Dumbbells in general are sports equipment that consists of a bar and two weights. The weights in spherical or disc shape are attached to both ends of the barbell. Lock washers, screw locks or adjusting rings are used as locks to fix the weights on the dumbbell bars. If spring washers are used as a lock, the weights can be changed very quickly. The disadvantage of spring washers is that they can slip and thus represent a safety risk. Adjusting rings are short pieces of pipe that are pushed over the barbell and tightened using Allen screws or adjusting toggle screws. Adjusting rings offer the highest level of security, as they securely fix the weights on the barbell. If the weights are fixed with screw caps, there must be a thread on both ends of the barbell in order to be able to accommodate the screw caps. The screw caps are also a secure variant of attachment. Training with these sports equipment is consequently called “dumbbell training”. While lighter dumbbells are mainly used for fitness training, heavier dumbbells are used in bodybuilding or weight training. Dumbbells are mainly used for muscle training. However, certain sports clubs have now found out that targeted dumbbell training can also improve jumping, throwing and pushing strength. Dumbbells are versatile and allow a lot of freedom of movement. As a result, they are used specifically in bodybuilding to train hidden muscles, which is often not possible with modern strength machines. For example, weaker muscle groups are subjected to targeted training. At the same time, this ensures even muscle growth. Since training with the dumbbell places increased demands on coordination, the muscle regions that are important for posture, the cardiovascular system and mobility are particularly addressed. Exercises such as fly (reverse), shrugs, lateral raises or curl are typical exercises with the dumbbell and are high on the popularity scale.