The purpose was to investigate fatigue effects in high school athletes. We wanted to determine if fatigued postural stability, as measured with the Y-balance device, declined compared to rested postural stability. If there was a fatigued effect we also wanted to see if the decline occurred deferentially for females and males or by sport played.
255 healthy high school athletes participating in basketball, baseball/softball, lacrosse, soccer or track participated. Rested postural stability testing was completed using the Lower Quarter Y Balance Test (YBT-LQ) at the playing field for each sport. The YBT-LQ requires the athlete to balance on one leg while reaching in 3 directions with the other leg, as far as possible without losing balance. The leg reach directions are anterior, posteromedial and posterolateral. The athletes then participated in a training session led by the team coach and consisting of sport specific maneuvers. The athletes returned for fatigued postural stability testing when they attained a rating of 14 or higher on the Borg Rating of Perceived Exertion scale. A rating of 14 indicates a feeling of "hard" exertion. The rested and fatigued YBT-LQ testing followed standardized procedures with athletes wearing their sport shoes. ANOVA procedures were used for statistical analysis of the data at the .01 level.
The effect of fatigue on how far an athlete could reach with the non-weight bearing leg before losing postural stability was present only for lacrosse players, as compared to other sports. Fatigue had a similar effect on female and male lacrosse athletes. The reach direction that showed consistent reduction in distance for any sport when fatigued was in the anterior direction. The fatigue affects for the anterior direction occurred for both the right and left legs in both female and male lacrosse athletes. The statistically calculated effect size for fatigue in lacrosse athletes was medium to large for both sexes. The actual reach distance reduction ranged from 1.3 to 1.6 cm.
Fatigue was shown to affect postural stability differently among the sports included in our study but not by sex. In adults, an asymmetry between legs in the anterior reach direction has been linked to injury during sport performance. The only reach direction that consistently showed fatigue effect in our study was also in the anterior direction. It is interesting that the anterior reach direction seems of importance in both adult and youth athletes.
Further research is needed to determine if the anterior reach distance reduction with fatigue is predictive of injury for youth athletes. If so, the YBT-LQ successfully used at the playing field in this study could be used by coaches and trainers to identify athletes with postural stability training needs.
fatigue
stability
