Fig. 2

Comparison of the time required by the ultrasound and manipulation methods. The time required by UR and MR were 27 s (20 s, 33 s) and 30 s (22 s, 44 s), respectively. Since the data were not normally distributed, the data were analyzed by the Mann-Whitney U test; the time required by ultrasound was significantly shorter than that required by manipulation (p = 0.001 < 0.05)