Each joint action, with the role and emphasis the graph assigns each muscle. These are qualitative anatomical labels, not measured muscle activation.
Shoulder extensionprimary action
Latissimus dorsi (prime mover, high emphasis); Teres major (prime mover, high emphasis); Posterior deltoid (synergist, moderate emphasis)
Shoulder horizontal abductionprimary action
Posterior deltoid (prime mover, high emphasis); Latissimus dorsi (synergist, moderate emphasis); Infraspinatus (synergist, low emphasis); Teres minor (synergist, low emphasis)
Elbow flexionsecondary action
Brachialis (synergist, high emphasis); Brachioradialis (synergist, moderate emphasis); Biceps brachii (synergist, moderate emphasis)
Scapula retractionsecondary action
Trapezius (synergist, moderate emphasis); Rhomboids (synergist, moderate emphasis)
Spine extensionsecondary action
Erector spinae (stabilizer, moderate emphasis); Multifidus (stabilizer, low emphasis)
Spine rotationsecondary action · resisted
External oblique (stabilizer, moderate emphasis); Internal oblique (stabilizer, moderate emphasis); Quadratus lumborum (stabilizer, low emphasis)