Table 1.

Mean peak acceleration and acceleration signal energy from five trials of hammer impact on freely suspended racquets. Values in parentheses represent one standard deviation. g = 9.81 m/s².

Axis	Peak acceleration (g)		Acceleration signal energy (g2)
	non-VDT	VDT	non-VDT	VDT
X	0.27 (0.06)	0.23 (0.08)	2.98 (1.25)	1.08 (0.46)
Y	1.08 (0.12)	0.98 (0.12)	3.33 (1.49)	0.83 (0.21)*
Z	0.39 (0.09)	0.27 (0.04)	3.28 (2.01)	0.73 (0.22)*
Resultant	1.47 (0.17)	1.43 (0.17)	3.41 (1.53)	0.88 (0.29)*

Note. See Fig. 1B for orientation of the acceleration axes x, y, and z.

*p < 0.05 between the two racquets indicated by Mann-Whitney U test.