Impact of Occupational Footwear on Occupational Task Performance and Musculoskeletal Injury Risk: A Scoping Review

[Executive Summary]
The aim of this program of research was to assist Steel Blue in their ongoing development of tactical footwear through the conduct of a detailed scoping review investigating the impacts of occupational footwear on physical task performance and injury risk with a contextualising of results to tactical occupations. The project was formally accepted on 05 October 2021 with the draft reported submitted on 07 November 2021.
The literature review protocol was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews and registered in the Open Science Framework. Key search terms were entered into five academic databases. Following duplicate removal, identified articles were subject to dedicated inclusion and exclusion criteria. Data from the final articles informing this review were extracted, tabulated, and synthesised.
Of an initial 19,614 identified articles, 50 articles remained to inform this review following screening and selection. Articles included various study types (e.g., randomised control trials, quasi-experimental, cross-sectional, cohort, etc.), review types (e.g., systematic and narrative), and conference abstracts. Articles from a total of 16 countries were represented with the majority from the United States of America followed by Australia. The most common populations investigated were military and firefighter populations, but a wide range of general occupations were represented (e.g., shipping, mining, construction, hairdressing, automotive, and healthcare workers). The types of footwear discussed included work safety boots/shoes (e.g., industrial, gumboots, steel capped, etc.,), military and firefighter boots, sports shoes (trainers, running, tennis, basketball, etc.,) and various other types (e.g., rocker-type, sandals, etc.).
Generally, occupational footwear was found to impact on gait and angular velocities, joint ranges of motion, posture and balance, physiological measures (like aerobic capacity, heart rates, temperatures, etc.), muscle activity, and occupational tasks (like running to an emergency department or lifting loads). Occupational footwear associated with injuries included boots (government issued, gumboot, leather, etc.), conventional running shoes, shoes with inserts, harder / stiffer outsoles or thin soles, and shoes with low comfort scores - although the findings were mixed. Occupational footwear was also linked to potentially causing injuries directly (musculoskeletal injuries, chaffing, pain and disability) as well as leading to mechanisms associated with causing injuries (like tripping and slipping).
More specifically, stiffer boots with a higher shaft height reduce ankle range of motion to a greater extent than lower shaft height boots while heavier boots were more likely to increase the energy cost of a given task and decrease foot clearance heights achieved when stepping over a hurdle. Wader style boots impacted joint range of motion to a greater extent than hiker style boots while rubber boots impacted joint range of movement and postural sway to a greater extent than leather boots. Polyurethane boots recorded higher instantaneous of ground reaction forces when compared to styrene-butadiene boots. Outer sole stiffness, thin soled shoes, and harder footwear may increase musculoskeletal disorders and discomfort. Gumboot wearers and leather boot wearers may be predisposed to different types of injuries.
One notable limitation in the current volume of evidence is the lack of research investigating the impacts of occupational footwear on actual occupational tasks with only three of the 50 papers (6%) specifically looking at occupational task impacts (1 study = running a short distance, and 2 studies = lifting an object). Recommendations for future product design specific to tactical populations are provided in the applied encapsulation and includes considerations for tactical footwear design and product testing. Only through planned and considered execution can human factors research into the impacts of occupational footwear be given meaning through which to inform and validate occupational footwear for a given occupation.