Alternating Bench Press (Dumbbell)
The Alternating Bench Press is a unilateral chest exercise where you press one dumbbell at a time while holding the other steady. It targets the pectorals while engaging the core and obliques for stability.
Because this exercise requires significant stabilization, fatigue often manifests in form breakdown before muscle failure. AI coaching analyzes your rep consistency and duration to detect if your non-working arm is drifting, indicating core fatigue. By correlating this performance data with your daily HRV and sleep scores, the app can recommend whether to push for heavy load or focus on controlled volume to correct left-right strength asymmetries without overtaxing your central nervous system.
Form Cues
- Keep the non-working arm fully extended and vertical while the other moves
- Plant your feet firmly on the ground to anchor your hips
- Squeeze your glutes and core to resist torso rotation
- Lower the working dumbbell until it touches the outside of your chest
- Press the weight up in a slight arc toward the center line
- Don't let the stationary arm bend or drift sideways
- Don't lift your head or hips off the bench
- Don't flare your elbows out to 90 degrees
- Don't bounce the dumbbell off your chest at the bottom
Common Mistakes
- Twisting the torso to help press the weight
- Dropping the stabilizing arm slightly with every rep
- Rushing the tempo and losing tension
- Shrugging shoulders up toward the ears
Muscles Worked
This exercise primarily strengthens the pectoralis major (middle chest) and anterior deltoids through a full range of motion. Secondary emphasis is placed on the triceps for lockout and the obliques, which must work isometrically to prevent the body from rotating on the bench while one side is loaded.
Primary
Secondary
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