Flexible Flat Foot Among Adults: Prevalence, Footwear Influence, and Implications for Fall Risk — A Narrative Review

Abstract

Introduction: Flexible flat foot (FFF) is a common postural variation in which the foot's medial arch collapses during weight-bearing. It is influenced by various factors, including long-standing hours, footwear, trauma, BMI, and sex. This review explores the prevalence of flexible flat feet in adults; the effects of footwear, particularly improper or inadequate arch support, on balance and fall risk; and their association with balance and fall risk.

Methodology: A narrative review was conducted by searching the PubMed, Scopus, Google Scholar, and ScienceDirect databases for studies published between 2015 and 2025. Keywords included “flat foot", “flexible flat foot", “pes planus", "footwear", "balance", and “fall risk". Studies on adults (18–35 years) assessing FFF or flat foot prevalence, the impact of footwear on flat foot and foot posture, and/or balance and falls were included in this review.

Results: Available studies report variable prevalence of flat feet, ranging from 11% to 26%, and of flexible flat feet, around 13% to 15%, in adults. Footwear emerged as a key modifying factor, as studies suggest that footwear choices and prolonged use can contribute to a higher prevalence of flat feet, particularly when wearing low-arch-support shoes. Footwear has also been linked to altered balance in adults with flat feet, potentially increasing the risk of falls and injuries.

Conclusion: Flexible flatfoot is a common yet under-researched musculoskeletal condition with notable functional and postural effects in adults. There is a need to raise awareness among adults about supportive footwear choices for daily use and to implement institutional-occupational reforms regarding footwear restrictions, as evidence suggests the prevalence of FFF among adults is increasing, predisposing individuals to increased fall risk.

Keywords: Adult, Flatfoot, Accidental Falls, Shoes, Prevalence, Footwear, Balance.