RT Journal Article SR Electronic T1 Cardiorespiratory fitness, exercise capacity and physical activity in children: are we measuring the right thing? JF Archives of Disease in Childhood JO Arch Dis Child FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP 455 OP 456 DO 10.1136/adc.2007.135202 VO 93 IS 6 A1 Ulf Ekelund YR 2008 UL http://adc.bmj.com/content/93/6/455.abstract AB