isometric exercise contracts the muscle and does not lengthen nor shorten.
isometric exercise contracts the muscle and does not lengthen nor shorten.
what form of exercise does the muscle contract and does not lengthen nor shorten?
isometric
muscle contractions can be described based on two variables: force and length. force itself can be differentiated as either tension or load. muscle tension is the force exerted by the muscle on an object whereas a load is the force exerted by an object on the muscle. when muscle tension changes without any corresponding changes in muscle length, the muscle contraction is described as isometric. if the muscle length changes while muscle tension remains the same, then the muscle contraction is isotonic. in an isotonic contraction, the muscle length can either shorten to produce a concentric contraction or lengthen to produce an eccentric contraction. in natural movements that underlie locomotor activity, muscle contractions are multifaceted as they are able to produce changes in length and tension in a time-varying manner. therefore, neither length nor tension is likely to remain constant when the muscle is active during locomotor activity.
muscle contraction
fiber length is also a key variable in muscle anatomy. fiber length is the product of both the number of sarcomeres in series in the fiber and their individual lengths. as a fiber changes length, the individual sarcomeres shorten or lengthen, but the total number does not change (except on long timescales following exercise and conditioning). to standardize fiber length, length is measured at the peak of the length-tension relationship (l0), ensuring all sarcomeres are at the same length. fiber length (at l0) does not affect force generation, much as the strength of a chain is unaffected by the length. similarly, increased fiber cross-section or multiple fibers increase the force, like having multiple chains in parallel. velocity is affected in the reverse manner - because sarcomeres shorten at a certain percentage per second under a certain force, fibers with more sarcomeres will have higher absolute (but not relative) velocities. muscles with short fibers will have higher pcsa per unit muscle mass, thus greater force production, while muscle with long fibers will have lower pcsa per unit muscle mass, thus lower force production. however, muscles with longer fibers will shorten at greater absolute speeds than a similar muscle with shorter fibers.
muscle architecture