This game can be played by one boy alone. Stand with both your arms to the front about level with the waist, cross your wrists so that one hand has knuckles up, the other knuckles down and clench the fists. Now make the lower hand press upwards and make the upper hand press downwards. Press as hard as you can with both wrists gradually, and only after great resistance let the lower push the upper one upwards till opposite your forehead, then let the upper press the lower down, the lower one resisting all the time. These two exercises, although they sound small and simple, if carried out with all your might, develop most muscles in your body and especially those about the heart. They should not be carried on too long at a time, but should be done at frequent intervals during the day for a minute or so. "Wrist Pushing" can also be played by two boys halt facing each other, each putting out the wrist nearest to his opponent, at arm's length, pressing it against the other wrist, and trying to turn him round backwards.