Kinematics and muscle activities of the lower limb during a side-cutting task in subjects with chronic ankle instability

The relationship between joint kinematic patterns during single-leg drop landing and perceived instability in individuals with chronic ankle instability

BACKGROUND

Perceived instability is a primary symptom among individuals with chronic ankle instability. However, the relationship between joint kinematics during landing remains unclear. Therefore, we investigated the relationships between landing kinematics and perceived instability in individuals with chronic ankle instability.

METHODS

In 32 individuals with chronic ankle instability, we recorded ankle, knee, and hip joint angles during a single-leg drop landing. Joint angle waveforms during 200 ms before and after initial contact were summarized into single values using two methods: peak joint angles and principal component scores via principal component analysis. Using Spearman's rank correlation coefficient (ρ), we examined the relationships of peak joint angles and principal component scores with the Cumberland Ankle Instability Tool score, with a lower score indicating a greater perceived instability (α = 0.05).

FINDINGS

The second principal component scores of ankle angle in the horizontal and sagittal planes significantly correlated with the Cumberland Ankle Instability Tool score (Horizontal: ρ = 0.507, P = 0.003; Sagittal: ρ = -0.359, P = 0.044). These scores indicated the differences in the magnitude of angles before and after landing. Significant correlations indicated a greater perceived instability correlated with smaller internal rotation and plantarflexion before landing and smaller external rotation and dorsiflexion after landing. In contrast, no peak joint angles correlated with the Cumberland Ankle Instability Tool score (P > 0.05).

INTERPRETATION

In individuals with chronic ankle instability, ankle movements during landing associated with perceived instability may be a protective strategy before landing and potentially cause ankle instability after landing.

The impact of whole-body vibration training and proprioceptive neuromuscular facilitation on biomechanical characteristics of lower extremity during cutting movement in individuals with functional ankle instability: A parallel-group study

BACKGROUND

We compared the effects of whole-body vibration training and proprioceptive neuromuscular facilitation on the biomechanical characteristics of the lower limbs in functional ankle instability patients during cutting movement to ascertain the superior rehabilitation method.

METHODS

Twenty-two male College students with unilateral functional ankle instability volunteered for this study and were randomly divided into whole-body vibration training group and proprioceptive neuromuscular facilitation group. Kinematics data and ground reaction forces were collected using infrared motion capture system and 3-D force plates synchronously during cutting. Repeated measures two-way ANOVA was performed to analyze the data.

FINDINGS

Both training methods reduced the maximum hip abduction angle (p = 0.010, effect size: proprioceptive neuromuscular facilitation = 0.69; whole-body vibration training = 0.20), maximum knee flexion angle (p = 0.008, effect size: proprioceptive neuromuscular facilitation = 0.39, whole-body vibration training = 1.26) and angular velocity (p = 0.014, effect size: proprioceptive neuromuscular facilitation = 0.62, whole-body vibration training = 0.55), maximum ankle inversion angular velocity (p = 0.020, effect size: proprioceptive neuromuscular facilitation = 0.52, whole-body vibration training = 0.81), and knee flexion angle at the time of maximum vertical ground reaction forces (p = 0.018, effect size: proprioceptive neuromuscular facilitation = 0.27, whole-body vibration training = 0.76), and increased the maximum ankle dorsiflexion moment (p = 0.049, effect size: proprioceptive neuromuscular facilitation = -0.52, whole-body vibration training = -0.22). Whole-body vibration training reduced the maximum ground reaction forces value in the mediolateral directions (p = 0.010, effect size = 0.82) during cutting movement.

INTERPRETATION

These findings suggested that the two types of training might increase neuromuscular conduction function around the ankle. After these two types of training, functional ankle instability patients showed a similar risk of injury to the lateral ankle ligaments during cutting.

Differences in intra-foot movement strategies during locomotive tasks among chronic ankle instability, copers and healthy individuals

Individuals with chronic ankle instability (CAI) suffer from the resulting sequela of repetitive lateral ankle sprains (LAS), whilst copers appear to cope with initial LAS successfully. Therefore, the aim of this study was to explore the intra-foot biomechanical differences among CAI, copers, and healthy individuals during dynamic tasks. Twenty-two participants per group were included and required to perform cutting and different landing tasks (DL: drop landing; FL: forward jump followed a landing). A five-segment foot model with 8 degrees of freedom was used to explore the intra-foot movement among these three groups. Smaller dorsiflexion angles were found in copers (DL tasks and prelanding task) and CAI (DL and FL task) compared to healthy participants. Copers presented a more eversion position compared to others during these dynamic tasks. During the descending phase of DL task, greater dorsiflexion angles in the metatarsophalangeal joint were found in copers compared to the control group. Joint moment difference was only found in the subtalar joint during the descending phase of FL task, presenting more inversion moments in copers compared to healthy participants. Copers rely on more eversion positioning to prevent over-inversion of the subtalar joint compared to CAI. Further, the foot became more unstable when conducting sport-related movements, suggesting that foot stability seems to be sensitive to the task types. These findings may help in designing and implementing interventions to restore functions of the ankle joint in CAI individuals.

Three-dimensional ankle kinematics of the full gait cycle in patients with chronic ankle instability: A case-control study

Objectives

The ankle kinematic characteristics of chronic ankle instability (CAI) at different gait phases and dimensions were not directly and overall explained. These characteristics have yet to be established. This study aimed to observe ankle kinematic changes of CAI, and explore their mechanisms, at different gait phases and dimensions in full gait cycle.

Methods

A three-dimensional (3D) motion capture system measured the 3D ankle movements of 53 individuals with CAI (meanage = 25.11 ± 6.01years, meanheight = 170.77 ± 7.80 cm, meanmass = 64.28 ± 9.28 kg) and 53 healthy controls (meanage = 24.66 ± 6.32 years, meanheight = 169.98 ± 9.00 cm, meanmass = 63.11 ± 9.62 kg) during barefoot walking overground at a self-selected speed. Once the acquisition results were processed with visual 3D software, the kinematics data were exported, and the eight phases of the gait cycle were identified.

Results

As compared with the control group, individuals with CAI displayed a significantly smaller plantarflexion in toe off (P = 0.049, Cohen's d = 0.387), a significantly increased inversion in heel strike (P = 0.007, Cohen's d = 0.271) and initial swing (P = 0.035, Cohen's d = 0.233), mid-swing (P = 0.019, Cohen's d = 0.232) and end-swing (P = 0.021, Cohen's d = 0.214), and significantly smaller eversion in mid stance（P = 0.010, Cohen's d = 0.288）and heel off (P = 0.033, Cohen's d = 0.089). Significant between-group differences in ankle kinematics were observed in the sagittal and frontal planes, but not in the horizontal plane, during walking.

Conclusion

When walking, patients with CAI have altered sagittal- and frontal-plane kinematics during different stance and swing phases. These kinematic changes require multi-dimensional, dynamic, continuous functional assessment and specialized rehabilitation intervention.

Regional plantar forces and surface geometry variations of a chronic ankle instability population described by statistical shape modelling

BACKGROUND

Understanding detailed foot morphology as well as regional plantar forces could provide insight into foot function and provide recommendation for footwear design for chronic ankle instability (CAI) people.

RESEARCH QUESTION

This study presented 3-dimensional statistical shape models of feet from three different populations including CAI, copers and healthy individuals, with regional plantar forces also acquired.

METHODS

Sixty-six males (22 participants per group) were included in this study to capture 3-dimensional foot shapes under a standing condition and regional plantar forces during a cutting maneuver. Principal component analysis was performed to generate a mean foot shape of each group as well as modes of variations. A generalized procrustes analysis was used to achieve rapid registration of mean shapes. Besides, regional plantar forces and contact duration among these three populations were compared.

RESULTS

For 3-dimensional foot shapes, although no significant differences of the average distance between each mode and mean shape were found among three populations, there were subtle variations in mean shapes. The CAI population presented a more bulging of the lateral malleolus; copers were characterized by the flexion of the lesser toes, a more bulging of the medial foot in the sagittal plane; and healthy individuals showed a greater heel width and a more bulging of the heel in the sagittal plane. In terms of plantar forces, healthy individuals had significantly greater summated plantar forces and greater plantar forces in the lateral heel area during the early contact phase compared to copers and CAI participants.

SIGNIFICANCE

Overall, this study suggested that repetitive ankle sprains may lead to the bulging of the lateral malleolus. Further, CAI and copers seem to stabilize the ankle joint by medially shifting the center of pressure compared to healthy individuals under the static and less challenging dynamic conditions.

Multidirectional Chronic Ankle Instability: What Is It?

Not all ankle sprains are the same and not all ankles behave the same way after an injury. Although we do not know the mechanisms behind an injury producing an unstable joint, we do know ankle sprains are highly underestimated. While some of the presumed lateral ligament lesions might eventually heal and produce minor symptoms, a substantial number of patients will not have the same outcome. The presence of associated injuries, such as additional medial chronic ankle instability, chronic syndesmotic instability, has been long discussed as a possible reason behind this. To explain multidirectional chronic ankle instability, this article aims to present the literature surrounding the condition and its importance nowadays.

Inter and intra-examiner reliability of musculoskeletal ultrasound scanning of Anterior Talofibular Ligament and ankle muscles

PURPOSE

Although the function of subjects with chronic ankle instability (CAI) has been examined, structural analysis by ultrasound scanning of the structures surrounding the ankle is limited. Before such structural comparisons between injured and uninjured people can be made it is important to investigate a reliable measurement protocol of structures possibly related to CAI. The aim of this study was to investigate the inter-intra examiner reliability of ultrasonic characteristics of selected structures in healthy subjects.

METHODS

Eleven healthy participants were assessed by an experienced sonographer and inexperienced certificated examiner. Ultrasound images were collected of the ATFL length and ankle muscles of gastrocnemius medialis (GM), tibialis anterior (TA) and peroneals. Thickness was measured for the muscles, whilst cross-sectional area (CSA) was measured for the peroneals. Inexperienced examiner repeated the measurements a week later.

RESULTS

Inter-examiner reliability was excellent for all structures (ICC3,1 = 0.91-0.98). Intra-examiner reliability shows excellent agreement for all structures (ICC3,1 = 0.92-0.98) except GM (good agreement) (ICC3,1 = 0.82). LoA, relative to structure size, ranged from 1.38 to 6.88% for inter-reliability and from 0.07 to 5.79% for intra-reliability.

CONCLUSION

This study shows a high level of inter-intra examiner reliability in measuring the structures possibly related to CAI. Future research has been planned to investigate the structural analysis in CAI by using applied MSUS protocol.

Effects of mental fatigue on biomechanical characteristics of lower extremities in patients with functional ankle instability during unanticipated side-step cutting

Background: Functional ankle instability (FAI) is the primary classification of ankle injuries. Competitive activities have complicated movements that can result in ankle re-injury among patients with FAI. Unanticipated movement state (MS) and mental fatigue (MF) could also happen in these activities, which may further increase their joint injury risk. Objective: This study aimed to clarify the biomechanical characteristics difference of the lower extremity (LE) between the injured side and the uninjured side among patients with FAI when they perform unanticipated side-step cutting after MF. Methods: Fifteen males with unilateral FAI participated in this study (age: 20.7 ± 1.3 years, height: 173.6 ± 4.4 cm, weight: 70.1 ± 5.0 kg). They used the injured side and the uninjured side of LE to complete anticipated and unanticipated side-step cutting before and after MF. The kinematic and kinetics data were evaluated using three-way ANOVA with repeated measures. Results: During patients with FAI performed anticipated side-step cutting, the ankle stiffness of both sides showed no significant change after MF; During they performed unanticipated side-step cutting, their injured side presented significantly lower ankle stiffness after MF, while the uninjured side did not have such change. In addition, after MF, the injured side exhibited increased ankle inversion, knee valgus and LR, but the uninjured side did without these changes. Conclusion: Influenced by MF, when patients with FAI use their injured side of LE to perform side-step cutting, this side LE has a higher risk of musculoskeletal injuries such as lateral ankle sprains and anterior cruciate ligament injury. The ankle stiffness of the injured side will be further reduced when patients with FAI perform unanticipated side-step cutting, which increases ankle instability and the risk of re-injury.

The prevalence and effect of the sites of pain in female soccer players with medial shin pain

BACKGROUND

Female soccer players are often diagnosed with medial shin pain, which includes tibial stress fracture, medial tibial stress syndrome, and chronic exertional compartment syndrome. As the possibility of varied sites of pain affecting sports activities has not been fully researched, an urgent discussion and evidence is required. This study investigates the prevalence and effect of sites of pain on the sports activities of female soccer players with medial shin pain.

METHODS

A questionnaire survey was conducted for 196 female soccer players with medial shin pain to assess symptom duration, the effect of practice and performance, and sites of pain. The players were classified into three conditions (tibial stress fracture, medial tibial stress syndrome, or medial shin pain with neurological symptoms) and compared based on sites of pain.

RESULTS

We observed that medial tibial stress syndrome had a lower impact on performance compared to that of tibial stress fracture and medial shin pain with neurological symptoms. While participants with tibial stress fracture had to suspend practice sessions more frequently, the difference in symptom duration between the classified groups was not statistically significant. The effect of sites of pain on sports activities was not significantly different in participants with medial tibial stress syndrome.

CONCLUSIONS

Medial shin pain should be evaluated carefully to differentiate between medial tibial stress syndrome and medial shin pain with neurological symptoms. Restriction of sports activities may help improve the patient's condition early, regardless of the presentation.

Chronic ankle instability modifies proximal lower extremity biomechanics during sports maneuvers that may increase the risk of ACL injury: A systematic review

The biomechanical changes in the lower extremity caused by chronic ankle instability (CAI) are not restricted to the ankle joint, but also affect the proximal joints, increasing the risk of joint injury. This study aimed to systematically review the research on CAI and lower extremity angle and movements during side-cutting, stop jumping, and landing tasks, to provide a systematic and basic theoretical basis for preventing lower extremity injury. Literature published from exception to April 2022 were searched in the PubMed, Web of Science, and SPORTDiscus databases using the keywords of “chronic ankle instability,” “side-cut,” “stop jump,” and “landing.” Only studies that compared participants with chronic ankle instability with healthy participants and assessed lower extremity kinetics or kinematics during side-cutting, stop jumping, or landing were included. The risk of bias assessment was conducted using a modified version of the Newcastle-Ottawa checklist. After title, abstract, and full text screening, 32 studies were included and the average score of the quality evaluation was 7 points (range 6–8). Among them five studies were related to the side-cut task, three studies were the stop-jump task, and twenty-four studies were related to landing. Although the results of many studies are inconsistent, participants with CAI exhibit altered lower extremity proximal joint movement strategies during side cut, stop jump, and landings, however, such alterations may increase the risk of anterior cruciate ligament injury.

Three-dimensional motion analysis of the hindfoot resulting from simulated contraction of individual lower leg muscles utilizing Thiel-embalmed cadavers

BACKGROUND

Joint movement within the foot is complex involving multiple muscles. We evaluated three-dimensional movement of the hindfoot through simulated traction of extrinsic tendons of the foot.

METHODS

Six Thiel-embalmed cadavers were utilized and thread was sutured to each tendon of the lower leg muscles. Traction of the thread was prescribed and the change of calcaneal position used to quantify foot motion was measured for each increment using a magnetic tracking system.

RESULTS

As the tendon traction length advanced, the angle of the calcaneus with respect to the tibia increased linearly. Eversion and abduction angles due to extensor digitorum longus (EDL) traction were significantly greater than that due to the peroneus longus. Plantarflexion due to Achilles tendon traction was significantly greater than that of other plantarflexors.

CONCLUSIONS

Our results demonstrated three-dimensional characteristics of hindfoot motion by simulated muscle contraction and importance of EDL as an evertor. These information should be applicable for tendon transfer procedures around the ankle and physical therapy for ankle dysfunction such as chronic ankle instability.

Lower limb kinematics during single leg landing in three directions in individuals with chronic ankle instability

OBJECTIVES

To compare the lower limb kinematics of participants with chronic ankle instability (CAI) and healthy participants during forward, lateral, and medial landings.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS

Eighteen athletes with CAI and 18 control athletes.

MAIN OUTCOME MEASURES

Hip, knee, and ankle joint kinematics during forward, lateral, and medial single-leg landings were compared between the groups using two-way ANOVA for discrete values and statistical parametric mapping two-sample t-tests for time-series data.

RESULTS

The CAI group had significantly greater ankle dorsiflexion than the control group (P ≤ 0.013), which was observed from the pre-initial contact (IC) for lateral and medial landings and post-IC for forward landing. The CAI group showed greater knee flexion than the control group from the IC for lateral landing and post-IC for forward landing (P ≤ 0.014). No significant differences in ankle inversion kinematics were found between the CAI and control groups. Lateral landing had a greater peak inversion angle and velocity than forward and medial landings (P < 0.001). Medial landing had a greater inversion velocity than forward landing (P < 0.001).

CONCLUSIONS

This study suggests that individuals with CAI show feedforward protective adaptations in the pre-landing phase for lateral and medial landings.

Inter-limb asymmetry of kinetic and electromyographic during walking in patients with chronic ankle instability

After an initial ankle sprain, a relevant number of participants develop chronic ankle instability (CAI). Compensatory strategies in patients with CAI may change the inter-limb symmetry needed for absorbing movement-related forces. Accordingly, an increased risk of injury can occur. The present study aimed to compare the inter-limb asymmetry of kinetic and electromyography between individuals with CAI and without a history of an ankle sprain (Non-CAI) during walking. In this cross-sectional study, fifty-six athletes (28 CAI; 28 Non-CAI) participated. Participants walked at a comfortable pace over level ground while vertical ground reaction force (vGRF) and muscle activity of the tibialis anterior, peroneus longus, medial gastrocnemius, and gluteus medius were recorded. Inter-limb asymmetry during walking was calculated for each of the variables. Patients with CAI exhibited a greater inter-limb asymmetry of the first peak of vGRF, time to peak vGRF, and loading rate (P < 0.001), as well as presenting a greater inter-limb asymmetry of peroneus longus activity (contact phase) (P = 0.003) and gluteus medius activity (midstance/propulsion phase) (P = 0.010) compared to the Non-CAI group. No other differences in vGRF or muscles activity were observed between the groups. Our findings indicate that patients with CAI walk with greater inter-limb asymmetry in vGRF and muscle activity in different phases of the gait cycle compared to Non-CAI group. Our results could inform future studies on gait training aimed to reduce asymmetry during walking in patients with CAI.

Energy dissipation during single-leg landing from three heights in individuals with and without chronic ankle instability

Inadequate energy dissipation during landing may increase the risk of ankle sprain. Mechanical demands (landing height) in landing tasks may affect the biomechanical differences between individuals with and without chronic ankle instability (CAI). However, energy dissipation strategies during landing from various heights in individuals with CAI are unclear. The purpose of this study was to compare the effect of landing height on lower extremity biomechanics between individuals with and without CAI. Eleven participants in each of the CAI and Control group performed a single-leg landing from three heights (30, 40, and 50 cm). We calculated the contribution of each joint to total energy dissipation at 50-ms intervals during 0-200 ms post-initial contact (IC). Peak joint angles and moments and joint stiffnesses were calculated during 0-200 ms post-IC. Two-way mixed analysis of variance revealed significant group-by-height interactions for hip energy dissipation at 101-150 ms post-IC and peak ankle plantarflexion and hip extension moment. These significant interactions suggested that the effects of landing height on the ankle and hip joints differ between individuals with and without CAI. The effect of mechanical demands on altered landing biomechanics among CAI populations should be considered in biomechanical studies and clinical practice.

Hip and knee muscle torque is not impaired in the first three months of a first-time lateral ankle sprain

OBJECTIVES

The primary objective was to compare hip and knee isometric muscle strength between individuals with a first-time acute lateral ankle sprain and controls. A secondary objective was to investigate hip and knee isometric muscle strength three months post-injury.

DESIGN

Cross-sectional and prospective follow-up components.

SETTING

Laboratory environment.

PARTICIPANTS

Forty-two participants (21 acute lateral ankle sprain and 21 controls) matched for age, sex, physical activity and leg dominance participated.

MAIN OUTCOME MEASURES

Hip and knee isometric muscle torque was assessed using a rigidly fixated hand-held dynamometer. Testing in acute lateral ankle sprain participants was performed within four weeks of injury and three months post-injury. Controls were tested at one timepoint.

RESULTS

There were no differences in hip or knee isometric muscle torque between acute lateral ankle sprain and control participants (mean differences <0.08). Hip and knee isometric muscle torque in acute ankle sprain participants did not differ between baseline and three months post-injury testing (mean difference <0.06).

CONCLUSIONS

Proximal lower limb isometric strength is not impaired within the first three months of sustaining a first-time lateral ankle sprain injury. This implies that hip and knee isometric strength deficits in individuals with CAI may occur at some later stage.

A review of the role of lower-leg strength measurements in ankle sprain and chronic ankle instability populations

Lower-leg strength training has been a cornerstone of ankle sprain and chronic ankle instability (CAI) rehabilitation and an important consideration for return-to-play in athletes with ankle injuries. The purpose of this literature review is to offer a contemporary, evidence-based overview of the role of ankle strength measurements as they relate to acute ankle sprain rehabilitation and those who have developed CAI. A comprehensive 20-year scan of the relevant research was conducted to assist us in providing this important update for clinicians and biomechanists working with patients and subjects with acute and chronic ankle sprains. While variability exists with measurement devices and methodology, strength assessment remains a critical component of ankle sprain and CAI treatment schemes. Helpful tips on obtaining and processing the most accurate strength assessments for lower-leg musculature are presented.

Ankle Stability and Movement Coordination Impairments: Lateral Ankle Ligament Sprains Revision 2021

This revised clinical practice guideline (CPG) addresses the distinct but related lower extremity impairments of those with a first-time lateral ankle sprain (LAS) and those with chronic ankle instability (CAI). Depending on many factors, impairments may continue following injury. While most individuals experience resolution of symptoms, complaints of instability may continue and are defined as CAI. The aims of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. J Orthop Sports Phys Ther 2021;51(4):CPG1-CPG80. doi:10.2519/jospt.2021.0302.

The effect of chronic ankle instability on muscle activations in lower extremities

BACKGROUND/PURPOSE

Muscular reflex responses of the lower extremities to sudden gait disturbances are related to postural stability and injury risk. Chronic ankle instability (CAI) has shown to affect activities related to the distal leg muscles while walking. Its effects on proximal muscle activities of the leg, both for the injured- (IN) and uninjured-side (NON), remain unclear. Therefore, the aim was to compare the difference of the motor control strategy in ipsilateral and contralateral proximal joints while unperturbed walking and perturbed walking between individuals with CAI and matched controls.

MATERIALS AND METHODS

In a cross-sectional study, 13 participants with unilateral CAI and 13 controls (CON) walked on a split-belt treadmill with and without random left- and right-sided perturbations. EMG amplitudes of muscles at lower extremities were analyzed 200 ms after perturbations, 200 ms before, and 100 ms after (Post100) heel contact while walking. Onset latencies were analyzed at heel contacts and after perturbations. Statistical significance was set at alpha≤0.05 and 95% confidence intervals were applied to determine group differences. Cohen's d effect sizes were calculated to evaluate the extent of differences.

RESULTS

Participants with CAI showed increased EMG amplitudes for NON-rectus abdominus at Post100 and shorter latencies for IN-gluteus maximus after heel contact compared to CON (p<0.05). Overall, leg muscles (rectus femoris, biceps femoris, and gluteus medius) activated earlier and less bilaterally (d = 0.30-0.88) and trunk muscles (bilateral rectus abdominus and NON-erector spinae) activated earlier and more for the CAI group than CON group (d = 0.33-1.09).

CONCLUSION

Unilateral CAI alters the pattern of the motor control strategy around proximal joints bilaterally. Neuromuscular training for the muscles, which alters motor control strategy because of CAI, could be taken into consideration when planning rehabilitation for CAI.

Hip and knee muscle torque and its relationship with dynamic balance in chronic ankle instability, copers and controls

OBJECTIVES

We compared hip and knee isometric muscle torque between individuals with chronic ankle instability (CAI), those who have sustained one ankle sprain with no ongoing problems (copers) and healthy controls. Our secondary objective was to compare balance between groups and investigate the relationship between muscle torque and balance.

DESIGN

Cross-sectional study.

METHODS

22 CAI, 20 copers and 22 uninjured participants were tested. Isometric torque (normalised to body mass (Nm/kg)) was measured using a rigidly-fixated hand-held dynamometer. Balance was assessed with the Y-balance test.

RESULTS

Knee and hip flexor and extensor, and hip adductor and abductor muscle torque was less in individuals with CAI compared to controls (standardised mean difference (SMD) >1.2). Hip and knee flexor and extensor muscle torque was less in CAI participants than copers (SMD: 0.69-1.1). Hip external and internal rotator torque did not differ between groups. There was no difference in hip or knee muscle torque between controls and copers (SMD: 0.01-0. 54). Balance was impaired in CAI participants compared to copers and controls in all directions. There was a strong positive correlation between posterolateral Y-balance test performance and torque of the hip adductors (r=0.53), flexors (r=0.52) and extensors (r=0.50).

CONCLUSIONS

Individuals with CAI have weak knee and hip muscles compared to copers and controls. Hip strength was shown to be related to posterolateral balance performance. Future studies may investigate the effect of hip and knee strengthening exercise on ongoing ankle problems, such as episodic giving way in individuals with CAI.

Prevalence and characteristics of chronic ankle instability and copers identified by the criteria for research and clinical practice in collegiate athletes

OBJECTIVES

To investigate the prevalence and characteristics of chronic ankle instability (CAI) and copers among collegiate athletes as identified by criteria for research (CAI-R and copers-R) and for clinical practice (CAI-C and copers-C).

DESIGN

Cross-sectional study.

SETTING

University.

PARTICIPANTS

Collegiate athletes (n = 507).

MAIN OUTCOME MEASURES

Participants were assessed by questionnaires based on the International Ankle Consortium guidelines. The percentages of participants with CAI-R, CAI-C, copers-R and copers-C were calculated, respectively. Demographic and injury data were statistically compared between CAI-R and copers-R groups.

RESULTS

The data of 470 participants was retained after exclusions. Of these, the prevalence of CAI-R (10.0%) was only half of that of CAI-C (19.8%), and that of copers-R and copers-C was about 5%. Seventy percent of unclassifiable participants had recurrent ankle sprains. CAI was most common in basketball, while copers were less prevalent in basketball, judo, rugby and gymnastics. The age at the initial injury was significantly younger in the CAI-R participants than in the copers-R.

CONCLUSIONS

The type of sport and the age at the initial injury may be associated with developing CAI. The standard criteria may not capture the entire clinical CAI population, therefore, care should be taken when applying the research to clinical practice.

Lower Limb Joint Kinetics During a Side-Cutting Task in Participants With or Without Chronic Ankle Instability

CONTEXT

Individuals with chronic ankle instability (CAI) demonstrate altered lower limb movement dynamics during jump landings, which can contribute to recurrent injury. However, the literature examining lower limb movement dynamics during a side-cutting task in individuals with CAI is limited.

OBJECTIVE

To assess lower limb joint kinetics and sagittal-plane joint stiffness during the stance phase of a side-cutting task in individuals with or without CAI.

DESIGN

Cohort study.

SETTING

Motion-capture laboratory.

PATIENTS OR OTHER PARTICIPANTS

Fifteen physically active, young adults with CAI (7 men, 8 women; age = 21.3 ± 1.6 years, height = 171.0 ± 11.2 cm, mass = 73.4 ± 15.2 kg) and 15 healthy matched controls (7 men, 8 women; age = 21.5 ± 1.5 years, height = 169.9 ± 10.6 cm, mass = 75.5 ± 13.0 kg).

INTERVENTION(S)

Lower limb 3-dimensional kinematic and ground reaction force data were recorded while participants completed 3 successful trials of a side-cutting task. Net internal joint moments, in addition to sagittal-plane ankle-, knee-, and hip-joint stiffness, were computed from 3-dimensional kinematic and ground reaction force data during the stance phase of the side-cutting task and analyzed.

MAIN OUTCOME MEASURE(S)

Data from each participant's stance phase were normalized to 100% from initial foot contact (0%) to toe-off (100%) to compute means, standard deviations, and Cohen d effect sizes for all dependent variables.

RESULTS

The CAI group exhibited a reduced ankle-eversion moment (39%-81% of stance phase) and knee-abduction moment (52%-75% of stance phase) and a greater ankle plantar-flexion moment (3%-16% of stance phase) than the control group (P range = .009-.049). Sagittal-plane hip-joint stiffness was greater in the CAI than in the control group (t₂₈ = 1.978, P = .03).

CONCLUSIONS

Our findings suggest that altered ankle-joint kinetics and increased hip-joint stiffness were associated when individuals with CAI performed a side-cutting task. These lower limb kinetic changes may contribute to an increased risk of recurrent lateral ankle sprains in people with CAI. Clinicians and practitioners can use these findings to develop rehabilitation programs for improving maladaptive movement mechanics in individuals with CAI.

Hop Stabilization Training Improves Neuromuscular Control in College Basketball Players With Chronic Ankle Instability: A Randomized Controlled Trial

CONTEXT

Neuromuscular control deficit has been reported in people with chronic ankle instability (CAI) and hopping exercises have been recommended as a functional training tool to prevent lower limb injury, but its effects on lower-extremity neuromuscular control in those with CAI are unclear.

OBJECTIVE

To investigate the effect of hop stabilization training on neuromuscular control and self-reported function in college basketball players with CAI.

STUDY DESIGN

A randomized controlled trial.

SETTING

Research Laboratory. Patients (or Other Participants): A total of 28 college basketball players with CAI were randomly assigned to the experimental hop stabilization group (age = 22.78 [3.09] y, weight = 82.59 [9.51] kg, and height = 187.96 [7.93] cm) or the control group (age = 22.57 [2.76] y, weight = 78.35 [7.02] kg, and height = 185.69 [7.28] cm).

INTERVENTION

Participants in the experimental group performed supervised hop stabilization exercises 3 times per week for 6 weeks. The control group received no intervention.

MAIN OUTCOME MEASURES

Preparatory and reactive muscle activation levels and muscle onset time were assessed from 8 lower-extremity muscles during a jump-landing task before and after the 6-week training program.

RESULTS

Significant improvements in preparatory muscle activation, reactive muscle activation, and muscle onset time were noted across the lower-extremity in the experimental group relative to the control group (P < .05). Self-reported function also improved in the experimental group relative to the control group (P < .05).

CONCLUSIONS

These findings demonstrate that 6 weeks of hop stabilization training is effective in improving neuromuscular control and self-reported function in college basketball players with CAI. Hop stabilization exercises can be incorporated into the rehabilitation program for CAI.

EMG-Informed Musculoskeletal Modeling to Estimate Realistic Knee Anterior Shear Force During Drop Vertical Jump in Female Athletes

The anterior cruciate ligament is the primary structural restraint to tibial anterior shear force. The anterior force occurring at the knee during landing contributes to anterior cruciate ligament injury risk, but it cannot be directly measured experimentally. The objective of this study was to develop electromyography-informed musculoskeletal simulations of the drop vertical jump motor task and assess the contribution of knee muscle forces to tibial anterior shear force. In this cross-sectional study, musculoskeletal simulations were used to estimate the muscle forces of thirteen female athletes performing a drop vertical jump using an electromyography-informed method. Muscle activation and knee loads that resulted from these simulations were compared to the results obtained with the more common approach of minimization of muscle effort (optimization-based method). Quadriceps-hamstrings and quadriceps-gastrocnemius co-contractions were progressively increased and their contribution to anterior shear force was quantified. The electromyography-informed method produced co-contraction indexes more consistent with electromyography data than the optimization-based method. The muscles that presented the largest contribution to peak anterior shear force were the gastrocnemii, likely from their wrapping around the posterior aspect of the tibia. The quadriceps-hamstring co-contraction provided a protective effect on the ACL and reduced peak anterior shear force by 292 N with a co-contraction index increase of 25% from baseline (31%), whereas a quadriceps-gastrocnemius co-contraction index of 61% increased peak anterior shear force by 797 N compared to baseline (42%). An increase in gastrocnemius contraction, which might be required to protect the ankle from the impact with the ground, produced a large quadriceps-gastrocnemius co-activation, increasing peak anterior shear force. A better understanding of each muscle's contribution to anterior shear force and, consequently, anterior cruciate ligament tension may inform subject-specific injury prevention programs and rehabilitation protocols.

An Updated Model of Chronic Ankle Instability

Lateral ankle sprains (LASs) are among the most common injuries incurred during participation in sport and physical activity, and it is estimated that up to 40% of individuals who experience a first-time LAS will develop chronic ankle instability (CAI). Chronic ankle instability is characterized by a patient's being more than 12 months removed from the initial LAS and exhibiting a propensity for recurrent ankle sprains, frequent episodes or perceptions of the ankle giving way, and persistent symptoms such as pain, swelling, limited motion, weakness, and diminished self-reported function. We present an updated model of CAI that aims to synthesize the current understanding of its causes and serves as a framework for the clinical assessment and rehabilitation of patients with LASs or CAI. Our goal was to describe how primary injury to the lateral ankle ligaments from an acute LAS may lead to a collection of interrelated pathomechanical, sensory-perceptual, and motor-behavioral impairments that influence a patient's clinical outcome. With an underpinning of the biopsychosocial model, the concepts of self-organization and perception-action cycles derived from dynamic systems theory and a patient-specific neurosignature, stemming from the Melzack neuromatrix of pain theory, are used to describe these interrelationships.

Altered Walking Neuromechanics in Patients With Chronic Ankle Instability

CONTEXT

The literature on gait kinematics and muscle activation in chronic ankle instability (CAI) is limited. A comprehensive evaluation of all relevant gait measures is needed to examine alterations in gait neuromechanics that may contribute to recurrent sprain.

OBJECTIVE

To compare walking neuromechanics, including kinematics, muscle activity, and kinetics (ie, ground reaction force [GRF], moment, and power), between participants with and those without CAI by applying a novel statistical analysis to data from a large sample.

DESIGN

Controlled laboratory study.

SETTING

Biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 100 participants with CAI (49 men, 51 women; age = 22.2 ± 2.3 years, height = 174.0 ± 9.7 cm, mass = 70.8 ± 14.4 kg) and 100 individuals without CAI serving as controls (55 men, 45 women; age = 22.5 ± 3.3 years, height = 173.1 ± 13.3 cm, mass = 72.6 ± 18.7 kg).

INTERVENTION(S)

Participants performed 5 trials of walking (shod) at a self-selected speed over 2 in-ground force plates.

MAIN OUTCOME MEASURE(S)

Three-dimensional GRFs, lower extremity joint angles, internal joint moments, joint powers, and activation amplitudes of 6 muscles were recorded during stance.

RESULTS

Compared with the control group, the CAI group demonstrated (1) increased plantar flexion or decreased dorsiflexion, increased inversion or decreased eversion, decreased knee flexion, decreased knee abduction, and increased hip-flexion angles; (2) increased or decreased inversion, increased plantar flexion, decreased knee extension, decreased knee abduction, and increased hip-extension moments; (3) increased vertical, braking, and propulsive GRFs; (4) increased hip eccentric and concentric power; and (5) altered muscle activation in all 6 lower extremity muscles.

CONCLUSIONS

The CAI group demonstrated a hip-dominant strategy by limiting propulsive forces at the ankle while increasing force generation at the hip. The different walking neuromechanics exhibited by the CAI group could represent maladaptive strategies that developed after the initial sprain or an injurious gait pattern that may have predisposed the participants to their initial injuries. Increased joint loading and altered kinematics at the foot and ankle complex during initial stance could affect the long-term health of the ankle articular cartilage.

Effect of External Ankle Support on Ankle and Knee Biomechanics During the Cutting Maneuver in Basketball Players

BACKGROUND

Despite the high prevalence of lower extremity injuries in female basketball players as well as a high proportion of athletes who wear ankle braces, there is a paucity of research pertaining to the effects of ankle bracing on ankle and knee biomechanics during basketball-specific tasks.

PURPOSE

To compare the effects of a lace-up brace (ASO), a hinged brace (Active T2), and no ankle bracing (control) on ankle and knee joint kinematics and joint reaction forces in female basketball athletes during a cutting maneuver.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty healthy, semi-elite female basketball players performed a cutting task under both ankle brace conditions (lace-up ankle brace and hinged ankle brace) and a no-brace condition. The 3-dimensional kinematics of the ankle and knee during the cutting maneuver were measured with an 18-camera motion analysis system (250 Hz), and ground-reaction force data were collected by use of a multichannel force plate (2000 Hz) to quantify ankle and knee joint reaction forces. Conditions were randomized using a block randomization method.

RESULTS

Compared with the control condition, the hinged ankle brace significantly restricted peak ankle inversion (mean difference, 1.7°; P = .023). No significant difference was found between the lace-up brace and the control condition ( P = .865). Compared with the lace-up brace, the hinged brace significantly reduced ankle and knee joint compressive forces at the time of peak ankle dorsiflexion (mean difference, 1.5 N/kg [ P = .018] and 1.4 N/kg [ P = .013], respectively). Additionally, the hinged ankle brace significantly reduced knee anterior shear forces compared with the lace-up brace both during the deceleration phase and at peak ankle dorsiflexion (mean difference, 0.8 N/kg [ P = .018] and 0.9 N/kg [ P = .011], respectively).

CONCLUSION

The hinged ankle brace significantly reduced ankle inversion compared with the no-brace condition and reduced ankle and knee joint forces compared with the lace-up brace in a female basketball population during a cutting task. Compared with the lace-up brace, the hinged brace may be a better choice of prophylactic ankle support for female basketball players from a biomechanical perspective. However, both braces increased knee internal rotation and knee abduction angles, which may be problematic for a population that already has a high prevalence of knee injuries.

Hip-ankle coordination during gait in individuals with chronic ankle instability

Individuals with chronic ankle instability (CAI) may have sensorimotor impairments that affect control at the hip in addition to the ankle. The purpose of this study was to compare hip-ankle coordination and coordination variability between individuals with CAI and healthy individuals during walking. Ten healthy subjects and 10 subjects with CAI were recruited to walk on a treadmill. Hip-ankle coordination was quantified using vector coding, and coordination variability was quantified using coefficient of correspondence. We found significant between-group differences in hip-ankle coordination in the frontal plane around loading response (Control: 165.9±18.4°; CAI: 127.6±48.6°, p=0.04) and in the sagittal plane around the first half of mid stance (Control: 307.2±9.8°; CAI: 291.8±11.4°, p<0.01), terminal stance (Control: 301.1±13°; CAI: 313.4±10.9°, p=0.04), and pre-swing (Control: 243.9±35.2°; CAI: 329.9±57.8°, p<0.01). We also found significant between-group differences in hip-ankle coordination variability in the frontal plane around the second half of mid stance (Control: 0.54±0.06; CAI: 0.45±0.07, P<0.01). CAI is associated with alteration of hip-ankle coordination and coordination variability in stance phase during walking. Gait training is important in CAI rehabilitation, and the training should address altered hip-ankle coordination to reduce the risk of recurrent injuries.