Gait Biomechanics of Older Adults in Outdoor and Simulated Environments: A Scoping Review

Although walking studies conducted in replicated outdoor environments (e.g., virtual reality) or surfaces (e.g., grass surface in a laboratory) provide a safe way to analyze how older adults walk outdoors, how gait variables compare for the outdoor adjacent studies and true outdoor studies are unknown. The objective of this scoping review is to compare and contrast gait variables among older adults across outdoor and outdoor adjacent settings (i.e., outdoor adjacent environments and outdoor adjacent surfaces) and identify commonly measured variables.

Primary source research papers were included that measured kinematic or spatiotemporal gait variables in an outdoor or adjacent environment/surface among adults 60+ years. Five bibliographic databases were searched for publications with terms related to older adults, walking/gait, outdoor/outdoor simulated environments, and kinematics/spatiotemporal variables. Articles were screened and summarized for sample information, collection methodology, and gait variables.

A sample of 1,020 articles were screened after duplicate removal, with only 16 studies meeting inclusion criteria. Studies conducted outdoors reported more variables than outdoor adjacent studies; however, few studies had overlapping spatiotemporal or kinematic variables. Across all studies, inconsistency of regularly measured spatiotemporal variables and reporting of variability exists. For instance, while gait velocity was reported in 63% of included studies, other measures such as step/stride width and step time were inconsistently reported.

Little is known about how older adults ambulate in outdoor and simulated outdoor environments/surfaces. Authors acknowledge the significance of studies done indoors, but hope we are at a time of transition. Spatiotemporal variability in outdoor environments is understudied; more research of spatiotemporal and kinematic variables in real-world environments could help move toward understanding how people move in everyday life. Significance/Implications: A better understanding of how older adults move in daily life can help improve established therapy modalities and fall prevention strategies; however, the lack of comprehensive data comparing gait variables in outdoor environments to gait variables in outdoor adjacent environments makes drawing conclusions difficult. This review offers suggestions for future research to strengthen the body of literature and increase ecological validity for collection of outdoor gait measures. They include (a) standardized reporting of spatial and temporal variability measures using percent coefficient of variation and SDs, (b) integrating advanced technologies to enhance ecological validity, and (c) including diverse populations to improve generalizability.