Table 1. Sensor locations.

Muscles	Starting posture	Location	Orientation
Rectus Femoris	Sitting on a table with the knees in slight flexion and the upper limbs slightly bends backward.	The electrodes need to be placed at 50% on the line from the anterior spina iliaca superior to the superior part of the patella.	In the direction of the line from the anterior spina iliaca superior to the superior part of the patella.
Vastus Medialis	Sitting on a table with the knees slightly flexed and the upper limbs slightly bent backward.	Electrodes need to be placed at 80% on the line between the anterior spina iliaca superior and the joint space in front of the anterior border of the medial ligament.	Almost perpendicular to the line between the anterior spina iliaca superior and the joint space in front of the anterior border of the medial ligament.
Vastus Lateralis	Sitting on a table with the knees in slight flexion and the upper limbs slightly bends backward.	Electrodes need to be placed at 2/3 on the line from the anterior spina iliaca superior to the lateral side of the patella.	In the direction of the muscle fibers.