Proprioception and ankle e/i strength ration in normal and functional instability ankle

Introduction

Ankle sprain is one of the most common injuries in sports. Freeman et al. (1965) hypothesized that trauma to mechanoreceptors of the ligaments can produce a proprioceptive deficit in the ankle. Weakness of muscular strength is another potential contribution factors that may contribute to functional instability ankle. Tropp et al.(1986), Ryan et al.(1994), Wilkson et al.(1997) founded that there were significant difference between FI and uninjured ankle, but others studies conducted by Lentell et al.(1990), Lentell et al.(1995), Bernier et al.(1997), and Kaminiski et al.(1999) showed contrary. Consideration of the conflicting results above, the purpose of this study was to examine the differences between NI and FI in ankle proprioception and eversion/inversion strength ratio.

Methods

Sixteen male college students, eight of those with symptoms of ankle functional instability, volunteered to participated in this study. Proprioception was defined as the ability to accurately match reference joint angles (active, 500°/s & passive, 2°/s) without visual feedback on BIODEX III isokinetic dynameter. Eversion/inversion strength ratio was defined as the ratio of everasion/inversion peak torque (30°/s & 120°/s) at ankle complex.

Results

The FI subjects had demonstrated poor performances in passive reposition sense than healthy leg and each leg in NI subjects. The E/I strength ratio at 120°/s in injured leg was greater than each leg in NI subjects.

Discussion/ Conclusion

The functional unstable ankles demonstrated poor passive reposition sense and abnormal high speed E/I strength ration. It was indicated that passive proprioception and proper high-speed strength training were needed in ankle injury rehabilitation and exercise training.

References

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[2]. Lentell, G., Baas, B., Lopez, D., McGuire, L., Sarrels, M. & Snyder, P. (1995). The contributions of proprioceptive deficits, muscle function, and anatomic laxity to functional instability of the ankle. J.O.S.P.T., 21, 206-215.
[3]. Kaminski, T. W., Perrin, D. H., & Gansneder, B. M. (1999). Eversion strength analysis of uninjured and functionally unstable ankles. Athl. Train., 34, 239-245