Objectives :
Motor point is the location of the skin above the muscle where muscle contraction can be evoked by the least electrical stimulation. It is often used to treat muscle dysfunction caused by various diseases.
This study was performed to compare the electrical methods of motor points mapping using surface EMG and electric probe(Pointer Excel Ⅱ).

Methods :
32 healthy adults (male 16, female 16) were selected. and classified into two groups; surface EMG group, electric probe(Pointer Excel Ⅱ) group. In surface EMG group, motor points were searched by recoding the compound muscle potentials. In electric probe(Pointer Excel Ⅱ) group, motor points were searched by scanning the skin with Pointer Excel Ⅱ at low level stimulation. The locations of the motor points were expressed as X and Y values in relation to the reference line. The horizontal reference line was set as elbow crease and the vertical reference line was set as the line connecting coracoid process to the center of the horizontal reference line. The data was analyzed by ''Independent T-test'' and ''equivalence test''.

Results :
1. The motor points of short head and long head of biceps brachii muscle were located at about 2/3 length of the vertical reference line from coracoid process and about 1/5～1/4 length of the half of the horizontal reference line from the vertical reference line in both group.
2. The motor points of the short head were located more distally and close to the vertical reference line(p<0.001).
3. In surface EMG group, the motor points of the long head were located more laterally in the female than male. And the motor points of the long head were located more distally in the left side than right side(p<0.05). In electric probe(Pointer Excel Ⅱ) group, similar tendency was observed but there was no statistically significant difference(p>0.05).
4. As a result of the equivalence test between surface EMG group and electric probe(Pointer Excel Ⅱ) group, the confidence intervals of the difference were within the equivalence limit. Therefore, the locations of the motor points searched by two ways are equal(p>0.05, equivalence interval=3%).

Conclusions :
The results indicate that electric probe(Pointer Excel Ⅱ) can be used to search the motor points instead of surface EMG. This might improve the clinical efficiency when using the motor points to treat muscle dysfunction.

Key words :
Motor point, Electric probe, Pointer Excel, Surface EMG, Biceps brachii.