Parallel-bar dip muscles worked
Every role here is for this technique: supported on parallel bars, torso upright, lowered until the upper arms are about parallel with the floor, pressed to straight arms.
What muscles does the parallel-bar dip work?
The prime movers of the parallel-bar dip are triceps brachii, the sternal part of pectoralis major and the anterior deltoid. They produce elbow extension and shoulder flexion from behind the body. Five synergists assist, among them the clavicular part of pectoralis major, pectoralis minor and the lower trapezius. Ten stabilizers hold joints and segments still, among them supraspinatus and infraspinatus.
Joint actions and their prime movers
| Joint action | Prime movers |
|---|---|
| Elbow extension | Triceps brachii |
| Shoulder flexion from behind the body | The sternal part of pectoralis major and the anterior deltoid |
Every muscle by role
A prime mover produces the lift’s main joint action against the load; a synergist assists that action, or adds a secondary action the lift needs; a stabilizer contracts mostly isometrically to hold a joint or a segment still. A role describes what the muscle does in the technique above, not how hard it works or how much it grows.
Prime movers 3
| Muscle | What it does here |
|---|---|
| Triceps brachii | Elbow extension, all three heads |
| Pectoralis major, sternal part | Drawing the upper arm forward and down |
| Anterior deltoid | Shoulder flexion from behind the body |
Synergists 5
| Muscle | What it does here |
|---|---|
| Pectoralis major, clavicular part | Shoulder flexion |
| Pectoralis minor | Pulling the shoulder blades down |
| Lower trapezius | Pulling the shoulder blades down |
| Latissimus dorsi | Holding the shoulders down, away from the ears |
| Coracobrachialis | Shoulder flexion |
Stabilizers 10
| Muscle | What it does here |
|---|---|
| Supraspinatus | Holding the head of the humerus in its socket |
| Infraspinatus | Holding the head of the humerus in its socket |
| Teres minor | Holding the head of the humerus in its socket |
| Subscapularis | Holding the head of the humerus in its socket |
| Rhomboids | Holding the shoulder blades steady |
| Rectus abdominis | Bracing the trunk against the load |
| External oblique | Bracing the trunk and resisting rotation |
| Internal oblique | Bracing the trunk and resisting rotation |
| Transversus abdominis | Raising abdominal pressure to stiffen the trunk |
| Wrist and finger flexors | Gripping the bars |
Lowering and lifting
| Phase | What the prime movers do |
|---|---|
| Lowering | Triceps, pectoralis major and the anterior deltoid lengthen as the body drops |
| Pressing | They shorten to push the body up |
Where these prime movers also work
- Triceps brachii: prime mover in the flat bench press, incline bench press, push-up, standing overhead press and cable triceps pushdown.
- The sternal part of pectoralis major: prime mover in the flat bench press and push-up; synergist in the incline bench press, pull-up, chin-up and lat pulldown.
- The anterior deltoid: prime mover in the flat bench press, incline bench press, push-up and standing overhead press; synergist in the dumbbell lateral raise.
Compared with the other vertical push lifts
- Standing overhead press: prime movers in both, the anterior deltoid and triceps brachii; prime movers only here, the sternal part of pectoralis major; prime movers only in the standing overhead press, the clavicular part of pectoralis major.
Sources
- NSCA, Essentials of Strength Training and Conditioning, 4th ed. (2016)
- Neumann, Kinesiology of the Musculoskeletal System, 3rd ed. (2017)
The cited studies that measured muscle activity used electromyography, and a larger signal need not mean more force or more growth (Vigotsky et al. (2018), Front Physiol 8:985). The roles draw on those studies for which muscles a lift involves and how two lifts differ, never to rank one muscle against another.
The values are facts and free to use; this page’s selection and presentation are © 2026 ScienceQuest.