Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Lie face down; arms straight overhead (palms face, thumbs up—I-shape). Brace core/glutes; forehead to mat, relaxed shoulders down. Lift arms: squeeze lower traps/upper back (keep straight; few inches OK). Top: retract/depress scapula, hold 1-2 sec (feel below blades). Lower controlled (2-3 sec). Repeat no full rest.
Straight arms like steel rods (no bend; lower reps if needed). Brace core/glutes (neutral spine, no lumbar arch). Gaze floor ("long neck")—no chin lead/high head. Arms straight overhead (12 o'clock, no Y-angle drift).
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