Document Type: Original Article


1 Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran

2 Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran


Background: The maintenance of postural control is a key component in dynamic physical activity, especially during muscle fatigue and against external forces. Despite many studies in this field, there is no consensus regarding the effects of plantar flexor muscles fatigue on postural control during different postural tasks.
Objective: To evaluate the effects of plantar flexor muscles fatigue on postural control during quiet stance and external perturbation in healthy subjects.
Material and Methods: Twenty four healthy individuals (20-35 years) participated this interventional study. The foot center of pressure data was measured using a single force platform, and then the postural control parameters, including the center of pressure displacement and velocity in the anterior-posterior and medial-lateral direction and also path length calculated under two conditions; quiet and perturbed stance, before and after plantar flexor muscles fatigue.
Results: The statistical analysis demonstrated that mean displacement and velocity of the center of pressure in the anterior-posterior direction and also path length increased after the fatigue protocol in the perturbed condition. However, fatigue had no significant effects on postural control parameters in the quiet standing condition.
Conclusion: These results indicated that the effects of muscle fatigue on postural control depend on the difficulty of the task and the relevance of proprioceptive information. The postural control system appears to use distinct control strategies in different situations such as quiet and perturbed stance conditions, and these strategies may be differentially altered by fatigue. In conclusion, due to the potential risk of loss of balance, it is important to take the role of plantar flexor muscle fatigue into account during more difficult postural tasks.


  1. Jacobs JV, Horak FB. Cortical control of postural responses. J Neural Transm (Vienna). 2007;114:1339-48. doi: 10.1007/s00702-007-0657-0. PubMed PMID: 17393068; PubMed Central PMCID: PMC4382099.
  2. Horak FB, Henry SM, Shumway-Cook A. Postural perturbations: new insights for treatment of balance disorders. Phys Ther. 1997;77:517-33. PubMed PMID: 9149762.
  3. Vuillerme N, Danion F, Forestier N, Nougier V. Postural sway under muscle vibration and muscle fatigue in humans. Neurosci Lett. 2002;333:131-5. PubMed PMID: 12419498.
  4. Ochsendorf DT, Mattacola CG, Arnold BL. Effect of orthotics on postural sway after fatigue of the plantar flexors and dorsiflexors. J Athl Train. 2000;35:26-30. PubMed PMID: 16558604; PubMed Central PMCID: PMC1323434.
  5. Gribble PA, Hertel J. Effect of lower-extremity muscle fatigue on postural control. Arch Phys Med Rehabil. 2004;85:589-92. PubMed PMID: 15083434.
  6. Gimmon Y, Riemer R, Oddsson L, Melzer I. The effect of plantar flexor muscle fatigue on postural control. J Electromyogr Kinesiol. 2011;21:922-8. doi: 10.1016/j.jelekin.2011.08.005. PubMed PMID: 21917475.
  7. Boyas S, Remaud A, Bisson EJ, Cadieux S, Morel B, Bilodeau M. Impairment in postural control is greater when ankle plantarflexors and dorsiflexors are fatigued simultaneously than when fatigued separately. Gait Posture. 2011;34:254-9. doi: 10.1016/j.gaitpost.2011.05.009. PubMed PMID: 21646020.
  8. Ivanenko YP, Talis VL, Kazennikov OV. Support stability influences postural responses to muscle vibration in humans. Eur J Neurosci. 1999;11:647-54. PubMed PMID: 10051765.
  9. Caron O. Effects of local fatigue of the lower limbs on postural control and postural stability in standing posture. Neurosci Lett. 2003;340:83-6. PubMed PMID: 12668242.
  10. Harkins KM, Mattacola CG, Uhl TL, Malone TR, McCrory JL. Effects of 2 ankle fatigue models on the duration of postural stability dysfunction. J Athl Train. 2005;40:191-4. PubMed PMID: 16284640; PubMed Central PMCID: PMC1250260.
  11. Kent-Braun JA. Central and peripheral contributions to muscle fatigue in humans during sustained maximal effort. Eur J Appl Physiol Occup Physiol. 1999;80:57-63. doi: 10.1007/s004210050558. PubMed PMID: 10367724.
  12. Baker AJ, Kostov KG, Miller RG, Weiner MW. Slow force recovery after long-duration exercise: metabolic and activation factors in muscle fatigue. J Appl Physiol (1985). 1993;74:2294-300. doi: 10.1152/jappl.1993.74.5.2294. PubMed PMID: 8335559.
  13. Wilder DG, Aleksiev AR, Magnusson ML, Pope MH, Spratt KF, Goel VK. Muscular response to sudden load. A tool to evaluate fatigue and rehabilitation. Spine (Phila Pa 1976). 1996;21:2628-39. PubMed PMID: 9045348.
  14. Granacher U, Gruber M, Forderer D, Strass D, Gollhofer A. Effects of ankle fatigue on functional reflex activity during gait perturbations in young and elderly men. Gait Posture. 2010;32:107-12. doi: 10.1016/j.gaitpost.2010.03.016. PubMed PMID: 20434345.
  15. Enoka RM. Muscle fatigue--from motor units to clinical symptoms. J Biomech. 2012;45:427-33. doi: 10.1016/j.jbiomech.2011.11.047. PubMed PMID: 22197185.
  16. Vuillerme N, Burdet C, Isableu B, Demetz S. The magnitude of the effect of calf muscles fatigue on postural control during bipedal quiet standing with vision depends on the eye-visual target distance. Gait Posture. 2006;24:169-72. doi: 10.1016/j.gaitpost.2005.07.011. PubMed PMID: 16226030.
  17. Salavati M, Moghadam M, Ebrahimi I, Arab AM. Changes in postural stability with fatigue of lower extremity frontal and sagittal plane movers. Gait Posture. 2007;26:214-8. doi: 10.1016/j.gaitpost.2006.09.001. PubMed PMID: 17049237.
  18. Adlerton AK, Moritz U. Does calf-muscle fatigue affect standing balance? Scand J Med Sci Sports. 1996;6:211-5. PubMed PMID: 8896093.
  19. Caron O. Is there interaction between vision and local fatigue of the lower limbs on postural control and postural stability in human posture? Neurosci Lett. 2004;363:18-21. Doi: 10.1016/s0304-3940(04)00338-6 .
  20. Gribble PA, Hertel J. Effect of hip and ankle muscle fatigue on unipedal postural control. J Electromyogr Kinesiol. 2004;14:641-6. doi: 10.1016/j.jelekin.2004.05.001. PubMed PMID: 15491838.
  21. Boyas S, Hajj M, Bilodeau M. Influence of ankle plantarflexor fatigue on postural sway, lower limb articular angles, and postural strategies during unipedal quiet standing. Gait Posture. 2013;37:547-51. doi: 10.1016/j.gaitpost.2012.09.014. PubMed PMID: 23102672.
  22. Kennedy A, Hug F, Bilodeau M, Sveistrup H, Guevel A. Neuromuscular fatigue induced by alternating isometric contractions of the ankle plantar and dorsiflexors. J Electromyogr Kinesiol. 2011;21:471-7. doi: 10.1016/j.jelekin.2011.02.001. PubMed PMID: 21376628.
  23. Pinsault N, Vuillerme N. Differential postural effects of plantar-flexor muscle fatigue under normal, altered and improved vestibular and neck somatosensory conditions. Exp Brain Res. 2008;191:99-107. doi: 10.1007/s00221-008-1500-z. PubMed PMID: 18663436.
  24. Vuillerme N, Pinsault N. Re-weighting of somatosensory inputs from the foot and the ankle for controlling posture during quiet standing following trunk extensor muscles fatigue. Exp Brain Res. 2007;183:323-7. doi: 10.1007/s00221-007-1047-4. PubMed PMID: 17643234.
  25. Janssens L, Brumagne S, Polspoel K, Troosters T, McConnell A. The effect of inspiratory muscles fatigue on postural control in people with and without recurrent low back pain. Spine (Phila Pa 1976). 2010;35:1088-94. doi: 10.1097/BRS.0b013e3181bee5c3. PubMed PMID: 20393397.
  26. Paillard T. Effects of general and local fatigue on postural control: a review. Neurosci Biobehav Rev. 2012;36:162-76. doi: 10.1016/j.neubiorev.2011.05.009. PubMed PMID: 21645543.
  27. Adlerton AK, Moritz U, Moe-Nilssen R. Forceplate and accelerometer measures for evaluating the effect of muscle fatigue on postural control during one-legged stance. Physiother Res Int. 2003;8:187-99. Doi: 10.1002/pri.289.
  28. Panzer VP, Bandinelli S, Hallett M. Biomechanical assessment of quiet standing and changes associated with aging. Arch Phys Med Rehabil. 1995;76:151-7. PubMed PMID: 7848073.
  29. Winter DA. Human balance and posture control during standing and walking. Gait Posture. 1995;3:193-214. Doi: 10.1016/0966-6362(96)82849-9.
  30. Amann M, Dempsey JA. Locomotor muscle fatigue modifies central motor drive in healthy humans and imposes a limitation to exercise performance. J Physiol. 2008;586:161-73. doi: 10.1113/jphysiol.2007.141838. PubMed PMID: 17962334; PubMed Central PMCID: PMC2375542.
  31. Bisson EJ, McEwen D, Lajoie Y, Bilodeau M. Effects of ankle and hip muscle fatigue on postural sway and attentional demands during unipedal stance. Gait Posture. 2011;33:83-7. doi: 10.1016/j.gaitpost.2010.10.001. PubMed PMID: 21050763.