Yo-Yo IR1 performance was substantially lower than the reported from other studies with elite team sport athletes [5, 6] and similar to the observed results in semi- elite soccer referees; for example [13]. Moreover, we have systematically observed similar Yo-Yo IR1 performances (i.e. < 1500 m) in previous evaluations (unpublished observations), and as recently reported [7]. This is an interesting finding that may be related to the playing style and/or habitual physical preparation of professional Brazilian futsal players. As there are no reference values from other countries, further studies with players of different national championships are needed for adequately testing this hypothesis. Additionally, these observations raise some concerns on the validity of Yo-Yo IR1 for the evaluation of futsal athletes. Alternatively, the Yo-Yo Intermittent Recovery test level 2 (Yo-Yo IR2) would be more appropriate as futsal is characterized by a greater number of HIA than other team sports but with a half of the mean total distance covered during matches when compared to soccer [14]