We have several options, one of them being the placement of electrodes between origin and insertion. Bearing in mind the large expanse of muscle place two electrodes at the height and perpendicular to the seventh dorsal vertebra, the distal electrodes are placed in the same position but further down perpendicular to the twelfth dorsal vertebra.
The latissimus dorsi muscle.

The latissimus dorsi muscle has its origin in the spinal apophysis of the seventh to twelfth dorsal vertebrae, dorsolumbar and sacral crest and posterior area of the iliac crest and it inserts into the floor of intertubercular groove of the humerus.

The latissimus dorsi is responsible for and internal rotation, abduction and extension of the shoulder joint. When the latissimus dorsi is weak, we are unable to abduct the arm,
and experience difficulty bending sideways.

The latissimus dorsi is a very powerful muscle and needs to be working well in order to play all kinds of sport, particularly those that require abduction and internal rotation of
the arm for example in parallel bars, swimming, rowing and sports involving throwing.