RESULTS	No significant difference was observed between the estimated ( x + / - SD = 8.9 + / - 2.4 mL/kg/min ) and observed ( x + / - SD = 9.4 + / - 3.8 mL/kg/min ) VO2 max ( mean difference , 0.5 mL/kg/min ; SD of the difference = 2.88 ) .\