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 (synergist, moderate emphasis); Posterior deltoid (synergist, moderate emphasis)
Elbow flexionsecondary action
Biceps brachii (synergist, moderate emphasis); Brachialis (synergist, moderate emphasis); Brachioradialis (synergist, moderate emphasis)
Scapula retractionsecondary action
Rhomboids (synergist, moderate emphasis); Trapezius (synergist, moderate emphasis)
Wrist extensionsecondary action · resisted
Wrist flexors (synergist, high emphasis)
Spine flexionsecondary action · resisted
Erector spinae (stabilizer, moderate emphasis); Gluteus maximus (stabilizer, moderate emphasis)