Multifactorial effect of testing single leg stance

Introduction Single leg standing (SLS) is one of the most commonly used balance assessment instrument in clinical settings. However, when a person stands on one leg, there may be many factors that may affect the person’s static standing ability. These factors could be external ones like surface firmness, shoes on or off, or standing leg straight or bent, or the internal factors like foot flat or dominant when kicking a ball. So far, there was still lack of studies investigating how these factors may affect the SLS. Therefore, the purpose of this study was to investigate whether these external and internal factors may affect the SLS assessment. Methods. Twenty-eight young subjects (age in average?) were selected with selection criteria for this study. Each of them was asked to stand on the balance platform with single leg standing for 20 seconds under the following 6 different external affecting conditions: surface firmness (hard verse soft with a foam), shoes on and off, and leg straight verse bent. All subjects have their left legs as the supporting legs and the right leg as the kicking legs when they jumped to shoot a basketball or kicked a soccer ball. To avoid fatigue effect on data results, the order of conditions for being tested was randomized. Also, the internal affecting conditions including foot flatness and leg dominance were compared. Results. There were no statistical significance (p [greater than] 0.05) noticed no mater shoes on or off under other conditions. The surface firmness affects the SLS only on the left side (p0.316) when the leg was straight with shoes off or when the leg was bent regardless of shoes on or off. Significant differences (p Conclusions This study showed that knee bending or not, and surface firmness for dominant or non-dominant leg or flat or non-flat foot to stand on could make significantly different results of SLS assessment. Clinicians should keep these affecting conditions in mind and be precautious when using the SLS for balance assessment.