Does it suffice to work out using the Isokinator exclusively or do I need to do something else too?

Working out with the ISOKINATOR is whole-body training. This makes all other forms of exercise unnecessary. All 7 main muscle groups are exercised and in addition to this up to 40 auxiliary muscles are trained too. If you do everything right, you will experience a "pleasant blaze" in your musculature, supplemented by cardiovascular effects. You will be able to tell by your athletic pulse and deepened respiration.