Dumbbells require more balance than training with barbells or machines . and balance is crucial for optimal performance. Dumbbells also require more muscular control than barbells . thus enhancing kinesthetic awareness. The best part of training with dumbbells is it allows the athlete to train through a greater range of motion than barbells on some exercises. Understand that it is sometimes more valuable to trade heavy weights (Barbells) for more sport-specific movements. Kettlebell exercises demand the use of multiple joints . which engage all the larger muscles of the body. Compound kettlebell moves burn calories faster than isolation moves . which only work one muscle.