Abstrakt
Lots of parameters like a strength, velocity or postural stability differs between age categories in football players and could be changing during the competition season. Postural stability is very close to the level of recondition and its parameters could be affected by the load and the fatigue during competition period.The purpose of this study is to determine level of postural stability at young football players in relation to their age and its changes during the football season.In before season tests statistical analyses showed significant difference between U13 and U15 in test SCE, where U15 has higher value in TTW parameter than U13 (ANOVA, Chi-square (62, 3) = 9,80; p<0,05, Post hoc Kruskal-Wallis Multiple-Comparison Z-Value Test (Dunn's Test), Z-test = 3,07, p = 0,05) and between U12 and U15 in FLP test (Z-test= 2,59; p = 0,05) and U12 - U14 in FLP test (Z-test= 2,69; p = 0,05), where U12 has in both cases higher values in TTW parameter.75 elite male football players in the age categories from 12 to 15 years participated in this study (U12: n = 18; age 11,4 years; height = 148,8 +- 7,4 cm; weight = 38,5 kg +- 5,8 kg; U13 n = 21; age 12,4 years; height = 154,1 +- 5,4 cm; weight = 43,7 kg +- 5,0 kg; U14 n = 16; age 13,4 years; height = 161,1 +- 8,5 cm; weight = 49,9 kg +- 10,1 kg; U15 n = 20; age 14,3 years; height = 170,7 +- 7,8 cm; weight = 55,8 kg +- 7,1 kg).
Four posture stability tests were used: narrow stance with opened eyes (SOE), narrow stance with closed eyes (SCE), flamingo test on the right foot (FLR), and flamingo on the left foot (FLL). Postural stability was measured using a Footscan pressure platform (RScan, Belgium) with frame rate 30 Hz and length of the test 30 s for standing on both lower limbs and 60 s for one lower limb standing.
The evaluated parameter was Total Traveled Way (TTW). There were no significant differences between age groups in after season tests.
Statistical analyses of values before and after season in all age groups together (pair t-tests) showed significantly higher values of TTW parameter in tests SOE, FLL and FLR after season (SOE: Z-value = 1,72, p<0,05; FLR: Z-value = 1,75, p<0,05; FLL: Z-value = 1,90, p<0,05) and significantly better values after season in SCE test(Z-value = 3,98, p<0,001).The results showed that postural stability at both-feet stance is comparable and statistically indifferent among the different age categories before and also after season. It is concluded that long-term training and matches workload within a season has a negative impact on the postural stability of the players.
At the end of the testing period (i.e. after concluding the first half of the football season), virtually all parameters in all age categories of the football players worsened. These negative effects on postural stability could be reduced by implementation of exercises to effect postural stability (Fig. 2) and the future research should aim to prove their effects.