How many reps of the single-arm machine fly should a beginner do?

Three sets of 10 to 12 on each side at the end of a chest session. Write down the weight and reps for each arm, because the whole reason to work one at a time is to watch a side-to-side difference shrink over a few weeks. Add a pause at the point of peak contraction before you add a plate.

What can I do instead of the single-arm machine fly?

A single cable pulley at chest height does the same thing with a longer arc across your body. At home, anchor a band at shoulder height to one side, stand square to it and sweep one arm across; set your feet firmly, because the band will try to turn you.

What is the single-arm machine fly for, and when is it not worth it?

One pec working at a time is how you find a side-to-side difference and then close it, and the machine steering the path makes that easy for a beginner to learn. The cost is time: every set runs twice, so it does not belong in a short session, and it is not a way to move meaningful weight. Once both sides match, the two-arm version gives you the same volume in half the time.

Beginner

Single-Arm Machine Fly

Training a single pec at a time lets you slow the arc, feel the muscle fully, and even out a stronger side. It also loads the core to resist the machine twisting your torso. Reach for it when you want to fix an imbalance or squeeze out extra quality reps after bilateral work.

Equipment: Machine
Body part: Chest
Type: Strength
Browse by muscle: Pectoralis Major Sternocostal
Browse by movement: Horizontal Adduction

How to do it

1
Set the seat height and sit with your back flat against the pad.
2
Grip a single handle with a slight bend in the elbow and brace the free hand on the frame or your thigh.
3
Sweep the working arm across your body toward the midline, squeezing the pec.
4
Pause at peak contraction near the center of your chest.
5
Return the arm out wide under control, then finish the set before switching sides.

Tips

Resist the pull that wants to rotate your torso toward the working side.
Keep the same fixed elbow angle throughout the arc.
Start with your weaker side and match its reps on the strong side.

Variations

Common mistakes

The seat is set so the handle sits above shoulder height, and the working arm then sweeps down across the body rather than straight in; the handle should start level with your mid chest.
Half of what you used with both arms feels far too light, so people load up and the machine starts dragging them sideways out of the seat between reps.
The second arm gets rushed because you are tired of waiting, and the tempo that made the first side useful disappears.
Resting the free hand on the frame turns into leaning on it, which tips your shoulders out of line with the arc the machine wants to move through.

Frequently asked

How many reps of the single-arm machine fly should a beginner do?: Three sets of 10 to 12 on each side at the end of a chest session. Write down the weight and reps for each arm, because the whole reason to work one at a time is to watch a side-to-side difference shrink over a few weeks. Add a pause at the point of peak contraction before you add a plate.
What can I do instead of the single-arm machine fly?: A single cable pulley at chest height does the same thing with a longer arc across your body. At home, anchor a band at shoulder height to one side, stand square to it and sweep one arm across; set your feet firmly, because the band will try to turn you.
What is the single-arm machine fly for, and when is it not worth it?: One pec working at a time is how you find a side-to-side difference and then close it, and the machine steering the path makes that easy for a beginner to learn. The cost is time: every set runs twice, so it does not belong in a short session, and it is not a way to move meaningful weight. Once both sides match, the two-arm version gives you the same volume in half the time.

Related exercises

Other movements among FitRay's 2,000+ exercises that load the same target muscle — same equipment and level first.

All Chest exercises