Submaximal Force Steadiness and Accuracy in Patients With Chronic Ankle Instability

Abstract

Context: Patients with chronic ankle instability (CAI) have demonstrated sensorimotor impairments. Submaximal force steadiness and accuracy measure sensory, motor, and visual function via a feedback mechanism, which helps researchers and clinicians to comprehend sensorimotor deficits associated with CAI. Objective: To determine if participants with chronic ankle instability experience deficits in hip and ankle submaximal force steadiness and accuracy compared to healthy controls. Design: A case-controlled study Setting: Research Laboratory Patients and Other Participants: Twenty-one CAI patients and 21 uninjured controls participated in this study. Intervention(s): n/a. Main Outcome Measure(s): Maximal voluntary isometric contraction (MVIC), force steadiness and accuracy (10% and 30% of their MVIC) of ankle evertors, invertors, and hip abductors. The central 10-sec (20–87% of the total time) of the 3 trials were analyzed. An independent t-test was used to assess MVIC. Two-way, 2 × 3, ANOVAs were used to assess force steadiness and accuracy. Results: Relative to controls, the CAI group demonstrated lower accuracy in invertors (p =.0006). Across all motions, the CAI group showed less steadiness (p = .0005) and lower accuracy (p = .0074) than the controls in 10% MVIC. In terms of MVIC, the CAI group showed less force output in hip abduction compared with the control group (p < .0001). Conclusions: CAI patients showed an inability to control ongoing fine force (10% and 30% of their MVIC) through a feedback mechanism during an active test. These findings suggest deficits in sensorimotor control that lead CAI patients to be more susceptible to injury positions since they have difficulty integrating the peripheral information and correcting their movement in relation to visual information.

Disrupted vision impairs force steadiness and accuracy in chronic ankle instability patients

“…As we hypothesized, the CAI group showed worse eversion steadiness than the coper and control groups. The results align with a previous study that CAI patients showed worse force steadiness than healthy controls 12 . Rice et al 5 have previously assumed that increased errors in force steadiness and accuracy represent impaired proprioceptive function, altered spinal interneuron modulation of motor‐neuron firing, and altered motor‐unit recruitment.…”

“…Rice et al 5 have previously assumed that increased errors in force steadiness and accuracy represent impaired proprioceptive function, altered spinal interneuron modulation of motor‐neuron firing, and altered motor‐unit recruitment. In addition, a recently published article reported that impaired force steadiness and accuracy may be due to impaired proprioceptive function that has been shown in individuals with CAI patients 12 . The literature has widely reported that CAI patients show impaired proprioceptive function, 2 which is a crucial factor for people to perform appropriate neuromuscular control 21 .…”

“…Our CAI patients might show worse steadiness due to one or more of the aforementioned factors after repeated LASs. This impaired proprioception could lead CAI patients to be more susceptible to repeated LASs as they have difficulty both integrating the peripheral proprioceptive information and correcting their force in relation to visual information 12 …”

“…Specifically, CAI patients showed worse accuracy of the invertors than matched‐healthy controls 12 . In addition, regardless of ankle movements including eversion, inversion, and hip abduction, CAI patients showed worse steadiness and accuracy than the matched healthy control group 12 . The increased variability in force steadiness and accuracy have been theorized to represent altered motor‐unit recruitment and firing rates, impaired proprioceptive information, increased activation of synergist and antagonist muscles, and altered spinal interneuron modulation of motor‐neuron firing 5,12 .…”

“…Specifically, CAI patients showed worse accuracy of the invertors than matched‐healthy controls 12 . In addition, regardless of ankle movements including eversion, inversion, and hip abduction, CAI patients showed worse steadiness and accuracy than the matched healthy control group 12 .…”