Which statement describes isometric exercise?

Which statement describes isometric exercise?

• A. Relaxation without contraction
• B. Muscle contraction with resistance
• C. Muscle shortening and active movement
• D. Muscle contraction without shortening

Answer: (D)

Isometric exercise involves a muscle tensing against resistance without changing its length or moving a joint. The muscle contracts and generates force, but the joint angle stays the same, so there’s no visible movement. That’s why the statement “Muscle contraction without shortening” is the best description. For context, think of holding a plank or pressing hands together against each other—the muscles work, but they don’t shorten or cause joint movement. By contrast, relaxation means no contraction, and contractions that produce movement involve shortening of the muscle, as seen in dynamic or isotonic exercises.

Isometric exercise involves a muscle tensing against resistance without changing its length or moving a joint. The muscle contracts and generates force, but the joint angle stays the same, so there’s no visible movement. That’s why the statement “Muscle contraction without shortening” is the best description.

For context, think of holding a plank or pressing hands together against each other—the muscles work, but they don’t shorten or cause joint movement. By contrast, relaxation means no contraction, and contractions that produce movement involve shortening of the muscle, as seen in dynamic or isotonic exercises.