The purpose of this study was to identify and quantify the magnitude of the slow component of VO2 (SC) in children during running exercise, performed at heavy intensity domain (75%delta), using two different mathematical models: a) three-exponential model and; b) deltaVO2 6-3 min. Eight healthy male children (11.92 ± 0.63 years; 44.06 ± 13.01 kg; 146.63 ± 7.25 cm; and sexual maturity levels 1 and 2), not trained, performed in different days the following tests: 1) incremental running treadmill test to determine the peak oxygen uptake (VO2peak) and the lactate threshold (LT); and 2) two transitions from baseline to 75%delta [75%D = LT + 0.75 x (VO2 peak - LT)] for six minutes on treadmill. The SC was deter mined by two models: a) three-exponential model (Exp3); and b) the VO2 difference between the sixth and the third exercise minute (deltaVO2 6-3min). The SC was expressed as the absolute (ml/min) and percent contribution (%) to the total change in VO2. The SC values determined by model Exp3 (129.69 ± 75.71 ml/min and 8.4 ± 2.92%) and deltaVO2 6-3 min (68.69 ± 102.54 ml/min and 3.6 ± 7.34%) were significantly different. So, the SC values in children during running exercise performed at heavy intensity domain (75%delta) are dependent of the analysis model (Exp3 x deltaVO2 6-3 min).
Running; Slow component; Heavy exercise; Children
