Balance- and Strength-Training Protocols to Improve Chronic Ankle Instability Deficits, Part I: Assessing Clinical Outcome Measures

Abstract

Context: Functional rehabilitation may improve the deficits associated with chronic ankle instability (CAI).

Objective: To determine if balance- and strength-training protocols improve the balance, strength, and functional performance deficits associated with CAI.

Design: Randomized controlled clinical trial.

Setting: Athletic training research laboratory.

Patients or other participants: Participants were 39 volunteers with CAI, which was determined using the Identification of Functional Ankle Instability Questionnaire. They were randomly assigned to 1 of 3 groups: balance-training protocol (7 males, 6 females; age = 23.5 ± 6.5 years, height = 175.0 ± 8.5 cm, mass = 72.8 ± 10.9 kg), strength-training protocol (8 males, 5 females; age = 24.6 ± 7.7 years, height = 173.2 ± 9.0 cm, mass = 76.0 ± 16.2 kg), or control (6 males, 7 females; age = 24.8 ± 9.0 years, height = 175.5 ± 8.4 cm, mass = 79.1 ± 16.8 kg).

Intervention(s): Each group participated in a 20-minute session, 3 times per week, for 6 weeks. The control group completed a mild to moderately strenuous bicycle workout.

Main outcome measure(s): Participants completed baseline testing of eccentric and concentric isokinetic strength in each ankle direction (inversion, eversion, plantar flexion, and dorsiflexion) and the Balance Error Scoring System (BESS), Star Excursion Balance Test (SEBT), and side-hop functional performance test. The same variables were tested again at 6 weeks after the intervention. Two multivariate repeated-measures analyses of variance with follow-up univariate analyses were conducted. The α level was set a priori at .05.

Results: We observed time-by-group interactions in concentric ( P = .02) and eccentric ( P = .01) inversion, eccentric eversion ( P = .01), concentric ( P = .001) and eccentric ( P = .03) plantar flexion, BESS ( P = .01), SEBT ( P = .02), and side hop ( P = .004). With pairwise comparisons, we found improvements in the balance- and strength-training protocol groups in concentric and eccentric inversion and concentric and eccentric plantar flexion and the BESS, SEBT, and side hop (all P values = .001). Only the strength-training protocol group improved in eccentric eversion. The control group did not improve in any dependent variable.

Conclusions: Both training protocols improved strength, balance, and functional performance. More clinicians should incorporate hop-to-stabilization exercises into their rehabilitation protocols to improve the deficits associated with CAI.

Keywords: Balance Error Scoring System; Star Excursion Balance Test; functional performance; rehabilitation.

Figure 1

Participant flow diagram.

Figure 2

Forest plot of the isokinetic strength measures including the mean differences and 95% confidence intervals for each group. ^a Improvement from pretest to posttest.

Figure 3

Forest plot of the Star Excursion Balance Test including the mean differences and 95% confidence intervals for each group. ^a Improvement from pretest to posttest.

Figure 4

Forest plot of the Balance Error Scoring System including the mean differences and 95% confidence intervals for each group. ^a Improvement from pretest to posttest. ^b Difference between balance-training protocol and control groups at posttest.

Figure 5

Forest plot of the side-hop functional performance test including the mean differences and 95% confidence intervals for each group. ^a Improvement from pretest to posttest.