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. 2022 Aug 27;19(17):10703. doi: 10.3390/ijerph191710703

Table 3.

Characteristics and key findings of studies assessing occupational footwear and impact on task performance and musculoskeletal injury risk.

Author Study Design Boot Construction Impact on Task Performance Impact on Injury Risk
Al-Ashaik et al. [27] 2015 Quasi-experimental
n = 7
University workers
Age =
29.3 ± 3.9 yr
Height =
166.1 ± 3.3 cm
Mass =
70.7 ± 4.2 kg		 3x different shoes all made by Shelterall Company, Italy:
Light duty (Reference):

  • similar to the regular leather shoes

  • full leather with double density with padded collar

  • rubber sole

  • steel toecaps

  • low cut

  • pair mass: 0.9 kg

Medium duty:

  • genuine full leather with double density

  • padded collar

  • polyurethane moulded sole

  • steel toecap

  • low cut

  • pair mass:1.05 kg

Heavy duty:

  • waxy full grain leather with double density with padded collar

  • polyurethane moulded sole

  • double steel toecaps high cut

  • pair mass: 1.45 kg

 Interaction between environmental temperature and type of safety boot had significant effect on Maximum acceptable weight of lift (MAWL) F(2,24) = 5.4, p < 0.012
MAWL while wearing heavy-duty shoes in 30 ° C was significantly less than wearing light-duty shoes at low temperatures p < 0.013
Aura Canal temperature was significantly higher in heavy duty shoes compared to medium (p = 0.02) or light (p < 0.0001) duty shoes
% Maximum voluntary contraction (MVC)

  • Significantly lower in biceps brachii while performing 1 lift/minute wearing light-duty safety shoes than wearing heavy-duty (p < 0.04) at 20 ° C

  • Significantly lower in biceps brachii while performing 5 lifts/min wearing medium-duty safety shoes than when wearing heavy-duty (p < 0.00) at 20 ° C

  • Significantly lower in biceps brachii while performing 1 lift/min wearing medium-duty shoes compared to heavy-duty (p 0.022) at 30 ° C

  • Significantly lower in biceps brachii while wearing light-duty shoes compared to heavy-duty (p < 0.002) at 30 ° C

  • Significantly lower in trapezius muscle group while wearing light-duty safety shoes compared to heavy-duty (p < 0.04) at 20 °C

Rating of Perceived Exertion in 30 °C was significantly lower while wearing light-duty safety shoes compared to heavy-duty (p < 0.01)Safety shoe discomfort rating

  • Light duty shoes rated as significantly more comfortable than medium-duty safety shoes (p < 0.0001)

  • Light duty shoes rates as significantly more comfortable than heavy-duty safety shoes (p < 0.001)

  • Medium-duty safety shoes were rated more comfortable during lifting than heavy-duty safety shoes (p < 0.0001)

Mean weight lifted per shoe:
Light-Duty

  • 20 °C: 26.3 kg

  • 30 °C: 25.2 kg

  • Average: 25.1 kg

Medium-Duty

  • 20 °C: 25.1 kg

  • 30 °C: 23.1 kg

  • Both: 24.2 kg

Heavy-Duty

  • 20 °C: 23.4 kg

  • 30 °C: 21.9 kg

  • Both: 22.7 kg
Alferdaws et al. [28] 2020 Quasi experimental
n = 10
University workers
Age =
29.7 ± 3.3 yr
Height =
167.3 ± 7.1 cm
Mass =
72.2 ± 7.2 kg		 3x different shoes all made by Shelterall Company, Italy:
Light duty (Reference):

  • similar to the regular leather shoes”

  • full leather with double density with padded collar

  • rubber sole

  • steel toecaps

  • low cut

  • pair mass: 0.9 kg

Medium duty:

  • genuine full leather with double density

  • padded collar

  • polyurethane moulded sole

  • steel toecap

  • low cut

  • pair mass: 1.05 kg

Heavy duty:

  • waxy full grain leather with double density with padded collar

  • polyurethane moulded sole

  • double steel toecaps high cut

  • pair mass: 1.45 kg

 MAWL significantly higher while wearing light duty shoes compared to wearing heavy duty shoes (p < 0.041)
No significant differences between medium and heavy or medium and light duty shoes
Shoe type had no effect on respiration rate, minute ventilation, VCO2, relative VO2 or heart rate
Shoe discomfort rating

  • Heavy-duty shoes produced significantly more discomfort than medium or light duty shoes (p < 0.000 for both)

  • Medium-duty shoes produced significantly more discomfort than light-duty shoes (p < 0.000)
Anderson et al. [29] 2021 Operating theatre practitioners:
n = 147
Female (n = 111)
Height =
163.0 ± 9.0 cm
Mass =
70.0 ± 14.7 kg
BMI =
26.0 ± 6.2 kg/m2
Male (n = 36)
Height =
176.0 ± 10.0 m
Mass =
83.7 ± 14.5 kg
BMI =
27.1 ± 3.5 kg/m2
 Four main footwear types:

  • Washable clog—usually made from EVA

  • Standard clog—usually leather/microfibre upper

  • Trainer

  • Dress shoe/flat

Other category—inclusive of Wellington boots and orthopaedic sandals		 Greater footwear comfort corresponded to decreased risk of suffering from

  • Hip/thigh pain (OR = 0.9, 95% CI 0.7–1.0)

  • Knee pain (OR = 0.9, 95% CI 0.7–0.9)

  • Foot pain (OR = 0.8, 95% CI 0.7–0.9)
Anderson et al. [62] 2017 Narrative Review The study notes that

  • There are clear limitations to the current studies

  • There is a lack of methodological standardisation, particularly in studies looking at solutions (i.e., flooring and footwear) is contributing to the conflicting results between studies. This is due to both a lack of detail in the reporting of some methods and to the range of techniques used to measure the same dependent variables

  • Harder footwear increased the risk for lower extremity self-reported fatigue 2.6-fold (CI = 1.3 to 5.3) versus footwear with a low hardness level

  • A thin sole in nursing shoes increased the number of discomfort complaints in the back, thigh, knee, and shin

  • Width of footwear had an impact on the pressure distribution in the toes and that an arch support increased the area of the foot in contact with the shoe, reducing peak pressures

  • Higher EMG values for the peroneus longus and gastrocnemius muscles were found in the footwear with the stiffest midsole
Armand et al. [55] 2014 Randomised Control Trial
n = 40 (36 female, 4 male)
Intervention
Age =
44.5 ± 7.9 yr
Height =
162.1 ± 9.1 cm
Mass =
66.2 ± 11.3 kg
BMI =
25.1 ± 3.9 kg/m2
Control
Age =
46.8 ± 8.8 yr
Height =
164.8 ± 7.8 cm
Mass =
71.6 ± 13.7 kg
BMI =
26.5 ± 5.5 kg/m2 		Intervention group: Wore unstable shoes
Control group: Wore conventional sports shoes (model Adidas Bigroar)		 Intervention group:

  • Significant decrease in pain while walking in lab barefoot (p = 0.037)

  • Significant decrease in pain while walking in lab shoes (p = 0.001)

  • Significant decrease in daily logbook of pain (p = 0.005)

  • No significant decrease in pain during the last 24 h (p = 0.199)

The Intervention showed a greater improvement in disability scores, but not statistically significantThe rate of satisfaction (satisfied and very satisfied) was 79% in the IG compared to 25% in the CG (p = 0.002).
Bell et al. [56] 2019 A two-arm cluster Randomised Controlled Study
Intervention n = 6629 school district workers
Control n = 4818 school district workers		 Intervention consisted of providing slip resistance footwear rather than recommending workers to utilise slip resistance footwear and purchase them on their own. Intervention significantly reduced probability of slipping injury (Oradj = 0.33, 95% CI 0.17–0.63).
Chander et al. [63] 2019 Narrative Review
Discussed potential benefits of utilising minimalist boots		 Heel-to-toe drop lower drop aids in neutral position of ankle and foot helping postural stability.
Heel height: lower heel height aids in neutral position helping postural stability.
Midsole: thin and firm midsole aids in better proprioception and somatosensory feedback.
Insole: textured insole aids in better proprioception and somatosensory feedback.
Foot-bed shape: heel seat lengths and heel wedge angle that promotes greater contact with the foot minimised foot pressure.
Mass; lower mass aids in less energy expenditure and lower rate of muscular fatigue.
Boot shaft: more flexible boot shafts that extend over the ankle can allow further joint ROM and promote joint position sense.		 Minimalist boot performed better in minimising slip-induced falls, improved static, and dynamic balance, and lowered muscular exertion.
Chiou et al. [30] 2012 Quasi-experimental
n = 27 Firefighters
13 female, 14 male
Female
Age =
33.2 ± 4.4 yr
Height =
166.6 ± 5.0 cm
Mass =
67.9 ± 8.0 kg
Male
Age =
28.4 ± 5.5 yr
Height =
178.5 ± 5.8 cm
Mass =
94.6 ± 15.6 kg		 Four models of firefighter boots conforming to NFPA standards for structural firefighting were selected for the study (NFPA, 2007).
These boots were pull-up bunkers boots that were commercially available:

  • Hybrid upper with a combination of leather and fabric upper and less flexible soles (HS): 2.05–2.48 kg

  • Leather upper with less flexible soles (LS): 2.46–2.93 kg

  • Leather upper and more flexible soles (LF): 2.56–3.10 kg

  • Rubber upper with more flexible soles (RF): 3.36–3.82 kg

 Of all 168 trials, 19 (11.3%) tripping incidents occurred.
The following number of trips was found for each model:
  • (a)

    HS = 6

  • (b)

    LS = 4

  • (c)

    LF = 6

  • (d)

    RF = 3

Results from the ANCOVA revealed a significant boot mass effect on trailing toe clearance for high (p < 0.02) and low obstacle heights (p < 0.003):

  • Significantly shorter trailing toe clearance with heavier boots: For every 1 kg increase in mass there was an estimated 2.9 cm and 4.4 cm decrease in trailing to clearance for high and low obstacles respectively

Significant interaction of boot mass on lead heel contact velocity (p < 0.02) and pre-obstacle distance (p < 0.05) while clearing a high obstacle:

  • Participants placed their trailing foot closer to the obstacle before crossing while wearing heavier boots

  • Heavier boots resulted in greater lead heel contact velocity

Significant boot mass effects (p < 0.05) were observed for:

  • Greater VE with heavier boot mass (significant for male only)

  • Greater VO2 with heavier boot mass (male and female)

  • Greater relative VO2 with heavier boot mass (male and female)

  • Greater VCO2 with heavier boot mass (both males and females)
Chorsiya et al. [67] 2018 Conference abstract
n = 25 male subjects		 Multiple ANOVA results showed the significant influence of shoe characteristics (toe cap, sole of shoe, mass of the shoe and ankle type) and their interaction on the centre of pressure displacement determinants.
Choukou et al. [68] 2013 Conference abstract
n = 10 workers
Age =: 23.3 ± 6.7 yr,
BMI =: 24.0 ± 2.0 kg/m2
Shoe size range: 43–44		 Four conditions:

  • Barefoot

  • Safety shoes respecting conventional standards (l)

  • Comfort safety shoes (OREGON)

  • Unstable safety shoes (MBT)

 There was no significant difference in gait frequency under the different conditions (p > 0.05)
Gait duration is greater when barefoot than shod (F (3, 116) = 4.7, p < 0.05).
Heel strike peak of force was higher with MBT than the other conditions (F (3, 116) = 4.4, p < 0.05).
Foot flat peak force was higher when barefoot than shod (F (3, 116) = 4.2, p < 0.05)
MBT was similar to other footwear conditions (p > 0.05).
Toe off peak of force was higher for MBT (F (3, 116) = 11.4, p < 0.05)
Choukou et al. [69] 2013 Conference abstract
n = 10 workers
Age =: 23.3 ± 6.0 yr
Height: =: 1.8 ± 0.1 m
Mass: =: 77.9 ± 8 kg,
Shoe size range: 43–44		 Four conditions:

  • Barefoot

  • Safety shoes respecting conventional standards (l)

  • Comfort safety shoes (OREGON)

  • Unstable safety shoes (MBT)

 Anteroposterior magnitude, total area, length and velocity of centre of pressure were significantly higher when wearing MBT (F(3,116) = 10.5;94.3; 94.3; 9.5; respectively p < 0.05).
Dobson et al. [13] 2017 Systematic Review
18 studies investigating the effect of boot design on walking		 Comparison between multiple boots with focuses on following categories:

  • Shaft Height

  • Shaft Stiffness

  • Boot Mass

 Shaft height

  • Shaft height could influence an individual’s foot and ankle ROM thereby altering lower limb mobility while walking

  • Walking in pull-up bunker firefighting boots, compared to low-cut running shoes, significantly reduced ball of foot flexion-extension and ankle plantar flexion-dorsiflexion ROM

  • Higher shafted firefighting boot led to increased ball of foot abduction-adduction and ankle inversion-eversion ROM in the frontal plane compared to when the participants wore the running shoe

Shaft stiffness

  • Manipulation of shaft stiffness in hiking boots, military boots and basketball boots has been found to significantly alter ankle ROM

  • A more flexible shaft increased ankle ROM during walking and a stiffer shaft reduced it

  • Restricting ankle joint motion is also thought to affect the hip by causing individuals to rely on hip motion changes to maintain balance

  • A military boot with a softer, more flexible shaft that allowed more ankle ROM was shown to increase power generation during push-off at the ankle joint by 33% compared to when participants wore a military boot with a stiffer shaft

Boot mass

  • Boot mass is the most variable element of work boot design and can typically range between 1 and 4 kg

  • Heavier footwear has been shown to alter the way individuals walk, particularly kinematic parameters characterising walking and oxygen consumption

  • Increased heel contact velocities and reduced trailing limb toe clearances have been found

  • Energy expenditure while walking increases with an increase in footwear mass

 Shaft height

  • Introducing a boot with a higher shaft, compared to a boot with a lower shaft, reduced the amount of ankle injuries incurred by Royal Marine recruits further supporting the notion of boot shaft height influencing ankle stability

  • Wearing combat assault boots led to significantly higher peak pressures (kPa) being generated under metatarsals and higher peak loading rates under all metatarsal heads compared to wearing a gym trainer

Shaft stiffness

  • Enclosing the ankle and shank with a stiffer boot shaft can create a protective effect in the lateral direction minimises lateral ligament ankle sprains
Dobson et al. [59] 2018 Cohort
n = 358 underground coal miners
Age = 39.2 ± 9.6 yr
Height = 178.7 ± 5.8 cm
Mass = 92.8 ± 12.6 kg 		Lower back was significantly related to

  • Heel breadth (χ2 = 8.1, p = 0.016)

  • Heel girth circumference (χ2 = 15.4, p = 0.038)

Foot pain was significantly related to

  • Ball of foot girth circumference (χ2 = 37.4, p = 0.021), specific to bunions

  • Instep Height (χ2 = 8.33, p = 0.034), specific to calluses

Hip pain was significantly related to

  • Instep height (χ2 = 12.7, p = 0.019)

Ankle pain occurrence was significantly related to toe angle (χ2 = 36.5, p = 0.013).
Instep height, ball of foot girth circumference, foot breadth, and toe angle were significant predictors of low back pain, hip pain, and foot problems. However, the R2 were low (0.062, 0.157, and 0.066 respectively).
Dobson et al. [47] 2017 Cross-Sectional
n = 358 Underground coal miners (335 male, 3 female)
Age =:
39.1 ± 10.7 yr
Height =
178.0 ± 31.0 cm
Mass =
92.1 ± 13.7 kg 		Participants were divided into two groups for analysis based on whether they chose to wear the employer-provided gumboot (n = 219 men and 3 women) or the other mandatory boot option of the leather lace-up boot (n = 109 men). No significant difference between boots for:

  • Presence of lower back pain

  • Presence of hip pain

  • Presence of knee pain

  • Presence of ankle pain

  • Presence of foot pain

There were significant differences between locations of foot pain.Gumboot wearers were more likely to have:

  • Ball of foot pain (χ2 = 12.87, p = 0.002)

  • Lateral malleolus pain (χ2 = 6.44, p = 0.040)

  • Arch pain (χ2 = 6.72, p = 0.035)

Leather boot wearers were more likely to have:

  • Corns (χ2 = 6.78, p = 0.034)

  • Navicular pain (χ2 = 7.09, p = 0.029)

  • Bunions (χ2 = 6.72, p = 0.035)

  • Sole pain (χ2 = 10.14, p = 0.006)

  • Heel pain (χ2 = 7.18, p = 0.028)

  • Cuboid pain (χ2 = 15.17, p = 0.001)
Dobson et al. [48] 2018 Cross-Sectional
n = 358 underground coal miners (335 male, 3 female)
Age =
39.1 ± 10.7 years
Height =
178.0 ± 31.0 cm
Mass =
92.1 ± 13.7 kg		 Participants with hip pain were more likely to rate their work boot fit as very poor, poor, or reasonable (χ2 = 11.9, p < 0.05).
Participants with foot pain were more likely to rate comfort as uncomfortable to indifferent (χ2 = 18.4, p < 0.001).
Dobson et al. [31] 2019 Quasi-experimental
n = 20 workers who habitually wore steel caped safety boots, 11 underground coal miners, 9 trade workers
Age =
36.0 ± 13.8 yr
Height =
174.8 ± 6.3 cm
Foot Length =
23.8 ± 0.6 cm
Foot Width =
9.2 ± 0.4 cm		 Four work boot conditions:
Flexible shaft and stiff sole

  • Mass: 0.94 kg

  • Shafter Height: 29.5 cm

  • Shaft Stiffness: 1.1 N

  • Shaft material: Leather and nylon blend

  • Sole Flexibility: 20.3°

Stiff shaft and stiff sole

  • Mass: 0.98 kg

  • Shafter Height: 30 cm

  • Shaft Stiffness: 1.7 N

  • Shaft material: Leather

  • Sole Flexibility: 20.3°

Stiff shaft and flexible sole

  • Mass: 0.98 kg

  • Shafter Height: 30 cm

  • Shaft Stiffness: 1.7 N

  • Shaft material: Leather

  • Sole Flexibility: 30.2°

Flexible shaft and flexible sole

  • Mass: 0.94 kg

  • Shafter Height: 29.5 cm

  • Shaft Stiffness: 1.1 N

  • Shaft material: Leather and nylon blend

  • Sole Flexibility: 30.2°

 Muscle burst onset relative to initial contact

  • Main effect boot shaft type (p < 0.001)

  • Main effect surface condition (p < 0.001)

  • Interaction between boot sole type and surface condition (p = 0.003)

  • Interaction between boot shaft, boot sole, and surface condition (p = 0.002)

Effects on muscle burst onset relative to initial contact when on gravel surface

  • Main effect of boot shaft type (p < 0.001)

  • Main effect of boot sole type (p = 0.032)

  • Boot shaft and sole interaction (p = 0.032)

Effects on muscle burst onset relative to initial contact when on soft surface

  • Main effect of boot sole type (p < 0.001)

  • Boot shaft and boot sole interaction (p = 0.044)

Thigh muscle onsets

  • Stiff shaft on gravel surface resulted in earlier vastus lateralis (p = 0.047) and semitendinosus (p = 0.003) onset relative to initial contact

  • Flexible sole with flexible shaft led to earlier semitendinosus onset (p = 0.004) on gravel

  • Flexible sole with flexible shaft led to earlier vastus lateralis onset (p) compared to stiff sole on soft surface

Shank muscle onsets

  • Stiff sole and stiff shaft resulted in earlier activation of peroneus longus (p = 0.023), and later activation of gastrocnemius (p = 0.005) compared to stiff sole and flexible shaft

  • Flexible shaft with flexible sole resulted in later tibialis anterior onset (p = 0.023) relative to initial contact on gravel surface compared to a stiff shaft

  • Stiff sole and stiff shaft led to earlier peroneus longus onset (p = 0.005) compared to a flexible sole on a soft surface

Peak muscle activity

  • Main effect boot sole type (p = 0.041)

  • Main effect surface condition (p < 0.001)

  • Interaction of boot shaft and boot sole type (p < 0.001)

  • Interaction of boot shaft type and surface (p = 0.035)

  • Interaction of boot sole type and surface (p = 0.002)

  • On gravel main effect of boot sole type (p = 0.029)

  • On gravel interaction of boot shaft and sole type (p < 0.001)

  • On soft surface main effect of boot shaft type (p = 0.026)

  • On soft surface main effect of boot sole type (p = 0.009)

  • On soft surface interaction effect of boot shaft and sole type (p < 0.001)

Peak thigh muscle activity

  • Gravel surface with stiff shaft and sole led to increase semitendinosus (p = 0.041) activity compared to flexible shaft

  • On gravel stiff sole with stiff shaft led to increased semitendinosus activity (p = 0.028)

  • On soft surface a stiff shaft and sole lead to higher semitendinosus activity (p < 0.001) compared to flexible shaft

  • On soft surface flexible sole and shaft led to higher semitendinosus activity (p < 0.001) compared to stiff sole

Peak shank muscle activity

  • On soft surface with flexible sole ad shaft led to higher peak medial gastrocnemius peak activity compared to stiff shaft

Muscle burst duration
No significant main effects of boot shaft or sole type on duration of lower limb muscle burst
Heel Contact Velocity
No significant main effects of boot shaft or sole type on heel contact velocity
Ankle alignment at initial contact

  • Main effect of boot shaft type (p = 0.022)

  • Interaction between boot shaft and sole type (p = 0.033)

  • Interaction between boot shaft and sole type and surface condition (p = 0.041)

  • On gravel surface significant main effect of boot shaft type (p = 0.010)

  • On gravel surface significant main effect of boot sole type (p = 0.027)

  • On gravel significant interaction between boot shaft and sole type (p = 0.027)

  • Boot with flexible sole and stiff shaft led to a greater eversion angle at initial contact compared to flexible shaft (p < 0.001)

  • Boot with stiff shaft and flexible sole resulted in greater eversion angle (p = 0.002) compared to a stiff boot sole
Dobson et al. [2] 2020 Quasi-experimental
n = 20 workers who habitually wore steel caped safety boots, 11 underground coal miners, 9 trades workers
Age =
36.0 ± 13.8 yr
Height =
174.8 ± 6.3 cm
Foot Length =
23.8 ± 0.6 cm
Foot Width
= 9.2 ± 0.4 cm		 Four work boot conditions:
Flexible shaft and stiff sole

  • Mass: 0.94 kg

  • Shafter Height: 29.5 cm

  • Shaft Stiffness: 1.1 N

  • Shaft material: Leather and nylon blend

  • Sole Flexibility: 20.3°

Stiff shaft and stiff sole

  • Mass: 0.98 kg

  • Shafter Height: 30 cm

  • Shaft Stiffness: 1.7 N

  • Shaft material: Leather

  • Sole Flexibility: 20.3°

Stiff shaft and flexible sole

  • Mass: 0.98 kg

  • Shafter Height: 30 cm

  • Shaft Stiffness: 1.7 N

  • Shaft material: Leather

  • Sole Flexibility: 30.2°

Flexible shaft and flexible sole

  • Mass: 0.94 kg

  • Shafter Height: 29.5 cm

  • Shaft Stiffness: 1.1 N

  • Shaft material: Leather and nylon blend

  • Sole Flexibility: 30.2°

 Significant main effect of boot shaft type on perceptions of foot (p = 0.025) and ankle (p = 0.48) ROM.
Significant main effect of boot sole type on perceptions of ankle support (p = 0.020)—No significant differences could be found on a post-hoc analysis.
Significant association (χ2 = 11.8, p = 0.008) between boot type and identification of best boot:Flexible shaft and still sole was preferred boot

  • Stiff shaft and still sole least preferred

No significant associations were identified between boot shaft or sole types and selection of best boot or worst boot.		 Significant main effect of boot shaft type (p = 0.043), boot sole type (p = 0.002), and foot region (p < 0.001) on:

  • Contact area

  • Contact time

  • Peak pressure

  • Pressure-time integral variables

  • Stiff boot shaft resulted in significantly:

  • Greater contact area and contact time under medial heel (p < 0.001)

  • Greater pressure-time integral and smaller contact area under medial midfoot (p = 0.015)

  • Greater contact time and peak pressure under middle metatarsals (p = 0.016)

Flexible sole resulted in significantly:

  • Greater peak pressure and pressure-time integral under medial heel (p < 0.001)

  • Reduced pressure-time integral under the hallux (p = 0.004)

Boot shaft and sole interactions significantly impacted:

  • Pressures under lateral midfoot (p < 0.001

  • Pressures under medial metatarsals (p = 0.038)

  • Pressures under lateral metatarsals (p = 0.009)

  • Pressures under lesser toes (p < 0.001)

A stiff sole with flexible shaft, when compared to stiff shaft resulted in significantly:

  • Increased contact area under lateral midfoot

  • Decreased peak pressure and pressure-time integral under medial metatarsals

A stiff shaft with flexible sole when compared to a flexible shaft:

  • Increased contact time under lateral midfoot

A stiff shaft with flexible sole compared to flexible shaft and stiff sole had:

  • Decreased peak pressure under lateral midfoot and metatarsals

  • Increased peak pressure under lesser toes

Flexible boot sole with stiff shaft compared to stiff sole.

  • Led to increased contact area and peak pressure under lateral midfoot compared to stiff sole

Flexible boot sole compared to a stiff boot sole led to a greater peak pressure under medial metatarsals.
Elbers et al. [57] 2020 Randomised Control Trial
n = 50 healthcare professionals (21 male, 29 female). Randomised to different clog sizes
Size 38 clogs
10 Male, 15 female
Age = 36.0 ± 12.0 yr
Height = 176.0 ± 10.0 cm
Size 47 clogs
Male 11, Female 14
Age = 38.0 ± 12.0 yr
Height = 176.0 ± 10.0 cm		 Randomised to either size 38 clogs or size 47 clogs. Size 38 clogs completed simulated course to emergency department in 34.2 ± 4.9 s
Size 47 clogs completed course in 38.8 ± 6.4 sec
Mean difference of −4.4 (95% CI −7.1- −1.6) s. No further modifications when accounting for gender, age, height, own shoe size, fitness, or staff function.		 No significant difference in comfort or adverse effects.
Garner et al. [32] 2013 Quasi-experimental
n = 12 professional firefighters
Age =
33.4 ± 6.8 yr
Height =
179.0 ± 6.5 cm
Mass =
95.8 ± 21.5 kg		 Comparison between rubber and leather boots.
Rubber mean mass per pair: 2.90 ± 0.20 kg.
Leather mean mass per pair: 2.40 ± 0.20 kg.		 Significant differences were found between boot types (F(1,11) = 3.522, p = 0.03).
Rubber boots resulted in greater sway (anteroposterior and medial-lateral) parameters, increased decrement in peak torque in lower limbs (which could lead to increase in localised fatigue).
Gell et al. [49] 2011 Cross-sectional
n = 407 automotive workers (309 male, 98 female)
Age = 48.4 ± 10.3 yr
BMI = 29.4 ± 5.3 kg/m2 		Significant differences in footwear between workers who reported feeling lower extremity fatigue at the end of the day and those that did not.
Individuals with harder outsoles were more likely to report lower limb fatigue (p < 0.01)
Having high hardness compared to low hardness increased odds of lower limb fatigue (OR = 2.6, 95% CI 1.3–5.3, p = 0.01).
Huebener et al. [33] 2014 Quasi-experimental
n = 10 canteen workers
Age Range = 25–48 yr, median = 38.5 yr		 Control Shoe: Standard safety shoe
Test Shoe: housed an exchangeable cushioning element in the heel of inner shoe sole. Cushioning element prescribed depending on mass.
Four categories:

  • <57 kg

  • 58–79 kg

  • 80–91 kg

  • >91 kg

Cushioning elements were then divided into three groups:

  • Dummy insert

  • Optimal prescription based on above categories

  • Too soft—cushion provided from lighter mass class than subject’s actual mass

 Cumulative muscle activity per distance travelled (CAMPD) (an indirect measure of required energy expenditure) was measured.
Significant differences across shoes were found only in back muscles at preferred (F(3,7) = 7.016, p = 0.016) and fast (F(3,7) = 4.568, p = 0.045) with optimal damping showing the lowest values.
While not significant too soft showed the lowest values in the leg muscles, while optimal and no damping were the most economical in the abdominal muscle groups.
Control shoes showed the highest values across all conditions.
Significant differences were found for normalised mean range for leg muscles at preferred (F(3,7) = 8.256, p = 0.011) and fast walking velocities (F(3,7) = 7.105, p = 0.016) with optimal dampening resulting in higher scores.
Though not significant lowest values occurred in control and non-dampened shoes in all muscle groups, with exception of abdominal muscles with optimal dampening resulting in highest values during preferred walking speed, control shoes showing values during fast walking speed, and marginal differences at slow speed.
Optimal and too soft damping led to reduced amplitude heel strike levels, but these were not significant.
Test shoes tended to have an earlier onset of back muscle activity.
Optimal cushioning suggested significantly and consistently smaller amplitude peaks at the back muscles (10/12 t-tests showing significant differences, mean effect of 1.00, individual results not disclosed).
Irmańska [60] 2015 Cohort
n = 45 firefighters
Group A (n = 15)
Age = 33.4 ± 3.5 yr
BMI = 25.4 ± 2.7 kg/m2
Group B (n = 15)
Age = 32 ± 5.5 yr
BMI = 25.7 ± 2.9 kg/m2
Group C (n = 15)
Age = 31.5 ± 2.48 yr
BMI = 25.0 ± 2.9 kg/m2 		Group A Boot:

  • Novel liner with ventilation

  • Polyester and Lyocell blend

  • Upper mass range: 170–200 g/m2

  • Insole mass range: 170–400 g/m2

Group B Boot:

  • Novel liner with no ventilation

  • Polyester and Lyocell blend

  • Upper mass range: 170–200 g/m2

  • Lower mass range: 80–400 g/m2

Group C Boot:

  • Standard liner

  • Wool

  • Upper mass 400 g/m2

  • Lower mass 400 g/m2

 No significant differences were identified for foot mobility between boots.
Thermal sensations (p < 0.05) and moisture sensations (p < 0.01) were more strongly reported in Group C and Group B compared to Group A.
Thermal sensations and moisture sensations were comparable between Group C and Group B.
No significant differences between groups with

  • Walking difficulty (χ2 = 7.71, p > 0.05)

  • Kneeling/crouching difficulty (χ2 = 1.09, p > 0.05)

 Significant difference between footwear with descriptions of chaffing (χ2 = 6.14, p < 0.05) with Group A noted as less chaffing
Group C had significantly less comfort (presence of rough, sharp, or hard areas that could cause injury or irritation) than Group A or B (χ2 = 10.49, p < 0.05).
Irmańska and Tokarski [34] 2016 Quasi-experimental
n = 40 males: 20 younger (Y) and 20 older (O)
Group Y:
Age Range = 20–30 yr
Height Range =167–186 cm
Mass Range = 66–90 kg
Occupations: firefighters, drivers, and farmers.
Group O:
Age Range = 60–65 yr
Height Range = 166–188 cm
Mass Range = 60–95 kg
Occupations: Farmers and security personnel.		 Two boot types:
Type A: low cut, sandal-like protective footwear

  • Slip resistance: 0.31

  • Impact absorption by materials at ankle: not tested due to construction

  • Sole tread: 3.31 mm

  • Energy absorption at the heel: 36 = 37 J

Type B: Protective ankle boots

  • Slip resistance: 0.35

  • Impact absorption at ankle: 9.8 kN

  • Sole tread: 3.36 mm

  • Energy absorption at heel: 35–36J

 No significant difference in hip ROM between Y & O groups while in footwear.
Significant difference in knee ROM between Y& O.
Footwear A

  • Treadmill test L t = −3.86, p < 0.001, O > Y

  • Stair climbing L t = −2.64, p < 0.05, O > Y

  • Treadmill test R t = −3.66, p < 0.05, O > Y

Footwear B

  • Treadmill test L t = −4.67, p < 0.001, O > Y

  • Stair climbing L t = −3.79, p < 0.001, O > Y

  • Significant difference in talocrural ROM between Y & O.

Footwear A

  • Treadmill test L t = 4.11, p <0.001 Y > O

  • Treadmill test R t = 2.08, p < 0.05 Y > O

  • Stairclimbing R t = 2.01, p < 0.05. Y > O

Footwear B

  • Treadmill R t = 4.09, p < 0.001 Y > O

  • Stairclimbing R t = 5.34, p < 0.001

Compared to barefoot

  • Footwear A resulted in significantly more flexion at left and right hip joints during treadmill walking for group Y (p < 0.05)

  • Footwear A resulted in significantly less L talocrural joint range during treadmill walking and stair climbing for group O (p < 0.05)

  • Footwear B resulted in significantly less joint L knee joint range during treadmill walking for group Y (p < 0.05)

  • Footwear B resulted in significantly less L talocrural joint range during stair climbing for group Y (p < 0.05)

  • Footwear B resulted in significantly less R talocrural joint range during stair climbing for group O (p < 0.05)

Compared to Footwear A

  • Footwear B resulted in significantly more L talocrural joint range during stair climbing for group Y (p < 0.05)
Knapik et al. [65] 2015 Systematic Review with meta-analysis.
Comparison of military physical training before and after 1982 when running shoes replaced military boots as footwear during physical training.		 Identified 12 data collection periods, three during the “boot” period of training and 9 post. Identified two separate injury definitions (overall and lower extremity injuries).
Meta analysis showed:

  • Injury incidence in males of 26.2% (95% CI 23.1–29.3) training in boots

  • Injury incidence in females of 54.0% (95% CI 48.9–59.1) training in boots

  • Overall injury incidence in males of 27.1% (95% CI 22.1–32.7) training in shoes

  • Overall injury incidence in females of 54.9% (95% CI 46.8–62.8)

χ2 results showed

  • Any injury male (RR shoe/ boot 1.04 (95% CI 0.91–1.18; p = 0.50)

  • Lower extremity injury male (RR shoe/boot 0.91 (95% CI 0.64–1.30) p = 0.66)

  • Any injury female (RR shoe/boot 0.94 (95% CI 0.85–1.05) p = 0.27)

  • Lower extremity injury female (RR shoe/boot 1.06 (0.89–1.27) p = 0.51)
Knapik et al. [64] 2015 Narrative Review Reviews injuries and running shoes in military populations over the transition from standard issue boots to running shoes in the U.S. Military in 1982. Cites previous literature showing that injury incidence was not significantly reduced with introduction of running shoes into PT:

  • Any injury male (26% injury incidence before 1982, 27% after, p = 0.50)

  • Lower extremity injury male (23% injury incidence before 1982, 21% after p = 0.66)

  • Any injury female (54% injury incidence before 1982, 51% after, p = 0.27)

  • Lower extremity injury female (42% before 1982, 45% after, p = 0.51)
Kocher et al. [36] 2020 Quasi-experimental
n = 10 workers (8 male, 2 female)
Age = 28.6 ± 6.0 yr
Mass = 86.9 ± 19.0 kg
Height = 182.0 ± 8.0 cm 		4 boot styles:

  • Hiker style (laces, shorter shank) with steel toe (HS)

  • Hiker style with metatarsal guard (HM)

  • Wader-style (slip on, taller shank) with steel toe (WS)

  • Wader-style with metatarsal guard (WM)

Wader style shanks were slightly rolled down to allow placement of gait analysis markers.		 Boot style significant interaction with:

  • Foot velocity (Ascending R: p = 0.03, effect size = 0.278)

  • Hip ROM: (Descending L: p = 0.005, effect size = 0.373, R p = 0.01, effect = 0.331)

  • Knee ROM: (Descending L: p = 0.004, effect size = 0.777, R p = 0.005, effect = 0.744)

  • Ankle ROM: (Ascending L: p < 0.001, effect size = 0.777, R: p < 0.001, effect size = 0.681; Descending L: p < 0.001, effect size = 0.703, R p < 0.001, effect = 0.512

Differences between boot type:

  • WS significantly less ROM than HS (ascending L and R ankle; descending R ankle), HM (ascending L and R ankle; descending L ankle)

  • WM significantly less ROM than HS (ascending L and R ankle; descending L and R ankle; descending L and R knee), HM (ascending L and R ankle; descending L ankle; descending L and R knee), WS (descending left hip)

Incline level and Boot significant interaction with:

  • Stride length (Ascending L: p = 0.02, effect size = 0.23)
Lee et al. [35] 2014 Quasi-experimental
n = 8 firefighters
Age = 39.4 ± 5.6 yr
Mass = 74.2 ± 10.0 kg
Height = 173.9 ± 3.8 cm
VO2Max = 42.0 ± 5.1 mL/kg/min
Experience = 10.4 ± 7.0 yr		 Tested various components of firefighter PPE with comparisons between firefighter boots and thin sandals. Total sweat rate (p < 0.05), rectal temperature (p < 0.05), skin temperature (p < 0.05), heart rate (p < 0.05), and oxygen consumption (p < 0.05) varied significantly (both during exercise and recovery) across PPE worn
The PPE condition of no boots (but other PPE worn such as self-breathing apparatus, helmet, and gloves) resulted in similar physiologic scores as no thermal clothing and no equipment and greater benefits compared to removing the breathing apparatus, helmet, or gloves
Majumdar et al. [37] 2006 Quasi-experimental
n = 8 infantry soldiers
Age = 26.7 ± 2.7 yr
Mass = 59.3 ± 5.1 kg
Height = 164.8 ± 4.4 cm		 Comparison between barefoot and standard issue military boots.
Testing conditions also included wearing combat vest.		 Military boot resulted in

  • Longer step & length [cm] (R 67.3 vs. 62.9, p < 0.001; L 65.7 vs. 61.5, p < 0.001 & R 132.9 vs. 124.6, p < 0.001; L 132.8 vs. 124.2, p < 0.001, respectively)

  • Slower cadence [steps/min] (R 100 vs. 105.4, p < 0.01; L 99.9 vs. 105.4 p < 0.01)

  • Less total support time [%] (R 59.0 vs. 59.6, p < 0.05; L58.5 vs. 59.7, p < 0.01)

  • Longer swing phase [%] (R 40.9 vs. 40.4, p < 0.05; L 41.5 vs. 40.3 p < 0.01

  • Less initial double support time [%] (R 8.8 vs. 9.4, p < 0.05, L 8.6 vs. 9.8 p < 0.05)

  • More single support time [%] (R 41.5 vs. 40.3, p < 0.01)

  • No significant difference between L single support time, step width, or forward velocity
Muniz et al. [38] 2021 Quasi-experimental
n = 24 male soldiers
Age = 18.9 ± 0.6 yr
Mass = 67.3 ± 8.6 kg
Height = 170.0 ± 10.0 cm		 Comparison between military boots made with styrene-butadiene rubber (SBR), polyurethane (PU). Compared in both unloaded and loaded (15 kg) conditions.
Boot Characteristics
SBR

  • Mass: 561.49 g

  • Energy absorption: 23 joules

  • Hardness: 63

  • Density: 1.132 g/cm3

  • Midsole rear-foot thickness: 36 mm

  • EVA insole thickness: 3 mm

PU

  • Mass: 380.33 g

  • Energy: absorption 31 joules

  • Hardness: 48

  • Density: 0.563 g/cm3

  • Midsole rear-foot thickness: 32 mm

  • EVA insole thickness: 3 mm

 Instantaneous loading rate (%BW/s):

  • SBR Unload 24.5 ± 6.6; Load 25.1 ± 5.2

  • PU Unload 26.1 ± 4.3; Load 27.8 ± 4.1

  • p = 0.04, η2 = 0.04

Median power frequency (Hz):

  • SBR Unload 21.8 ± 3.3; Load 22.4 ± 4.7

  • PU Unload 24.6 ± 2.8; Load 24.9 ± 2.2

  • p < 0.01, η2 = 0.16

No significant difference in first peak force (%BW) or significant interactions between load and footwear.
Muniz and Bini [39] 2017 Quasi-experimental
n = 20 Army recruits
Age = 18.9 ± 0.6 yr
Mass = 67.3 ± 8.6 kg
Height = 170.0 ± 10.0 cm		 Compared three boot conditions:
Boot 1

  • SBR

  • Mass: 631.8 g

  • Rear-foot thickness: 30 mm

  • EVA: 3 mm thickness

Boot 2

  • SBR

  • Mass: 530.3 g

  • Rear-foot thickness: 20.6 mm

  • EVA: 3 mm thickness

Boot 3

  • PU

  • Mass: 423 g

  • Rear-foot thickness: 31.7 mm

  • EVA: 3 mm thickness

 Significant difference in one component of the vertical principal component analysis (Boot 1 = −0.095 ± 0.13; Boot 2 = −0.030 ± 0.15; Boot 3 = − 0.064 ± 0.11; p < 0.001).
Significant difference in one component of the anteroposterior component analysis (Boot 1 = 0.05 ± 0.09; Boot 2 = −0.04 ± 0.10; Boot 3 = −0.03 ± 0.37).
Significant difference in two components of the mediolateral component analysis between Boot 1 (PC2 −0.03 ± 0.05; PC4 −0.02 ± 0.04) and Boot 2 (PC2 0.04 ± 0.05; PC4 0.02 ± 0.04).
Significant difference in comfort between Boot 1 (5.5 ± 1.7) and Boot 3 (7.7 ± 2.3) as measured by visual analogue scale.
Neugebauer and Lafiandra [40] 2018 Quasi-experimental
n = 15 male soldiers		 Comparison between military boots and athletic footwear across 4 loads—0 kg, 14 kg, 27 kg, and 46 kg. Hardness of footwear did was not a significant predictor of max ground reaction force (p = 0.70).
Type of footwear was a significant model factor, but did not improve predictions considerably (r2 = 0.892) over predictive. Model without footwear type (r2 = 0.891).
The average absolute percent difference with and without footwear term were similar (4.8% and 4.7% respectively).
Oschman et al. [9] 2016 Quasi-experimental
n = 20 male automotive workers
Age = 33.2 ± 10.5 yr
Mass = 80.1 ± 7.8 kg
Height = 177.9 ± 3.9 cm
Median foot size (range)
27.8 cm (26 cm–28.7 cm)		 Tested three safety shoes:
Shoe 1

  • Steel safety cap

  • Mass: 530 g

  • No varying widths

  • Little cushioning

  • No insole

  • Treadsole—PU

  • No ergonomic specifics

Shoe 2

  • Aluminium safety cap

  • Mass: 630 g

  • Different widths

  • Cushioning in heel and forefoot

  • Insole present

  • Treadsole—thermoplastic polyurethane (TPU)

  • Mass dependent heel absorption

Shoe 3

  • Steel safety cap

  • Mass: 720 g

  • No varying widths

  • Heel cushioning

  • Insole present

  • Combination of PU and TPU

  • Rocker-bottom sole (curve in anterior-posterior direction)

 Significant differences between trunk inclination 50th percentile between Shoe 1 (8.9 ± 2.2°) and Shoe 2 (6.7 ± 3.5°), p = 0.005, Shoe 1 and Shoe 3 (5.9 ± 2.4°), p < 0.001.
Significant difference in the 50th percentile of hip flexion between all shoes (Shoe 1: 14.0 ± 3.6°, Shoe 2: 11.5 ± 3.9°, Shoe 3: 10.2 ± 2.8°)

  • Shoe 1 and Shoe 2 p = 0.015

  • Shoe 1 and Shoe 3 p = 0.001

  • Shoe 2 and Shoe 3 p = 0.046

Significant differences in knee flexion (95th–5th percentiles) between Shoe 1 (62.3 ± 3.4°) and Shoe 2 (64.0 ± 3.6°), p = 0.008 and Shoe 2 and Shoe 3 (62.0 ± 4.3°), p < 0.001.
No significant differences in 50th percentile knee flexion hip flexion ROM (95th–5th percentile) or trunk ROM (95th–5th percentile).		 Significant differences between Shoe 1 and Shoe 2 in maximum plantar pressure (N/cm2):

  • Rearfoot zone 1: 27.9 ± 3.1 vs. 24.2 ± 2.0 p < 0.001

  • Rearfoot zone 2: 19.7 ± 3.1 vs. 14.4 ± 2.6 p < 0.001

  • Midfoot zone 3: 4.7 ± 1.3 vs. 5.5 ± 1.0 p = 0.002

  • Midfoot zone 4 2.8 ± 0.7 vs. 4.5 ± 1.2 p < 0.001

  • Midfoot zone 5 2.9 ± 0.9 vs. 4.7 ± 1.5 p < 0.001

  • Forefoot zone 6 12.0 ± 5.7 vs. 17.9 ± 5.9 p < 0.001

  • Forefoot zone 7 25.0 ± 4.0 vs. 22.9 ± 3.5 p = 0.003

Significant differences between Shoe 1 and Shoe 3 in maximum plantar pressure: (N/cm2):

  • Rearfoot zone 1: 27.9 ± 3.1 vs. 24.2 ± 2.9 p < 0.001

  • Midfoot zone 3: 4.7 ± 1.3 vs. 5.6 ± 1.1 p = 0.005

  • Midfoot zone 4: 2.8 ± 0.7 vs. 5.2 ± 1.5 p < 0.001

  • Midfoot zone 5: 2.9 ± 0.9 vs. 4.0 ± 1.1 p < 0.001

  • Forefoot zone 7: 25.0 ± 4.0 vs. 20.9 ± 3.5 p < 0.001

Significant differences between Shoe 2 and Shoe 3 in maximum plantar pressure (N/cm2):

  • Rearfoot zone 2: 14.4 ± 2.6 vs. 18.1 ± 2.7 p < 0.001

  • Midfoot zone 4: 4.5 ± 1.2 vs. 5.2 ± 1.5 p = 0.002

  • Midfoot zone 5: 4.7 ± 1.5 vs. 4.0 ± 1.1 p = 0.002

  • Forefoot zone 6: 17.9 ± 5.9 vs. 14.0 ± 5.3 p < 0.001

  • Forefoot zone 7: 22.9 ± 3.4 vs. 20.9 ± 3.4 p < 0.001

  • Forefoot zone 8: 17.1 ± 6.5 vs. 19.8 ± 4.9 p < 0.001

Significant differences in centre of pressure posterior-anterior 95–5th percentile for all 3 shoes (Shoe 1 159.5 ± 10.8 mm, Shoe 2 149.1 ± 10.3 mm, Shoe 3 143.7 ± 10.5 mm):

  • Shoe 1 and Shoe 2 p < 0.001

  • Shoe 1 and Shoe 3 p < 0.001

  • Shoe 3 and Shoe 3 p = 0.003

Significant difference in 50th percentile centre of pressure medial lateral:

  • Shoe 1 (2.0 ± 1.7 mm) and Shoe 2 (3.5 ± 2.0 mm) p < 0.001

  • Shoe 2 (3.5 ± 2.0 mm) and Shoe 3 (2.0 ± 2.0 mm) p = 0.002

Significant difference in 95th–5th percentile centre of pressure medial lateral:

  • Shoe 1 (22.1 ± 5.1 mm) and Shoe 3 (20.2 ± 4.7 mm) p = 0.022

  • Shoe 2 (22.2 ± 4.7 mm) and Shoe 3 (20.2 ± 4.7 mm) p = 0.001
Oliver et al. [41] 2011 Quasi-experimental
n = 16 Reserve Officer Training Corps cadets (13 male, 3 female)
Age = 21.0 ± 3.0 yr
Mass = 79.0 ± 12.0 kg
Height = 172.0 ± 10.0 cm		 Comparison between bare feet, tennis shoes, and issued military boots. No significant differences in the degree of knee valgus between conditions.
Significant differences for ground reaction force as percentage of bodyweight (bare feet: 1646 ± 359%, tennis shoe: 1880 ± 379%, boot: 1833 ± 438%, p < 0.05).
Pace et al. [8] 2020 Quasi-experimental
n = 14 male Reserve Officer Training Corps cadets
Age Range 20–30 yr
Mass = 86.2 ± 10.4 kg
Height = 177.0 ± 6.0 cm
Body Fat = 8.1 ± 3.2%
Load VO2Max = 46.6 ± 7.3 mL/kg/min
No load VO2Max = 47.1 ± 5.7 mL/kg/min		 Comparison between minimalist style (MIN) and standard issue military boots. Significant difference in respiratory exchange ratio (RER) between MIN (0.94 ± 0.06) and standard issue (1.00 ± 0.07) p < 0.01, Cohen’s d = 0.90.
Significant difference in VO2 while running MIN 34.4 ± 3.3 mL/kg/min, standard issue 35.5 ± 3.5 mL/kg/min p < 0.05, Cohen’s d = 0.31
Significant different in rating of perceived exertion (RPE) in breathing during:

  • walking: MIN 2.0 ± 0.9, standard issue 2.4 ± 1.2, p < 0.05, Cohen’s d 0.33

  • running: MIN 4.0 ± 1.8, standard issue 4.8 ± 1.5, p < 0.01, Cohen’s d = 0.43

Significant difference between RPE in legs while running MIN 4.4, standard issue 5.7 ± 1.7 p < 0.05, Cohen’s d = 0.69.
Park et al. [10] 2015 Quasi-experimental
n = 12 (8 male, 4 female) firefighters
Male:
Age = 28.6 ± 8.3 yr
Mass = 85.5 ± 15.7 kg
Height = 183.5 ± 3.8 cm
Female:
Age = 31.5 ± 13.5 yr
Mass = 68.3 ± 14.3 kg
Height = 170.8 ± 7.6 cm		 Comparison between running shoes, rubber firefighting boots, and leather firefighting boots.
Running shoes

  • Mass: 0.71 ± 0.24 kg

  • Flex resistance: 5.97 ± 2.28 N

Rubber boots

  • Mass: 3.15 ± 0.29 kg

  • Flex resistance: 27.2 ± 1.2 N

  • Collar height: 38 cm

  • Outsole height: 3 cm at heel, 1.5 cm at forefoot

  • Rubber in upper and outsole

  • Metal toe cap and metal shank

Leather boots

  • Mass: 3.02 ± 0.19 kg

  • Flex resistance: 34.4 ± 2.6 N

  • Collar height: 34 cm

  • Outsole height: 3.5 cm at heel, 1.8 cm at forefoot

  • 60%kevlar/40% Nomex fabric for upper

  • Metal toe cap and metal shank

 Significant differences existed between running shoes and both rubber and leather boots in:

  • Normalised anterior-posterior excursion (67.24% running shoes, 64.27% rubber, 63.35% leather) p < 0.001

  • Centre of pressure velocity (58.55 cm/s running shoes, 55.07 cm/s rubber, 53.42 cm/s) p < 0.001

  • Stride time (1.11 sec running shoes, 1.17 sec rubber, 1.17 sec leather) p < 0.001

  • Stance phase (59.92% running shoes, 61.31% leather) p < 0.001. No significant difference between running shoes and rubber (59.74%)

  • Double support (8.96% running, 10.5% leather) p < 0.001. No significant difference between running shoes and rubber (8.9%)

Significant differences existed between rubber and leather boots in:

  • Stance phase (59.74% rubber, 61.31% leather) p < 0.001

  • Double support (8.9% rubber, 10.5% leather) p < 0.001
Park et al. [43] 2015 Quasi-experimental
n = 12 (8 male, 4 female) firefighters
Male:
Age = 28.6 ± 8.3 years
Mass = 85.5 ± 15.7 kg
Height = 183.5 ± 3.8 cm
Female:
Age = 31.5 ± 13.5 years
Mass = 68.3 ± 14.3 kg
Height = 170.8 ± 7.6 cm		 Comparison between running shoes, rubber firefighting boots, and leather firefighting boots.
Running shoes

  • Mass: 0.71 ± 0.24 kg

  • Flex resistance: 5.97 ± 2.28 N

Rubber boots

  • Mass: 3.15 ± 0.29 kg

  • Flex resistance: 27.2 ± 1.2 N

  • Collar height: 38 cm

  • Outsole height: 3 cm at heel, 1.5 cm at forefoot

  • Rubber in upper and outsole

  • Metal toe cap and metal shank

 Range of motion in the sagittal plane significantly differed in:

  • Hip (Running shoes 49 ± 1.21°, boots 50.99 ± 1.21°) p < 0.001. Indicates more hip flexion in boots

  • Knee (Running shoes 64.14 ± 1.13°, boots 67.82 ± 1.14°) p < 0.001. Indicates more knee flexion in boots

  • Ankle (Running shoes 42.25 ± 1.59°, boots 36.59 ± 1.60°) p < 0.001. Indicates less dorsiflexion in boots

  • Ball of foot (Running shoes 63.71 ± 1.81°, boots 52.91 ± 1.86°) p < 0.001. Indicates less hallux flexion in boots

Range of motion in the frontal plane significantly differed in:

  • Ankle (Running shoes 16.19 ± 1.46°, boots 18.53 ± 1.49°) p = 0.026. Indicates more inversion in boots

  • Ball of foot (Running shoes 18.30 ± 1.62°, boots 26.19 ± 1.67°) p < 0.001. Indicates more adduction in boots

Range of motion in the transversal plane significantly differed in:

  • Ankle (running shoes 22.05 ± 2.05°, boots 17.97 ± 2.07°) p < 0.001. Indicates more extra-rotation in boots

  • Ball of foot p (running shoes 8.15 ± 0.904°, boots 11.10°) < 0.001, Indicates more extra-rotation in boots
Park et al. [42] 2019 Quasi-experimental
n = 14 firefighters (11 male, 3 female)
Age = 32.7 ± 12.3 yr
Mass = 79.2 ± 13.4 kg
Height = 177.3 ± 4.7 cm		 3 leather boot heights were tested:

  • Low: 25.4 cm

  • Medium: 30.48 cm

  • High: 35.56 cm

 Greater ROM for low boots than high boots regardless of knee heights for hip, knee, and ankle (mean differences = 2.0 −5.3°; F = 5.398–5.648 p = 0.004–0.005).
Greater knee ROM for low boots compared to higher during duckwalking (F = 6.67, p = 0.002)
Greater ROM in low compared to high boots
accounting for knee height in hip ROM during duckwalking (mean difference: 10.5–12.8°; F = 15.127, p = 0.006).
Firefighters with taller knee height had significantly smaller ankle ROM in high boots (15.35°) than in low boots (17.53°) (p = 0.025) during ladder ascension.
Schulze et al. [44] 2014 Quasi-experimental
n = 32 soldiers
Age Mean (Median) = 29.0 (26.0) yr
Mass Mean (Median) = 81.6 (81.0) kg
Height Mean (Median) = 177.8 (179.0) cm		 5 shoe variations compared:
Dress shoe

  • Mass: 530 g

  • Cow leather

  • Rubber sole

  • 3-hole lacing

Combat boot

  • Mass: 1135 g

  • Adherent rubber sole

  • Leather with leather lining

  • Bolstered boot leg

  • 8-hole lacing

Outdoor athletic shoe (old design)

  • Mass: 500 g

  • Leather

  • Nubby rubber sole

  • Ankle padding

  • 6-hole lacing

Outdoor athletic shoe (new design)

  • Mass: 720 g

  • Leather and textile

  • Moulded rubber sole

  • Padded boot leg and insole

  • Toe protection

  • 6-hole lacing

Indoor athletic

  • Mass: 600 g

  • Cow leather

  • Texon Baking insole

  • Moulded rubber sole (fine)

  • Textile lining

  • 6-hole lacing

 Significant increase in stride length in combat boot compared to barefoot (p < 0.001).
Greater increase in stride length in combat boot compared to outdoor shoe (p = 0.005).
Significant reduction in plantar flexion in combat boot compared to barefoot (p < 0.001) and all other shoe types (p < 0.05).
No significant change in knee ROM in combat boot compared to barefoot.
No significant change in hip ROM in combat book compared to barefoot.
Scott et al. [50] 2015 Cross Sectionsn = 195 Army Cadets (165 male, 30 female)
Age range = 18 to 33 yr
BMI = 23.5 ± 2.9 kg/m2 		Most frequent boot type worn was collected through survey. 41 cadets suffered a lower extremity injury.
7 wearing government issued footwear.
17 wearing conventional running shoes.
17 wearing “other”.
Boot type was not significantly associated with injury (χ2 = 0.19, p = 0.91).
Simeonov et al. [45] 2018 Quasi-experimental
n = 24 male construction workers
Age (Range) = 39 (23–53) yr
Height = 178.3 ± 6.9 cm
Mass = 86.4 ± 12.6 kg		 6 shoe styles compared:
Running Shoe

  • Mass: 312 g

  • Impact-peak acceleration (PG): 8.43 gravity unit for acceleration (G)

  • Impact-time to peak acceleration (TTP): 14.20 ms

  • Initial flex stiffness: 0.17 Nm/deg

  • Torsion: 3.80 Nm

  • Heel width: 8.5 cm

Tennis Shoe

  • Mass: 416 g

  • Impact-PG: 8.59 G

  • Impact-TTP: 12.60 ms

  • Initial flex stiffness: 0.35 Nm/deg

  • Torsion: 5.34 Nm

  • Heel width: 9.1 cm

Basketball Shoe

  • Mass: 472 g

  • Impact-PG: 8.79 G

  • Impact-TTP: 11.20 ms

  • Initial flex stiffness: 0.35 Nm/deg

  • Torsion: 5.70 Nm

  • Heel width: 9.2 cm

Work low-cut

  • Mass: 642 g

  • Impact-PG: 8.76 G

  • Impact-TTP: 10.10 ms

  • Initial flex stiffness: 0.42 Nm/deg

  • Torsion: 7.22 Nm

  • Heel width: 8.7 cm

Work boot

  • Mass: 690 g

  • Impact-PG: 10.05 G

  • Impact-TTP: 9.27 ms

  • Initial flex stiffness: 0.47 Nm/deg

  • Torsion: 7.16 Nm

  • Heel width: 8.7 cm

Safety boot

  • Mass: 768 g

  • Impact-PG: 11.91

  • Impact-TTP: 9.43 ms

  • Initial flex stiffness: 0.54 Nm/deg

  • Torsion: 7.59 Nm

  • Heel width: 8.7 cm

 Significant main effects for footwear F65, 490.7 = 3.39 p < 0.0001 and the interaction of footwear and environment F195, 3319.2 = 1.66, p < 0.0001)
Trunk angular velocity (T-AV):

  • Similar while walking at simulated ground level

  • High cut shoes resulted in significantly (p < 0.05) lower T-AV compared to low cut shoes on 15 and 25 cm planks

  • Safety boots had the lowest T-AV on 15 cm plank

  • Generally lower T-AV for work and safety boots compared to work shoes, but not significant

  • T-AV less affected by plank width when wearing safety (p = 0.0516) or work (p = 0.0005) compared to low-cut work shoe

Rearfoot angular velocity (F-AV):

  • Similar F-AV between work shoes when walking on ground level

  • High-cut shoes resulted in significantly (p < 0.05) less F-AV than low-cut shoes on 15 cm, but not 25 cm planks

  • Surface lateral slope caused less increase in F-AV for work low-cut shoes compared to safety boots

 Perceptions of instability (PI)

  • Similar PI regardless of shoe when walking on simulated ground level

  • Workers felt significantly more stable in high cut shoes (p < 0.05) compared to low cut shoes on 15 and 25 cm planks

Work boots had a higher, but not significantly so, perception of comfort compared to other work shoes.
Sousa et al. [70] 2016 Case-Control
n = 30 female hairdressers, 14 experiment and 16 in control
Experimental Group
Age = 34.6 ± 7.7 yr
Mass = 65.3 ± 9.6 kg
Height = 159.0 ± 6.0 cm
Control Group
Age = 34.9 ± 8.0 yr
Mass = 61.1 ± 6.3 kg
Height = 162.0 ± 6.0 cm		 Unstable shoe with rounded sole use for 8 weeks compared to regular footwear. Wearing unstable shoe for 8 weeks presented:

  • Decreased in Centre of pressure area (F(1,27) = 8.296, p = 0.01)

  • Decreased Medial-lateral centre of pressure root mean square (RMS) (F(1,27) =4.376, p = 0.046)

  • Decreased Anteroposterior movement to a reference point (RM) peak to peak amplitude (F(1,27) = 8.414, p = 0.007)

  • Increased Anteroposterior RM mean velocity (F(1,27) = 4.641, p = 0.040)

  • Increased medial-lateral RM peak to peak amplitude (F(1,27) = 17.457, p < 0.001)

  • Decreased anteroposterior RMS of body movement around a reference point (F(1,27) = 8.069, p < 0.001)

  • Higher anteroposterior centre of pressure mean velocity (F(1,27) = 6.684, p = 0.015)

  • Higher anteroposterior centre of pressure RMS (F(1,27) = 37.694, p < 0.001)

  • Higher medial-lateral centre of pressure (F(1,27)—83.820, p < 0.001) RMS and area (F(1,27)—40.175, p < 0.001)

  • Lower RM peak to peak amplitude anteroposterior (F(1,27) = 5.073, p < 0.001) and lower RMS anteroposterior F(1,27) = 21.667, p < 0.001)

  • Higher RM peak to peak amplitude and higher RMS in medial-lateral (F(1,27) = 137.664, p < 0.001, F(1,27) = 11.084, p = 0.003)

  • Higher medial lateral RM area (F(1,27) = 102.5334, p < 0.001)

  • Reference through which the body oscillates (TR) was observed for anteroposterior RMS (F(1,27) = 18.704, p < 0.001)

  • Increased medial-lateral TR RMS (F(1,27)—6.804, p = 0.015)

  • Increased medial-lateral TR area (F(1,27) = 37.721, p < 0.001)

  • Increased thigh antagonist co-activation (F(1,27) = 6.414, p = 0.012)

  • Decreased thigh co-activation (F(1,28) = 21.038, p < 0.001)

  • Increased reciprocal activation (F(1,28) = 18.23, p < 0.001)

  • Decreased leg co-activation (F(1,28)—8.131, p = 0.008)

  • Increased reciprocal activation (F(1,28) = 22.292, p < 0.001)

  • Decreased lobal antagonist co-activation (F(1,28) = 12.940, p = 0.001)

  • Increased total agonist activity (F(1,28) = 25.711, p < 0.001)
Svenningsen et al. [46] 2017 Quasi-experimental
n = 14 working adults across various professions (7 male, 7 female)
Age = 39.3 ± 6.8 yr
Mass = 75.9 ± 12.6 kg
Height = 175.7 ± 7.3 cm		 Unstable shoe

  • Rocker sole shoes

  • Sole 2.0 cm at heel, 3.9 cm at midfoot, 3.5 cm in forefoot

Control

  • 1.9 cm height at heel, 3.0 cm in midfoot, 3.0 cm in forefoot

 No main effects of shoes or load, or interaction effects between the two were found on stride duration or stride frequency. Significantly higher EMG peak in longissimus thoracis wearing unstable shoes (p = 0.01, ηp2 = 0.143).
Significantly higher RMS for longissimus thoracis (p = 0.001, ηp2 = 0.614) and iliocostalis lumborum (p = 0.0001, ηp2 = 0.487).
Talley et al. [61] 2009 Cohort
n = 38 ship injury reports		 Probability of ship injury wearing steel-toed safety boot versus not wearing such boots. 42.1% of individuals injured were wearing safety boots.
Wearing safety boots was significantly likely to decrease probability of injury on container ship 2 (decrease by 0.609) (separated by container ship 1 by having different union officers).
Tojo et al. [51] 2018 Cross-sectional
n = 636 nurses
Mean demographic data not provided		 Low shoe comfort score was associated with:

  • Reported presence of foot and ankle pain (OR 2.12 (95% CI 1.31–3.50, p = 0.002)

  • Presence of foot pain assessed with Manchester Foot Pain and Disability Index (OR 1.78 (95% CI 1.18–2.69) p = 0.006)

  • Presence of disabling foot pain as assessed with Manchester Foot Pain and Disability Index (OR 1.76 (95% CI 1.01–3.11), p = 0.04)

Medium comfort not significantly associated with presence of foot and ankle pain (p = 0.21).
Viera et al. [58] 2016 Randomised Control Trial
n = 10 female nurses and 10 matched pairs
Control Group
Age = 31.0 ± 5.0 yr
Mass = 66.0 ± 9.0 kg
Height = 161.0 ± 5.0 cm
Experimental Group
Age = 34.0 ± 6.0 yr
Mass = 68.0 ± 11.0 kg
Height = 165.0 ± 7.0 cm		 Unstable shoes compared to regular occupational footwear. Experimental group reported significantly lower levels of pain at Weeks 4 (p = 0.016) and 6 (p < 0.001).
Significantly lower levels of disability at Week 6 (p = 0.020). Participants started at moderate levels of disability at baseline and were at minimal post intervention.
Vu et al. [7] 2017 Quasi-experimental
n = 20 male firefighters
Age = 41.3 ± 8.8 yr
Mass = 84.4 ± 11.6 kg
Height = 181.0 ± 6.0 cm		 Comparison between firefighting boots and athletic footwear.
Firefighting boots

  • 178 mm shaft height in EU size 41 or 42

  • 192 mm shaft size for size 45 and above

  • Type 2 structural Haix Fire Flash Xtreme boot

 Landing in firefighter boots resulted in:

  • Significantly increased vertical GRF (2.40 times BW compared to 2.14 times, p < 0.05)

  • Reduction of right ankle plantarflexion angle in unloaded (control −36.41 ± 10.43°, boot −25.59 ± 9.17°) and loaded comparisons (control −40.73 ± 11.55°, boot −28.31± 13.51°) p < 0.05

  • Greater peak lumbopelvic flexion angular velocity while unloaded (222.89 ± 18.47 °/s) and load (240.91 ± 24.37 °/s) compared to control unloaded (187.56 ± 60.96 °/s), p < 0.05

  • Increased peak lumbopelvic flexion force (unloaded 13.40 ± 1.48 N/kg, loaded 14.46 ± 1.46 N/kg) compared to control (unloaded 12.32 ± 5.44 N/kg, loaded 14.37 ± 6.94 N/kg), p < 0.05

  • Greater peak lumbopelvic adduction force (control 19.84 ± 11.44 N/kg, boot 30.54 ± 19.76 N/kg), p < 0.01

  • Greater peak lumbopelvic adduction moments (control 2.21 ± 1.01 Nm/kg, boots 3.15 ± 0.50 Nm/kg), p < 0.001

  • Greater peak lumbar internal rotation angular velocities unloaded (111.06 ± 13.07 °/s) and loaded (114.49 ± 16.40 °/s) compared to unloaded control (80.51 ± 47.23 °/s), p < 0.05

  • Greater peak lumbar internal rotation moments unloaded (3.26 ± 0.34 Nm/kg) and loaded (3.81 ± 0.42 Nm/kg) compared to control (2.60 ± 0.78 Nm/kg) p < 0.05
Werner et al. [52] 2010 Cross sectional study
n = 407 automotive workers
Age = 48.4 ± 10.3 yr
BMI = 29.4 ± 5.3 kg/m2 		Rotation of shoes during the work week reduced risk of presenting with plantar fasciitis (OR 0.30, p = 0.01, 95% CI 0.1–0.7).
No significant effect of outer sole stiffness on plantar fasciitis.
Werner et al. [54] 2010 Cross-sectional study
n = 407 automotive workers
Age = 48.4 ± 10.3 yr
BMI = 29.4 ± 5.3 kg/m2 		Shoe rotation not significantly associated with foot/ankle disorders (p = 0.75).
Outer sole stiffness not significantly associated with foot/ankle disorders (p = 0.77) but was associated with new foot and ankle disorders:

  • Stiffness middle tertile OR 8.2, p = 0.05, 95% CI 1.01–65.5

  • Stiffness upper tertile OR 18.9, p = 0.01, 95% CI 2.2–165.8
Werner et al. [53] 2011 Cross-sectional study
n = 407 automotive workers
Age = 48.4 ± 10.3 years
BMI = 29.4 ± 5.3 kg/m2 		No significant association between firmness of heel (p = 0.75), firmness of insole (p = 0.91) or shoe rotation (p = 0.35) and incidence of hip disorders.
Yeung et al. [66] 2011 Systematic Review
Military personnel		 Identified two studies that compared a tropical combat boot cotton/nylon blend to a leather combat boot. No significant difference between footwear and lower limb soft-tissue injuries for any location.

All descriptive values represent mean and standard deviation unless otherwise noted. ANOVA: Analysis of Variance; ANCOVA: Analysis of Covariance; BMI: Body Mass Index; BW: Body weight; CAMPD: Cumulative muscle activity per distance travelled; CI: Confidence Interval; EMG: Electromyography; EVA: Ethylene-vinyl acetate; MIN: Minimalist; NFPA: National Fire Protection Association; OR: Odds Ratio; PPE: Personal Protective Equipment; PU: Polyurethane; RCT: Randomised Control Trial; RER: Respiratory Exchange Ratio; RMS: Root Mean Square; ROM: Range Of Movement; RPE: Rating Of Perceived Exertion; RR: Risk Ratio; SBR: Styrene-butadiene rubber; VO2: Volume of Oxygen; VCO2: Volume of Carbon Dioxide; VE: Ventilatory Exchange, Yr: year.