WildnSwole is reader-supported. When you buy through links on my site, I may earn an affiliate commission at no extra cost to you.
Lateral raises and rear delts flys are often confused as being the same exercise. This is because rear delt flys are sometimes referred to as bent-over lateral raises. However, the movement of the arms and heads of the deltoids being targeted do differ between the two.
Lateral raises target the side delts as the arms are lifted out to the sides via vertical shoulder abduction. Conversely, rear delt flys primarily work the rear delts since the arms are raised behind the body through horizontal shoulder extension.
Those are not the sole distinctions of these two exercises, but they are the main ones. Below I’ll cover additional differences, including the secondary muscles they each work.
Table of Contents
1. Lateral Raises Target the Side Deltoids
Confusion occurs when rear delt flys are called bent-over lateral raises. If you’re trying to target the side delts over the rears, recognize that regular lateral raises are performed from an upright position.
Upright lateral raises are not for the rear delts because the arms move away from the sides of the waist to shoulder height. This is called vertical abduction, which is a function of the shoulder joint mainly performed by the side delts.
In research, side and rear delt activation were analyzed across 8 exercises using EMG. Activation of the side delts was greatest during upright lateral raises, but there was no resounding recruitment of the rear delts.
If you’re still skeptical, you should read my article explaining why lateral raises aren’t enough for the rear delts.
2. Rear Delt Flys Target the Rear Deltoids
Rear delt flys involve moving the arms behind the body while they’re being held out to the sides at roughly a 45-degree angle. This targets the rear delts through a combination of shoulder extension and abduction.
The backward movement of the arm is known as extension while the holding of the arms away from the torso is called horizontal abduction. Don’t confuse this with the vertical abduction that occurs during upright lateral raises.
Interestingly, reverse pec deck flys (a variation of the rear delt fly) did recruit the side deltoids fairly well in the EMG study I mentioned above.
3. Lateral Raises Hit Front Delts, Rear Flys Don’t
Lateral raises hit the front delts as the arms lift toward the ceiling via shoulder flexion. This is because when done properly, the arms should raise out to the sides while slightly angled in front of the body.
Looking back once more at the EMG data I mentioned earlier, front delt activation during lateral raises was not notable. However, they are still more activated here compared to rear delt flys as the arms won’t be traveling toward the head during the flys.
4. Lateral Raises Work the Supraspinatus More
Because lateral raises involve abduction they work the supraspinatus to some extent. It is mostly active during the initial pulling phase of each rep for the first 20 degrees or so while the arms are moving away from the body.
Recruitment of this rotator cuff muscle is more prevalent in lateral raises than in rear delt flys.
5. Rear Delt Flys Work the Infraspinatus More
Rear delt flys do provide their fair share of rotator cuff strengthening as well, but to the infraspinatus. This muscle assists the rear delts in performing horizontal shoulder extension.
Also, if your palms are facing each other during the movement the teres minor, another rotator cuff muscle, will activate more too. This is due to the external rotation created from the neutral hand position.
With upright lateral raises, the infraspinatus isn’t as active since the shoulders don’t move horizontally. Most lateral raises are also performed with an overhand grip using slight internal rotation. This activates the subscapularis over the teres minor.
6. Lateral Raises Hit the Upper Trapezius
If you lift your hands higher than your shoulder blades during lateral raises, odds are your upper traps are getting involved. At this point, the scapula rotates upward, causing them to take over.
To isolate the side delts, your hands should only raise to shoulder height when performing lateral raises. Unfortunately, trainees are often unaware of this.
7. Rear Delt Flys Hit The Middle Trapezius
Just like the lateral raise, trainees often get the traps involved when doing rear delt flys. However, the middle traps are hit instead of the uppers.
This occurs if you squeeze your shoulder blades while moving the arms behind your body. Scapular retraction is the anatomical term, which engages the rhomboids too.
8. Lateral Raises Are Performed Standing Upright
As I mentioned, regular lateral raises are almost always performed while standing upright with the torso vertical to the floor. This is especially true when performing them with cables or dumbbells for keeping tension on the side delts.
9. Rear Delt Flys Can Be Performed While Bent-Over
Remember I said rear delt flys are sometimes referred to as bent-over lateral raises? This is mainly true when they’re performed with dumbbells. And it’s because the torso will be angled parallel to the floor with the arms moving out and up laterally.
Conversely, when they’re performed on a machine the torso tends to be vertical, so the arms move out and back instead.
10. Lateral Raises Have a Distinct Name
Whether you do them with dumbbells, cables, bands, or a machine, lateral raises are always referred to as lateral raises.
Less commonly, they are also called side lateral raises, but this is repetitive as “lateral” is defined as “movement in a sideways direction”.
The main distinction is the name of the equipment used being placed in front of the name. If you perform them with dumbbells, they are called dumbbell lateral raises, while on a machine, they’re called machine lateral raises, etc.
11. Rear Delt Flys Have 4 Name Variations
On the other hand, rear delt flys have four other name variations. The one they’re referred to as is usually dependent on the equipment they’re being executed on.
Regardless of the slang term being used the motion of the arms and shoulders always remains the same.
These are the names:
- Reverse flys: When doing them on a high cable machine or a pec deck. The dumbbell version is sometimes referred to as this too.
- Reverse pec deck: When performed on a pec deck machine.
- Rear delt raises: When doing them with dumbbells.
- Bent-over lateral raises: Any time you do them with your upper body bent-over such as on low cable pulleys or with dumbbells.
I made this list to reduce the confusion you might have had in regards to these two similar, but different deltoid exercises. Hopefully, now you can effectively incorporate them both into your workouts to build fully developed shoulders!