The same demo you get in the GymAdapt app for this exercise.
How to do it
What it should feel like
A strong stretch across the chest at the bottom and the inside of the chest squeezing at the top. No pain at the front of the shoulder.
Common mistakes
- Turning it into a press. If the elbows bend and straighten, it becomes a sloppy press. Keep the elbow angle fixed.
- Going too heavy. Heavy flies pull on the shoulder at the bottom. Choose a weight you can control for 10 or more reps.
- Dropping too low. Stop when the upper arms reach the bench line.
- Straight, locked arms. A small bend protects the elbows.
Variations
Constant tension through the whole range.
The machine version: easy to set up and safe to push hard.
The pressing movement for heavier loading.
Sets, reps and programming
| Goal | Sets × reps | Effort | Rest |
|---|---|---|---|
| Muscle | 3 × 8–15 | 0–2 reps in reserve | 60–90 s |
| Small muscles (delts, calves) | 3–4 × 12–20 | 0–2 reps in reserve | 45–75 s |
| Learning it | 2 × 12–15, light | Slow, 1 s squeeze | 60 s |
Do it after your main press. Progress by adding reps before adding weight. The simplest rule that works: add reps inside the range first, and once every set hits the top of the range, add weight next session. GymAdapt does this for you from the sets you log, and tells you why the target changed.
Questions people ask
Are dumbbell flies good for the chest?
Yes, as an accessory. They stretch and isolate the chest well, but pressing should still be your main chest work.
How heavy should dumbbell flies be?
Light enough to keep the elbow angle fixed for 10 to 15 reps. Much lighter than your press.
Flies or pec deck?
Both work. The pec deck is easier to set up and keeps tension at the top; dumbbells give a bigger stretch at the bottom.
How many sets and reps for dumbbell flies?
2 to 3 sets of 10 to 15 reps, close to failure.
GymAdapt is free to start. Want Pro free for a month?
The free version gives you an AI-built plan and unlimited workouts. Code TRYFREE01 adds a full month of Pro on top: weights that adjust from what you log and unlimited coach chats.
Redeem the free month → Opens the App Store with the code filled in. iPhone only. After the month it's $4.99/mo unless you cancel in Settings, and the free version stays yours either way.Every exercise in GymAdapt comes with a demo like this, plus a target that moves.
An AI plan for your goal and equipment, a video for every lift, and next session's weight set from what you logged.
Get GymAdapt on the App Store → Free to start. Pro is $4.99 a month or $24.99 a year (7-day free trial), or $79.99 once for lifetime. iPhone only.