Dumbbell Alternate Bench Press (high start)
- Synergist muscles
- Deltoid Posterior, Triceps Brachii
- Equipment
- Dumbbell
- Body part
- Chest
- Type
- Strength
The dumbbell alternate bench press (high start) is a unilateral chest-building exercise that targets both heads of the pectoralis major — the upper (clavicular) and lower (sternal) fibers — with the triceps and rear deltoids assisting. You begin with both dumbbells pressed up and lock-out, then lower and press one arm at a time while the other stays extended, which keeps constant tension on the chest and challenges core stability.
How to do the Dumbbell Alternate Bench Press (high start)
- 1Sit on the end of a flat bench with a dumbbell standing on each thigh, then kick the weights back as you lie down so they end up at shoulder height.
- 2Plant your feet on the floor, pull your shoulder blades down and together against the bench, and press both dumbbells straight up until your arms are fully extended over your chest — this is the high start position.
- 3Keeping one arm locked out at the top, lower the opposite dumbbell under control until it is level with your chest, with your elbow at roughly a 45–75° angle to your torso.
- 4Press that dumbbell back up to lock-out, squeezing your chest at the top until both arms are extended again.
- 5Repeat with the other arm, lowering it while the first stays pressed up at the top.
- 6Continue alternating arms for the prescribed reps, keeping your wrists stacked over your elbows throughout.
- 7When finished, lower both dumbbells under control to your chest, then set them down on your thighs or the floor — do not drop them out to the sides.
Form tips
- Keep the resting arm fully locked out and stable at the top so the working side has a fixed base to press against and your shoulders stay protected.
- Move at a controlled tempo — lower for about two to three seconds and press up under control, since alternating presses are about chest tension, not speed.
- Keep your shoulder blades retracted and your upper back tight against the bench to create a stable, safe pressing platform.
- Train with weights you can fully control and always have a way to bail — set the safety arms or use a spotter when going heavy, since dropping a dumbbell on yourself is a real risk with free weights.
Common mistakes
- Letting the resting dumbbell drift or sag instead of holding it locked out, which removes the stable base and strains the shoulder of the supporting arm.
- Lowering the working dumbbell too far below chest level, which over-stretches the shoulder joint and risks injury.
- Flaring the elbow straight out to 90°, which shifts stress off the chest and onto the shoulder.
- Rushing the alternation and using momentum to swing the weights up, which cuts the tension on the pecs and turns it into a sloppy rep.
- Letting the wrists bend backward under the load instead of keeping them stacked over the forearms, which strains the wrist joint.
Frequently asked questions
What muscles does the dumbbell alternate bench press work?
It works the full chest — both the upper (clavicular head) and lower (sternal head) of the pectoralis major — with the triceps and rear deltoids assisting as you press and stabilize each dumbbell.
What does the 'high start' mean in this exercise?
High start means you begin with both dumbbells already pressed up and locked out over your chest. You then lower and press one arm at a time while the other stays extended at the top, rather than starting from the bottom with both at chest level.
Is the dumbbell alternate bench press good for beginners?
It can be, but it demands more stability than a standard two-arm press because one side holds at the top while the other works. Beginners should start light, master the two-arm dumbbell press first, and keep the resting arm firmly locked out.
How many sets and reps should I do?
For most lifters, 3 to 4 sets of 8 to 12 reps per arm is a solid range for chest size and strength. Pick a weight you can control through the full set on both arms.
How is this different from a regular dumbbell bench press?
In a regular dumbbell bench press both arms move together. Here you alternate — one dumbbell stays locked out at the top while the other lowers and presses — which keeps constant tension on the chest and forces your core to resist twisting.
