The present study aimed to examine the contribution of gait impairment, postural stability and muscle weakness to the level of fear of falling in people with Parkinson's disease (PD). Fifty-seven community-dwelling individuals with PD completed the study. Fear of falling was assessed by the Activities-specific Balance Confidence (ABC) scale. Postural stability and gait difficulty were determined by the posture and gait subscores of the Unified Parkinson's Disease Rating Scale (UPDRS-PG). A Cybex dynamometer was used to measure isokinetic knee muscle strength. Individuals with PD achieved a mean ABC score of . In the multiple regression analysis, after accounting for basic demographics, fall history and disease severity, the UPDRS-PG score remained independently associated with the ABC score, accounting for 13.4% of the variance ( ). The addition of knee muscle strength significantly improved the prediction model and accounted for an additional 7.3% of the variance in the ABC score ( ). This is the first study to demonstrate that the UPDRS-PG score and knee muscle strength are important and independent determinants of the level of fear of falling in individuals with PD. Improving balance, gait stability and knee muscle strength could be crucial in promoting balance confidence in the appropriately targeted PD population. 1. Introduction Fear of falling (FoF) is a common and potentially serious problem in people with Parkinson’s disease (PD). Previous studies have consistently reported that community-dwelling individuals with PD have a greater FoF than age-matched healthy subjects [1–4]. The level of FoF is further increased in those who have had a fall history [5]. In a prospective study, we found that FoF is also a significant risk factor for predicting future falls [4]. While some level of FoF has a protective role against falls, irrational FoF, either too much or too little, may increase fall risk. Delbaere et al. [6] have recently addressed this complex psychological factor in a large cohort of older population and revealed that discrepancies between psychological and physiological risk factors in those who had excessive or unduly low level of FoF. However, only those with excessive FoF had a higher risk of injurious falls. Repeated falls may lead to avoidance of activity, physical deconditioning, and increased institutionalization. Therefore, interventions aiming to enhance balance confidence have the potential to reduce fall risk in appropriately targeted individuals with PD. To design effective treatment intervention, it is crucial to understand
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