[header] How to improve reaction speed [title] Test your speed by having a friend drop a card. [step] Cut a piece of cardstock so that it's about 8 inches (20 cm) long and 2 inches (5.1 cm) wide. Ask a friend to hold it vertically by the top. 
Line up your fingers with the bottom edge of the card and ask your friend to drop the card without warning. When the card is dropped, grab the card with your fingers as quickly as you can.