Search tips
Search criteria 


Logo of jathtrainLink to Publisher's site
J Athl Train. 1999 Jul-Sep; 34(3): 239–245.
PMCID: PMC1322917

Eversion Strength Analysis of Uninjured and Functionally Unstable Ankles

Thomas W. Kaminski, PhD, ATC/L,* David H. Perrin, PhD, ATC, and Bruce M. Gansneder, PhD



Functional ankle instability (FAI) afflicts many athletes. Several causes of FAI have been implicated, including peroneal muscle weakness. Traditional musculoskeletal rehabilitation programs have focused on concentric muscle strength. The purpose of our study was to compare concentric and eccentric isokinetic and isometric eversion ankle strength measurements between subjects identified as having unilateral FAI and subjects having no history of inversion ankle sprain.

Design and Setting:

Employing a matched-pairs technique, subjects with no history of ankle injury were compared with subjects with unilateral FAI using isokinetic and isometric measures of eversion ankle strength. Strength testing was performed in a sports medicine clinic setting.


Forty-two subjects volunteered for this study: 21 subjects suffered from unilateral FAI (age = 19.3 ± 1.1 years, wt = 84.0 ± 9.5 kg, ht = 181.5 ± 9.2 cm), while 21 subjects served as matched-paired controls (age = 19.5 ± 1.2 years, wt = 82.5 ± 10.9 kg, ht = 179.5 ± 7.9 cm).


Ankle eversion concentric and eccentric strength (peak torque) was assessed at 0°/s, 30°/s, 60°/s, 90°/s, 120°/s, 150°/s, and 180°/s using an isokinetic dynamometer.


We found no significant differences in concentric, eccentric, or isometric eversion ankle strength between the 2 groups of subjects.


The exact cause of FAI remains elusive. Based on our results, those who suffer from unilateral FAI do not appear to have eversion strength deficits. Unless clear evidence of weakness exists, clinicians may find that eversion strength training exercises are unnecessary. Future research should examine other causes of FAI, including reciprocal muscle group strength ratios and proprioception deficits.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.4M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Jackson DW, Ashley RL, Powell JW. Ankle sprains in young athletes. Relation of severity and disability. Clin Orthop Relat Res. 1974 Jun;(101):201–215. [PubMed]
  • Garrick JG. The frequency of injury, mechanism of injury, and epidemiology of ankle sprains. Am J Sports Med. 1977 Nov-Dec;5(6):241–242. [PubMed]
  • Freeman MA. Instability of the foot after injuries to the lateral ligament of the ankle. J Bone Joint Surg Br. 1965 Nov;47(4):669–677. [PubMed]
  • BOSIEN WR, STAPLES OS, RUSSELL SW. Residual disability following acute ankle sprains. J Bone Joint Surg Am. 1955 Dec;37-A(6):1237–1243. [PubMed]
  • Freeman MA, Dean MR, Hanham IW. The etiology and prevention of functional instability of the foot. J Bone Joint Surg Br. 1965 Nov;47(4):678–685. [PubMed]
  • Cahill BR. Chronic orthopedic problems in the young athlete. J Sports Med. 1973 Mar-Apr;1(3):36–39. [PubMed]
  • Staples OS. Ruptures of the fibular collateral ligaments of the ankle. Result study of immediate surgical treatment. J Bone Joint Surg Am. 1975 Jan;57(1):101–107. [PubMed]
  • Glencross D, Thornton E. Position sense following joint injury. J Sports Med Phys Fitness. 1981 Mar;21(1):23–27. [PubMed]
  • Tropp H, Odenrick P, Gillquist J. Stabilometry recordings in functional and mechanical instability of the ankle joint. Int J Sports Med. 1985 Jun;6(3):180–182. [PubMed]
  • Tropp H. Pronator muscle weakness in functional instability of the ankle joint. Int J Sports Med. 1986 Oct;7(5):291–294. [PubMed]
  • Cornwall MW, Murrell P. Postural sway following inversion sprain of the ankle. J Am Podiatr Med Assoc. 1991 May;81(5):243–247. [PubMed]
  • Broström L. Sprained ankles. 3. Clinical observations in recent ligament ruptures. Acta Chir Scand. 1965 Dec;130(6):560–569. [PubMed]
  • Redler I, Brown GG, Jr, Williams JT. Operative treatment of the acutely ruptured lateral ligament of the ankle. South Med J. 1977 Oct;70(10):1168–1171. [PubMed]
  • Evans GA, Hardcastle P, Frenyo AD. Acute rupture of the lateral ligament of the ankle. To suture or not to suture? J Bone Joint Surg Br. 1984 Mar;66(2):209–212. [PubMed]
  • Staples OS. Result study of ruptures of lateral ligaments of the ankle. Clin Orthop Relat Res. 1972;85:50–58. [PubMed]
  • Kannus P, Renström P. Treatment for acute tears of the lateral ligaments of the ankle. Operation, cast, or early controlled mobilization. J Bone Joint Surg Am. 1991 Feb;73(2):305–312. [PubMed]
  • Bernier JN, Perrin DH, Rijke A. Effect of unilateral functional instability of the ankle on postural sway and inversion and eversion strength. J Athl Train. 1997 Jul;32(3):226–232. [PMC free article] [PubMed]
  • Lentell G, Baas B, Lopez D, McGuire L, Sarrels M, Snyder P. The contributions of proprioceptive deficits, muscle function, and anatomic laxity to functional instability of the ankle. J Orthop Sports Phys Ther. 1995 Apr;21(4):206–215. [PubMed]
  • Glick JM, Gordon RB, Nishimoto D. The prevention and treatment of ankle injuries. Am J Sports Med. 1976 Jul-Aug;4(4):136–141. [PubMed]
  • Highgenboten CL, Jackson AW, Meske NB. Concentric and eccentric torque comparisons for knee extension and flexion in young adult males and females using the Kinetic Communicator. Am J Sports Med. 1988 May-Jun;16(3):234–237. [PubMed]
  • Ashton-Miller JA, Ottaviani RA, Hutchinson C, Wojtys EM. What best protects the inverted weightbearing ankle against further inversion? Evertor muscle strength compares favorably with shoe height, athletic tape, and three orthoses. Am J Sports Med. 1996 Nov-Dec;24(6):800–809. [PubMed]
  • Termansen NB, Hansen H, Damholt V. Radiological and muscular status following injury to the lateral ligaments of the ankle. Follow-up of 144 patients treated conservatively. Acta Orthop Scand. 1979 Dec;50(6 Pt 1):705–708. [PubMed]
  • Baumhauer JF, Alosa DM, Renström AF, Trevino S, Beynnon B. A prospective study of ankle injury risk factors. Am J Sports Med. 1995 Sep-Oct;23(5):564–570. [PubMed]
  • Tropp H, Askling C, Gillquist J. Prevention of ankle sprains. Am J Sports Med. 1985 Jul-Aug;13(4):259–262. [PubMed]
  • Seto JL, Brewster CE. Treatment approaches following foot and ankle injury. Clin Sports Med. 1994 Oct;13(4):695–718. [PubMed]
  • Ebig M, Lephart SM, Burdett RG, Miller MC, Pincivero DM. The effect of sudden inversion stress on EMG activity of the peroneal and tibialis anterior muscles in the chronically unstable ankle. J Orthop Sports Phys Ther. 1997 Aug;26(2):73–77. [PubMed]
  • Löfvenberg R, Kärrholm J, Sundelin G, Ahlgren O. Prolonged reaction time in patients with chronic lateral instability of the ankle. Am J Sports Med. 1995 Jul-Aug;23(4):414–417. [PubMed]
  • Garn SN, Newton RA. Kinesthetic awareness in subjects with multiple ankle sprains. Phys Ther. 1988 Nov;68(11):1667–1671. [PubMed]

Articles from Journal of Athletic Training are provided here courtesy of National Athletic Trainers Association