Table 2.

The locations of electrodes and MVIC positions

Muscle	Electrode location	MVIC position
Upper trapezius	The halfway point between the spinous process of the seventh cervical vertebra and the acromion	In a sitting position with abduction at 90°
Middle trapezius	The halfway point between the scapular medial border and the T3	In a prone position with horizontal abduction at 90° and external rotation
Lower trapezius	At 2/3 on the line from the trigonum spinea to the T8	In a prone position with horizontal abduction in 120° in line with the fibers of the muscle and the thumb pointing upward
Serratus anterior	In the mid-axillary line over the fifth rib	In a sitting position with maximum resistance given to upward rotation of the scapula with the shoulder flexed
Middle deltoid	The halfway point of the acromion and the deltoid tuberosity	In a sitting position with abduction at 90°