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A Comparison of Excitability Measures, ROM, Laxity, and Dynamic Postural Control between Ankle Copers and Patients with Chronic Ankle Instability and their Influences on Dynamic Postural Control

Bowker, Samantha
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1396012540

Abstract Details

, Master of Science, University of Toledo, Exercise Science.
Context: Mechanical and neuromuscular deficiencies are commonly studied in participants with chronic ankle instability (CAI). Recent evidence suggests mechanical laxity alone may not characterize the condition of CAI. Alterations in the central nervous system (CNS) following ankle sprains are likely to characterize the condition of CAI, yet few studies have quantified CNS alterations directly in CAI populations. Ankle sprain copers are individuals that do not present with prolonged dysfunctions following an initial ankle sprain. There have been limited examination of CNS alterations in patients with ankle sprain history, and to our knowledge none that have attempted to comprehensively consider CNS and mechanical differences between CAI, ankle copers, and healthy control groups. Objective: Determine if differences exist in spinal reflex excitability and ankle laxity between ankle sprain copers, CAI patients, and healthy controls. To identify which variables best predict performance on the star excursion balance test (SEBT) for each group. Design: Case control study. Setting: Research laboratory. Patients or Other Participants: Thirty-five participants with CAI (17M, 18F; 21.97±3.55yrs; 169.26±8.35cm; 72.40±14.79kg), 26 participants categorized as ankle sprain copers (10M, 16F; 21.50±4.17yrs; 168.35±10.83cm; 73.22±19.84kg) and 22 healthy control participants (8M, 14F; 21.45±3.43yrs; 166.75±7.63cm; 67.07±13.50kg) volunteered. Interventions: Spinal reflex excitability was assessed using Hoffman reflex (H-reflex) testing. Participants' ankle laxity was measured with an ankle arthrometer. Corticomotor excitability was assessed using transcranial magnetic stimulation (TMS). Range of motion was assessed using the weight bearing lunge test (WBLT) and open kinetic chain dorsiflexion (OKCDF) was assessed using a bubble inclinometer. Dynamic postural control was assessed using the SEBT. Main Outcomes: Spinal reflex excitability was assessed for the maximal H-reflex and muscle-response, from which the H:M ratio was calculated. Ankle laxity was measured as the total displacement in the anterior-posterior directions (mm) and total motion in the eversion-inversion directions (degrees). Corticomotor excitability was analyzed using active motor threshold (AMT) and silent periods (SP). Dorsiflexion was measured as distance from the wall during the WBLT (cm) and as possible range of motion for OKCDF (deg). Normalized reach distances for the anterior, posterolateral, and posteromedial reach distances of the SEBT. One-way ANOVAs were used to make groups comparisons for each dependent variable. Significance was set a priori at P < 0.05. Cohen's d effect sizes with associated 95% confidence intervals (CI) were calculated using the pooled standard deviations. Results: Spinal reflex excitability (H:M ratio) was diminished in CAI participants (0.41 ± 0.18) compared to copers (0.55 ± 0.24) and control participants (0.51 ±0.19) ((F2, 82=4.086, P=0.020, dCAI-Coper=-0.79, 95% CI: -1.32, -0.26; dCAI-control=-0.55, 95% CI =-1.09, -0.01, ). No statistical differences were seen between any of the groups for anterior-posterior displacement, inversion-eversion laxity, ankle dorsiflexion, or dynamic postural control. Regression models showed composite SEBT performance to be best predicted by AMT and WBLT within the CAI group (R2 =0.226, P=0.100); by AMT and H:M ratio within the copers group (R2=0.425, P=0.109); and by SP and WBLT within the control group (R2=0.476,P=0.039). Conclusion: Spinal reflex excitability was decreased within the soleus in the CAI compared to the control group; but no differences existed between the copers and control participants. Neuromuscular changes that likely impact dynamic ankle stability were seen only in the CAI group, yet no mechanical differences were noted between any of the groups. Based on results of regression models, we can suggest that soleus excitability at the spinal and supraspinal level and ankle dorsiflexion-ROM may be targets for intervention when deficits are found on global functional tests such as the SEBT. These findings support the importance of finding effective ways to increase spinal reflex excitability for the purpose of treating neuromuscular dysfunction in CAI patients. Further research should determine if diminished H:M ratios will predict those who will go on to develop CAI following an ankle sprain.
Phillip Gribble (Committee Chair)
Abbey Thomas (Committee Member)
Brian Pietrosimone (Committee Member)
Kinesiology

Recommended Citations

Citations

  • Bowker, S. (n.d.). A Comparison of Excitability Measures, ROM, Laxity, and Dynamic Postural Control between Ankle Copers and Patients with Chronic Ankle Instability and their Influences on Dynamic Postural Control [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1396012540

    APA Style (7th edition)

  • Bowker, Samantha. A Comparison of Excitability Measures, ROM, Laxity, and Dynamic Postural Control between Ankle Copers and Patients with Chronic Ankle Instability and their Influences on Dynamic Postural Control. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1396012540.

    MLA Style (8th edition)

  • Bowker, Samantha. "A Comparison of Excitability Measures, ROM, Laxity, and Dynamic Postural Control between Ankle Copers and Patients with Chronic Ankle Instability and their Influences on Dynamic Postural Control." Master's thesis, University of Toledo. Accessed MAY 01, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1396012540

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Toledo and OhioLINK.