Table 1. Group labels and number of subjects involved in the study.

Group label	Category Italian name	Level	Weekly training frequency	No. of athletes analyzed	Age (years)	Height (cm)	Weight (kg)
A	Serie A	Professional	5-7	15	26.2 ± 3.7	181.9 ± 6.9	79.4 ± 4.7
B	Serie B	Professional	5-7	16	23.4 ± 5.1	182.6 ± 2.4	78.1 ± 4.0
C	Lega Pro - 1a Divisione	Professional	5-7	15	21.4 ± 1.7	182.7 ± 3.5	78.9 ± 4.4
D	Lega Pro - 2a Divisione	Professional	5-7	17	25.3 ± 4.1	180.6 ± 5.5	77.8 ± 7.9
E	Serie D	Non professional	4-5	17	19.9 ± 3.7	180.0 ± 4.2	72.5 ± 6.6
F	Eccellenza	Non professional	4	23	22.3 ± 5.8	178.3 ± 4.7	74.1 ± 7.5
G	Promozione	Non professional	3	18	21.2 ± 3.1	177.3 ± 5.4	70.4 ± 4.5
H	Prima Categoria	Non professional	3	16	22.6 ± 4.4	174.4 ± 6.0	68.5 ± 5.8
I	Seconda Categoria	Non professional	2	17	24.8 ± 5.5	174.8 ± 7.1	71.1 ± 9.4
L	Terza Categoria	Non professional	2	16	24.4 ± 4.7	176.9 ± 4.6	73.5 ± 6.1
X	-	Control group	-	15	27.3 ± 5.2	177.1 ± 4.4	73.7 ± 8.8
			TOT	185	23.3 ± 4.9	179.0 ± 5.7	74.7 ± 7.8

Level (professional or non professional) and typical weekly training frequencies for the different soccer categories are also reported, as well as age, height and weight of the subjects involved in the study. Data are reported as mean value ± standard deviation.