Back Exercise · Dumbbell
Biomechanical cues verified by the PlanWorkouts Science Review Board under CSCS editorial oversight; see our editorial standards.
The Dumbbell Side Plank With Rear Fly is a targeted isolation back movement designed to train the Upper Back with direct engagement of the Core.
Single-joint horizontal adduction isolating the sternal and clavicular pectoralis fibers without triceps tricep fatigue limiting set termination. Executing this with strict form maximizes muscle fiber recruitment while protecting joint structures.
Quick Exercise Facts
Target Muscle Activation
Stacking a rear-delt fly on top of a side plank turns a shoulder isolation move into a full anti-rotation core exercise — the obliques and hips have to hold the plank steady while one arm swings a dumbbell out to the side. It's a combination move better suited to conditioning or accessory work than to loading the rear delts heavy on their own.
How to Do the Dumbbell Side Plank With Rear Fly
- Begin lying on your side with your legs straight and stacked one on top of the other.
- Set your forearm on the floor directly beneath your shoulder, elbow bent at roughly 90 degrees.
- Hold a dumbbell in your upper hand with your arm hanging straight down toward the floor.
- Brace your core and raise your hips off the ground so your body forms a straight line from head to heels.
- From this side plank position, lift the dumbbell toward the ceiling, pulling your shoulder blades together.
- Bring the dumbbell back down to the starting position.
- Repeat for the desired number of reps, then switch to the other side.
Recommended Sets & Reps by Training Goal
65–75% 1RM · 60s rest
50–60% 1RM · 30–45s rest
Controlled 3s eccentric · 60s rest
Biomechanical & Joint Load Cues
Single-joint horizontal adduction isolating the sternal and clavicular pectoralis fibers without triceps tricep fatigue limiting set termination.
Common Mechanical Mistakes & Form Errors to Avoid
- Bending Elbows into a Press: Excessively bending elbows into 90 degrees during flyes turns the movement into a press, recruiting triceps instead of isolating pectorals.
- Overstretching the Shoulder Capsule: Dropping arms too far behind the torso plane strains the anterior capsule without adding meaningful pec activation.
- Rushing the Converging Squeeze: Failing to pause briefly at peak contraction in front of the chest misses the maximal short-muscle fiber recruitment.
Proper Breathing Patterns & Core Engagement
Inhale as arms open into full chest stretch; exhale as hands converge in front of the chest.
Add the Dumbbell Side Plank With Rear Fly to Your Custom Workout Routine
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Injury Modification & Joint Safety
Do not overstretch past comfortable range in the bottom position if you have a history of anterior shoulder subluxation or AC joint sprain. If joint irritation persists, immediately stop and substitute this movement with another exercise from the Back exercises category.
Muscles Worked
The Dumbbell Side Plank With Rear Fly primarily targets the Upper Back, with Shoulders as the primary synergist muscle group, along with the Core.
More Back Exercises
Alternate Lateral Pulldown
Archer Pull Up
Assisted Parallel Close Grip Pull-Up
Assisted Pull-Up
Assisted Standing Chin-Up
Assisted Standing Pull-Up
More Upper Back Exercises
Back Lever
Band One Arm Standing Low Row
Band One Arm Twisting Seated Row
Barbell Bent Over Row
Barbell Incline Row
Barbell One Arm Bent Over Row
Equipment Alternatives
Don't have dumbbell? These target the same upper back with different equipment.
FAQ
- What muscles does the Dumbbell Side Plank With Rear Fly work?
- The Dumbbell Side Plank With Rear Fly primarily targets the upper back as the primary agonist. Synergist assistance is provided by the shoulders along with the core. Maintaining strict biomechanical alignment ensures maximal tension remains focused on the intended muscle fibers rather than shifting to surrounding stabilizer joints.
- What equipment do I need for the Dumbbell Side Plank With Rear Fly?
- The Dumbbell Side Plank With Rear Fly is performed using a dumbbell. Ensure all equipment is securely positioned with collars or safety pins locked before loading working sets. If you train in a home gym or minimal setup, explore our equipment-free and resistance band alternatives below.
- What is the most common form mistake on the Dumbbell Side Plank With Rear Fly?
- The most frequent error is bending elbows into a press: Excessively bending elbows into 90 degrees during flyes turns the movement into a press, recruiting triceps instead of isolating pectorals.. Controlling the 2 to 3-second eccentric lowering phase ensures maximal hypertrophic stimulus while shielding connective tissue.
- How many sets and reps should I perform on the Dumbbell Side Plank With Rear Fly?
- For muscle growth and density, execute 3 to 4 working sets of 10 to 15 controlled repetitions with 60 seconds rest, emphasizing a deep stretch and deliberate peak contraction on every rep.
- What's a good alternative to the Dumbbell Side Plank With Rear Fly?
- If you don't have access to a dumbbell, the Back Lever targets the same upper back using body weight instead. This alternative replicates the same joint angle and movement plane while allowing you to train effectively with different available gear. You can also substitute it seamlessly in our free Workout Plan Builder.