Vol. 53 - No. 5 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS 461 when activity is light or the player is static. From a metabolic point of view indoor soccer, like other team sports such as basketball, football, volleyball etc., is classiied among activities where both aero- bic and anaerobic energy sources are recruited. 1, 2 An important itness component of these court sports is what has been termed repeated-sprint abil- ity (RSA), which refers to the players’ capacity of performing high intensity exercises, such as sprint- ing, together with the capacity to recover during the low-intensity phases of the game. 3 For instance, it was found in high level soccer players that the RSA relates to important measures of in-match physical performance, such as the distance covered during very high-intensity running. 4, 5 Furthermore, it was reported that physiological responses to the RSA test can distinguish between professional and amateur soccer players with similar levels in maximal oxy- gen uptake (V’O 2max ). 4, 5 Various protocols have been developed in order to study RSA in several sport ac- tivities. 6-10 However, the scientiic literature is not abundant with studies investigating the physiology of RSA. In particular, while some investigations have focused on football, a research dealing with elite indoor football is to the best of our knowledge still lacking, even though RSA may be considered as a futsal speciic physical ability to be trained. 2 Aim. The aims of this study were: 1) to examine the gas ex- change responses of elite indoor football players to a repeated sprint ability (RSA) test; and 2) to verify whether or not the excess of carbon dioxide production (CO 2excess ) correlates with blood lactate accumulation during RSA ield testing. Methods. Eleven elite male indoor football players were re- cruited. A preliminary incremental exercise test on a tread- mill was performed to elicit V’O 2max . Then, participants un- derwent an RSA test consisting in a shuttle running through a course with various changes of direction while wearing a portable gas analyzer able to provide values of oxygen up- take, carbon dioxide production, and CO 2excess . BLa concen- trations during recovery were also measured. Results. The main results were that: 1) during the RSA test subjects did not reached the V’O 2max level achieved in the pre- liminary test; 2) during the RSA test BLa levels were higher compared with the preliminary test; 3) the peak BLa concen- tration during recovery was signiicantly correlated with the average CO 2excess Conclusion. It was concluded that the RSA test did not ap- pear to be useful to elicit V’O 2max. Rather, it seemed suitable to recruit subjects’ lactic anaerobic capacity. Moreover, CO- 2excess appeared suitable for qualitatively estimate BLa accu- mulation during ield testing. Key words: Oxygen - Pulmonary gas exchange - Football. I ndoor football (also known as futsal) is a sport played between two teams of ive players on a 40x20 m court during two 20 min halves. Players move on the court with variable velocity and the effort is characterized by phases of great intensity and of short duration spaced by periods of recovery, 1 Department of Medical Science, Sport Physiology Lab. University of Cagliari, Cagliari, Italy 2 Regional School of Sport of Sardinia Italian Olympic Committee, Cagliari, Italy J SPORTS MED PHYS FITNESS 2013;53:461-9 L. ANGIUS 1 , M. COMINU 1 , M. FILIPPI 1 , C. PIREDDA 1 , G. M. MIGLIACCIO 2 , M. PINNA 1 , R. MILIA 1 , F. TOCCO 1 , A. CONCU 1 , A. CRISAFULLI 1 Measurement of pulmonary gas exchange variables and lactic anaerobic capacity during ield testing in elite indoor football players Corresponding author: Dr. A. Crisafulli, Department of Medical Sci- ence, Sport Physiology Lab., University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy. E-mail: crisafulli@tiscali.it MINERVA MEDICA COPYRIGHT® This document is protected by international copyright laws. No additional reproduction is authorized. 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