Table 2.

Descriptive statistics (mean ± SD) and differences between elite and sub-elite youth tennis players in the D4T(n = 32)

	Elite (n=l5)	Sub-elite (n-17)	Total (n = 32)	Level t-value(df)	db
VA-iudex	30.53 ± 5.44	20.86 ±7.81	25.40 ± 8.30	4.010-(30)**	1.437
Mean velocity (kph)	106.12 ±5.31	9771 ± 7.48	101.65 ± 7.73	3.623 (30)**	1297
Mean accuracy (points)	2.44 ± .40	1.92 ±.55	2.16 ±.55	3,048 (30)**	1.091
Percentage errors (%)	35.22 ± 4.06	40,78 ± 9.87	38.17 ± 8.1	-2.127(21.822)*	.736

^at-test (one-tailed) for all variables; ^beffect size using Cohen’s d,> 2 = small > .5 = medium, > ,8 = large, > 13 = very large;

^*p<.05

^**p<.005