If agonist and antagonist muscles are not (yet) equal in strength
An ISOKINATOR often trains agonist and antagonist muscles simultaneously. According to modern theories of exercise, it is important for muscles which impact the same joint or generate the same body posture to be of equal strength. For example, biceps and triceps. If two muscles are not equally strong, you should still exercise them using the same resistance, however. What constitutes 70% of its maximum strength for the weaker muscle amounts to somewhat less than 70% performance for the stronger antagonist muscle at first, but this still allows the stronger muscle to grow. Through the mutual dynamics of agonist and antagonist during training, the level of strength gets balanced out.