Masafumi Terada

Prediction of Lateral Ankle Sprains in Football Players Based on Clinical Tests and Body Mass Index

Background: The lateral ankle sprain (LAS) is the most common injury suffered in sports, especially in football. While suggested in some studies, a predictive role of clinical tests for LAS has not been established. Purpose: To determine which clinical tests, focused on potentially modifiable factors of movement patterns and body mass index (BMI), could best demonstrate risk of LAS among high school and collegiate football players. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 539 high school and collegiate football players were evaluated during the preseason with the Star Excursion Balance Test (SEBT) and Functional Movement Screen as well as BMI. Results were compared between players who did and did not suffer an LAS during the season. Logistic regression analyses and calculated odds ratios were used to determine which measures predicted risk of LAS. Results: The LAS group performed worse on the SEBT–anterior reaching direction (SEBT-ANT) and had higher BMI as compared with the noninjured group (P < .001). The strongest prediction models corresponded with the SEBT-ANT. Conclusion: Low performance on the SEBT-ANT predicted a risk of LAS in football players. BMI was also significantly higher in football players who sustained an LAS. Identifying clinical tools for successful LAS injury risk prediction will be a critical step toward the creation of effective prevention programs to reduce risk of sustaining an LAS during participation in football.

Alterations in stride-to-stride variability during walking in individuals with chronic ankle instability

The aim of this study was to evaluate stride-to-stride variability of the lower extremity during walking in individuals with and without chronic ankle instability (CAI) using a nonlinear analysis. Twenty-five participants with self-reported CAI and 27 healthy control participants volunteered for this study. Participants walked on a motor-driven treadmill for 3 min at their selected speed. Lower extremity kinematics in the sagittal and frontal planes were recorded using a passive retroreflective marker motion capture system. The temporal structure of walking variability was analyzed with sample entropy (SampEn). The CAI group produced lower SampEn values in frontal-plane ankle kinematics compared to the control group (P=.04). No significant group differences were observed for SampEn values of other kinematics (P>.05). Participants with CAI demonstrated less stride-to-stride variability of the frontal plane ankle kinematics compared to healthy controls. Decreased variability of walking patterns demonstrated by participants with CAI indicates that the presence of CAI may be associated with a less adaptable sensorimotor system to environmental changes. The altered sensorimotor function associated with CAI may be targets for clinical interventions, and it is critical to explore how interventions protocols affect sensorimotor system function.

Alterations in neuromuscular control at the knee in individuals with chronic ankle instability.

CONTEXT Few authors have assessed neuromuscular knee-stabilization strategies in individuals with chronic ankle instability (CAI) during functional activities. OBJECTIVE To investigate the influence of CAI on neuromuscular characteristics around the knee during a stop-jump task. DESIGN Case-control study. SETTING Research laboratory. Participants or Other Participants: A total of 19 participants with self-reported unilateral CAI and 19 healthy control participants volunteered for this study. INTERVENTION(S) Participants performed double-legged, vertical stop-jump tasks onto a force plate, and we measured muscle activation around the knee of each limb. MAIN OUTCOME MEASURE(S) We calculated the integrated electromyography for the vastus medialis oblique, vastus lateralis, medial hamstrings, and lateral hamstrings muscles during the 100 ms before and after initial foot contacts with the force plate and normalized by the ensemble peak electromyographic value. Knee sagittal-plane kinematics were also analyzed during a stop-jump task. RESULTS Compared with control participants, the CAI group demonstrated greater prelanding integrated electromyographic activity of the vastus medialis oblique (CAI = 52.28 ± 11.25%·ms, control = 43.90 ± 10.13%·ms, t36 = 2.41, P = .021, effect size = 0.78, 95% confidence interval = 0.11, 1.43) and less knee-flexion angle at the point of initial foot contact (CAI = 7.81° ± 8.27°, control = 14.09° ± 8.7°, t36 = -2.28, P = .029, effect size = -0.74, 95% confidence interval = -1.38, -0.07) and at 100 ms post-initial foot contact (CAI = 51.36° ± 5.29°, control = 58.66° ± 7.66°, t36 = -3.42, P = .002, effect size = -1.11, 95% confidence interval = -1.77, -0.40). No significant results were noted for the other electromyographic measures. CONCLUSIONS We found altered feed-forward patterns of the vastus medialis oblique and altered postlanding knee sagittal-plane kinematics in the CAI group. These observations may provide insight regarding sensorimotor characteristics that may be associated with CAI.

Jump Landing Biomechanics During a Laboratory Recorded Recurrent Ankle Sprain.

Recurrent ankle sprains and resultant episodes of giving way are the common precursors of chronic ankle instability (CAI). CAI can occur after an initial acute lateral ankle sprain in physically active people, leading to decreased activity levels and impaired quality of life. Establishing the injury mechanisms of recurrent ankle sprains is a critical step in developing preventive interventions. Altered preparatory and reactive neuromuscular control patterns following an initial ankle sprain are factors associated with CAI. A more definitive description of movement patterns during challenging tasks that mimic sport activities, such as a stop-jump task, would improve the understanding of recurrent ankle injury mechanisms, especially if an injury mechanism was actually experienced. It is unethical to produce an injury to examine biomechanical characteristics during an actual ankle sprain incident; however, an accidental recurrent lateral ankle sprain in a person with CAI during biomechanical testing while voluntarily participating in a research study could provide vital information. Recently published case reports of acute lateral ankle sprains have described biomechanical and neuromuscular characteristics in the lower extremity during accidental ankle sprains recorded during participation in research laboratories. These case studies suggest that a sudden increase in lateral excursion of center of pressure, ankle inversion, ankle internal rotation, and activations of the tibialis anterior and peroneus longus muscles likely contribute to the injury mechanism of a lateral ankle sprain. It has been suggested that examining the capacity of lower extremity joints to dissipate and control the ground reaction forces (GRFs) experienced after landing (energy dissipation pattern) may be important for prevention of lower extremity joint injury. While altered energy dissipation patterns have been observed in patients with CAI, to our knowledge, no case studies have reported these joint energetic characteristics during a recurrent ankle sprain incident. Observing energy dissipation patterns during an injurious episode would provide more comprehensive biomechanical information than joint kinematics or kinetics alone and would expand our knowledge of the mechanisms of recurrent ankle sprains, possibly contributing to the development of prevention programs for ankle injury. Additionally, the location of the center of mass (COM) influences lower extremity movement and energy dissipation patterns during landing, but little evidence is available to describe the association between the location of COM and injury mechanism. Therefore, the current case report provides observations, including lower extremity joint energy dissipation patterns as well as position and movement of the COM, which may help explain the mechanisms and consequences of a lateral ankle sprain.

Therapeutic interventions for improving self-reported function in patients with chronic ankle instability: a systematic review

Objective To identify which therapeutic intervention may be most effective for improving self-reported function in patients with chronic ankle instability (CAI). Design Systematic literature review. Articles were appraised using the Downs and Black Checklist by 3 reviewers. Data sources PubMed along with CINAHL, MEDLINE and SPORTDiscus within EBSCOhost for pertinent articles from their inception through August 2016. Eligibility criteria for selected studies Articles included were required to (1) be written in English, (2) report adequate data to calculate effect sizes, (3) identify patients with CAI, (4) use some form of therapeutic intervention and (5) use a self-reported questionnaire as a main outcome measurement. Results A broad spectrum of therapeutic interventions were identified related to balance training, multimodal rehabilitation, joint mobilisation, resistive training, soft-tissue mobilisation, passive calf stretching and orthotics. All of the articles included in the balance training category had moderate-to-strong Hedges g with none of the 95% CIs crossing 0. Hedges g effect sizes ranged from −0.67 to −2.31 and −0.51 to −1.43 for activities of daily living and physical activity, respectively. The multimodal rehabilitation category also produced moderate-to-strong Hedges g effect sizes but with large CIs crossing 0. Hedges g effect sizes ranged from −0.47 to −9.29 and −0.62 to −24.29 for activities of daily living and physical activity, respectively. Conclusions The main findings from this systematic review were balance training provided the most consistent improvements in self-reported function for patients with CAI.

Corticospinal Excitability and Inhibition of the Soleus in Individuals With Chronic Ankle Instability

Understanding the mechanisms of neurophysiological alterations with chronic ankle instability (CAI) may be essential in the development of the most‐effective intervention programs to treat neuromuscular dysfunction in patients with CAI. Specifically, the presence of CAI may be associated with an altered supraspinal mechanism within the central nervous system to inhibit neural drive to the undamaged soleus surrounding the injured ankle joint.

Altered visual focus on sensorimotor control in people with chronic ankle instability.

Abstract The purpose of this investigation was to examine the effects of the combination of chronic ankle instability (CAI) and altered visual focus on strategies for dynamic stability during a drop-jump task. Nineteen participants with self-reported CAI and 19 healthy participants performed a drop-jump task in looking-up and looking-down conditions. For the looking-up condition, participants looked up and read a random number that flashed on a computer monitor. For the looking-down condition, participants focused their vision on the force plate. Sagittal- and frontal-plane kinematics in the hip, knee and ankle were calculated at the time points of 100 ms pre-initial foot contact to ground and at IC. The resultant vector time to stabilisation was calculated with ground reaction force data. The CAI group demonstrated less hip flexion at the point of 100 ms pre-initial contact (P < 0.01), and less hip flexion (P = 0.03) and knee flexion at initial contact (P = 0.047) compared to controls. No differences in kinematics or dynamic stability were observed in either looking-up or looking-down conditions (P > 0.05). Altered visual focus did not influence movement patterns during the drop-jump task, but the presence of CAI did. The current data suggests that centrally mediated changes associated with CAI may lead to global alterations in the sensorimotor control.

Quantifying levels of function between different subgroups of chronic ankle instability

The purpose of this original investigation was to determine if selected sensorimotor, mechanical, and self‐reported measures are different among chronic ankle instability (CAI) subgroups, healthy control participants, and lateral ankle sprain copers (LAS‐Copers). Ninety‐four participants volunteered and were categorized into perceived ankle instability (PI) alone (n = 13), recurrent ankle sprains (RAS) alone (n = 12), PI in combination with RAS (PI‐RAS; n = 25), LAS‐Copers (n = 18), and controls (n = 26). Participants completed self‐assessed global, regional, and psychological health‐related quality‐of‐life (HRQOL) questionnaires and assessments of sensorimotor function and mechanical joint laxity. One‐way ANOVAs were performed with the intention of reducing the number of original outcomes into a smaller number of predictor variables. Discriminant functional analysis was used to establish which specific measures best differentiate between groups. Eight outcome measures from neural excitability, postural control, static postural control, and HRQOL showed a significant differentiation between five groups (Wilks λ = 0.26, χ232 = 114 45, P < 0.001, canonical correlation = 0.80) and correctly determined only 58.1% of group membership, and the PI‐RAS and control groups were the only fit in the proposed model. A different model or other sensorimotor outcomes from more dynamic and complex tasks may be needed for the PI, RAS, and LAS‐Coper groups.

Potential Corticomotor Plasticity in Those with and without Chronic Ankle Instability

Introduction Quantifying corticomotor alterations is important to understand the neurophysiological mechanisms that likely contribute to the neuromuscular control deficits observed in patients with chronic ankle instability (CAI). Corticomotor output mapping provides further insight into the changes within the motor cortex and identifies potential changes in the area of the motor cortex associated with selected muscles. Therefore, this investigation compared the corticomotor map output for the fibularis longus (FL) muscle in patients with and without CAI. Methods Eighteen CAI patients and 16 healthy controls (HC) volunteered. Transcranial magnetic stimulation was used to map the motor cortex’s representation of the FL. The normalized average of three motor evoked potentials at 100% of active motor threshold intensity was recorded for each scalp site on a 6 × 6 cm grid. Corticomotor output map was compared between groups through 1) the size of the corticomotor map area, 2) the volume of the corticomotor map, and 3) the location of cortical representation. Independent t-tests were used to assess group differences in each mapping outcome variable. Cohen’s d effect sizes along with 95% confidence intervals were calculated using the pooled SD values. Results CAI patients exhibited less map volume (P = 0.018, CAI = 8.2 ± 3.2 cm2 mV vs HC = 11.3 ± 3.9 cm2 mV) and map area (P = 0.046, CAI = 12.8 ± 6.0 cm2 vs HC: 17.4 ± 6.9 cm2) compared with HC. Conclusions The smaller map area and volume suggest a more concentrated area of neurons communicating with the FL muscle in patients with CAI. Consequently, motor cortical cells on the border of the FL excitation area are less committed to the proper function of the FL muscle and may be recruited by other surrounding areas. This may explain altered movement strategies that lead to ankle reinjury.

Associations between Functional and Isolated Performance Measures in Collegiate Women’s Soccer Players

CONTEXT The Star Excursion Balance Test (SEBT) and Functional Movement Screen (FMS) are functional performance measures capable of predicting lower-extremity injury risk. While suboptimal SEBT and FMS performances are influenced by multiple factors, the contribution of hip strength and flexibility to these tests is mostly unknown. Examination of hip strength and flexibility influences on the SEBT and FMS may direct clinicians to better methods of correcting functional deficits. OBJECTIVE Determine the relationships of isometric hip strength and hip passive range of motion (PROM) with functional performance measures. DESIGN Cross-sectional. SETTING Athletic training facility. PARTICIPANTS 43 NCAA Division I womens soccer players (19.65 ± 1.12 y; 166.93 ± 3.84 cm; 60.99 ± 4.31 kg) volunteered. DATA COLLECTION AND ANALYSIS All participants were tested bilaterally in the SEBT; the deep squat, in-line lunge, hurdle step, and straight leg raise, comprising a lower-extremity FMS (FMS-LE); hip internal and external rotation PROM; and isometric hip extension strength (HEXT). The mean of the 3 averaged, normalized SEBT scores was used as a composite score. Pearson product moment correlations assessed relationships of SEBT and FMS-LE scores with PROM and HEXT. Significance was set a priori at P < .05. RESULTS Pearson correlations revealed anterior (ANT) SEBT scores had a low negative association with HEXT (r = -0.33,P = .004) and a low positive association with hip internal rotation PROM (PROM-IR) (r = .43,P = .003). All other correlations were negligible. CONCLUSIONS Flexibility training aimed at PROM-IR may contribute to improved ANT scores. Targeting HEXT and hip external rotation PROM are likely not preferred means of correcting deficits in SEBT and FMS-LE performance.