Page 24 - OHS, November/December 2024

P P E : F O O T P R O T E C T I O N
Forging a Confi dent Connection to Footwear
Ensuring optimal fi t, durability and protection is critical for worker performance and safety.
BY DAN FEENEY, PH.D.
tasks in dynamic environments to earn their liveli-
Workers demand the best gear to perform challenging
hood. Due to the inherent risks on the job, the United
States Congress enacted the Occupational Safety and
Health Act in 1970, stipulating specifi c standards to keep workers
safe. Mirrored by similar measures enacted worldwide, these safety
acts protect hundreds of thousands of workers from injury.
Standards include requirements that shoes worn on the job have
specifi c features such as safety toes to prevent crushing of the forefoot,
stiff and slip-resistant soles, and typically have a height requirement
to provide ankle support. Shoe durability is also critical because of
the diffi cult conditions and potential impact of breakage on income.
Th e fi t of work boots is tantamount to other safety features.
Workers, employers, and governmental agencies need to under-
stand more about optimizing fi t since:
• For most workers, their feet do not match the shape of their
footwear (Dobson et al., 2018).
• Footwear that does not fi t appropriately is associated with
pain and risk of injury (Buldt and Menz, 2018).
• Footwear designed to wrap and conform to the foot dramati-
cally improves performance in a laboratory (Pryhoda et al., 2021)
and real-world setting (Honert et al., 2023).
While safety toes, rigid boot cuff s, and stiff , puncture-resistant
soles have prevented many injuries, they create unique challenges
in fi nding an optimal fi t for workers, which may cause diff erent
injuries and ineffi ciencies on the job.
Traditional methods of footwear manufacturing coupled with
common safety features make it diffi cult to fi nd shoes that protect
against hazards while fi tting well to ensure a secure heel lock for
long days on the job. Most shoes are manufactured using a “U-
Th roat”—a broad opening on either side of the tongue cut into the
shape of a “U.” Footwear maker have employed this method since
the 19th century, because it is effi cient for factories.
When manufacturers combine a U-Th roat with a safety toe, it can
create a bubbling eff ect in the fore and midfoot. Shoes are so volumi-
nous that workers need to fi nd a way to secure the midfoot and heel.
Because the optimal fi t of shoes is primarily associated with
holding the instep, workers compensate for the looser forefoot by
selecting too much lace tension right over the instep. Th is practice
inadvertently causes reduced circulation and pressure points as
workers over tension laces to get the heel hold they need.
Additionally, the midfoot undergoes up to 30 degrees of motion
during walking, so overtightening the product here can cause inef-
fi ciencies in every step during the day, leading to increased fatigue.
A solution for this problem is brands releasing products designed to
wrap over the midfoot, conforming to the instep with broad panel
structures, eschewing—or modifying—a traditional U Th roat and
moving the ‘closure’ to the lateral side of the foot, which can be more
signifi cantly eff ective in creating heel hold (Honert et al., 2023).
Intending to create stable and durable products, work boot
manufacturers oft en design rigid shaft s and soles. However, too
much rigidity creates ineffi cient movements and alters how work-
ers move throughout the day (Dobson et al., 2017). Research on
how workers navigate a work environment found that boots with
diff erent, targeted stiff ness between the sole and shaft created the
safest shoe, and reduced worker slip risk (Dobson et al., 2019).
Also, workers preferred shoes with a stiff sole and fl exible shaft ,
which signifi cantly aff ected the pressured distribution on their feet
(Dobson et al., 2020) and is a primary risk factor for metatarsal
fracture. Workers should try on multiple products to fi nd a boot
that does not overly restrict movement, conforms to their midfoot,
locks the heel into place, and has a shaft that supports the ankle
without excess rigidity. Footwear makers should use these fi ndings
and innovative materials to create safer end products that tune the
stiff ness in the sole, shaft , and upper for various needs.
Th ere is good reason to try on multiple options and seek shoes
that conform to your foot before buying: footwear and products
designed to fi t and conform to feet can oft en be perceived im-
mediately and may reduce injury risk (Mündermann and Nigg,
2001). Moreover, when manufacturers design shoes to conform to
key aspects of the foot, such as the instep, they materially improve
heel hold without excessive pressure points (Honert et. al., 2023),
ultimately allowing safety toes to protect the foot without causing
detrimental changes in how workers move through the day.
Dan Feeney, Ph.D., is the Senior Director Partner Product Innova-
tion & Development at BOA Technology.
REFERENCES
• Buldt AK, Menz HB. Incorrectly fi tted footwear, foot pain and foot disorders: a systematic
search and narrative review of the literature. J Foot Ankle Res. 2018 Jul 28;11:43. doi:
10.1186/s13047-018-0284-z. PMID: 30065787; PMCID: PMC6064070.
• Dobson JA, Riddiford-Harland DL, Bell AF, Steele JR. Work boot design affects the way
workers walk: A systematic review of the literature. Appl Ergon. 2017 May;61:53-68. doi:
10.1016/j.apergo.2017.01.003. Epub 2017 Jan 19. PMID: 28237020.
• Dobson JA, Riddiford-Harland DL, Bell AF, Steele JR. The three-dimensional shapes of
underground coal miners’ feet do not match the internal dimensions of their work boots.
Ergonomics. 2018 Apr;61(4):588-602. doi: 10.1080/00140139.2017.1397201. Epub
2017 Nov 3. PMID: 29065793.
• Dobson JA, Riddiford-Harland DL, Bell AF, Wegener C, Steele JR. Effect of work boot
shaft stiffness and sole fl exibility on lower limb muscle activity and ankle alignment
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• Pryhoda, M. K., Wathen, R. J., Dicharry, J., Shelburne, K. B., Feeney, D., Harrison, K., &
Davidson, B. S. (2021). Alternative upper confi gurations during agility-based movements:
part 1, biomechanical performance. Footwear Science, 13(1), 91–103. doi.org/10.1080/
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