Each joint action, with the role and emphasis the graph assigns each muscle. These are qualitative anatomical labels, not measured muscle activation.
Hip extensionprimary action
Gluteus maximus (prime mover, high emphasis); Biceps femoris long head (prime mover, high emphasis); Semitendinosus (prime mover, moderate emphasis); Semimembranosus (prime mover, moderate emphasis); Adductor magnus (synergist, moderate emphasis)
Knee extensionprimary action
Vastus lateralis (prime mover, high emphasis); Vastus medialis (prime mover, high emphasis); Vastus intermedius (prime mover, high emphasis)
Spine extensionsecondary action
Erector spinae (stabilizer, high emphasis)
Scapula retractionsecondary action
Trapezius (stabilizer, high emphasis); Rhomboids (stabilizer, moderate emphasis)
Scapula depressionsecondary action
Trapezius (stabilizer, high emphasis)