Table 2.

MVIC test positions with primary and secondary muscles used for data analysis

Primary muscle	Secondary muscles	Isometric contraction
Anterior deltoid	Biceps brachii	Resisted elevation in scapular plane, shoulder at 0°
	Pectoralis major
Middle deltoid	Supraspinatus	Resisted abduction, shoulder at 0°
Posterior deltoid	Latissimus dorsi	Resisted extension, shoulder at 0°
Pectoralis major	Biceps brachii	Resisted horizontal adduction, shoulder at 90° elevation in scapular plane
	Latissimus dorsi
Upper trapezius	–	Resisted shoulder shrug while seated, shoulder at 0°
Middle trapezius	–	Scapular retraction, shoulder at 0°
Lower trapezius	–	Resisted shoulder flexion, shoulder at maximum elevation
Latissimus dorsi	Posterior deltoid	Resisted extension, shoulder at 45° elevation in scapular plane
Serratus anterior	–	Shoulder protraction, shoulder at 90° elevation in scapular plane
Biceps brachii	–	Resisted elbow flexion, shoulder at 0°, elbow at 90° flexion
Supraspinatus	Anterior deltoid	Resisted forward flexion in scapular plane, shoulder at 90°
	Middle deltoid
Infraspinatus	Posterior deltoid	Resisted external rotation, shoulder at 0°
Upper subscapularis	Anterior deltoid	Resisted internal rotation, shoulder at 0°
	Pectoralis major
	Latissimus dorsi
	Lower subscapularis
Lower subscapularis	Anterior deltoid	Resisted internal rotation, shoulder at 90° elevation in scapular plane
	Pectoralis major
	Latissimus dorsi
	Upper subscapularis

Muscles where indwelling electrodes were used are italicized