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); Triceps brachii (synergist, low emphasis)
Elbow flexionsecondary action
Brachialis (synergist, moderate emphasis); Biceps brachii (synergist, moderate emphasis); Brachioradialis (synergist, moderate emphasis)
Shoulder horizontal abductionsecondary action
Posterior deltoid (synergist, moderate emphasis); Latissimus dorsi (synergist, low emphasis)
Scapula retractionsecondary action
Trapezius (synergist, moderate emphasis); Rhomboids (synergist, moderate emphasis)
Scapula depressionsecondary action
Trapezius (synergist, moderate emphasis); Pectoralis minor (synergist, low emphasis)