Purpose:
Futsal is a very dynamic indoor team sport. Like in soccer, futsal players perform a number of efforts of different intensity during a match. In each match there are a few return substitutions to allow players to have some rest. The aim of the study was to assess the intensity and energy expenditure of single efforts and the dynamics of restitution after the efforts during successive futsal matches.

Methods:
The study consisted in measuring the players’ (n = 11) heart rate (HR) during four matches: A, B, C, D. The HR measurement started during a pre-match warm-up and ended 5 min after the match.

Results:
The highest intensity of single efforts was noticed in match A. It equalled 90.22 ± 4.90% HR_max and it was the highest in comparison with other matches (p < 0.05). The energy expenditure of efforts performed by players in the matches was 395.11 ± 118.70 kcal. The mean energy expenditure of a single effort was 16.33 ± 5.36 kcal/min. The highest energy expenditure was registered in match A, and it equalled 17.31 ± 4.71 kcal/min during a single effort on the pitch after a return substitution.

Conclusions:
The intensity was very high, much higher than that of players’ efforts in 11-a-side soccer. It should be concluded that an appropriate reduction in the time players spend on the pitch during their successive efforts in one match and the consecutive tournament matches can result in reducing the decrease in the effort intensity.