Perception of unilateral lower extremity weightbearing during bilateral upright stance.

The primary purpose of this study was to describe the error in 61 healthy subjects' perceptions of weight-bearing at three target levels during bilateral upright stance. The secondary purpose was to describe the effects of age, sex, lower extremity dominance and target weightbearing level on the error in perceptions of weightbearing. Weightbearing was determined while subjects stood on digital scales. They adjusted their weight in an attempt to bear 25, 50, and 75% of their weight through a designated lower extremity. Three trials were allowed at each weightbearing target, and the results were averaged. Each subject's error in perception of weightbearing at each target level was determined by taking the absolute value of the target percent weightbearing minus the mean actual percent weightbearing. The mean errors at the 25, 50, and 75% targets were 7.3, 3.3, and 7.7%, respectively. The magnitude of the error was unrelated to age. An analysis of variance showed that error was not dependent on sex or whether the dominant lower extremity was used for making judgements. The error did differ between target levels. Clinicians cannot assume, based on the findings of this study, that individuals can accurately judge the percent weightbearing they are placing through one of their lower extremities during bilateral upright stance.