Standing

Any standing exercise will help you develop the balance and stability necessary for advanced training with free weights. Although it will depend on the exercise, performing reps while standing straight with your back flat and your chest out will develop the small stabilizer muscles near the targeted muscle group, as well as the stabilizers in your legs and back. For dumbbell exercises, the standing position provides a better overall workout, but the drawback is that the standing position distributes the stress of the lift across a broad network of muscles, which diminishes the impact on the target muscle. For example, standing dumbbell curls improve overall strength and fitness, but if you want to push your biceps for mass or performance gains, it’s going to take a lot longer.

Seated

Dumbbell exercises performed from the seated position provide the opposite benefit to standing exercises. Performing your reps while seated in a rigid workout chair or flat bench helps you isolate your target muscle for more intensive gains. The seated position provides a solid platform for performing your reps, concentrating the stress of the lift squarely on the target muscle. Performing your reps while seated is also well-suited for beginners who still need to master the form of an exercise, because the seated position doesn’t allow you to “cheat out” your reps by using other muscle groups.

Combinations

The truth is, neither position is “better” than the other. A solid, well-rounded routine will feature dumbbell exercises performed while seated and while standing. Since you can perform most dumbbell exercises from either position, alternate between them every few workouts. It’s a simple switch that will make it harder for your body to grow accustomed to your workout, while maintaining the basic muscle memory for completing your reps. For example, for two weeks of a training session, perform your dumbbell raises while seated, then for two weeks, do them while standing. Variability will minimize plateaus and give you more consistent gains.

Considerations

For standing exercises, minimize the amount of “sway” you use to complete certain exercises, especially when using dumbbells. For example, it’s natural for your body to swing your back into the upward motion of curls, but this ultimately diminishes your performance, and it can cause injury. When doing any exercise, seated or standing, follow the correct form through all phases of the motion. This will direct the stress of the lift where it’s supposed to go, and it will reduce the risk of injury significantly.