Does Isokinator training require an adaptation phase?

No, not generally. But it doesn’t hurt to try out some exercises in STAND-BY mode to begin with (at the lowest resistance level). This way you can learn the exercise movements and get to know how the cockpit display works (the golden balls) and the proper breathing technique in a relaxed manner. You can add more resistance any time. It is normal for your first attempts to take more time than they normally should. But your workout sessions will soon start running much more smoothly, and you will know your 7 exercises by heart. You won’t need to constantly consult the manual.