Methods: Subjects of this study participated in 3 separate testing sessions and did not use or used a different brace at each session i.e. no brace (NB), lace-up ankle brace (AB), and Aircast ankle brace (AA). Through each testing sessions the functional fatigue protocol was performed and dynamic postural control test was performed by Biodex Balance System (single leg stability testing in difficulty level 4) after induced functional fatigue. They were 15 volleyball players with at least 3 years playing record in the national and or Kerman Province leagues at youth and teenagers levels (mean age 19.46±1.50 years, mean height 182.53±5.28 cm, mean mass 67.70±5.91 kg, VO2max 52.05±2.97 mL/kg/min) and stratified sampling method was used. All two by two comparisons were performed by using 1-way repeated measures analysis to investigate the effects of different braces. Data analysis was done by SPSS 16 and significance level was P≤0.05. 

Results: According to the results, both types of ankle brace could improve dynamic postural control under functional fatigue condition. Although lace-up ankle brace was more efficient than Aircast ankle brace, the difference was not statistically significant. 

Conclusion: In athletes with unstable ankle, a brace can prevent ankle sprain via improving dynamic postural control in fatigue condition.