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J Athl Train. 2006 Jul-Sep;41(3):294-304.

Fatigue, vertical leg stiffness, and stiffness control strategies in males and females.

Journal of athletic training

Darin A Padua, Brent L Arnold, David H Perrin, Bruce M Gansneder, Christopher R Carcia, Kevin P Granata

Affiliations

  1. Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. [email protected]

PMID: 17043698 PMCID: PMC1569557

Abstract

CONTEXT: Fatigue appears to influence musculoskeletal injury rates during athletic activities, but whether males and females respond differently to fatigue is unknown.

OBJECTIVE: To determine the influence of fatigue on vertical leg stiffness (K (VERT)) and muscle activation and joint movement strategies and whether healthy males and females respond similarly to fatigue.

DESIGN: Repeated-measures design with all data collected during a single laboratory session.

SETTING: Laboratory.

PATIENTS OR OTHER PARTICIPANTS: Physically active males (n = 11) and females (n = 10).

INTERVENTION(S): Subjects performed hopping protocols at 2 frequencies before and after fatigue, which was induced by repeated squatting at submaximal loads.

MAIN OUTCOME MEASURE(S): We measured K (VERT) with a forceplate and peak muscle activity of the quadriceps, hamstrings, gastrocnemius, soleus, and anterior tibialis muscles with surface electromyography. Sagittal-plane kinematics at the knee and ankle were recorded with an electrogoniometer.

RESULTS: After fatigue, K (VERT) was unchanged for all subjects. However, both males and females demonstrated reduced peak hamstrings ( P = .002) and anterior tibialis ( P = .001) activation, coupled with increased gastrocnemius ( P = .005) and soleus ( P = .001) peak activity, as well as increased quadriceps-hamstrings ( P = .005) and gastrocnemius/soleus-anterior tibialis coactivation ratios ( P = .03) after fatigue. Overall, females demonstrated greater quadriceps-hamstrings coactivation ratios than males, regardless of the fatigue condition ( P = .026). Only females showed increased knee flexion at initial contact after fatigue during hopping ( P = .03).

CONCLUSIONS: Although K (VERT) was unaffected, the peak muscle activation and joint movement strategies used to modulate K (VERT) were affected after fatigue. Once fatigued, both males and females used an ankle-dominant strategy, with greater reliance on the ankle musculature and less on the knee musculature. Also, once fatigued, all subjects used an antagonist inhibition strategy by minimizing antagonist coactivation. Overall, females used a more quadriceps-dominant strategy than males, showing greater quadriceps activity and a larger quadriceps-hamstrings coactivation ratio. Changes in muscle activation and coactivation ratios because of fatigue and sex are suggested to alter knee joint stability and increase anterior cruciate ligament injury risk.

References

  1. J Appl Physiol (1985). 1999 Apr;86(4):1292-300 - PubMed
  2. J Biomech. 1982;15(2):111-21 - PubMed
  3. J Physiol. 1981 Feb;311:113-25 - PubMed
  4. J Biomech. 1999 Dec;32(12):1349-53 - PubMed
  5. Am J Sports Med. 1992 May-Jun;20(3):299-306 - PubMed
  6. Med Sci Sports Exerc. 2000 Mar;32(3):647-53 - PubMed
  7. J Electromyogr Kinesiol. 2002 Apr;12(2):119-26 - PubMed
  8. Am J Sports Med. 1997 Jul-Aug;25(4):500-7 - PubMed
  9. IEEE Trans Biomed Eng. 1997 Jun;44(6):493-504 - PubMed
  10. Am J Sports Med. 1999 Nov-Dec;27(6):699-706 - PubMed
  11. Eur J Appl Physiol Occup Physiol. 1998 Nov;78(6):555-9 - PubMed
  12. J Exp Biol. 1993 Dec;185:71-86 - PubMed
  13. Spine (Phila Pa 1976). 1998 Apr 1;23(7):774-80; discussion 781 - PubMed
  14. J Orthop Res. 2001 Nov;19(6):1178-84 - PubMed
  15. J Appl Physiol (1985). 1993 Jan;74(1):170-5 - PubMed
  16. J Athl Train. 1999 Apr;34(2):106-14 - PubMed
  17. Eur J Appl Physiol Occup Physiol. 1996;73(5):393-403 - PubMed
  18. Am J Sports Med. 1995 Jan-Feb;23(1):24-34 - PubMed
  19. J Gerontol A Biol Sci Med Sci. 1999 Feb;54(2):B63-70 - PubMed
  20. Clin Biomech (Bristol, Avon). 2001 Jun;16(5):438-45 - PubMed
  21. J Athl Train. 1999 Apr;34(2):137-43 - PubMed
  22. J Biomech. 1999 Mar;32(3):267-73 - PubMed
  23. Med Sci Sports Exerc. 2001 Jul;33(7):1157-67 - PubMed
  24. Orthopedics. 2000 Jun;23(6):573-8 - PubMed
  25. J Athl Train. 1999 Apr;34(2):86-92 - PubMed
  26. Eur J Appl Physiol Occup Physiol. 1990;60(6):425-9 - PubMed
  27. J Mot Behav. 2005 Mar;37(2):111-25 - PubMed
  28. J Biomech. 1999 Apr;32(4):395-400 - PubMed
  29. Muscle Nerve. 1998 Sep;21(9):1224-7 - PubMed
  30. J Appl Physiol (1985). 1998 Sep;85(3):1044-55 - PubMed
  31. Eur J Appl Physiol Occup Physiol. 1999 Jan;79(2):160-7 - PubMed
  32. Eur J Appl Physiol Occup Physiol. 1998 Oct;78(5):403-10 - PubMed
  33. Spine (Phila Pa 1976). 1997 Nov 15;22(22):2647-54 - PubMed
  34. Eur J Appl Physiol Occup Physiol. 1996;72(5-6):401-9 - PubMed
  35. Neurosci Lett. 1994 Jan 17;166(1):101-5 - PubMed
  36. J Electromyogr Kinesiol. 2000 Apr;10(2):117-26 - PubMed
  37. J Biomech. 1996 Feb;29(2):181-6 - PubMed
  38. Biol Cybern. 1982;44(1):35-46 - PubMed
  39. Eur J Appl Physiol. 2001 Jan-Feb;84(1-2):26-35 - PubMed
  40. Spine (Phila Pa 1976). 1997 Nov 1;22(21):2564-70 - PubMed
  41. Am J Sports Med. 1996 Jul-Aug;24(4):427-36 - PubMed
  42. Am J Sports Med. 1987 Jan-Feb;15(1):59-62 - PubMed
  43. Am J Sports Med. 2002 Mar-Apr;30(2):261-7 - PubMed
  44. Med Sci Sports Exerc. 2001 Jan;33(1):127-41 - PubMed
  45. Clin Orthop Relat Res. 2002 Aug;(401):162-9 - PubMed
  46. Am J Sports Med. 1997 Nov-Dec;25(6):823-9 - PubMed
  47. Phys Sportsmed. 2000 Apr;28(4):53-60 - PubMed
  48. Eur J Appl Physiol Occup Physiol. 1987;56(6):662-7 - PubMed
  49. Am J Sports Med. 1983 May-Jun;11(3):147-51 - PubMed
  50. Med Sci Sports Exerc. 2000 Apr;32(4):839-43 - PubMed
  51. J Am Acad Orthop Surg. 2000 May-Jun;8(3):141-50 - PubMed
  52. J Electromyogr Kinesiol. 2002 Apr;12(2):127-35 - PubMed
  53. J Appl Physiol (1985). 1987 Jun;62(6):2326-37 - PubMed
  54. J Biomech. 1998 Jan;31(1):71-6 - PubMed

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