The question of whether dumbbells vs. barbells are better for building muscles has been debated for ages. And let's not start on the whole free weights vs. machines debate,” we'll save that for another day. When it comes to which is best in the battle of the 'bells, the answer isn't always so cut and dry...
As an example, on certain exercises, like any type of bench press movement, dumbbells allow a fuller range of motion, less stress on your shoulders, and a more natural overall movement. On the other hand, a barbell allows you to drive inward statically with your hands on the bar, and that creates a unique chest contraction throughout the movement. Plus, balance doesn't play as much of a role as it does with dumbbells.
So, for something like bench presses, which type of weight is best for building muscle? The answer isn't tough at all. The best option is
The same is true for most exercises where that question comes up. As long as you don't experience joint pain, the best option will almost always be the one that you feel best in the target muscle. This is true for bench presses, curls, rows, or any other exercise you can think of.
Back exercises are another place where people get into a big debate. Some people prefer chest-supported dumbbell rows because the 'bells come together at the bottom for more of a stretch in the mid-back. Others prefer to have their hands locked in one position on a barbell so they can squeeze the mid-back harder for a better contraction.
What if you genuinely don't have a preference and can't decide which exercise feels best for you? Simply alternate between exercises, using dumbbells at one workout and a barbell at the next.
Most people will experience a considerably different feel between dumbbells and barbells on any given exercise, but if you struggle to truly feel a difference, try some adding in some training variation. Consider pre-exhausting the muscle first...
Pre-exhaustion is when you target a muscle directly, usually with a contracted movement, before using a compound exercise. As an example, do cable crossovers before bench presses, concentration curls before barbell curls, etc. You can either do a couple or a few sets first, or you can superset the two exercises. That would also give you the benefit of more work in less time, but that might be tough in a crowded gym.
So, the general rule of thumb in the battle of dumbbells vs. barbells is that the better choice is whichever you feel the most.