An elbow flexion is a movement that occurs when the arm is bent at the elbow and the forearm and the upper arm come together. This is the opposite of an elbow extension, during which the arm is straightened and the forearm and upper arm move away from one another. An alternate definition that is sometimes used clarifies that a flexion occurs when the angle of the joint decreases, so an elbow flexion occurs when the angle of the arm, with the elbow as a vertex, decreases.
Most people use elbow flexion many times every day, whether through deliberate exercise or simply completing daily activities. A few examples of the many activities that typically require elbow flexion are raising silverware to the mouth while eating, picking up and carrying an object close to the chest, or putting on a pair of glasses. Since activities that require elbow flexion are such a large part of most people's daily lives, many people strive to exercise and strengthen the elbow flexors. Many fitness enthusiasts try to increase the size of the bicep muscles as a demonstration of overall strength and fitness.
Several weightlifting exercises focus on building and strengthening the muscles of the upper arm, some of which are integral to elbow flexion. Weight lifters commonly use bicep curls to exercise these muscles. Curls and other exercises can be modified using various positions, angles, and movements to exercise different upper arm muscles or even different areas of the same muscles, leading to improved strength and toned appearance throughout the length of the muscles. For example, many weight lifters rotate the wrist while performing curls, or do the exercise on an incline or lying down on a bench. Doing chin ups can also strengthen the elbow flexor muscles.
The elbow can be flexed while the arm and hand are in various positions, for example with the palm facing up or down, or with the arm hanging down or held straight out to the side at the shoulder. This is why varying the positioning of exercises works different muscles and areas of the muscles, which in turn can affect how much force each movement can generate. Depending on the position, a stronger or weaker muscle may be activated to complete the elbow flexion movement, resulting in a difference in the difficulty of the movement when the same amount of resistance is used.