Identifying the Number of Steps Required for Familiarisation to Athletic Footwear in Healthy Older Adults.

Introduction: Research on athletic footwear familiarisation within an older population is sparse. This is problematic because unfamiliar footwear may act as a new perturbation and modify older adults' walking gait and stability. In addition, while athletic footwear has been suggested to enhance older adults' comfort and support during activities of daily living, the necessary period for familiarisation with athletic footwear is unknown. Therefore, this study aimed to identify the number of steps required for older adults to be familiarised with athletic footwear of different midsole thicknesses.

Methods: Twenty-six healthy and physically active community-dwelling older adults, 21 females (71.1 ± 4.5 years; 164.5 ± 5.3 cm; 68.4 ± 11.4 kg) and five males (70.6 ± 2.3 years; 175.2 ± 7.8 cm; 72.8 ± 9.7 kg), completed a walking-based protocol. Participants walked two trials of 200 steps at their habitual speed on a 10-m track of an optical measurement system in three footwear conditions: (1) New Balance® REVlite 890v6 (thick midsole); (2) New Balance® REVlite 1400v5 (moderate midsole); and (3) New Balance® Minimus 20v7 (thin midsole). Gait speed (m.s-1) and walking time (min) were analysed for each participant over the 400 steps. Number of required familiarisation steps were established over three analysis phases, consisting of steady-state gait assessment, averaging and analysis of blocks of 40 steps, and sequentially comparing these steps with a predetermined threshold. Footwear familiarisation was assumed when the mean gait speed fell within an acceptable level (±2 SD from 320 to 360 step values) and subsequently maintained.

Results: Most participants were familiarised with all three footwear conditions (thick n = 18; moderate and thin n = 20) after walking 80 steps. For all participants, the moderate midsole had the shortest familiarisation period (160 steps). The highest number of familiarisation steps was found in the thick (320 steps) and thin midsoles (240 steps) for some participants.

Conclusion: A minimum of 320 familiarisation steps is recommended to account for both individual differences and midsole thicknesses. Implementing this walking-based footwear familiarisation protocol would improve validity of future studies, ensuring they analyse footwear effects rather than familiarisation with the footwear.