For toned arms do you go with the tried-and-true dumbbells or the new kid on the block – kettlebells? Actually, each have their own specific uses and each excel at their specific use. But for toned arms, dumbbells are better and here is why.
Because of the shape of the dumbbell, it is easier to perform isolation exercises that focus the effort on just one group of muscles. In the case of arms, dumbbells are easier to grasp and control through various movements aimed at toning and defining the two major muscles of the arms: triceps and biceps. Take the simple bicep curl for example.
With a dumbbell, it is easy to grab it in its middle part and run through the exercise bringing your forearm up to the vertical position. However due to the shape of the kettlebell with the handle directly over the ball of the weight instead of between the two weights, coming to full vertical position is not possible without bending your wrist to an unnatural position. It also increases the risk of a wrist injury.
Also with a dumbbell, you can twist your wrist so the dumbbell comes up in a vertical position instead of horizontal, something you can’t do with a kettlebell. Doing it this way works the bicep differently.
Performing this exercise would be much more difficult (alright impossible) using a kettlebell than a dumbbell. The dumbbell is more balanced with the weight at each end of the bar, rather than the all of the weight centered directly under the handle.
Kettlebells excel when the desired movement involves swinging the weight as with kettlebell swings, which combines cardio and strength training. And they are also the better choice if developing more grip strength is your goal.
However, kettlebells excel at developing muscles in the shoulders. Most the kettlebell exercises are compound moves that employ multiple muscles, not isolation moves targeting just one muscle as do dumbbells. For example, shoulder presses with lateral flexion not only targets the shoulders, but also helps develop the core, hips, with its rotation of the torso to the right and left while holding the kettlebell at shoulder height.
So kettlebells do have their place in a workout routine aimed at developing toned arms, but their place is to develop toned and defined shoulder muscles that support and complement toned arms.
And they help develop the lower body muscle groups in the process.