The CSA monitor provides a precise tool for measuring changes in acceleration in laboratory settings. Technically, the device performs well, and is likely to prove a useful tool in the assessment of physical activity in children and adults.

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A football can be swerved considerably in flight by the application of spin. The paper considers the movement and spin of a football in three dimensions and seeks to quantify how much lateral deflection and spin can be achieved by a player in a realistic situation. The football is tracked in three dimensions by means of four markers on its surface, with tetrahedral symmetry, so that spin and deflection can be monitored under field conditions. The lift coefficients for the ball are compared with those for smooth and rough spheres.