This series of studies examined the anaerobic performance of children using accumulated oxygen deficit (AOD). Initially a cross-sectional maturational profile of anaerobic performance was investigated with accompanying blood borne markers of exercise intensity. The second study varied the methodology prescribed by Medbo and his colleagues (1989) and investigated whether discrete or continuous submaximal exercise had an impact on AOD. The final study determined whether there was a difference in AOD when cycling and running were used as the exercise modes in the same group of participants.