Measures Of Postural Stability Research Articles

Postural stability during standing and its association with physical and cognitive functions in non-dialysis chronic kidney disease patients

PurposeChronic kidney disease (CKD) is characterised by poor physical function. A possible factor may be aberrant changes to balance and postural stability (i.e. ability to maintain centre of pressure (COP)). Previous research has exclusively focused on patients undergoing renal replacement therapy (RRT). The current study investigated postural stability in a group of CKD patients not requiring RRT.Methods30 CKD patients (aged 57.0 ± 17.8 years, 47% female, mean eGFR 42.9 ± 27.2 ml/kg/1.73 m2) underwent a series of physical function assessments including the sit-to-stand-5 and -60, incremental shuttle walk test, gait speed, and short physical performance battery. Postural stability (defined as total COP ellipse (mm2) displacement) was measured using the Fysiometer board. Control reference data were provided by the manufacture. Cognitive function was assessed using the ‘Montreal Cognitive Assessment-Basic’ (MOCA-B)’.ResultsCKD patients had poorer postural stability during quiet standing than reference values across all age categories (≤ 39 years, 24.9 ± 11.3 vs. 10.4 ± 1.8 mm2; 40–59 years, 34.3 ± 19.0 vs. 17.7 ± 6.2 mm2; ≥ 60 years, 39.7 ± 21.2 vs. 16.8 ± 2.9 mm2, all comparisons P < 0.001). Reductions in postural stability were associated with both physical and cognitive functioning. In females only, postural stability worsened with declining renal function (r = − 0.790, P < 0.01).ConclusionsTo our knowledge, this is the first and largest experimental report concerning measurement of postural stability of CKD patients not requiring RRT. Our findings suggest that postural stability is associated with worse physical and cognitive functioning in this patient group.

Rehabilitation to improve gaze and postural stability in people with multiple sclerosis: study protocol for a prospective randomized clinical trial

BackgroundThe use of vestibular rehabilitation principles in the management of gaze and postural stability impairments in people with multiple sclerosis (PwMS) has shown promise in pilot work completed in our lab and in a recently published randomized clinical trial (RCT). However, further work is needed to fully quantify the gaze and postural impairments present in people with multiple sclerosis and how they respond to rehabilitation.Methods/designThe study is a single blind RCT designed to examine the benefit of a gaze and postural stability (GPS) intervention program compared to a standard of care (SOC) rehabilitation program in dizzy and balance impaired PwMS. Outcomes will be collected across the domains of body structure and function, activity, and participation as classified by the World Health Organization International Classification of Functioning, Disability, and Health (ICF). Our primary outcomes are the Dizziness Handicap Inventory (DHI) and the Functional Gait Assessment (FGA). Secondary outcomes include other measures of gaze and postural stability, fatigue, and functional mobility. Participants who are interested and eligible for enrollment will be consented prior to completing a baseline assessment. Following the baseline assessment each participant will be randomized to either the GPS or SOC intervention group and will complete a 6 week treatment period. During the treatment period, both groups will participate in guided exercise 3x/week. Following the treatment period participants will be asked to return for a post-treatment evaluation and again for a follow-up assessment 1 month later. We anticipate enrolling 50 participants.DiscussionThis study will be an innovative RCT that will utilize gaze and postural stability metrics to assess the efficacy of vestibular rehabilitation in PwMS. It will build on previous work by examining measures across the ICF and improve the current evidence base for treating PwMS.Trial registrationClinicalTrials.gov, May 29th 2018, NCT03521557.

POST-CONCUSSIVE CHANGES IN BALANCE AND POSTURAL STABILITY MEASURED WITH CANESENSE™ AND THE BALANCE ERROR SCORING SYSTEM (BESS) IN DIVISION I COLLEGIATE FOOTBALL PLAYERS: A CASE SERIES

Impairments in postural stability have been identified following sports-related concussion. CaneSense™ is a recently developed mobile lower limb motion capture system and mobile application for movement assessment which provides an objective measure of postural stability. One of the components within CaneSense™ is the Post-Concussive Excursion Index (PCEI), a measure of postural stability expressed as a percentage of symmetry between lower limbs. The purpose of this case series is to examine pre- and post-concussion differences using two separate measures, CaneSense™, and a known test, the Balance Error Scoring System (BESS), in Division I collegiate football players. A convenience sample of eight football players diagnosed with a concussion, were the subjects in this case series. All subjects underwent baseline testing prior to the start of pre-season camp consisting of the single limb stance (SLS) test with CaneSense™ and the BESS test. Twenty-four to 72 hours following their concussion, SLS with CaneSense™ test and the BESS test, were administered. Segmental excursions for the thigh and shank segments for each lower limb were combined into the Post-Concussion Excursion Profile (PCEP), which represents each segment's maximum excursion in the medial-lateral and anterior-posterior direction. The PCEI is a single metric generated to quantify differences within subjects by comparing the PCEP value between lower limbs during SLS where 100% suggests absolute symmetry. The PCEI value decreased significantly post-concussion (41.43 ± 15.53% vs. 87.41 ± 6.05%, p < 0.001) demonstrating a 52.6% decrease in inter-limb symmetry when compared to baseline values. There was an unanticipated 36.36% improvement in composite BESS performance post-concussion (10.5 ± 4.87 errors vs. 16.5 ± 8.49 errors, p = 0.10). Differences in inter-limb postural stability were found in subjects post-concussion. By assessing postural stability in both lower limbs individually, using the PCEI, impairments were detected that otherwise would have likely gone undiagnosed using the BESS test alone. Therapy, Level 4.

The Validity of an Oculus Rift to Assess Postural Changes During Balance Tasks.

To investigate whether shifts in head position, measured via an Oculus Rift head-mounted display (HMD), is a valid measure of whole-body postural stability. The inverted single-link pendulum model of balance suggests shifts in whole-body center of mass can be estimated from individual body segments. However, whether head position describes postural stability such as center-of-pressure (COP) remains unclear. Participants (N = 10) performed six conditions while wearing an HMD and performing a previously validated virtual reality (VR)-based balance assessment. COP was recorded with a Wii Balance Board force plate (WBB), while an HMD recorded linear and angular head displacement. Visual input was presented in the HMD (stable scene, dark scene, or dynamic scene) and somatosensory information (with or without foam) was varied across each condition. The HMD time series data were compared with the criterion-measure WBB. Significant correlations were found between COP measures (standard deviation, range, sway area, velocity) and head-centered angular and linear displacements (roll, pitch, mediolateral and anteroposterior directions). The Oculus Rift HMD shows promise as a measure of postural stability without additional posturography equipment. These findings support the application of VR HMD technology for assessment of postural stability across a variety of challenging conditions. The human factors and ergonomic benefit of such an approach is in its portability, low cost, and widespread availability for clinic and home-based investigation of postural disturbances. Fall injury affects millions of people annually, so assessment of fall risk and treatment of the underlying causes has enormous public health benefit.

Applicability of Smartphone for Dynamic Postural Stability Evaluation.

The purpose of this study was to determine the accuracy of smartphone's gyroscope for dynamic postural stability among young healthy adults. The research included convenience sample of 85 healthy adults—37 women (mean age 22.1±1.6, body height 167.2±7.0) and 48 men (mean age 22.4±1.7, body height 176.1±13.8). In order to assess the accuracy of stabilometric measurement recorded by mobile phone, the raw data obtained at the same time by Sigma Balance Platform and Smartphone (SP) were correlated. Two thirty-second trials with one-minute interval break were performed (first in the frontal plane and second in the sagittal plane). A total of 170 measurements of postural stability were recorded (85 in frontal and 85 in the sagittal plane). The following parameters were included: the path of the stabilogram (in the case of SP, angular path) and the variation of the swing (standard deviation of the horizontal deflection of the platform). The results have shown strong and significant relationship between body sway variability measured by Sigma platform and smartphone in frontal (r=0.997) and sagittal (r=0.990) plane. For the geometric center of the platform and angular path distances, the correlation coefficient was also statistically significant and high, considering both lateral (r=0.999) and anterior-posterior sway (r=0.981). Our research shows that smartphones with gyroscope have potential for accurate assessment of postural balance, as an alternative for expensive and specialized equipment.

Effects of 7-Day Ketone Ingestion and a Physiological Workload on Postural Stability, Cognitive, and Muscular Exertion Measures in Professional Firefighters

Background: Postural stability and cognitive performance are challenged in firefighters. The purpose of this investigation was to examine the impact of 7-day ketone supplementation on postural stability, cognitive performance, and muscular activation before and after a physiological workload. Methods: Nine professional firefighters completed two experimental sessions (pre- and post-workload) in a counterbalanced, double-blind design. Participants ingested either a ketone salt (KS) or placebo (PLA) daily for seven days, and had an eighth ingestion 30 min prior to testing. Each experimental testing consisted of maximal voluntary contractions (MVIC) for four muscles (knee flexors—BF, extensor—VM, ankle dorsiflexors—TA, and plantar flexors—MG) using electromyography and postural stability testing (eyes open (EO), eyes closed (EC), and eyes open-dual-task using a FitLight™ system (EOT)), before (pre-workload) and after (post-workload) a simulated physiological workload. The workload consisted of 35 min steady state exercise at 60% of peak oxygen consumption wearing firefighter personal protective equipment (PPE). Results: Significant differences were limited to time effects (pre-workload vs. post-workload), with no differences between groups (KS vs. PLA). Significantly lower muscle activity in VM, TA, and MG during MVIC, greater postural sway and muscle activity in BF during EC and EOT, and slower response time during EOT were evident post-workload. Conclusions: A 7-day ketone supplementation does not impact postural stability, muscle activity, and cognitive tasks, but a fatiguing workload causes significant performance reduction.

Effects of backpack and double pack loads on postural stability

Measurement of postural stability is crucial for identifying predictors of performance, determining the efficacy of physical training and rehabilitation techniques and evaluating and preventing injuries, particularly for heavy load carriage in hikers, mountain search and rescue personnel and soldiers. This study investigated the effect of load distribution on postural stability in an upright stance using backpack and double pack loads under conflicting or impaired somatosensory, visual and vestibular conditions. The sensory organisation tests were conducted on 20 young adults before and after a 10-min level walking exercise. Young adults’ ability to use inputs from somatosensory and visual systems to maintain postural stability was significantly reduced following a 10-min walking exercise with a heavy backpack (30% of body weight), whereas no significant changes were observed for double pack carriage. Thus, the distribution of heavy loads to the front and back provides superior balance control compared with back-only loading. Practitioner summary: This study investigated the effects of heavy (30% of body weight) load distribution on postural stability after a 10-min walking exercise. Backpack carriage significantly reduced postural stability, whereas there was no significant effect under double pack loads. Distribution of heavy loads on the front-and-back is desirable for superior balance control.

Subjective stability perception is related to postural anxiety in older subjects

BackgroundUnder static conditions, the objective and subjective measures of postural stability correlate well. However, age-related changes in postural control and task-related anxiety may modify the relationship between these subjective and objective measures. Ultimately, patients’ symptoms represent subjective reports, thus understanding this relationship has clinical implications. AimsThis study investigates the relationship between subjective-objective measures of postural stability in dynamic conditions and whether this relationship is influenced by age or task-related anxiety. Methods50 healthy participants (aged 18–83 years) stood on a platform oscillating at variable amplitudes, with-without a fall-preventing harness to modulate task-related anxiety. Trunk sway path, hip velocity and foot lifts (objective measures) and subjective scores of instability and task-related anxiety were recorded. ResultsThe subjective perception of stability accurately matched objective body sway, following a logarithmic function profile (r2 = 0.72, p < 0.001). This function did not change significantly with age, harness or task presentation order. A strong relationship was observed between subjective measures of stability and task-related anxiety for all subjects (r = 0.81, p < 0.001). Task repetition reduced anxiety in the young, uncoupling anxiety changes from subjective instability, but not in the elderly who retained higher anxiety levels in line with subjective unsteadiness. DiscussionSubjects accurately rate their own instability during dynamic postural challenges, irrespective of age and actual fall risk. However, anxiety may selectively modulate the perception of instability in older subjects. The perception of stability relies upon the integration of sensory afferents but also recruits emotional-cognitive processes, particularly in older individuals. The use of a safety harness has no influence on subjective or objective postural stability.

Smartphone technology can measure postural stability and discriminate fall risk in older adults

BackgroundFalls are the leading cause of injury related death in older adults. Impaired postural stability is a predictor of falls but is seldom objectively assessed in clinical or home settings. Embedded accelerometers within smartphones offer potential to objectively measure postural stability. The purpose of this study was to determine if a smartphone embedded accelerometer can measure static postural stability and distinguish older adults at high levels of fall risk. MethodsThirty older adults (age: 65.9 ± 8.8) underwent seven balance tests while standing on a force plate and holding a smartphone against their chest in a standardized order. Participants also completed the Physiological Profile Assessment to assess their fall risk. Center of pressure (COP) parameters from the force plate including velocity in the anterioposterior (AP) and mediolateral (ML) directions and 95% confidence ellipse were derived. Maximum acceleration and root mean square (RMS) in ML, AP and vertical axes were derived from the smartphone. Spearman rank-order correlations between force plate and smartphone measures were conducted, and receiver operating characteristic (ROC) and the area under the curves (AUC) were constructed to distinguish between low and high fall risk. ResultsThere were moderate to strong significant correlations between measures derived from the force plate and measures derived from the smartphone during challenging balance conditions (ρ = 0.42–0.81; p < 0.01–0.05). The AUC for ROC plots were significant for all COP measures during challenging balance conditions (p < 0.01–0.05). The AUC for ROC plots were significant for RMS vertical and AP during challenging balance conditions (p = 0.01–0.04). SignificanceThis study provides evidence that a smartphone is a valid measure of postural stability and capable of distinguishing fall risk stratification in older adults. There is potential for smartphones to offer objective, fall risk assessments for older adults.

Cleveland Clinic Postural Stability Index Norms for the Balance Error Scoring System.

Despite the widespread utilization of the Balance Error Scoring System (BESS) in the evaluation of concussion, it has been criticized for its error-based scoring that is susceptible to floor and ceiling effects and substantial inter-rater variability. A biomechanical outcome, Cleveland Clinic Postural Stability Index (CC-PSI), has been developed as an alternative to subjective BESS scoring. The CC-PSI uses inertial sensor data within a mobile device to provide an objective measure of postural sway during the BESS. This project aimed to determine the effect of age and sex on the CC-PSI and report normative values for healthy, active children, adolescents, and young adults. A cross-sectional sample of 6762 student-athletes completed BESS testing. Participants were stratified according to three age groups for each sex. The groups included the following: youth (age, 5-13 yr), males (n = 360), females (n = 246); high school (age, 14-18 yr), males (n = 3743), females (n = 1673); and college (age, 19-23 yr), males (n = 497), females (n = 243). Percentile rankings were determined for each participant to characterize movement of COM in the medial-lateral, anterior-posterior, and trunk rotation directions relative to the entire cohort during the BESS stances. Overall, postural stability was worse in youth compared with high school and collegiate athletes. Specifically, the CC-PSI was significantly worse in youth male athletes compared with high school and collegiate male athletes (P < 0.001). Females exhibited significantly better scores compared with males in youth and high school cohorts (P < 0.01). The CC-PSI provides a quantitative, objective measure of postural stability, overcoming the limitations associated with conventional BESS scoring. Optimal concussion management should use objective age- and sex-specific values in the evaluation of postural stability. The normative values of the CC-PSI may be used in the absence of a baseline BESS evaluation to aid clinical decision making.

Validating Virtual Time to Contact With Home Based Technology in Young and Older Adults.

Virtual time to contact (VTC) is a measure of postural stability that estimates the virtual time it would take to reach an individual's stability boundary. This study aimed to validate VTC as measured by a depth sensor, and to determine if VTC from the depth sensor distinguishes between older adult fallers and non-fallers compared to a force platform. VTC was assessed in 10 young and 20 older adults by having participants lean in a circular direction followed by five balance tests: eyes open, dual task, eyes open foam, eyes closed, and eyes closed foam. Spearman's correlations and Bland-Altman plots were conducted to determine validity, and Receiver Operating Curves were constructed to discriminate between fallers and non-fallers. Significant correlations were found in the dual task (p = 0.03), eyes open foam (p < 0.01), and eyes closed foam conditions (p = 0.05). The depth sensor discriminated between fallers and non-fallers in the eyes open (p = 0.02), dual task (p = 0.03), and eyes open foam conditions (p = 0.04). VTC was in agreement between the two devices, and VTC derived from a depth sensor and may be used to discriminate between older adult fallers and non-fallers during challenging balance conditions.

Pedobarographic and stabilometric analysis and exercises for children with recurrent ankle haemarthrosis

Background/Aims: To investigate the dynamic plantar loading characteristics, postural stability and the effectiveness of an exercise programme in children with recurrent ankle haemarthrosis. Methods: In an exploratory study, 56 children with haemophilia (Group A) and 23 typically developing children (Group B) were initially assessed. Group A received a progressive exercise programme twice a week for 6 weeks in succession. Midstance plantar loading and the dynamic limit of stability were measured using Tekscan HR MatTM pressure measurement system and Biodex Balance System respectively. Findings: Heel pressure in Group A was significantly lower than Group B (P&lt;0.05), whereas mid-foot, forefoot, and hallux pressure were significantly higher (P&lt;0.05). Also, Group A showed poorer postural stability (P&lt;0.05). Furthermore, a significant correlation between postural stability and plantar loading measures was indicated in Group A. Following the completion of 6 weeks of exercises, the plantar pressure (except the medial mid-foot) and postural stability (except the mediolateral stability) for Group A were not significantly different in comparison to Group B (P&gt;0.05). Conclusion: Dynamic plantar loading provides a potentially valuable directory for the clinicians to understand variations of postural stability in children with ankle haemarthrosis. Further, adherence to a 6-week exercise rehabilitation programme might be helpful.

Effect of six-week intervention program on postural stability measures and muscle coactivation in senior-aged women.

ObjectiveThe objective involved the analysis of the efficiency of the Program of Movement Recreation of Elderly People (PMREP) exercise program expressed in terms of the stabilography measures and coactivation of muscles in women in the age group of 60–70 years. The assumption that was assumed stems from theoretical implications that the adequate postural stability is manifested in the decrease of the body sways measured by means of a force plate.Materials and methodsThe study involved a group of 60 females, all members of the active seniors’ association. The subjects were in the age range from 60 to 70 years. The subjects were divided into 2 groups of equal size: control and experimental. Subjects in both groups participated in the rehabilitation exercises: experimental (n=16, PMREP – twice a week/60 minutes), control (n=27, PMREP – only once a week/60 minutes).ResultsThe study demonstrated that the completion of a 6-week PMREP program resulted in a decrease in the variability and velocity as well as indicators representing center of pressure displacement measured in the feet for the exercises performed with closed eyes with subjects standing on a high foam pad located on a force plate (P=0.001). No significant changes in coactivation of the calf muscles were recorded in the subjects.ConclusionThe study concludes that a PMREP rehabilitation plan with an adequate program and frequency leads to an improvement of the vestibular system coupled with proprioception understood as an integrated process of sensor activation in the body. However, in regard to the coactivation of the muscles involved in maintaining postural stability, no significant differences have been observed.

ACL reconstructed individuals do not demonstrate deficits in postural control as measured by single-leg balance

BackgroundFollowing anterior cruciate ligament reconstruction (ACLR), patients undergo a battery of performance assessments to determine progression of return to sport activity. Rates of reinjury following ACLR are high, indicating that current assessments may not accurately identify deficits at the time point of return to sport progression. Research questionTo assess single-leg postural control in ACLR patients around the time point of return to sport progression and their relationships to subjective function. Study designDescriptive Laboratory Study. Methods198 individuals (108 ACLR, 90 healthy) participated. All ACLR participants were at the time point of return to play progression. Postural stability was quantified by center of pressure (COP) average velocity measured through a straight-knee single-leg balance assessment for 10-seconds with the participant’s eyes closed. Subjective knee function was measured from the International Knee Documentation Committee (IKDC) Subjective Knee Form and the Knee Osteoarthritis Outcome Score (KOOS) subscales. ResultsNo significant differences existed between COP average velocity between limbs (uninvolved, involved) or groups (ACLR, Healthy). As a secondary aim, no significant relationships existed between measures of subjective knee function and postural stability. SignificanceIndividuals following ACLR demonstrate similar patterns of postural stability as healthy individuals in a straight knee single leg balance task. Single-leg balance in a straight knee position may not be sensitive enough to detect impairments and does not predict subjective function in ACLR patients at the time of return to sport progression.

INFLUENCE OF ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION ON DYNAMIC POSTURAL CONTROL

Athletes that have had anterior cruciate ligament (ACL) reconstruction are at a greater risk for reinjury. The relationship between ACL reconstruction and the dynamic postural sway index (DPSI) has not yet been examined. The purpose of this study was to examine the DPSI in a surgically reconstructed ACL limb compared to the uninjured leg in athletes that had been cleared for sport. It was hypothesized that in a bilateral limb comparison, the leg that underwent ACL reconstruction would demonstrate poorer postural stability measures (greater DPSI) during a single leg landing activity as compared to the non-surgical limb. Case-control study. 14 subjects (7 male, 7 female; age range 16-23 years) with a history of unilateral ACL reconstruction and clearance for return to sport (mean 14 months post-operatively, range 8 to 24 months) performed five single leg hops over a 12 inch hurdle in the anterior direction from a distance corresponding with 40% of their height, onto a force platform. DPSI for the medial-lateral, anterior-posterior, vertical directions and a composite score were calculated for each trial on the surgical and non-surgical legs. A multivariate analysis with repeated measures was used to compare surgical and non-surgical legs for the total DPSI measure as well as for each component. Significant differences (p < .05) in dynamic postural stability were observed in the medial-lateral, anterior-posterior, vertical indices and DPSI total between the surgical and non-surgical limb. Deficits in dynamic postural control persist in ACL-reconstructed limbs compared to the non-surgical limb after the clearance for full activity. Clinicians should consider assessing single limb dynamic stability prior to releasing the athlete back to full activity. Level 3.

Examining the diagnostic accuracy of static postural stability measures in differentiating among knee osteoarthritis patients with mild and moderate to severe radiographic signs

BackgroundClinicians need a reliable and accurate tools that can best identify and classify balance impairments between mild and moderate to severe grades of knee osteoarthritis (OA). Research questionThis study was designed to investigate the accuracy of postural measurements to discriminate between these two groups of knee OA. MethodsA total of 130 patients with knee OA based on the Kellgren-Lawrence (KL) grading scale were categorized into 65 patients with mild (a KL grade≤ 2) and 65 patient with moderate to severe (a KL grade≥3) radiographic sign. Static postural control was assessed on the force plate in three conditions of double leg stance with open (DO) and closed eyes (DC) and single leg stance with open eyes (SO). The accuracy for static postural control parameters was determined by calculation of sensitivity, specificity, area under the Receiver Operating Characteristic (ROC) curve (AUC) and likelihood ratios (LRs). ResultsOur results showed that standard deviation (SD) of velocity in anterior-posterior (AP) direction had the highest sensitivity and specificity in conditions of DO and DC, respectively. ROC curve analysis indicated that measures of mean and SD velocity in medio-lateral (ML) direction in conditions of DO and DC had acceptable levels of accuracy (AUC > 0.70) in discriminating between the two groups of knee OA patients. Also, based on LR results, SD of velocity in AP direction had the best ability for ruling in and ruling out moderate to severe grade of knee OA patients in conditions of DC and DO, respectively. SignificanceOur findings provide evidence for selection of mean velocity and SD of velocity in identifying and discriminating static postural performance in patients with mild and moderate to severe grades of knee OA.

Effects of backpack load on stair gait in young male adults

Backpack load has been found to be a potential risk factor for accidental falls during level walking. Stairs are considered one of the most hazardous locations in occupational settings, and falls often occur on stairs. However, how backpack load affects stair gait in young adults was still unknown. The objective of the present study was to reveal the effects of backpack load on stair gait in young male adults. Thirty male adults participated, and completed three ascent and three descent trials in the no load, low load, and high load conditions, respectively. Four categories of dependent measures were used to characterise stair gait, including lower limb and trunk kinematics, foot clearance measures, spatial-temporal gait parameters, and postural stability measures. We found that participants adjusted their postural control to compensate for the disturbance caused by backpack load and maintain their postural stability as in the no load condition. However, loaded participants may encounter increased risk of stair contact during ascent and increased risk of over-stepping during descent when passing over a step. These findings support that backpack load could be a risk factor for stair falls and imply that loaded people should pay more attention to the step when passing over it. Relevance to industryFindings from this study could aid in developing instructions for safe stair negotiation in occupational settings.

The efficacy of elastic therapeutic tape variations on measures of ankle function and performance

ObjectivesTo investigate the effects of different variations of elastic therapeutic taping (ETT) on tests used to screen for ankle injury risk and function. DesignRandomized crossover. SettingLaboratory. ParticipantsTwelve professional male soccer players completed three experimental trials: No tape (NT), RockTape™ (RT), and Kinesio™ Tape (KT) applied to the ankle complex. Outcome MeasuresClinical and functional ankle screening tests were used to assess the effects of ETT on measures of joint position sense, postural stability and ground reaction forces. ResultsKT (P = 0.04) and RT (P = 0.01) demonstrated significant improvements in end range joint position sense. When compared to NT, RT significantly (P = 0.02) improved mid-range joint position sense at 15°, and time to complete a drop landing task. No significant differences were observed for measures of postural stability (P ≥ 0.12) nor ground reaction force variables (P ≥ 0.33). ConclusionsResults advocate the use of ETT for proprioceptive and functional tasks when applied to the ankles of healthy male soccer players. However, a greater number of practical and significant differences were observed when RT only was applied, indicating that practitioners may potentially advocate the use of RT for tasks requiring proprioception and functional performance.

Modeling margin of stability with feet in place following a postural perturbation: Effect of altered anthropometric models for estimated extrapolated centre of mass

BackgroundMaintaining the centre of mass (CoM) of the body within the base of support is a critical component of upright balance; the ability to accurately quantify balance recovery mechanisms is critical for many research teams. Research questionThe purpose of this study was to investigate how exclusion of specific body segments in an anthropometric CoM model influenced a dynamic measure of postural stability, the margin of stability (MoS), following a support-surface perturbation. MethodsHealthy young adults (n = 10) were instrumented with kinematic markers and a safety harness. Sixteen support-surface translations, scaled to ensure responses did not involve a change in base of support, were then issued (backwards, forwards, left, or right). Whole-body CoM was estimated using four variations of a 13-segment anthropometric model: i) the full-model (WFM), and three simplified models, ii) excluding upper limbs (NAr); iii) excluding upper and lower limbs (HTP); iv) pelvis CoM (CoMp). The CoM calculated for each variant was then used to estimate extrapolated CoM (xCoM) position and the resulting MoS within the plane of postural disturbance. ResultsComparisons of simplified models to the full model revealed significant differences (p < 0.05) in MoS for all models in each perturbation condition; however, the largest differences were following sagittal plane based perturbations. Poor estimates of WFM MoS were most evident for HTP and CoMp models; these were associated with the greatest values of RMS/maximum error, poorest correlations, etc. The simplified models provided low-error approximates for frontal plane perturbations. SignificanceFindings suggest that simplified calculations of CoM can be used by researchers without reducing MoS measurement accuracy; however, the degree of simplification should be context-dependent. For example, CoMp models may be appropriate for questions pertaining to frontal plane MoS; sagittal plane MoS necessitates inclusion of lower limb and HTP segments to prevent underestimation of postural stability.

Postural deviations in individuals with chronic obstructive pulmonary disease (COPD)

ABSTRACTRATIONALE: While upper back pain in chronic obstructive pulmonary disease (COPD) suggests that postural dysfunction is a potential cause, the extent of postural deviation in COPD is unknown.OBJECTIVE: This study compared postural measurements in people with COPD to healthy controls and explored the relationship between posture deviations and pain in COPD.METHODS: Participants with COPD and age, gender, BMI and comorbidity-matched healthy controls. Participants underwent a postural geometric measurement in upright standing. 3-D motion analysis generated the coordinates of skeletal structures from anatomical landmarks. Participants with COPD completed questionnaires related to pain. Postural stability measures of center of pressure in the anteroposterior (A/P) and mediolateral (M/L) directions, spinal alignment, thoracic kyphosis, scapula and sternal orientation were completed.RESULTS: Twenty-one participants with COPD and 21 matched controls completed the study. The method of postural stability and alignment demonstrated excellent reliability in both groups (all ICC > 0.75). Those with COPD had a trend towards a greater center of pressure M/L sway compared to controls (mean 4.3 cm vs 2.9 cm), with no difference in center of pressure A/P sway. Thoracic kyphosis was greater in COPD (51.8° vs 39.1°, p = 0.001), but there was no difference in spinal alignment (p > 0.05). Those with COPD had an increase in left (p = 0.003) and right (p = 0.002) scapula protraction. Increased thoracic kyphosis and altered scapula position were unrelated to back pain in COPD (all p > 0.05).CONCLUSIONS: Postural deviations are evident in COPD, but the small number of those with pain limited analysis of the association between postural deviations and pain.