressing forces were determined according to the An-pressing forces of the clinical tuina physicians; the pressing time and frequency parameters were determined according to the literatures about An-pressing manipulation. The volunteers were stimulated by the homemade An-pressing manipulation stimulator on the right Xinshu (BL 15), and then the three-factor and three-level orthogonal tests were carried out according to the test sequence specified by the L 9 (3 4 ) orthogonal table, and the temperature before and after pressing was recorded by an infrared thermal imaging system to screen the best parameters for the thermal effect of the An-pressing manipulation, thus to determine the optimal pressing parameters. The optimal parameters were then used for both continuous and rhythmic An-pressing manipulations to stimulate the bilateral Xinshu (BL 15). The temperature changes after pressing and the duration of the thermal effect (temperature difference ≤0.5 °C on both sides) were recorded by the infrared thermal imaging system, to explore the differences in the thermal effects of different An-pressing manipulations. Results Among the three factors of pressing force, time and frequency, the influences of different pressing forces on temperature were significantly different ( F =32.843, P =0.030), and the influence of 2.5 kg pressing force was the most significant; the effects of different pressing time on temperature were significantly different ( F =54.102, P =0.018), and the pressing time of 7.5 min was the most significant; the influences of different pressing frequencies on temperature were not statistically significant ( F =2.181, P =0.314), though the influence of 10 times/min pressing frequency was the largest. The influences on temperature difference of the rhythmic and the continuous An-pressing manipulations were significantly different ( P =0.031 on the left side and P =0.045 on the right side), but there was no statistical difference in the duration of the thermal effect ( P =0.690). Conclusion The An-pressing manipulation parameters that significantly affect the temperature difference are pressing force and time. The optimal combination of thermal effect parameters is pressing force of 2.5 kg, time of 7.5 min, and frequency of 10 times/min. The local thermal effect of the rhythmic An-pressing manipulation is significantly greater than of the continuous An-pressing manipulation.