Isokinetic contractions are similar to isotonic contractions in that the muscle changes length during contraction, differing in that isokinetic contractions produce movements at a constant rate. To measure this, a special device known as an isokinetic dynamometer is required. Examples of the use of isokinetic contractions in everyday life and during sports activities are rare. Breaststroke is best when swimming, where water provides constant and uniform resistance to the movement of the supply. This method involves an isotonic or isometric contraction of a muscle, immediately followed by a contraction of its antagonist. Sherrington believed that this would increase flexibility, i.e. bending would improve extensibility, etc. (McAtee, 1993). Eccentric contractions are the opposite of concentric and occur when the muscle lengthens as it contracts. This happens when lowering the dumbbell in a biceps loop exercise. The muscle still contracts to maintain the weight at the bottom, but the biceps muscle lengthens.
To strengthen weakened muscles such as arthritis or after local or generalized immobilization. If passive movements are limited, for example, by arthritis, isotonic exercises should be performed in the painless area to avoid an increase in synovial inflammation. Isometric contractions are performed without joint movement and muscle length remains constant. The use of isometric contractions may be indicated when joint damage is present and joint movement is contraindicated or likely to increase pain (video 1.6), during early strengthening when the limb is supported, or to promote blood circulation through alternating contractions. Isometric contractions are also required for some functional activities (Fig. 1.3). concentric: (Of a movement), in the direction of the contraction of a muscle. (Z.B. Extension of the forearm on the elbow joint in contraction of the triceps and other extensor muscles of the elbow. Muscle contraction is called beisometric when the muscle does not shorten during contraction, not isotonic when it shortens but the tension on the muscle remains constant throughout the contraction.
The recording systems for both types of muscle contraction are shown in Figure 6-12. In contrast, an eccentric action (i.e. an eccentric phase) generates greater forces at a lower cost, which means that the muscles are stronger and consume less energy. Even after decades of research, the mechanism of this property is still not fully understood. Several explanations are currently accepted and studied: Isometric contractions are sometimes described as yielding or surmounting. Muscle contraction involves the activation of muscle fibers and the formation of strength, which facilitate body movements and the maintenance of posture. Muscles create strength by changing the length of their fibers or increasing the tension inside the fibers. On this basis, there are two types of contraction of skeletal muscles; A muscle fiber creates tension through a transverse bridge cycle based on actin and myosin. Under tension, the muscle can lengthen, shorten or remain the same. Although the term contraction implies a shortening, compared to the muscles, it means the generation of tension in a muscle fiber. Different types of muscle contractions occur and are defined by changes in muscle length during contraction. Concentric muscle contraction is a muscle shortening because the muscle creates tension when the introduction moves to the origin.
Movement occurs in the same direction as tension and joint movement, because the contractile force is greater than the resistance force. Based on the sliding filament theory, the transverse bridges over the myosin filament attach to the active site of the actin filament. When all muscle crossover bridges shorten in a single cycle, the muscle shortens by about 1%. Muscles have the ability to shorten up to 60% of their rest length; therefore, the contraction cycle must be repeated several times.17 Isometric contractions are contractions in which the length of the muscle does not change. There is no movement of the joint or limb. Isotonic contractions occur when the muscle changes length and creates limb movements. .