Reaction Time

You can easily measure your reaction time with a ruler and a helper. Hold out your thumb and forefinger and have your helper hold the ruler just barely above them. Your helper then says "go" and lets the ruler drop straight down. You grab it as quickly as you can with your thumb and forefinger. Look where you caught the ruler (that is, measure how far the ruler dropped between when your friend said "go" and you caught it) You can convert this distance to reaction time with the following table (from Brody, 1987, p. 147):

Drop Distance		Reaction Time	Drop Distance		Reaction Time	Drop Distance		Reaction Time	Drop Distance		Reaction Time
(inches)	(cm)	(ms)	(inches)	(cm)	(ms)	(inches)	(cm)	(ms)	(inches)	(cm)	(ms)
1.0	2.5	72.0	7.0	17.8	190.5	13.0	33.0	259.6	19.0	48.3	313.8
2.0	5.1	101.8	8.0	20.3	203.6	14.0	35.6	269.4	20.0	50.8	322.0
3.0	7.6	124.7	9.0	22.9	216.0	15.0	38.1	278.8	21.0	53.3	329.9
4.0	10.2	144.0	10.0	25.4	227.7	16.0	40.6	288.0	22.0	55.9	337.7
5.0	12.7	161.0	11.0	27.9	238.8	17.0	43.2	296.9	23.0	58.4	345.3
6.0	15.2	176.4	12.0	30.5	249.4	18.0	45.7	305.5	24.0	61.0	352.7

Resource

Brody, H, 1987. Tennis Science for Tennis Players. Philadelphia: The University of Pennsylvania Press.