Table 2 Muscle, EMG sensor location, and EMG sensor orientation^40,42,43.

# 1

Brachioradialis (BR)

Electrode needs to be placed approximately 1/3 of the distance between the lateral epicondyle of the humerus and the styloid process of the radius

In the direction of the muscle fibers, which run longitudinally along the forearm

# 2

Biceps brachii (BB)

Electrodes need to be placed on the line between the medial acromion and the fossa cubit at 1/3 from the fossa cubit

In the direction of the line between the acromion and the fossa cubit

# 3

Triceps brachii (TB)

Electrodes need to be placed at 50% on the line between the posterior crista of the acromion and the olecranon at 2 finger widths medial to the line

In the direction of the line between the posterior crista of the acromion and the olecranon

# 4

Infraspinatus (IS)

Electrodes need to be placed approximately two fingerbreadths below the spine of the scapula, which is the bony ridge that runs along the posterior surface of the scapula

In a horizontal orientation, with the long axis of the sensor aligned with the direction of the muscle fibers, which run diagonally across the posterior aspect of the scapula

# 5

Upper Trapezius (UT)

Electrodes need to be placed at 50% on the line from the acromion to the spine on vertebra C7

In the direction of the line between the acromion and the spine on vertebra C7

# 6

Paraspinal Cervical Spine (PCS)

Electrodes need to be placed at the level of the muscle belly, which is typically located 2–3 cm lateral to the midline of the spine

In a vertical orientation, with the long axis of the sensor aligned with the direction of the muscle fibers, which run parallel to the spine

# 7

Middle Trapezius (MT)

Electrodes need to be placed at 50% between the medial border of the scapula and the spine, at the level of T3

In the direction of the line between T5 and the acromion

# 8

Lower Trapezius (LT)

Electrodes need to be placed at 2/3 on the line from the trigonum spinea to the 8th thoracic vertebra

In the direction of the line between T8 and the acromion

# 9

Anterior Deltoid (AD)

Electrodes need to be placed at one finger width distal and anterior to the acromion

The direction of the line between the acromion and the thumb