I did 100 reverse flyes every day for a week – here’s how my posture changed

Hands up if you spend most of the day sitting – I’ll raise both! Modern life is relentlessly (and often unconsciously) front-loaded: laptops, steering wheels, and phones all seem to pull our shoulders forward until our posture starts to resemble Quasimodo.

One simple fix? The humble reverse fly. This light dumbbell move targets the muscles in your upper back and shoulders – a small daily effort that can make a noticeable difference in how you sit straighter, stand taller, and move freely.

Why your desk-bound body needs the reverse fly

“Reverse flyes target the rear deltoids, plus the rhomboids and traps, the same muscles that pin your shoulders back and help you stand tall,” says Jack Claxton, Level 3 Personal Trainer and Personal Training Ambassador at David Lloyd. “Strengthen them and you’ll not only look more athletic but also reduce your risk of neck and shoulder pain.”

This is exactly why, armed with a pair of 2kg dumbbells, I set myself a simple challenge: 10 sets of 10 reverse flyes, scattered throughout the day. A set while the kettle boiled, one between emails, a couple to bookend my gym session – and a few more while waiting for dinner. Snackable strength training at it’s finest.

How to do a reverse fly

• Stand with your feet hip-width apart, knees slightly bent and core engaged. Hinge at the hips so your torso is almost parallel to the ground, letting the dumbbells hang below your shoulders with palms facing each other.
• Pull your shoulders back and down, then raise the dumbbells out to the sides in a wide arc. Keep a slight bend in your elbows and avoid shrugging. Lift until your arms are in line with your shoulders, squeezing your shoulder blades together at the top.
• Pause, then lower the weights with control — no swinging or momentum. Keep the movement smooth and deliberate to get the most from your upper back and rear delts.

I did 100 reverse flyes a day for a week – here’s what happened

If you're anything like me, back day isn’t always top of the list. The rear delts, rhomboids, traps, and lats are often an afterthought, as the chest, abs, arms, the mirror muscles get all the attention. So I set myself a challenge: one week focused purely on the back of my body. No heavy weights allowed — just 2kg dumbbells and 100 reverse flyes a day.

On Day 1, I went all in – 100 reps in one go. Big mistake. My shoulders were on fire, but not in a good way. I was powering through with momentum and totally missing the point — that all-important squeeze between the shoulder blades - your Rhomboids. On day 2, I stuck to the plan: 10 sets of 10 scattered throughout the day. Way better. I could focus on form and feel every rep where it counted.

By Day 3, my rear delts, the muscles located at the back of your shoulders, felt more ‘awake’. I was already standing taller, and that gentle shoulder burn became a constant reminder not to slump. As natural bodybuilder Bryan Tan puts it, “Rear delts are one of the hardest muscle groups to engage. An underdeveloped rear delt can increase your risk of rotator cuff injuries – so train them as hard as you do your front and side delts.”

The rest of the week followed the same formula: short sets, strict form, no ego. Reverse flyes target underused muscles, and if you start swinging or rushing the movement, you’ll miss them entirely, and likely strain something in the process.

By day 7, reverse flyes had earned their place in my regular routine. The posture perks alone were worth it. Plus, the added shoulder definition was a bonus. But here’s the deal: don’t go heavy. This move rewards control and consistency, not brute strength. To get the most out of them, you need to park your ego, focus on the squeeze, and make every rep count.

Another tip: pair reverse flyes with a pec stretch. Tight chest muscles pull your shoulders forward, which can undo all your hard work. A balanced physique isn’t just about aesthetics, it’s about posture, symmetry, and long-term resilience. And this little move, paired with a chest stretch ticks all three boxes.