Exercise guide
Arm Crossover Chest Out
- Intermediate
- Isolation
- Rep-based
- Shoulders
A dynamic mobility exercise that improves shoulder range of motion while activating the pectorals and posterior deltoids through rhythmic horizontal abduction and adduction.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Stand tall with your feet shoulder-width apart and your core engaged.
- Extend your arms straight out to your sides at shoulder height, palms facing forward.
- Maintain a slight bend in your elbows to protect the joints.
How to do it
- Swing both arms horizontally across the front of your body, crossing one arm over the other while exhaling.
- Inhale and swing your arms back out as wide as possible, pulling your shoulder blades together to open the chest.
- Continue the movement in a controlled, rhythmic tempo, alternating which arm crosses on top each time.
Form checklist
- Keep your arms level with your shoulders; do not let them drop toward your waist.
- Maintain a neutral spine and avoid arching your lower back as you open your chest.
- Keep your shoulders depressed and away from your ears throughout the movement.
- Control the momentum to ensure the muscles are doing the work, not just gravity.
Pro tips
- Focus on the mind-muscle connection by consciously squeezing your shoulder blades at the widest point of the movement.
- Vary your hand orientation—try palms up during the 'chest out' phase to further engage the external rotators of the shoulder.
Make it harder
- Hold light weights or water bottles to increase the resistance on the posterior deltoids.
- Perform the movement while in a shallow squat to increase total body tension and stability demands.
Frequently asked
- What muscles does the arm crossover chest out work?
- The arm crossover chest out primarily targets the pectorals, and also works the serratus anterior as secondary muscles.
- What equipment do you need for the arm crossover chest out?
- The arm crossover chest out requires no equipment — just your body weight.
- Is the arm crossover chest out good for beginners?
- The arm crossover chest out is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.