1. ERGOnomics TECHnologies
Miss. Natalie Ross
A-TEMP ISSUE 002
An investigation into the biomechanical impact of military combat boots
14 September 2017

2. Background
Lower limb injuries remain a significant factor impacting military personnel and combat readiness
Overuse injuries that worsen with repeated exposure to stress
Footwear design is a major factor influencing injury mechanisms of lower limbs – little attention from military stand point
Training and operational activities of soldiers typically performed in combat boots – suspected that design features may contribute to injury
Belief is presented in literature for advantages for performing military training activities in running shoes as opposed to combat boots
Only one study has compared injury incidence between military
boots and running shoes (Knapik et al., 2015).
No biomechanical comparison

3. Background
Designed to provide protection and increased stability over unpredictable terrains:
Stiffer boot shaft
Stronger material make-up
Stiffer mid-sole
Increased traction properties

4. ? ? Background Durability Thicker material Protection
Stiffer mid-sole
Torsional stability
Protective functions
Stiffer boot shaft
Ankle stability
Traction properties
Increased grip
Increased mass ? ?
Muscle activity
Limited ankle range of motion
Biomechanical consequences
Ground reaction forces
Injury risk
Decreased shock absorption
Contact pressure

5. Background
Aim was to compare the biomechanical responses of soldiers walking in running shoes to military boots

6. Experimental design Lab based study 22 injury free male soldiers
Gradient %
-10 10
Footwear
Barefoot
Running shoes
Military combat boots

7. Ground reaction forces
Dependent variables
Ground reaction forces
Impact peak
Peak loading rate
Propulsive peak
Braking peak
Bertec Instrumented Treadmill
Muscle activity
Rectus femoris
Biceps femoris
Gastrocnemius
Tibialis anterior
Delsys Wireless EMG
Pressure analysis
Peak contact pressure at foot-shoe interface
Tekscan System

8. Results

9. Ground reaction forces (GRFs)* *
Impact peak
Peak loading rate

10. Ground reaction forces
Greater amount of vertical force exerted through the musculoskeletal system
More rapidly exerted
Increased stress placed onto the joints and soft tissues increasing the risk of injury

11. Running shoes vs barefoot
Muscle activity
Downhill
Level
Uphill
Muscle
Running shoes vs barefoot
Boots vs barefoot
Boots vs running shoes
Gastrocnemius -
Rectus femoris
Biceps femoris
Tibialis anterior
Significant increase
No significant change -

12. Rectus femoris
Knee extension during swing, heel strike and support phases
Responsible for positioning the foot for landing and controlling weight acceptance
Increased muscle activation required for weight acceptance during declined walking in military boots
Increased energetic cost

13. Gastrocnemius Plantar flexion during toe-off
Generates forward propulsion of foot
Increased propulsive force is required during inclined walking
Increased strain on Achilles tendon
Increased energetic cost

14. Pressure analysis * * *

15. Pressure analysis Significantly higher peak contact pressure
Running shoes:
Military combat boots:
Significantly higher peak contact pressure
Pressure map (KPa) at the right shoe-foot interface

16. Conclusions and recommendations
This study provides evidence to support that training in combat boots results in unfavourable biomechanical responses, when compared to training in running shoes:
Increased vertical GRFs
Increased gastrocnemius muscle activation during inclined walking
Increased rectus femoris muscle activation during declined walking
Increased plantar pressure at foot-shoe interface at all gradients .

17. Conclusions and recommendations
The study highlights the importance to consider the impact of footwear on the energetic cost of locomotion and lower limb injury occurrence among military personnel.
These factors should be considered for optimal shoe design
Emphasis should be placed on reducing the mass of military combat boots as well as providing improved shock absorption properties to help distribute plantar pressure and transmission of ground reaction forces.
The use of running shoes should be considered for certain military training activities as opposed to military boots.
Future research: analysis of hip, knee and ankle kinematic data .