Noun | 1. | isometrics - muscle-building exercises (or a system of musclebuilding exercises) involving muscular contractions against resistance without movement (the muscles contracts but the length of the muscle does not change) exercise, exercising, physical exercise, physical exertion, workout - the activity of exerting your muscles in various ways to keep fit; "the doctor recommended regular exercise"; "he did some exercising"; "the physical exertion required by his work kept him fit" |