Not just fitness, but above all the basic knowledge of hiking are combined to make up your technical level:
You have no hiking experience, but you practise outdoor sports;
You are able to follow the trails leading to huts, i.e. to complete Level E excursions;
You are able to follow the normal ascent trails to the summit, even with short facilitated stretches, i.e. to complete Level EE excursions;
You are able to follow normal ascent routes to the summit; you have experience in ascents with medium difficulty vie ferrate. Are you able to complete Level EEA/PD excursions;
You are able to follow normal ascent routes to the summit, along long and rarely-used routes, even with easy and short stretches of climbing and you have experience of ascents with difficult vie ferrate. You are able to complete Level EEAPD+ excursions.