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January 21, 2022
Dumbbells and barbells, otherwise known as free weights, get the most love from gym rats, and rightfully so, but you can't overlook weight machines. You likely know someone who frowns upon machines, but if you ask a season lifter, they know machines have their place in the regimen of body sculpting. One machine being the pec deck (and on the flip side, the reverse pec deck).
The major advantage of weight machines like the pec deck is that increased stability provides more focus and juice to the targeted muscles because stabilizing muscles are not used. Why? Because your path of motion is fixed. Essentially, you can really hone in on the muscle for added volume and activation, which is great for hypertrophy.
In this post, we are looking at the reverse pec deck machine, which isolates the rear delts and upper back. We will go into what a pec deck/reverse pec deck is, how the muscles are trained, how to do a reverse pec deck fly properly, common mistakes people make, and alternatives to a reverse pec deck if you don't have access to the machine or you simply want exercise variety.
The pec deck is a machine based on a chest fly. As such, it is a machine fly or seated lever fly. You sit down in the seat with your back against the pad and your elbows are kept at the same angle as your arms move through an arc that targets the pecs and delts. This machine is designed to isolate the chest muscles to increase size and strength. As you perform the fly, the back rest stabilizes your shoulder blades, and as you move your arms back the lever system allows you to maintain/control a safe range of motion.
All that said, a pec deck is also a reverse fly machine! It can be used for chest flys as well as reverse flys by simply sitting the opposite way and adjusting the handles back toward the weight stack.
The reverse pec dec does the complete opposite of the pec deck. You sit down facing the weight stack and you pull your scapula together (adduction) instead of spreading them apart. As such, it is a machine rear delt fly, which is why the machine is also known as a reverse fly machine. This is exercise targets an area of your shoulders that is difficult to train – the rear delts - as well as your upper back.
What the reverse pec dec does is isolate the rear delts and muscles of the upper back (rhomboids major and minor) because it trains pure scapular adduction (aka retraction) without using stabilizing muscles of the lower body because you are sitting down. You also use the pad to rest your chest against for leverage, which allows you to reverse fly with a greater load.
All in all, it is a fixed machine movement with no deviation so you can hit the targeted muscle group for better hypertrophy benefits.
The main muscles trained with the reverse pec deck are the rear delts, rhomboids major and minor, teres major, infraspinatus, and to a lesser extent the middle traps. This machine is designed to target these muscles of the upper back through scapular adduction as all these muscles work together to pull the arms back and the scapular together.
Although they’re only a smaller muscle groups compared to the lats and the chest, training the rear delts and upper back has important benefits in the performance of the big 3 and also health benefits.
When performing the squat and deadlift the upper back plays a vital role in keeping a neutral spine and good posture.
By keeping the upper back tight with your shoulder blades pulled together while deadlifting or squatting, you can keep your body upright against heavy loads, which is essential for good technique and lower back health.
A strong and engaged upper back provides a solid foundation to bench press from too because it supports and controls the bar path. This is essential for good technique, keeping your shoulders healthy, and hopefully pressing more weight.
On top of all that, a nice set of rear delts and defined upper back looks very impressive. It is a sign of a seasoned lifter. The rear delts are particularly hard to develop well.
If you’re a collision athlete like for example football player or boxer and have a risk for concussion having a strong muscular neck and upper back will protect the athlete from the severity of concussions (study).
Plus, today where we find ourselves sitting down and looking down at the screens in our hands has the potential to damage your posture (rounded shoulders and forward head) and upper back strength.
This is due to the fact that for every inch your ears are forward from the shoulders, you increase the weight of the head on the spine by an additional 10 pounds. And if left unchecked the upper back muscles get stretched and weak which may lead to injury or chronic pain (study).
Note: If you the seat adjustment doesn't allow you to sit high enough up so your shoulders are aligned with the handles and your hands, then you can stand and lean forward to support your chest on the back rest rather than sit.
A slight variation to the above is to use a neutral grip by holding onto the vertical part of the handles as seen below. The same form applies, but you may need to lower the seat a bit to keep your shoulders aligned with the handle. By doing it this way, you can slightly alter how the muscles are hit. It's good to switch it up here and there.
This study shows that activation of the posterior delt and infraspinatus are significantly greater with a neutral grip when using the reverse fly machine. However, it's good to try both to see what you feel is working best for you. Plus, changing variables like grip positioning is generally a smart tactic over time.
Another variation is to do one arm at a time. Working unilaterally can allow you to focus on one side, which can help iron out muscle imbalances. It can also work to increase you range of motion a bit on the concentric phase.
The rear delts and upper back are not big and strong like the chest and lats and therefore concentrating on hypertrophy and endurance rather than strength is your best bet. This is not a maximum strength exercise so keep the weight submaximal and really focus on good form. Plus, this is best programmed at the end of your training after your heavy strength work for extra volume and maximum muscle pump.
It's advisable to choose a weight you can do 15-20 reps with good form, yet is still challenging. Reverse pec deck is great for a straight-set burnout at the end of your training.
Here is an example:
Although this is a simple exercise to perform make sure to avoid these three mistakes so you can get the best out of this exercise:
When you don’t have access to a reverse pec deck machine there are four alternatives that do a fantastic job of isolating the rear delts and upper back. Here they are...
1. STABILITY BENT OVER DUMBBELL REAR DELT RAISE
This exercises is typically used to increase volume to the rear deltoid, so it is done towards the end of a shoulder, push or pull workout (or whatever training split you are running). While it’s considered an isolation exercise for the rear delts, it also works the rhomboids and traps. The reason why we like this exercise so much is because it allows you to strengthen imbalances between sides and by holding onto a bench or squat rack your stability is better which means you can handle more weight. That’s a win-win for your delts and upper back.
Here’s how to perform the Stability Bent Over Dumbbell Rear Delt Raise:
Best Rep Range: 12-20
2. FACE PULLS
Face pulls train the same muscles as the reverse pec dec and will help add size, strength, and endurance to rear deltoids and upper back. This exercise can be trained with either a band or cable machine and both do a great job of targeting the rear delts and upper back muscles. The bonus of this movement is the external rotation at the end will help pull the shoulders back into a better position for improved posture and decreased injury risk.
Here’s how to perform the Face Pulls:
Best rep range: 12-15
3. BAND PULL APARTS
The band pull-apart is a simple isolation exercise that targets the same muscles as the reverse pec deck the upper back muscles and is a great way to add more pulling volume to your training. Because the resistance band gets harder the more it is stretched, this makes the lockout more difficult and gives you a nice change of pace from dumbbells or the cable machine.
Here’s how to perform Band Pull Aparts:
Best rep range: 15-25
4. REAR DELT ROW
By positioning yourself on an incline bench (or a bent over hinge position or even seal row position) and rowing the dumbbells with the elbows wide, you target the rear delts and upper back. It's a great alternative that allows for heavier loads than dumbbell reverse flys. Although, it does bring a little more focus on the back than the rear delts when comparing to a rear delt fly movement. That said, the ability to use more weight than reverse fly variations due to the assistance of the biceps and lats makes up for the less targeted aspect in terms of the rear delts. Basically, you sacrifice isolation for greater load, making it a good addition to your work even if you are doing pec deck machine reverse flys.
Here’s how to perform The Rear Delt Row:
Note: This exercise can be done on a cable machine too, from a seated position, or a t-bar, basically any row with your arms held out wide works the same.
Best rep range: 8-15
The reverse pec dec is a great exercise to isolate and strengthen the rear deltoids and upper back. Adding size and strength to this area will improve your other lifts and will improve your posture and shoulder stability.
More Rear Delt Exercise Guides:
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