Keywords: 400 m sprint indoor, tactics The aim of the study is to determine and characterize the most preferred variants for distribution of the efforts in the 400m indoors by athletes with different qualification. Object of the study are 67 athletes in 98 runnings, which are expertly divided in 3 groups: 1st group . results of high rank (HR) with results faster than 47,5 sec (n=19); 2nd group . results of medium rank (MR) with results from 47,5 to 49,5 sec (n=50); 3rd group results of low rank (LR) with results slower than 49,6 (n=29). By method of A. Slavchev on the basis of intermediate times the average speed of running in each of the segments was determined. In order to have possibility for comparing and analysis it was showed as a relative average speed in percents of the average speed for the whole distance. The analysis shows that the possible variants for distribution of the efforts in 400m sprint indoors are 5 and they could be related to the rank of the results. Variant 1 . running with very fast beginning is a tactic that was used in 1/3 of the HR results. Variant 2 . running with fast beginning is the most preferred variant by the competitors with HR results. Variant 3 . running in the middle zone is the most common tactic as in the MR and LR competitors as well as in the HR. Variant 4 . running with slow beginning is a tactic natural for the LR results. Variant 5 . running with very slow beginning is very rare in the sport practice and it is rather an exception. The authors recommend for realization of high rank results the variants with very fast and fast first half of the distance to be used with the aim to create a favorable position for realization of the potential abilities in the means of special endurance of the competitors. Criteria for evaluation of the level of relative average speed of running in the intermediate segments of 400 meters indoors towards the average speed of the whole distance are offered. It is showed that in distributing his efforts, Keron Klement, that achieved a new world record in 400m indoors (44,57) in the winter of 2005, has ran his first segment of 200m for 21,08 sec and the second 200m segment for 23,49 sec. According to the suggested methods the relative average speed in the two halves of the competition distance is respectively 105,71% and 94,87% ­ i.e. The competitor is using a variant with distribution of efforts with fast beginning of the running, which is confirming the made during the study conclusions.