Results showed that the stationary 10-m test, flying 30-m test and T-test, were all significantly correlated (P<0.05). This would suggest that acceleration, maximum speed and agility share common determining factors. However, the coefficient of determination calculations show that even the most significantly correlated tests share only 30% common variance. Thomas and Nelson (1990) stated that “when common variance between the two variables is less than 50%, it indicates that they are specific or somewhat independent in nature”. It appears that acceleration, maximum speed and agility are relatively independent attributes in professional footballers. The requirement of high power production for each speed component, which is partly dependant on muscle fibre size, length and proportion, means that the different speed components show some significant relationships. However, it is clear that several distinct factors contribute to successful performance in each speed discipline.