Dumbbell flyes have always been a mainstay of my chest program. Since the function of the pecs is to pull the upper arms forward and toward the center of the body, flyes are designed as an isolation exercise that hits the chest without involving the triceps and other muscles. As such, it is a great movement with which to hit the pecs with maximum intensity for maximum growth.
To do dumbbell flyes correctly, lie faceup on a flat, incline or decline bench while holding the weights above you and over your face. Turn your palms in so they face each other and bend your elbows slightly, keeping them at that angle throughout the movement. Next, lower the dumbbells out to your sides in a wide arc until your pecs are fully stretched or your hands are about even with your shoulders. Pause at the bottom, then bring the weights back up, following the same arc you took on the way down.
When I was competing, a common mistake that trainees often made was keeping their arms perfectly straight during the movement, which can put undue stress on the elbow joints. This seems to have been corrected since, with most people employing the slight elbow bend I just mentioned. Two other examples of incorrect technique are using too much weight and lowering the dumbbells too far to the sides.
The idea of using too much weight doesn’t need much explanation. Flyes aren’t a power exercise, and if you can’t perform reps without excessively bending your elbows, you’re working too heavy. In this case, decrease the weight. If you’re struggling with 40-pound dumbbells, try 25s or 30s.
Using too great a range of motion is also a recipe for disaster. Once you’ve lowered the weights to the point at which your hands are even with your shoulders or you can feel a moderate, not painful, stretch in the pecs, that’s far enough. Lowering too far puts way too much stress on the pectoral muscles, shoulders and biceps, not to mention the vulnerable shoulder joint itself. To avoid this, always lower the dumbbells slowly so that momentum doesn’t carry you past the desired range of motion. Again, as soon as you feel the onset of a stretch in your pecs, switch directions smoothly.
Remember, nothing sets your development back further and faster than serious injury. You need to stay within your limits, train with the appropriate weight and use safe, strict technique to keep your development on schedule. - FLEX