Posterior Deltoid
Sources and review status
Review pending — this text hasn’t been signed off by a reviewer yet.
Historical reference: its only source is the original reference manual, and some of it may be out of date. Not used for AI answers until re-sourced.
See this lesson’s sources0% read · 1 min left
The rear deltoid head; produces horizontal abduction, backward extension, and external rotation — the most under-emphasized deltoid head.
Detail
The posterior deltoid's functions are: (1) horizontal abduction, (2) backward extension, and (3) external rotation. Exercises include the seated row (pronated grip) with a low seat position, bent-over rows (pronated grip), side-lying horizontal abduction, and dumbbell shoulder extensions. It is the most under-emphasized muscle of all three deltoid heads, and movements for this muscle are rarely done properly — the key is horizontal abduction (extension). The press-behind-neck exercise is not recommended because it involves too much external rotation.
Key facts
- Functions: horizontal abduction; backward extension; external rotation.
- Most under-emphasized of the three deltoid heads.
- Key training action: horizontal abduction (extension).
- Behind-neck press not recommended (too much external rotation).
Connections
- Deltoids — group it belongs to.
- Horizontal Extension (Abduction) — key action.
- External Rotation — one of its actions.
- Seated Rows / Bent-Over Barbell Row — training exercises.
Sources
Keep this lesson, or ask how it applies to you.
Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.