Efficacy and effectiveness of a balance-enhancing insole. - Perry SD; Radtke A; McIlroy WE; Fernie GR; Maki BE; Perry, Stephen D; Radtke, Alison; McIlroy, William E; Fernie, Geoff R; Maki, Brian E (Journals of Gerontology Series A: Biological Sciences & Medical Sciences, 2008)