Isometric hip strength and dynamic stability of individuals with chronic ankle instability

Ryan S. McCann, Brenn A. Bolding, Masafumi Terada, Kyle B. Kosik, Ian D. Crossett, Phillip A. Gribble

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Context: Compared with individuals who have a history of lateral ankle sprain (LAS) without markers of chronic ankle instability (CAI; LAS copers) and healthy people, those with CAI often exhibit neuromuscular impairments and dynamic-stability deficits at the hip. However, the influence of hip-strength deficits on dynamic stability remains unknown. Objective: To compare isometric hip strength and dynamic stability in individuals with or without CAI and examine the degree of dynamic-stability variance explained by isometric hip strength. Design: Case-control study. Setting: Research laboratory. Patients or Other Participants: Sixty individuals (47 women, 13 men; age = 23.7 6 4.6 years, height = 166.6 6 7.7 cm, mass = 70.8 6 15.7 kg) separated into CAI, LAS coper, and control groups based on previously established criteria. Main Outcome Measure(s): Group differences in resultant vector time to stabilization (RVTTS) and isometric hip-extension, -abduction, and external-rotation strength were determined using 1-way analyses of covariance that controlled for sex and limb (dominant or nondominant) tested and Cohen d effect sizes (95% confidence intervals) Backward linear re ressions and Cohen f 2 effect sizes (95% confidence intervals) determined the amount of RVTTS variance explained by isometric hip strength. Significance was set a priori at P, .05. Results: The CAI group had less isometric hip-extension strength than LAS copers (P = .02, d = 0.72 [0.06, 1.34]) and controls (P = .01, d = 1.19 [0.50, 1.84]) and less external-rotation strength than LAS copers (P = .03, d = 0.78 [0.13, 1.41]) and controls (P = .01, d = 1.02 [0.34, 1.65]). No group differences existed for RVTTS (F2,57 = 1.16, P = .32) or abduction strength (F2,57 = 2.84, P = .07). Resultant vector time to stabilization was explained by isometric hip strength for LAS copers (R 2 = 0.21, f 2 = 0.27 [0.22, 0.32], P = .04) but not for the CAI (R 2 = 0.12, f 2 = 0.14 [0.06, 0.22], P = .22) or control (R 2 = 0.10, f 2 = 0.11 [0.03, 0.19], P = .18) groups. Conclusions: Participants with CAI had decreased isometric hip strength, but that did not equate to dynamic-stability deficits. Clinicians should include hip-muscle strengthening in rehabilitation protocols for patients with CAI, yet these gains may not enhance dynamic stability when landing from a jump.

Original languageEnglish
Pages (from-to)672-678
Number of pages7
JournalJournal of Athletic Training
Issue number7
StatePublished - Jul 2018

Bibliographical note

Publisher Copyright:
© by the National Athletic Trainers’ Association Inc.


  • Copers
  • Handheld dynamometry
  • Time to stabilization

ASJC Scopus subject areas

  • General Medicine


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