• Humans
• Joint Instability/physiopathology
• Joint Instability/therapy
• Joint Instability/rehabilitation
• Postural Balance/physiology
• Male
• Female
• Double-Blind Method
• Young Adult
• Electric Stimulation Therapy/methods
• Ankle Joint/physiopathology
• Adult
• Chronic Disease
• Muscle, Skeletal/physiopathology
• Treatment Outcome
• Peroneal Nerve/physiopathology

• ankle sprain
• breathing mechanics
• joint instability
• postural stability

• Humans
• Ankle
• Diaphragm/diagnostic imaging
• Ankle Joint/diagnostic imaging
• Cross-Sectional Studies
• Postural Balance
• Joint Instability/diagnostic imaging

• Balance control
• Chronic ankle instability
• Local muscle vibration
• Proprioception

• Humans
• Ankle
• Ankle Joint
• Vibration/therapeutic use
• Postural Balance/physiology
• Muscles
• Joint Instability/rehabilitation
• Chronic Disease

• ankle strategy
• center of pressure deviation
• chronic ankle instability
• joint dysfunction
• knee joint immobilization
• posture transition

• Humans
• Ankle
• Posture/physiology
• Ankle Joint
• Lower Extremity
• Joint Instability
• Postural Balance/physiology
• Athletes
• Chronic Disease

• Humans
• Athletic Performance/physiology
• Fatigue
• Muscle Fatigue/physiology
• Workload
• Heart Rate/physiology
• Athletes

• ankle injuries
• complex foot and ankle conditions
• high-arched feet
• tendon imbalance
• unstable ankle

Postural stability of athletes is commonly tested with single-leg stance (SLS) tests. However, for this population, these tests are insufficiently challenging to achieve high sensitivity. Therefore, a new dynamic SLS test based on standardized translational surface perturbations was developed. This study aimed to assess reliability, sensitivity to learning effects, and internal and concurrent validity of this novel test.

Healthy soccer players (21 females, 21 males) performed 2 test sessions. Each session consisted of 2 trials. For one trial, the participant performed a 30-seconds, unperturbed SLS on each leg, followed by 12 platform perturbations per leg.

Intraclass Correlation Coefficients (ICC) and correlations between outcomes were calculated for the Center of Pressure speed (CoPs) and Time To Stabilization (TTS). ANOVA was used to assess learning effects. CoPs and TTS showed a fair reliability between sessions (ICC = 0.73–0.76). All variables showed improvement over time within and between sessions (all p < 0.01) and were moderately correlated with CoPs during unperturbed SLS (r = 0.39–0.56).

Single-leg dynamic postural stability testing through standardized horizontal platform perturbations yielded sufficiently reliable CoPs and TTS outcome measures in soccer players. The moderate correlations with unperturbed SLS support concurrent validity, but also indicates that the new test captures aspects of postural stability that differ from the conventional, unperturbed SLS test.

• Center of Pressure speed
• Perturbation
• Postural stability
• Time To Stabilization

• balance
• center of pressure
• force plate
• time-to-boundary

The ability to balance on one foot for a certain time is a widely used clinical test to assess the effects of age and diseases like peripheral neuropathy on balance. While state-space methods have been used to explore the mechanical demands and achievable accelerations for balancing on two feet in the sagittal plane, less is known about the requirements for sustaining one legged balance (OLB) in the frontal plane.

While most studies have focused on ankle function in OLB, can age and/or disease-related decreases in maximum hip abduction strength also affect OLB ability?

A two-link frontal plane state space model was used to define and explore the ‘feasible balance region’ which helps reveal the requirements for maintaining and restoring OLB, given the adverse effects of age and peripheral neuropathy on maximum hip and ankle strengths.

Maintaining quasistatic OLB required 50%-106% of the maximum hip abduction strength in young and older adults, and older patients with peripheral neuropathy. Effectiveness of a ‘hip strategy’ in recovering OLB was heavily dependent on the maximum hip abduction strength, and for healthy older women was as important as ankle strength. Natural reductions of strength due to healthy aging did not show a meaningful reduction in meeting the strength requirement of clinical OLB. However deficits in hip strength typical of patients with peripheral neuropathy did adversely affect both quasistatic OLB and recoverable OLB states.

The importance of hip muscle strength has been underappreciated in the clinical OLB test. This is partly because the passive tissues of the hip joint can mask moderate deficits in hip abduction strength until it is needed for recovering OLB. Adding a follow up OLB test with a slightly raised pelvis would be a simple way to check for adequate hip abductor muscle strength.

• Adult
• Algorithms
• Biomechanical Phenomena
• Foot/physiology
• Humans
• Middle Aged
• Models, Biological
• Normal Distribution
• Postural Balance/physiology
• Posture/physiology
• Standing Position
• Stochastic Processes
• Transducers
• Young Adult

[Purpose] This study aimed to develop a method for assessing anticipatory postural adjustments associated with voluntary movements in individuals with functional ankle instability. We examined whether the peroneus longus muscle exhibits anticipatory activation before unilateral abduction of the lower limb in individuals without disability. [Participants and Methods] Twelve healthy young adults participated in this study. Participants maintained a standing posture with 95 ± 2.5% of their weight on the left side and with the thenar of their right foot in contact with a small wooden board fixed to a force platform. Thereafter, they abducted their right lower limb by approximately 35° at maximum speed; during this time, electromyographic activities of the focal and postural muscles were recorded. [Results] The peroneus longus, external oblique, and erector spinae muscles on the left side of the body were activated before the right gluteus medius muscle, which is a focal muscle of abduction of the right lower limb. The activation timing of the left peroneus longus was the fastest among these postural muscles. [Conclusion] These findings suggest that the peroneus longus muscle plays an important role in anticipatory postural adjustments associated with unilateral abduction of the lower limb and that an ankle strategy is adopted in anticipatory postural adjustments during this task.

• Anticipatory postural adjustments
• Electromyography
• Peroneus longus muscle

Static standing postural stability has been measured by multiscale entropy (MSE), which is used to measure complexity. In this study, we used the average entropy (AE) to measure the static standing postural stability, as AE is a good measure of disorder. The center of pressure (COP) trajectories were collected from 11 subjects under four kinds of balance conditions, from stable to unstable: bipedal with open eyes, bipedal with closed eyes, unipedal with open eyes, and unipedal with closed eyes. The AE, entropy of entropy (EoE), and MSE methods were used to analyze these COP data, and EoE was found to be a good measure of complexity. The AE of the 11 subjects sequentially increased by 100% as the balance conditions progressed from stable to unstable, but the results of EoE and MSE did not follow this trend. Therefore, AE, rather than EoE or MSE, is a good measure of static standing postural stability. Furthermore, the comparison of EoE and AE plots exhibited an inverted U curve, which is another example of a complexity versus disorder inverted U curve.

• ankle injuries
• chronic pain
• discomfort
• joint instability
• sprains and strains

• ankle sprains
• anterior talofibular ligament
• calcaneofibular ligament
• diagnosis
• rehabilitation

Many diseases and conditions decrease the ability to control balance. In clinical settings, there is therefore a major interest in the assessment of postural control. Trunk accelerometry is an easy, low-cost method used for balance testing and constitutes an alternative method to the posturography using force platforms. The objective was to assess the responsiveness of accelerometry in a battery of 12 quiet standing tasks. We evaluated the balance of 100 healthy adults with an accelerometer fixed onto the sternum. We used the average amplitude of acceleration as an indirect measure of postural sways. The tasks of increased difficulty were realized with or without vision. The battery of tasks was repeated four times on two different days to assess reliability. We analyzed the extent to which the task difficulty and the absence of vision affected the trunk sway. The influence of individual characteristics (age, height, mass, sex, and physical activity level) was also assessed. The reliability analysis revealed that four repetitions of the battery of tasks are needed to reach a high accuracy level (mean ICC = 0.85). The results showed that task difficulty had a very large effect on trunk sways and that the removal of vision further increased sways. Concerning the effects of individual characteristics, we observed that women tended to oscillate more than men did in tasks of low difficulty. Age and physical activity level also had significant effects, whereas height and mass did not. In conclusion, age, sex, and physical fitness are confounders that should be considered when assessing patients’ balance. A battery of simple postural tasks measured by upper-trunk accelerometry can be a useful method for simple balance evaluation in clinical settings.

• Accelerometry/instrumentation
• Accelerometry/methods
• Adult
• Aged
• Female
• Humans
• Male
• Middle Aged
• Postural Balance/physiology
• Sex Factors
• Standing Position
• Wearable Electronic Devices

• Balance
• Hip osteoarthritis
• Physical activity
• Pressure
• Stability

• Adult
• Aged
• Case-Control Studies
• Disease Management
• Female
• Hip Joint/pathology
• Hip Joint/physiopathology
• Humans
• Kinesthesis
• Middle Aged
• Neurologic Examination/methods
• Osteoarthritis, Hip/complications
• Osteoarthritis, Hip/physiopathology
• Poland
• Postural Balance
• Proprioception
• Random Allocation
• Sensation Disorders/diagnosis
• Sensation Disorders/etiology
• Sensation Disorders/physiopathology

• Ankle disc
• Ankle sprain
• Balance assessment
• Chronic ankle instability
• Postural control

• Adult
• Ankle/physiopathology
• Case-Control Studies
• Exercise Test/instrumentation
• Female
• Humans
• Joint Instability/diagnosis
• Male
• Postural Balance
• Reproducibility of Results
• Young Adult

• Accidental Falls
• Humans
• Physical Therapy Modalities
• Postural Balance
• Reproducibility of Results
• Stroke

To investigate the impact of extrinsic visual feedback and additional cognitive/physical demands on single-limb balance in individuals with ankle instability.

Sixteen subjects with ankle instability participated in the study. Ankle instability was identified using the Cumberland Ankle Instability Tool (CAIT). The subject’s unstable ankle was examined using the Athletic Single Leg Stability Test of the Biodex Balance System with 4 different protocols: (1) default setting with extrinsic visual feedback from the monitor; (2) no extrinsic visual feedback; (3) no extrinsic visual feedback with cognitive demands; and (4) no extrinsic visual feedback with physical demands. For the protocol with added cognitive demands, subjects were asked to continue subtracting 7 from a given number while performing the same test without extrinsic visual feedback. For the protocol with added physical demands, subjects were asked to pass and catch a basketball to and from the examiner while performing the same modified test.

The subject’s single-limb postural control varied significantly among different testing protocols (F = 103; P = 0.000). Subjects’ postural control was the worst with added physical demands and the best with the default condition with extrinsic visual feedback. Pairwise comparison shows subjects performed significantly worse in all modified protocols (P < 0.01 in all comparisons) compared to the default protocol. Results from all 4 protocols are significantly different from each other (P < 0.01) except for the comparison between the “no extrinsic visual feedback” and “no extrinsic visual feedback with cognitive demands” protocols. Comparing conditions without extrinsic visual feedback, adding a cognitive demand did not significantly compromise single-limb balance control but adding a physical demand did. Scores from the default protocol are significantly correlated with the results from all 3 modified protocols: No extrinsic visual feedback (r = 0.782; P = 0.000); no extrinsic visual feedback with cognitive demands (r = 0.569; P = 0.022); no extrinsic visual feedback with physical demands (r = 0.683; P = 0.004). However, the CAIT score is not significantly correlated with the single-limb balance control from any of the 4 protocols: Default with extrinsic visual feedback (r = -0.210; P = 0.434); no extrinsic visual feedback (r = -0.450; P = 0.081); no extrinsic visual feedback with cognitive demands (r = -0.406; P = 0.118); no extrinsic visual feedback with physical demands (r = -0.351; P = 0.182).

Single-limb balance control is worse without extrinsic visual feedback and/or with cognitive/physical demands. The balance test may not be a valid tool to examine ankle instability.

• Ankle
• Balance
• Instability
• Motor control
• Rehabilitation

• Ankle injuries
• Articular
• Joint instability
• Postural balance
• Range of motion

• Aged
• Cross-Sectional Studies
• Hemiplegia/etiology
• Hemiplegia/physiopathology
• Humans
• Japan
• Postural Balance
• Reproducibility of Results
• Stroke/complications
• Walking

• Compliant surface
• Osteoarthritis
• Postural sway
• Rheumatoid arthritis

Objective: To investigate whether a sensorimotor deficit of the upper limb following a brachial plexus injury (BPI) affects the upright balance.

Design: Eleven patients with a unilateral BPI and 11 healthy subjects were recruited. The balance assessment included the Berg Balance Scale (BBS), the number of feet touches on the ground while performing a 60 s single-leg stance and posturographic assessment (eyes open and feet placed hip-width apart during a single 60 s trial). The body weight distribution (BWD) between the legs was estimated from the center of pressure (COP) lateral position. The COP variability was quantified in the anterior-posterior and lateral directions.

Results: BPI patients presented lower BBS scores (p = 0.048) and a higher frequency of feet touches during the single-leg stance (p = 0.042) compared with those of the healthy subjects. An asymmetric BWD toward the side opposite the affected arm was shown by 73% of BPI patients. Finally, higher COP variability was observed in BPI patients compared with healthy subjects for anterior-posterior (p = 0.020), but not for lateral direction (p = 0.818).

Conclusions: This study demonstrates that upper limb sensorimotor deficits following BPI affect body balance, serving as a warning for the clinical community about the need to prevent and treat the secondary outcomes of this condition.

• brachial plexus
• peripheral nerve injuries
• postural balance
• posturography
• weight-bearing

• Aged
• Biomechanical Phenomena
• Female
• Humans
• Leg/physiology
• Male
• Postural Balance/physiology
• Posture/physiology

For young adults, balance is essential for participation in physical activities but is often disrupted following lower extremity injury. Clinical outcome measures such as single limb balance (SLB), Y-balance (YBT), and the single limb hop and balance (SLHB) tests are commonly used to quantify balance ability following injury. Given the varying demands across tasks, it is likely that such outcome measures provide useful, although task-specific, information. But the extent to which they are independent and contribute to understanding the multiple contributors to balance is not clear. Therefore, the purpose of this study was to investigate the associations among these measures as they relate to the different contributors to balance. Thirty-seven recreationally active young adults completed measures including Vertical Jump, YBT, SLB, SLHB, and the new Lower Extremity Dexterity test. Principal components analysis revealed that these outcome measures could be thought of as quantifying the strength, multijoint coordination, and sensorimotor processing contributors to balance. Our results challenge the practice of using a single outcome measure to quantify the naturally multidimensional mechanisms for everyday functions such as balance. This multidimensional approach to, and interpretation of, multiple contributors to balance may lead to more effective, specialized training and rehabilitation regimens.

The compensation for a sudden balance perturbation, unpracticed and unpredictable in timing and magnitude is accompanied by pronounced postural instability that is suggested to be causal to falls. However, subsequent presentations of an identical perturbation are characterized by a marked decrease of the amplitude of postural reactions; a phenomenon called adaptation or habituation. This study aimed to identify cortical characteristics associated with adaptive behavior during repetitive balance perturbations based on single-trial analyses of the P1 and N1 perturbation-evoked potentials. Thirty-seven young men were exposed to ten transient balance perturbations while balancing on the dominant leg. Thirty two-channel electroencephalography (EEG), surface electromyography (EMG) of the ankle plantar flexor muscles and postural sway (i.e., Euclidean distance of the supporting platform) were recorded simultaneously. The P1 and N1 potentials were localized and the amplitude/latency was analyzed trial by trial. The best match sources for P1 and N1 potentials were located in the parietal (Brodmann area (BA) 5) and midline fronto-central cortex (BA 6), respectively. The amplitude and latency of the P1 potential remained unchanged over trials. In contrast, a significant adaptation of the N1 amplitude was observed. Similar adaptation effects were found with regard to postural sway and ankle plantarflexors EMG activity of the non-dominant (free) leg; i.e., an indicator for reduced muscular co-contraction and/or less temporary bipedal stance to regain stability. Significant but weak correlations were found between N1 amplitude and postural sway as well as EMG activity. These results highlight the important role of the midline fronto-central cortex for adaptive behavior associated with balance control.

• EEG
• N1
• P1
• adaptation
• falls
• posture

• Horizontal hip abduction
• Load
• Posterior fibers of the gluteus medius

• Ankle joint
• Biomechanical phenomena
• Kinematics
• Kinetics
• Postural balance

Chronic ankle instability (CAI) is attributed to functional instability driven by insufficient proprioception. However, it is not clear whether the deficits are related to global impaired performance or to specific decrease in ankle motor-control. The aim of this study was to assess the correlation between lower limb postural control and upper limb position sense among people with CAI, in order to further explore the function of the central neural control in people with CAI.

Fourteen participants (10 males, 4 females) with self-reported CAI and 14 age- and gender-matched, healthy controls participated in this study. Each participant completed single-limb stance postural control tests and shoulder position sense tests. The Overall Stability Index (OSI) was used as a measure of postural stability. The average of the absolute error score (AES) was calculated as a measure of shoulder position sense. Pearson correlations between the scores of the four body sites –lower limb postural stability (preferred/non-preferred), shoulder (preferred/non-preferred) were determined separately for each group.

In the control group, significant correlations were found between the OSI score of the right and left ankles (r = 0.887, p < 0.001), between the AES of the right and left shoulders (r = 0.656, p = 0.011), as well as between the OSI score and the AES of the non-preferred side (r = 0.649, p = 0.012). In the CAI group, significant correlation was found only between the OSI score at both ankles (r = 0.6, p = 0.002).

Individuals with CAI demonstrated lower limb postural control and upper limb position sense similar to those shown in healthy controls. However, correlations between the lower and upper limbs were observed only in the healthy controls. Clinicians can use this information and employ activities that focus on coordinating the upper and lower extremities when designing neuromuscular control training programs for people with CAI.

• Ankle-sprain
• Chronic ankle instability
• Proprioception

• Acceleration
• Ankle sprain
• Postural control

• Ankle sprain
• Athlete
• Chronic ankle instability
• Functional ankle testing
• Return to play
• Return to sport

• Ankle joint [MeSH]
• Biomechanical phenomena [MeSH]
• Kinematics [MeSH]
• Kinetics [MeSH]
• Postural balance [MeSH]

• postural control
• rehabilitation
• sprains

• chronic ankle instability
• functional ankle instability
• lateral ankle sprain
• mechanical ankle instability

• Gait disturbance
• Gait perturbation
• Inclination angle
• Lower limb amputee
• Prosthesis
• Stiffness

[Purpose] This study aimed to investigate the postural control characteristics of individuals with and without a history of ankle sprain during single-leg standing by examining the relationship between various parameters of center of pressure (COP) and head and foot acceleration. [Subjects] Twenty subjects with and 23 subjects without a history of ankle sprain (sprain and control groups, respectively) participated. [Methods] Mean and maximum COP velocity and maximum COP range in the anteroposterior and mediolateral components of movement were calculated using a gravicorder. The anteroposterior and mediolateral maximum accelerations of the head and foot, as well as the root mean square (RMS) of each acceleration parameter, were measured using accelerometers. [Results] In the mediolateral component, a significant positive correlation was found between maximum acceleration of the foot and all COP parameters in the sprain group. [Conclusion] Our findings suggest that mediolateral momentary motion of the foot in individuals with a history of ankle sprain has relevance to various parameters of COP.

• Postural control assessment
• Postural strategy
• Recurrent ankle sprain