Daily activity restriction is an expected physical behavior aiming to prevent falls in the older population. However, it plays dual roles in preventing falls, both positive and harmful. Therefore, the degree of daily activity restriction is proposed as a critical factor influencing the weight ratio of the positive and negative roles and finally determining the efficacy of fall prevention. Thus, quantification of daily activity restriction is essential to learn its efficacy. We proposed using activity frequency to quantify activity restriction and have testified its good sensitivity to discriminate the degree of activity restriction in older populations. We further attempted to link the degree of activity restriction with the degree of fear of falling to estimate the dual roles of activity restriction in preventing falls. Based on it, a new Composite Activity-specific Risk of Falls Scale tool has been developed. It is promising to use for guiding the modification of physical behavior to prevent falls in older populations. However, further studies are required to establish the evidence for its application.