BARBELL MATHS
the IWF colour code and the plate count: from target weight to each side of the bar, no calculator
US$2.50
TORQUE
why the same dumbbell grows heavier as the arm rises, and how to work it out in advance
US$2.50
FOOTBALL: THE BALL
Law 2, three codes of the game, five sizes and three FIFA quality marks — what a ball must survive
US$2.50