Static and dynamic plantar foot shape following long-term use of military boots

Foot structure can be influenced by various factors, such as footwear, body weight and physical activity. A change in foot structure can alter shock absorption and force transition. The main objective of this study is to investigate the effect of the long-term use of military boots on foot shape parameters. Thirty military and thirty non-military subjects participated in this case-control study. All participants had been regularly wearing military boots for the past 12 years. After introducing the experiment, static and dynamic footprints were recorded via paper and ink while standing and walking. The footprints were analysed using ImageJ software to extract foot width indices, area indices, truncated arch index, footprint index and arch angle index. The findings indicated no significant difference in comparison static and dynamic variables in the military and non-military groups (p ≥ 0.05). However, there was a significant difference between the two groups in both static (midfoot area, arch index (AI), truncated arch index, footprint index and arch angle index) and dynamic (midfoot width, Staheli Index (SAI), truncated arch index and arch angle index) conditions, when static and dynamic variable were compared (p < 0.05). Findings revealed the military personnel have low arch, making them susceptible to musculoskeletal disorders. To mitigate this risk, it is recommended that military boots be reassessed or that insoles be used. Furthermore, it is suggested that military boots be limited to specific activities and fewer hours of usage to avoid potential health issues.

Military personnel; Military boot; Foot biomechanics; Foot deformities; Gait

[1] Grassi A, Mosca M. Anatomy and biomechanics of the foot and ankle. In D’Hooghe P, Hunt KJ, McCormick JJ (eds.) Ligamentous injuries of the foot and ankle: diagnosis, management and rehabilitation (pp. 5–16). Springer: Cham. 2022.

[2] Price C, Schmeltzpfenning T, Nester CJ, Brauner T. Foot and footwear biomechanics and gait. In Luximon A (ed.) Handbook of footwear design and manufacture (pp. 79–103). 2nd edn. Woodhead Publishing: Cambridge. 2021.

[3] Lai Z, Liu M, Wang L, Zhang ZW. Plantar loads characteristics of male non-rearfoot strikers running on different overground surfaces at preferred speed. Journal of Men’s Health. 2022; 18: 105.

[4] Peng Y, Wong DW, Chen TL, Wang Y, Zhang G, Yan F, et al. Influence of arch support heights on the internal foot mechanics of flatfoot during walking: a muscle-driven finite element analysis. Computers in Biology and Medicine. 2021; 132: 104355.

[5] Neumann DA. Kinesiology of the musculoskeletal system. 3rd edn. Elsevier Health Sciences: New York. 2016.

[6] Maiwald C, Mayer TA, Milani TL. Alterations of plantar pressure patterns and foot shape after long distance military marching. Footwear Science. 2018; 10: 203–213.

[7] McWhorter JW, Wallmann H, Landers M, Altenburger B. The effects of walking, running, and shoe size on foot volumetrics. Physical Therapy in Sport. 2003; 4: 87–92.

[8] Kelley PW. Military preventive medicine: mobilization and deployment. Borden Institute, Walter Reed Army Medical Center: Washington, D.C. 2003.

[9] Jo J, Sokolowski S, McQuerry M, Griffin L, Park H. Firefighters’ feet: differences by sex and weight-bearing. Applied Ergonomics. 2022; 102: 103753.

[10] Escalona-Marfil C, Prats-Puig A, Ortas-Deunosajut X, Font-Lladó R, Ruiz-Tarrazo X, Evans AM. Children’s foot parameters and basic anthropometry—do arch height and midfoot width change? European Journal of Pediatrics. 2023; 182: 777–784.

[11] Barati AH, Bagheri A, Azimi R, Darchini MA, Nik HN. Comparison balance and footprint parameters in normal and overweight children. International Journal of Preventive Medicine. 2013; 4: S92–S97.

[12] Desai M, Gandhi S. Foot posture and balance in marathon runners, badminton players and footballers. Journal of Exercise Science & Physiotherapy. 2020; 16: 19–29.

[13] Acak M, Korkmaz M, Taskiran C, Demirkan E. Investigating the effects of wrestling gear in flatfoot deformity of wrestlers. Physical Education and Sport Pedagogy. 2020; 24: 106–110.

[14] Bini RR, Kilpp DD, Júnior PA, Muniz AM. Comparison of ground reaction forces between combat Boots and sports shoes. Biomechanics. 2021; 1: 281–289.

[15] Xiong S, Goonetilleke RS, Witana CP, Weerasinghe TW, Au EY. Foot arch characterization: a review, a new metric, and a comparison. Journal of the American Podiatric Medical Association. 2010; 100: 14–24.

[16] Windle C, Gregory S, Dixon S. The shock attenuation characteristics of four different insoles when worn in a military boot during running and marching. Gait & Posture. 1999; 9: 31–37.

[17] Sandhu K, Chatterjee MS, Srivastava V, Pal M. Effect of different combat boots on peak ground reaction forces during walking. International Journal of Human Factors and Ergonomics. 2023; 10: 283–294.

[18] Bhattacharyya D, Chatterjee T. Military footwear and extreme environment operations: an ergonomics perspective. In Tulsawani R, Vohora D (eds.) Adaptation under stressful environments through biological adjustments and interventions (pp. 161–184). Springer: New Delhi. 2024.

[19] Yoon YS, An D, Lee Y, Lee DY, Kyung MG. Comparison of in-shoe plantar pressure between Korean combat boots and running shoes. To be published in BMJ Military Health. 2024. [Preprint].

[20] Lullini G, Giangrande A, Caravaggi P, Leardini A, Berti L. Functional evaluation of a shock absorbing insole during military training in a group of soldiers: a pilot study. Military Medicine. 2020; 185: e643–e648.

[21] Muniz A, Bini R. Shock attenuation characteristics of three different military boots during gait. Gait & Posture. 2017; 58: 59–65.

[22] Majumdar D, Banerjee PK, Majumdar D, Pal M, Kumar R, Selvamurthy W. Temporal spatial parameters of gait with barefoot, bathroom slippers and military boots. Indian Journal of Physiology and Pharmacology. 2006; 50: 33–40.

[23] Hakimi Poor M, Minoonejad H, Rajabi R, Mousavi SH. Validity of the most common footprint indices in measuring medial longitudinal arch in comparison with a radiographic method as a gold standard. Journal of Advanced Sport Technology. 2022; 6: 86–95.

[24] Menz HB, Munteanu SE. Validity of 3 clinical techniques for the measurement of static foot posture in older people. Journal of Orthopaedic & Sports Physical Therapy. 2005; 35: 479–486.

[25] Hu A, Arnold JB, Causby R, Jones S. The identification and reliability of static and dynamic barefoot impression measurements: a systematic review. Forensic Science International. 2018; 289: 156–164.

[26] Cureton TK. The validity of footprints as a measure of vertical height of the arch and functional efficiency of the foot. Research Quarterly. American Physical Education Association. 1935; 6: 70–80.

[27] Fascione JM, Crews RT, Wrobel JS. Dynamic footprint measurement collection technique and intrarater reliability: ink mat, paper pedography, and electronic pedography. Journal of the American Podiatric Medical Association. 2012; 102: 130–138.

[28] Gutiérrez-Vilahú L, Massó-Ortigosa N, Costa-Tutusaus L, Guerra-Balic M. Reliability and validity of the footprint assessment method using Photoshop CS5 software. Journal of the American Podiatric Medical Association. 2015; 105: 226–232.

[29] Vijayakumar K, Subramanian R, Senthilkumar S, Dineshkumar D. An analysis of arches of foot: a comparison between ink foot print method and custom made podoscope device method. Journal of Pharmaceutical Research International. 2021; 33: 249–256.

[30] Houston VL, Luo G, Mason CP, Mussman M, Garbarini M, Beattie AC. Changes in male foot shape and size with weightbearing. Journal of the American Podiatric Medical Association. 2006; 96: 330–343.

[31] Kim D, Lewis CL, Gill SV. Effects of obesity and foot arch height on gait mechanics: a cross-sectional study. PLOS ONE. 2021; 16: e0260398.

[32] Zhang L, Yick KL, Li PL, Yip J, Ng SP. Foot deformation analysis with different load-bearing conditions to enhance diabetic footwear designs. PLOS ONE. 2022; 17: e0264233.

[33] Aydog S, Tetik O, Demirel H, Doral MN. Differences in sole arch indices in various sports. British Journal of Sports Medicine. 2005; 39: e5.

[34] Berdejo-del-Fresno D, Lara Sánchez A, Martinez-Lopez E, Cachón-Zagalaz J. Footprint modifications according to the physical activity practised. Revista Internacional de Medicina y Ciencias de la Actividad Fisica y del Deporte. 2013; 13: 19–38.

[35] Jiang H, Mei Q, Wang Y, He J, Shao E, Fernandez J, et al. Understanding foot conditions, morphologies and functions in children: a current review. Frontiers in Bioengineering and Biotechnology. 2023; 11: 1192524.

[36] D’AoÛt K, Pataky TC, De Clercq D, Aerts P. The effects of habitual footwear use: foot shape and function in native barefoot walkers. Footwear Science. 2009; 1: 81–94.

[37] Holowka NB, Wallace IJ, Lieberman DE. Foot strength and stiffness are related to footwear use in a comparison of minimally- vs. conventionally-shod populations. Scientific Reports. 2018; 8: 3679.

[38] Chander H, Arachchige SNK, Wilson SJ, Knight AC, Burch VRF, Carruth DW, et al. Impact of military footwear type and a load carriage workload on slip initiation biomechanics. International Journal of Human Factors and Ergonomics. 2020; 7: 125–143.

[39] Nikolaidou M, Boudolos K. A footprint-based approach for the rational classification of foot types in young schoolchildren. The Foot. 2006; 16: 82–90.

[40] innofoot. Biomechanical assessment. 2020. Available at: http://innofoot.ibv.org/index.php/en/biomechanical-assessment-procedures (Accessed: 12 December 2017).

[41] Hinz P, Henningsen A, Matthes G, Jäger B, Ekkernkamp A, Rosenbaum D. Analysis of pressure distribution below the metatarsals with different insoles in combat boots of the German Army for prevention of march fractures. Gait & Posture. 2008; 27: 535–538.

[42] Gerych D, Tvrznik A, Prokesova E, Nemeckova Z. Analysis of peak pressure, maximal force, and contact area changes during walking and running with conventional and shock-absorbing insoles in the combat boots of the Czech army. Journal of Mechanics in Medicine and Biology. 2013; 13: 1350042.

[43] Mundermann A, Stefanyshyn DJ, Nigg BM. Relationship between footwear comfort of shoe inserts and anthropometric and sensory factors. Medicine & Science in Sports & Exercise. 2001; 33: 1939–1945.

[44] Sayyah A, Rahimi A, Hosseini SM, Baghban AA. Effects of long-term use of the high-heel shoes on the plantar pressure pattern in women’s feet. The Scientific Journal of Rehabilitation Medicine. 2016; 5: 12–21.

[45] Babu D, Bordoni B. Anatomy, bony pelvis and lower limb, medial longitudinal arch of the foot. StatPearls Publishing: Treasure Island (FL). 2023.