An isometric contraction is a specific type of muscle contraction used in some forms of training. Neither the joint angle or the length of the muscle changes during this type of muscle contraction. It takes place while the body is in a static pose, without any range of motion.
Beginners may not understand isometric exercise because it's not as easy to see the muscle contracting while it is immobile. This type of contraction is a specific training tool that only works on a muscle in its static position. By contrast, lots of sports related training requires isotonic contraction that happens through a range of motion.
Some experts believe that isometric contractions are helpful for specific kinds of training. Some examples of common isometric exercise drills include wall sitting, where the individual maintains an unsupported sitting position against the wall for a specific period of time. Others might include holding free weights at static angles from the body, or pushing against a wall or other unmovable barrier.
Some bodybuilders in various training programs use this type of exercise. The renowned strongman Charles Atlas included some similar kinds of activities in his “Dynamic Training” program, although fitness guides point out that most of these were not truly isometric because, while there was resistance balanced against a muscle group, the muscles still moved during the contractions.
Any activity where the body pushes against a static resistance is an isometric activity, and all kinds of muscle groups can get stronger as a result. The core, the central muscle area that supports the body, can especially benefit from this type of exercise. Trainers can get their limbs stronger and more capable with isometric training, though many experts still recommend mixing it with the more common isotonic training, such as free weights, to allow for development through a range of motion.
Beginners who want to include isometric contraction in a routine can take a look at public materials from a gym or health club that show a range of upper and lower body activities for promoting strength and body response. Trainers can analyze a person’s condition and fitness history, and recommend a personalized program that contains both isometric and isotonic exercises. With a diversity of exercise types, muscle groups can develop fuller capabilities for sports, recreation, or functional use.