Ergonomic design of shoe inserts for reducing lower extremity musculoskeletal discomfort in male Participants: An analysis of shape and size

Abstract

Background

The human foot endures substantial forces during daily activities such as walking and standing, often bearing loads 1.5 to 5 times the individual's body weight. These forces propagate through the lower extremity musculoskeletal structures, placing stress on critical joints, which can lead to discomfort, musculoskeletal issues, and reduced productivity. Shoe inserts (SIs) have emerged as effective ergonomic interventions, provided additional support and redistributed pressure to alleviate discomfort and enhance gait stability.

Objective

This study investigates the ergonomic effects of shoe insert placement, shape, and surface area on perceived comfort and plantar pressure distribution during static standing.

Methods

Twenty-six healthy male participants were assessed using flat and contoured inserts of varying surface areas (30 × 30 mm², 40 × 40 mm², and 50 × 50 mm²). Comfort ratings were measured using a Visual Analogue Scale (VAS), while plantar pressures (peak and mean) were evaluated using F-Scan sensors. Data were analysed using paired t-tests and repeated-measures ANOVA, with Bonferroni corrections applied for multiple comparisons.

Results

Inserts placed 2–4 cm anterior to the lateral midfoot region provided the highest comfort ratings. Contoured inserts consistently outperformed flat designs in improving comfort and reducing plantar pressures across all surface areas (p < 0.017). Larger surface area inserts (50 × 50 mm²) were the most effective in enhancing subjective and objective outcomes, demonstrating significant improvements compared to smaller designs (p < 0.001).

Conclusion

This study underscores the importance of precise placement, contoured designs, and larger surface areas in optimizing the ergonomic benefits of shoe inserts. These findings have practical implications for the design of ergonomic footwear and orthotics, particularly for individuals in occupations requiring prolonged standing.