Table 2 Data on the number of strokes and stroke distribution for return games in the three tournaments: return games.

Stroke type		US Open	French Open	Wimbledon
Total strokes		12.2 (10.0)	14.8 (9.2)	10.4 (6.0)
Returns	Fore	2.0 (1.5)	2.8 (1.9)	2.3 (1.5)
	Back	3.2 (2.3)	3.0 (1.7)	2.9 (1.6)
Topspin	Fore	3.2 (3.8)	3.2 (3.8)	2.0 (2.2)
	Back	2.5 (3.5)	3.7 (3.7)	1.8 (1.8)
Slice	Fore	0.2 (0.5)	0.4 (1.1)	0.1 (0.4)
	Back	0.9 (1.4)	0.7 (0.9)	0.8 (1.2)
Half volley	Fore	0.03 (0.2)	0.06 (0.2)	0.1 (0.3)
	Back	0.05 (0.3)	0.02 (0.2)	0.08 (0.3)
Volley	Fore	0.04 (0.2)	0.09 (0.3)	0.09 (0.3)
	Back	0.09 (0.3)	0.07 (0.3)	0.1 (0.5)
Overhead		0.0 (0.0)	0.03 (0.2)	0.04 (0.2)

See results section for statistical analysis. Values are mean (SD).