Kresimir conditioning coach for football club Dinamo Zagreb, created a variation of Yo Yo test which he finds is very good for making distinction between aerobic and anaerobic work point of deflection is more clear. Players change speed quicker and that makes anaerobic point of deflection much easier to see on a graph. The modification is based on Recovery Int. Level 1 test, where the distance is a fixed variable, and time is decreasing. The players start at 8 km h and run 4 intervals 1 interval is consisted of 2x20m pause 5 sec, as in the yoyo endurance test. After every 4 intervals the test speeds increases by 1 km h.