Document Type : Research Paper


1 Ph.D. Student of Corrective Exercises and Sports Injuries, University of Tehran

2 Professor of Sports Medicine, University of Tehran

3 Associated Professor of Corrective Exercises and Sports Injuries, University of Tehran

4 Associated Professor of Biomechanics, University of Social Welfare and Rehabilitation Sciences

5 Assistant Professor of Corrective Exercises and Sports Injuries, Sport Sciences Research Institute of Iran


The purpose of this study was to compare maximum vertical, and posterior ground reaction force and loading rate between flexible flatfoot and normal foot football players in single leg drop – landing from 30 cm height. 10 flexible flatfoot and 11 normal foot football players participated in this study. After warm- up and familiarization with single leg drop-landing task, each participant performed 5 successful trials. The results showed that, there is no significant difference in maximum vertical ground reaction force, maximum posterior ground reaction force and loading rate between flexible flatfoot football players and normal foot football players. Kinetic parameters in flexible flatfoot football players probably can’t be result in injury incidence in this population.


  1. Mootanah R, Song J, Lenhoff MW, Hafer JF, Backus SI, Gagnon D, et al. Foot type biomechanics. Part 2: Are structure and anthropometrics related to function? Gait Posture. 2013;37(3):452-6.
  2. Dare DM, Dodwell ER. Pediatric flatfoot: Cause, epidemiology, assessment, and treatment. Curr Opin Pediatr. 2014;26(1):93-100.
  3. Shibuya N, Kitterman RT, LaFontaine J, Jupiter, DC. Demographic, physical, and radiographic factors associated with functional flatfoot deformity. J Foot Ankle Surg. 2014;53(2):168-72.
  4. Bouchard M, Mosca VS. Flatfoot deformity in children and adolescents: Surgical indications and management. J Am Acad Orthop Surg. 2014;22(10):623-32.
  5. Echarri JJ, Forriol F. The development in footprint morphology in 1851 Congolese children from urban and rural areas, and the relationship between this and wearing shoes. J Pediatr Orthop B. 2003;12(2):141-6.
  6. Pauk J, Ezerskiy V, Raso JV, Rogalski M. Epidemiologic factors affecting plantar arch development in children with flat feet. J Am Podiatr Med Assoc. 2012;102(2):114-21.
  7. Ghorbani M. Prevalence of flat foot: Comparison between male and female primary school students. Iran Rehabil J. 2013;18)11(:22-4.
  8. Kordi YA. The evaluation and prevalence of foot problems among iranian students using alfoots company scanner. Health Sci. J. 2014;8(3):393-9.
  9. Pauk J, Szymul J. Differences in pediatric vertical ground reaction force between planovalgus and neutrally aligned feet. Acta Bioeng Biomech. 2014;16(2):95-101.
  10. Hargrave MD, Carcia CR, Gansneder BM, Shultz SJ. Subtalar pronation does not influence impact forces or rate of loading during a single-leg landing. J Athl Train. 2003;38(1):18-23.
  11. Choi JH, An HJ, Yoo KT. Comparison of the loading rate and lower limb angles on drop-landing between a normal foot and flatfoot. J Phys Ther Sci. 2012;24(11):    1153-7.
  12. Blackburn JT, Padua DA. Sagittal-plane trunk position, landing forces, and quadriceps electromyographic activity. J Athl Train. 2009;44(2):174-9.
  13. Van Der Harst J, Gokeler A, Hof A. Leg kinematics and kinetics in landing from a single-leg hop for distance. A comparison between dominant and non-dominant leg. Clin Biomech. 2007;22(6).674-80.
  14. Wang L-I. The lower extremity biomechanics of single-and double-leg stop-jump tasks. J Sports Sci Med. 2011;10(1):151-6.
  15. Zhang S, Derrick TR, Evans W, Yu YJ. Shock and impact reduction in moderate and strenuous landing activities. Sports Biomech. 2008;7(2):296-309.
  16. McNitt-Gray JL. Kinetics of the lower extremities during drop landings from three heights. J Biomech. 1993;26(9):1037-46.
  17. Farahpour N, Jafarnezhad A, Damavandi M, Bakhtiari A, Allard P. Gait ground reaction force characteristics of low back pain patients with pronated foot and able-bodied individuals with and without foot pronation. J Biomech. 2016;49(9):1705-10.
  18. Niu W, Feng T, Jiang C, Zhang M. Peak vertical ground reaction force during two-leg landing: A systematic review and mathematical modeling. Biomed Res Int. 2014; [Accessed 31 Agu 2016]. Availible from:
  19. Sadeghi H, Shoja AS, Akbari H. Comparison of anterior knee shear force in pronated and supinated foot in single leg landing. Journal of Movement Science & Sports. 2008;6 (11):1-12.
  20. Akbari H, Rajabi M, Ebrahimi Atri A, Hashemi Javaheri SAA, Khademi Nejad S. Does pronated foot predispose the females to risk of anterior Cruciate ligament injury. Int J Sport Stud. 2013;3(5):492-7.
  21. Pauk J, Griškevičius J. Ground reaction force and support moment in typical and flat-feet children. Mechanics. 2011;17(1):93-6.
  22. Decker MJ, Torry MR, Wyland DJ, Sterett WI, Steadman JR. Gender differences in lower extremity kinematics, kinetics and energy absorption during landing. Clin Biomech. 2003;18(7):662-9.
  23. Newton RU, Young WB, Kraemer WJ, Byrne C. Effects of drop jump height and technique on ground reaction force with possible implication for injury. Res Sports Med. 2001;10(2):83-93.
  24. Hakimipoor M. The validity and reliability of the foot photo box in measuring selected footprint indexes [MSc thesis]. Tehran: Tehran university; 2015.
  25. Staheli L. Evaluation of planovalgus foot deformities with special reference to the natural history. J Am Podiatr Med Assoc. 1987;77(1):2-6.
  26. Gehring D, Melnyk M, Gollhofer A. Gender and fatigue have influence on knee joint control strategies during landing. Clin Biomech. 2009;24(1):82-7.
  27. Willson JD, Ireland ML, Davis I. Core strength and lower extremity alignment during single leg squats. Med Sci Sports Exerc. 2006;38(5):945-52.
  28. Sung PS. The ground reaction force thresholds for detecting postural stability in participants with and without flat foot. J Biomech. 2016;49(1):60-5.
  29. 29.Coventry E, O’Connor KM, Hart BA, Earl JE, Ebersole KT. The effect of lower extremity fatigue on shock attenuation during single-leg landing. Clin Biomech. 2006;21(10):1090-7.
  30. Dufek JS, Bates BT. The evaluation and prediction of impact forces during landings. Med Sci Sports Exerc. 1990;22(3):370-7.
  31. Sadeghi H, Abbasi A, Khaleghi M, Pourbakhshi M. Lower extremity muscles torques and rate of loading during single leg drop landing. Research on Sport Science. 2008;6(19):157-69.
  32. Nigg BM. Biomechanics, load analysis and sports injuries in the lower extremities. Sports Med. 1985;2(5):367-79.
  33. Neely FG. Biomechanical risk factors for exercise-related lower limb injuries. Sports Med. 1998;26(6):395-413.
  34. Hewett TE, Myer GD, Ford KR, Heidt RS, Colosimo AJ, McLean SG, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes a prospective study. Am J Sports Med. 2005;33(4):492-501.
  35. McNair PJ, Marshall RN. Landing characteristics in subjects with normal and anterior cruciate ligament deficient knee joints. Arch Phys Med Rehabil. 1994;75(5):584-9.