If you have yet to hear someone argue why dumbells are better than barbells for one or more exercises…you haven’t been in the gym enough. For some it may seem obvious how dumbells and barbells are different, but what is not always obvious is why one may be better than the other for different exercises.

The Basic Difference

Barbells are just oversized dumbells. They’re longer in the middle so you can fit two hands around the grip, the grip width is much more versatile, and the amount of resistance is virtually limitless. By superficial design, there’s not much difference. By application, however, these David and Goliath kin are quite different.

If you read our previous post, you should know why free weights are inherently more beneficial than resistance equipment that reduces the stabilization required to execute the movement under load. Both barbells and dumbells qualify as free weights, so each are superior choices for most training movements compared to fixed equipment. Depending on the desired affect of training though, that does not make them equally beneficial choices.

Barbells are designed to be used with two hands, allowing both sides of the body to work together to stabilize and move the resistance. By using both sides of the body, we are not only able to balance better and recruit our muscles more efficiently, but we are able to train the entire human movement system to work together, resulting in a more uniform, all-encompassing neuromuscular adaptation that produces higher levels of strength and size.

Dumbells break this connection between the two sides of the body resulting in less uniformity during movements and more stabilization work required to control the resistance. With over 600 muscles in our body, most of which are intended to stabilize, challenging our stabilization can be more benefiial than gaining maximal strength or size. The more stable our joints are, the less energy we will lose at points of instability during our movements and therefore the stronger we will be. This is not dissimilar to a sturdy bridge that doesn’t move at all compared to one that shakes under load; my guess is you not only believe the more stable bridge to be able to handle more load, you would probably avoid the shaky bridge at all costs.

But sometimes we need to find points of shakiness so we can improve the stability in the joints associated with this lack of security. Substituting a pair of dumbells in place of the bar on basic movements like the overhead press, bent over row, bench press and event squats and deadlifts can help us identify weaknesses we did not know we had.  Training these instabilities directly though unilateral or isolated exercises using dumbells can produce significant strength improvements once said instabilities have been eliminated. Isolating specific muscle groups in this fashion is extremely difficult if not impossible with a barbell compared to a dumbell.

In fact, sometimes dumbells can be superior to barbells for muscle development in compound lifts. The bench press is a good example of this. The pectoralis major (the primary muscle targeted in the bench press) is responsible for bringing the humerus (upper arm bone) across the front of the rib cage (horizontal adduction for those of you who speak the language).  This movement requires the humerus to start beside the torso and be pulled across the front of the body. While most grip widths on a barbell will produce a significant amount of horizontal adduction, since we can’t shift our grip mid-movement on the bar (safely anyway), we’re actually restricted in our range of motion when it comes to this exercise. Executing this movement with a pair of dumbells, however, allows us to completely adduct the humurus across the chest to produce greater muscular contraction. Albeit, the lack of assistance from the opposing side of the body will make the movement harder to control, especially as the weight gets heavier, but in theory you can produce a more maximal pectoral contraction using dumbells in certain exercises than if you were using a barbell. This also applies to cables, resistance bands, kettlebells and other forms of resistance that allow more free range of motion during particular exercises. That freedom comes at the cost of extra effort stabilizing the resistance, but depending on the intention of the training that may be preferential.

Conclusion

While barbells may be superior for lifting more weight utilizing the entire body to move a single resistance, strength requires stabilization. All free weights require stabilization, but dividing the load of a barbell into two dumbells virtually doubles the amount of work necessary to control the load. So barbells may be better for strength, but dumbells will plant the seed necessary for strength to accrue.