The Influence of Footwear Sole Hardness on Slip Characteristics and Slip‐Induced Falls in Young Adults

Theoretically, a shoe that provides less friction could result in a greater slip distance and foot slipping velocity, thereby increasing the likelihood of falling. The purpose of this study was to investigate the effects of sole hardness on the probability of slip‐induced falls. Forty young adults were randomized into a hard or a soft sole shoe group, and tested under both nonslippery and slippery floor conditions using a motion analysis system. The proportions of fall events in the hard‐ and soft‐soled shoe groups were not statistically different. No differences were observed between shoe groups for average slip distance, peak and average heel velocity, and center of mass slipping velocity. A strong association was found between slip distance and the fall probability. Our results demonstrate that the probability of a slip‐induced fall was not influenced by shoe hardness. Once a slip is induced, slip distance was the primary predictor of a slip‐induced fall.     

Choice,Discrimination, and the Motherhood Penalty

Recent studies have documented substantial penalties associated with motherhood and suggest that discrimination plays an important role in producing them. In this article, I argue that the degree to which motherhood is conceptualized as a choice affects the penalties associated with making this choice. Two methods are employed to evaluate this argument. The first method is an analysis of state differences in the wage penalties for motherhood, in which hierarchical linear modeling is used with data from the 1988–2004 Current Population Survey. The second method is a hiring experiment in a highly controlled setting. The wage analysis shows that, net of the usual individual and state‐level factors that affect wages, mothers are penalized more in states where motherhood is perceived to be a woman's choice. The hiring experiment distinguishes between productivity‐based and discrimination‐based explanations for the penalty and provides strong evidence for a causal relationship between perceptions of choice and discrimination against mothers.