A machine with hydraulic cylinders offering a resistance that takes account of variations in the strength of the user. Resistance varies throughout the range of movement. It is high at the strongest points and low at the weakest points. The machines can offer resistance in both directions of a movement so that, for example, after pushing your arm up, you have to actively pull against a resistance to bring the arm down again. Training on such machines is sometimes called hydrafitness training. A typical workout lasts about 30 minutes and uses up to 400 calories. See also variable resistance exercise.
Subjects: Medicine and Health.