Anteroposterior Sway Research Articles

The Effect of Competition Sounds on Balance Performance in Football Players

Abstract Objective This study aimed to investigate the impact of competition environment sounds on the static and dynamic balance of football players. Materials and Methods Thirty-two football players with a mean age of 21.12±2.99 years and a body mass index of 21.98±2.58 kg/m² were included in this study. The initial assessment condition (whether in a quiet environment or with competition sounds) was determined by simple randomization. Forty-eight hours later, at the same time of day, the tests were repeated with the environmental conditions reversed. Balance performance was assessed using the Tecnobody device for both static and dynamic balance. Results In the static balance test, it was found that the surface area covered significantly decreased in the environment where competition sounds were played (p=0.014), while there was no significant change in overall sway (p=0.313), anteroposterior sway (p=0.852), or mediolateral sway (p=0.104). In the dynamic balance test, no significant change was observed in anteroposterior sway (p=0.411), but mediolateral sway (p=0.025) and overall sway (p=0.042) significantly decreased. Additionally, there was a significant improvement in the athletes’ score for reaching the target (p=0.003). The perceived difficulty levels during the tests were found to be significantly lower in both the static (p=0.048) and dynamic (p=0.001) balance tests in the environment where competition sounds were played. Conclusion In conclusion, competition environment sounds were found to positively affect the balance performance of football players and reduce the perceived difficulty level. Incorporating balance training with competition sounds during athlete rehabilitation may contribute to improved balance recovery.

Corticocortical and corticomuscular connectivity dynamics in standing posture: electroencephalography study.

Cortical mechanism is necessary for human standing control. Previous research has demonstrated that cortical oscillations and corticospinal excitability respond flexibly to postural demands. However, it is unclear how corticocortical and corticomuscular connectivity changes dynamically during standing with spontaneous postural sway and over time. This study investigated the dynamics of sway- and time-varying connectivity using electroencephalography and electromyography. Electroencephalography and electromyography were recorded in sitting position and 3 standing postures with varying base-of-support: normal standing, one-leg standing, and standing on a piece of wood. For sway-varying connectivity, corticomuscular connectivity was calculated based on the timing of peak velocity in anteroposterior sway. For time-varying connectivity, corticocortical connectivity was measured using the sliding-window approach. This study found that corticomuscular connectivity was strengthened at the peak velocity of postural sway in the γ- and β-frequency bands. For time-varying corticocortical connectivity, the θ-connectivity in all time-epoch was classified into 7 clusters including posture-relevant component. In one of the 7 clusters, strong connectivity pairs were concentrated in the mid-central region, and the proportion of epochs under narrow-base standing conditions was significantly higher, indicating a functional role for posture balance. These findings shed light on the connectivity dynamics and cortical oscillation that govern standing balance.

The Effect of Weight Distribution in the Foot on Balance and Plantar Pressure in Female Adolescent Athletes.

It is widely reported that the weight distribution in each foot is approximately 60% in the rearfoot and 40% in the forefoot. For balance training, it is recommended to transfer some weight to the forefoot. However, it is still unclear whether fore-rear foot weightbearing ratio affects balance and plantar pressure parameters. There is a relationship between the forefoot weightbearing ratio and balance and plantar pressure in female adolescent athletes. Cross-sectional study. Level 3. A total of 91 adolescent female athletes aged between 10 and 19 years were included in the study. Weightbearing ratios of the forefoot, balance, and plantar pressure were assessed using a plantar pressure platform (FootWork, AMCube IST). In the static and stabilometric evaluation, the weightbearing ratio (%), mean and maximum plantar pressure (kPa), center of pressure (CoP) total, antero-posterior and medio-lateral sway length (cm), CoP surface area (cm2), and length over area (cm-1) were recorded. In the dynamic evaluation, the maximum pressure (kPa) acting on each foot was recorded. Two groups with forefoot weightbearing ratio <40% and ≥40% were compared. Maximum pressure values in static conditions, CoP anteroposterior, and total sway length were significantly different between these groups. In addition, as the amount of load transferred to the forefoot increased, CoP total and anteroposterior sway length increased postural stability. Although postural control mechanisms are quite complex, plantar pressure and postural control parameters can be varied by optimizing rear-to-fore foot weight transfer. This study will contribute to the development of appropriate training and rehabilitation strategies to optimize athlete performance and reduce injury risk.

Identifying the Problem Side with Single-Leg Squat and Hamstrings Flexibility for Non-Specific Chronic Low Back Pain.

Background and Objectives: In patients with non-specific chronic low back pain (LBP), their pain and problem sides can differ. Clinical Pilates assessment provides an approach to identify the problem side, but this approach requires experience and can be subjective. This study aimed to investigate if objective measures of single-leg squat postural control and hamstrings flexibility could identify the problem side in adults with non-specific chronic LBP. Materials and Methods: Forty adults with non-specific chronic LBP were tested on single-leg squat postural control and hamstrings flexibility. The problem side of participants was assessed with the Clinical Pilates method. Paired t-tests were used to compare the postural sway parameters of the single-leg squat and hamstrings flexibility between the problem and non-problem sides. Cohen's kappa was then used to assess the agreement of postural sway and flexibility measures with the Clinical Pilates method. Results: The problem side showed smaller vertical force variance, larger sway path distances, lower peak vertical force, smaller terminal knee flexion angle, longer time to complete the five single-leg squats, and tighter hamstrings as compared to the non-problem side. However, only the overall and anteroposterior sway path distances, terminal knee flexion angle, total squat duration, and hamstrings flexibility yielded moderate to strong agreement with the Clinical Pilates method. Conclusions: Single-leg squat postural sway parameters and hamstrings flexibility can objectively identify the problem side in adults with non-specific chronic LBP.

Postural control behavior in women with dizziness

Vestibular dysfunctions normally manifest as dizziness, which is characterized by a subjective body balance disturbance. The present study aimed to analyze the influence of women’s self-perception of the level of dizziness on their postural behavior. This cross-sectional research was conducted with women 30 years old or more with a complaint of dizziness for at least three months. Anthropometric data were collected, as well as information on the level of dizziness and static postural control assessment (both with eyes open and closed). The descriptive and inferential analyses of the data were carried out with the SPSS 23.0 software. The clinical test scores were submitted to the Kolmogorov-Smirnov normality test and Student’s t-test for independent samples. The sample comprised 59 women, mean age 69.05 (±13.77) years. Regarding intensity, 37.2% had mild dizziness, 32.2% had moderate dizziness, and 30.5% had severe dizziness. The balance motor control pattern identified a lower limb prevalence on the total sway surface of the elliptic area both with eyes open (p = 0.012) and closed (p = 0.024), as well as anteroposterior sway with eyes open in the group with severe dizziness (p = 0.041). The self-perception of the level of dizziness influenced these women’s postural behavior.

Effects of Anodal tDCS Applied Over the Cerebellum Combined with Physical Therapy on Center of Gravity Sway in a Patient with Cerebellar Ataxia: A Single-Case Study.

Damage to the cerebellum results in dysfunctional standing postural control. Patients with cerebellar ataxia have a larger sway in the center of gravity (COG) while standing. Transcranial direct current stimulation (tDCS) has been applied in the rehabilitation of patients with central nervous system disorders; however, its effect on COG sway in patients with cerebellar ataxia remains unknown. We aimed to confirm the effects of anodal cerebellar tDCS (ctDCS) combined with physical therapy on COG sway in a patient with cerebellar ataxia using a retrospective ABA single-case study design. This study involved a patient with left cerebellar hemorrhage. Walking and postural balance rehabilitation were conducted in phase A. Anodal ctDCS was combined with the walking and postural balance rehabilitation in phase B. We measured COG sway in the open- and closed-eyes standing conditions daily throughout all the phases. In the open-eyes standing condition, there was no significant change in COG sway in phase B. Conversely, in the closed-eyes standing condition, the circumferential area, total sway path length, and anteroposterior sway path length decreased in phase B. No change was observed in the mediolateral sway path length. The combination of anodal ctDCS and physical therapy may decrease COG sway in patients with cerebellar ataxia in the closed-eyes standing condition, and its effect may be greater in the anteroposterior direction.

Impact of professional dance training on characteristics of postural sway.

The stability of human upright posture determines the range and dynamics of movements performed. Consequently, the repertoire and quality of the movements performed by a dancer are mainly determined by the efficiency of postural control. This is of particular importance in professional dance training that should focus on shaping optimal movement‑posture interaction. To get a deeper insight into this problem, the impact of the training on postural sway characteristics during quiet stance was analyzed in 16 female students in the seventh grade of a ballet school and compared with the size‑ and age‑matched group of secondary school students. Center of pressure trajectories were recorded for 25.6 s while standing quiet with eyes open (EO) and then with eyes closed (EC). The assessment of postural control was based on novel normalized sway parameters including sway vector (SV), sway anteroposterior (AP) and mediolateral (ML) directional indices (DIAP and DIML), and sway ratios (SRAP and SRML). The results document a significant contribution of vision to postural stability control in ballet students, which seems to compensate for training‑related changes in joint mobility and altered activity ranges of the legs' muscles. In the control group standing with EC, SV amplitude increased only by 18% whereas in the ballet students tested in the same conditions, the increase exceeded 72%. Under full control of standing posture (EO test), the training‑related increase of leg muscle forces allows dancers to maintain balance with lesser effort as documented here by 21% reduced SRAP. Additionally, the dancers while tested with their EC exhibited a 12% increase in the anteroposterior sway with a concomitant reduction of the mediolateral sway. The resulting changes in the postural control asymmetry were documented by both DIAP/DIML and SV azimuth. In conclusion, our novel analysis of postural sway seems a useful tool in monitoring the effects of training as well as the proper course of postural control development in children and adolescents.

Clarifying the relationships between trunk muscle endurance, respiratory muscle strength and static/dynamic postural control in Latin dancers

ABSTRACT Sufficient study has not been performed to clarify the role of trunk/respiratory muscles strength/endurance in providing postural control in dancers. The purpose of this study was to identify predictors affecting static/dynamic postural control in Latin dancers and to compare these measurements with non-dancers. The study included 38 (26F; 12 M) Latin dancers and 33 (21F; 11 M) non-dancers. Static/dynamic postural control, trunk muscle endurance, respiratory muscle strength/pulmonary functions, flexibility, and reaction tests were assessed with a force platform system, the McGill battery, spirometer, sit-and-reach test and Nelson-reaction-tests, respectively. Trunk muscle endurance times, respiratory muscle strength, FEV1/FVC, gender, hours of training per week and dancing experience were significant predictors of static/dynamic postural control in dancers (p < 0.05). All the trunk muscle endurance times, reaction tests results, and maximal inspiratory pressure were higher in the dancers compared to the non-dancers (p < 0.05). The limits of stability for forward and backward directions were higher, and anteroposterior sway in normal stability with eyes open was lower in the dancers compared to the non-dancers (p < 0.05). Trunk muscles endurance, respiratory muscle strength, dancing experience, and hours of training per week were positively associated with static/dynamic postural control. These predictors should be taken into consideration to improve postural control in dancers.

Effects of kinesio taping on static balance performance and muscle activity in children with developmental coordination disorder: a single-group pretest-posttest study.

To compare the effects of various kinesio tape applications on static balance and muscle activity in children with developmental coordination disorder. Methods: Four taping conditions were applied to 48 children with developmental coordination disorder: no taping, gastrocnemius taping, tibialis anterior taping; and peroneus longus taping. Postural sway and electromyographic data were assessed, with eyes closed (30 s), standing still in 2-leg stance, dominant-leg stance, and non-dominant-leg stance. Kinesio taping significantly reduced postural sway in both anteroposterior and mediolateral directions for dominant-leg stance and non-dominant-leg stance, but not 2-leg stance. During single-leg stances, anteroposterior sway was significantly lower for the gastrocnemius taping condition than for the no taping, tibialis anterior and peroneus longus taping conditions, and significantly lower in the tibialis anterior and peroneus longus taping conditions than in the no taping condition (gastrocnemius < tibialis anterior = peroneus longus < no taping). In addition, mediolateral sway was significantly lower in the tibialis anterior and peroneus longus taping conditions than in the no taping and gastrocnemius taping conditions, and significantly lower in the gastrocnemius taping condition than in the no taping condition (tibialis anterior = peroneus longus < gastrocnemius < no taping). Electromyographic data showed that muscle activity was significantly greater only for muscles where kinesio tape was applied. Various kinesio tape applications can differentially reduce postural sway and increase muscle activity during single-leg stances in children with developmental coordination disorder.

Comparison of static postural sway characteristics between pregnant and non-pregnant women

The present study aimed to compare the postural sway between pregnant and non-pregnant women during eight different sensory conditions including those in which vision, proprioception, and base of support are compromised. Forty primigravidae at the 32nd week of pregnancy and forty non-pregnant women who were matched for age and anthropometric measurements participated in this cross-sectional comparison study. Static posturography equipment was used to record the anteroposterior sway velocity, mediolateral sway velocity, and velocity moment during normal stance and when vision, proprioception, and base of support were compromised. Pregnant women (mean age: 25.4) demonstrated a larger median velocity moment and mean anteroposterior sway velocity compared to non–pregnant women (mean age:24.4) across all tested sensory conditions (p < 0.05). Although mediolateral sway velocity did not show any statistically significant difference, the ANCOVA results suggested that there was a statistically significant difference in mediolateral sway velocity in Eyes open feet apart condition on the firm surface [F (1,77, p = 0.030, ηp2 = 0.121] and Eyes closed feet apart condition on the firm surface [F (1,77, p = 0.015, ηp2 = 0.15] between pregnant and non-pregnant women. There was a larger velocity moment and anteroposterior postural sway velocity in pregnant women in their third trimester compared to non-pregnant women when exposed to different sensory conditions.Title: Comparison of static postural sway characteristics between pregnant and non-pregnant women.

Utilizing the ISway to Identify and Compare Balance Domain Deficits in People with Multiple Sclerosis

Background and Purpose Balance impairments are a common symptom in people with Multiple Sclerosis (PwMS). The instrumented sway (ISway) is a reliable clinical balance assessment; however, this approach yields a vast range of outcomes that may hinder interpretation and delivery of evidence-based care. Identifying balance domains that are both altered in PwMS and clinically relevant would help isolate treatment targets. Therefore, we sought to develop a multiple sclerosis (MS)-specific model of balance and examine differences between 1) PwMS and neurotypical controls and 2) PwMS with (MS-F) and without a fall history (MS-NF). Methods 118 people with relapsing-remitting MS (MS-F = 39; MS-NF = 79) and 46 age-matched neurotypical controls completed the ISway balance assessment. 22 sway measures obtained from the ISway were entered into an exploratory factor analysis (EFA) to identify underlying balance domains. The model-derived balance domains were compared between 1) PwMS and age-matched, neurotypical controls and 2) MS-F and MS-NF. Results 3 distinct balance domains were identified: 1) sway amplitude and velocity, 2) sway frequency and jerk mediolateral (ML), and 3) sway frequency and jerk anteroposterior (AP), explaining 81.66% of balance variance. PwMS exhibited worse performance (i.e., greater amplitude and velocity of sway) in the sway velocity and amplitude domain compared to age-matched neurotypical controls (p = .003). MS-F exhibited worse performance in the sway velocity and amplitude domain compared to MS-NF (p = 0.046). The AP and ML sway frequency and jerk domains were not different between PwMS and neurotypical controls nor between MS-F and MS-NF. Discussion PwMS exhibited deficits within the sway amplitude and velocity domain compared to neurotypical controls, with a similar effect observed between MS-F and MS-NF. Recognizing balance domains altered in PwMS and related to falls may be useful for efficient and strategic balance assessment and rehabilitation. Balance impairments are a common symptom in people with Multiple Sclerosis (PwMS). The instrumented sway (ISway) is a reliable clinical balance assessment; however, this approach yields a vast range of outcomes that may hinder interpretation and delivery of evidence-based care. Identifying balance domains that are both altered in PwMS and clinically relevant would help isolate treatment targets. Therefore, we sought to develop a multiple sclerosis (MS)-specific model of balance and examine differences between 1) PwMS and neurotypical controls and 2) PwMS with (MS-F) and without a fall history (MS-NF). 118 people with relapsing-remitting MS (MS-F = 39; MS-NF = 79) and 46 age-matched neurotypical controls completed the ISway balance assessment. 22 sway measures obtained from the ISway were entered into an exploratory factor analysis (EFA) to identify underlying balance domains. The model-derived balance domains were compared between 1) PwMS and age-matched, neurotypical controls and 2) MS-F and MS-NF. 3 distinct balance domains were identified: 1) sway amplitude and velocity, 2) sway frequency and jerk mediolateral (ML), and 3) sway frequency and jerk anteroposterior (AP), explaining 81.66% of balance variance. PwMS exhibited worse performance (i.e., greater amplitude and velocity of sway) in the sway velocity and amplitude domain compared to age-matched neurotypical controls (p = .003). MS-F exhibited worse performance in the sway velocity and amplitude domain compared to MS-NF (p = 0.046). The AP and ML sway frequency and jerk domains were not different between PwMS and neurotypical controls nor between MS-F and MS-NF. PwMS exhibited deficits within the sway amplitude and velocity domain compared to neurotypical controls, with a similar effect observed between MS-F and MS-NF. Recognizing balance domains altered in PwMS and related to falls may be useful for efficient and strategic balance assessment and rehabilitation.

The effects of optic flow on postural stability: Influence of age and fall risk

BackgroundOptic flow provides dynamic information relating to body position and motion with respect to visual frames of reference. This study investigated the effects of optic flow stimuli presented in four directions on postural stability in young and older adults. MethodsTwenty-five young (20–40 years) and 51 older (≥65 years) people participated in this study, with the older group classified into low fall risk (n = 27), and high fall risk (n = 24) sub-groups. While standing in a dark room, participants viewed static scattered white dots for 30 s, followed by 30 s periods of optic flow consisting of white dots “moving” in one of four flow directions, randomised: radial expansion and contraction, circular anti-clockwise and clockwise. Centre of pressure (CoP) position, postural sway in anteroposterior (AP) and mediolateral (ML) axes, and muscle activity of tibialis anterior (TA), gastrocnemius medialis (GM) and tensor fascia latae (TFL) were recorded. ResultsAcross groups, the four optic flow stimuli induced increased AP sway and three of the four optic flow stimuli induced increased ML sway, with concomitant increases in muscle activity, indicating optic flow stimuli induced a generalised destabilising, rather than a direction-specific, effect. Only one optic flow condition (radial contraction) induced a change in average CoP position, and this may reflect the adoption of a protective stance position to avoid a backward fall. Optic flow destabilised postural control more in older people compared with younger people, and radial expansion stimuli destabilised ML postural control more in the older high fall risk group compared with the older low fall risk group. ConclusionOptic flow stimuli have a generalised destabilising effect on postural control across groups as shown by non-directional specific increases in postural sway and muscular activity. Optic flow stimuli have a greater impact on postural stability in older compared with younger adults and this is more pronounced in the ML plane for older people at increased risk of falls.

Mediation Effect of Pain on the Relationship between Kinesiophobia and Postural Control: Comparison and Correlations in Individuals with Fibromyalgia Syndrome and Asymptomatic Individuals-A Cross-Sectional Study.

Individuals with fibromyalgia syndrome (FM) usually present with a fear of movement (kinesiophobia), which causes their symptoms to be maintained and exacerbated. Kinesiophobia can significantly impact postural control; ascertaining their association is crucial in evaluating and managing individuals with FM. This study aims to (1) compare postural control between individuals with FM and asymptomatic individuals, (2) estimate the relationship between kinesiophobia and postural control in individuals with FM, and (3) evaluate whether pain intensity mediates the association between kinesiophobia and postural control in individuals with FM. This study enrolled 92 individuals (mean age: 51.52 ± 7.7 years) diagnosed with FM and 106 asymptomatic individuals (mean age: 50.47 ± 6.6 years). The examiners estimated the fear of movement and the intensity of pain utilizing the Tampa scale of kinesiophobia (TSK) scores and the visual analogue scale (VAS), respectively. The postural control variables included anteroposterior (A-P) sway in mm, medio-lateral (M-L) sway in mm, and ellipse area in mm2. The individuals with FM had impaired postural control compared to the asymptomatic individuals (p &lt; 0.001). Kinesiophobia exhibited mild-to-moderate correlations with the postural control variables (nondominant side: A-P sway: r = 0.48, M-L sway: r = 0.49, ellipse area: r = 0.43. Dominant side: A-P sway: r = 0.41, M-L sway: r = 0.33, ellipse area: r = 0.44). The pain intensity significantly mediated the relationship between kinesiophobia and postural control (p &lt; 0.001). Kinesiophobia showed a significant positive relationship with postural control. The individuals with FM with higher TSK scores had decreased postural control. Pain intensity mediated the relationship between kinesiophobia and postural control. These factors must be considered when evaluating and formulating treatment strategies for people with FM.

Relationships among postural stability, physical fitness, and shooting accuracy in Olympic female goalball players.

This study aims to examine the relationship between postural perfor-mance, physical fitness level, and shooting performance in Olympic fe-male goalball players. Eight Olympic-level goalball players (age: 20.63± 4.37 years) were recruited from the Turkish National Women's Goalball Team. Postural stability, physical fitness, and shooting performance of the players were measured. The postural stability was determined us-ing body sway measurements during parallel and single-leg stances on a force plate. The physical fitness level of the players is evaluated by curl-up, isometric push-up, trunk lift, and grip strength (dominant hand) tests. A goalball-specific shooting accuracy test was used for shooting performance. Independent sample t-test and Pearson correlation were used for statistical processing. No statistical difference was observed in body sway parameters between open eyes and closed eyes condi-tions except for the anteroposterior sway area. Some of the body sway parameters performed under different stances positively correlated with all physical fitness tests (P<0.05). There was a positive correlation between the shooting accuracy and trunk lift score (r=0.767). Right leg sway area anterior-posterior and ellipse area negatively correlated with shooting accuracy (r=-0.629 and r=-0.692 respectively). It is necessary to attach importance to the improvement of the physical fitness level specific to core strength to maintain postural stability for visually im-paired athletes. In our study, some factors affecting shooting accuracy were identified, but it is necessary not to restrict a complex structure such as shooting accuracy within certain concepts.

Unilateral cathodal transcranial direct current stimulation over the parietal area modulates postural control depending with eyes open and closed.

ObjectiveCathodal transcranial direct current stimulation (C-tDCS) is generally assumed to inhibit cortical excitability. The parietal cortex contributes to multisensory information processing in the postural control system, and this processing is proposed to be different between the right and left hemispheres and sensory modality. However, previous studies did not clarify whether the effects of unilateral C-tDCS of the parietal cortex on the postural control system differ depending on the hemisphere. We investigated the changes in static postural stability after unilateral C-tDCS of the parietal cortex.MethodsTen healthy right-handed participants were recruited for right- and left-hemisphere tDCS and sham stimulation, respectively. The cathodal electrode was placed on either the right or left parietal area, whereas the anodal electrode was placed over the contralateral orbit. tDCS was applied at 1.5 mA for 15 min. We evaluated static standing balance by measuring the sway path length (SPL), mediolateral sway path length (ML-SPL), anteroposterior sway path length (AP-SPL), sway area, and the SPL per unit area (L/A) after 15-minute C-tDCS under eyes open (EO) and closed (EC) conditions. To evaluate the effects of C-tDCS on pre- and post-offline trials, each parameter was compared using two-way repeated-measures analysis of variance (ANOVA) with factors of intervention and time. A post-hoc evaluation was performed using a paired t-test. The effect sizes were evaluated according to standardized size-effect indices of partial eta-squared (ηp2) and Cohen’s d. The power analysis was calculated (1-β).ResultsA significant interaction was observed between intervention and time for SPL (F (2, 27) = 4.740, p = 0.017, ηp2 = 0.260), ML-SPL (F (2, 27) = 4.926, p = 0.015, ηp2 = 0.267), and sway area (F (2, 27) = 9.624, p = 0.001, ηp2 = 0.416) in the EO condition. C-tDCS over the right hemisphere significantly increased the SPL (p < 0.01, d = 0.51), ML-SPL (p < 0.01, d = 0.52), and sway area (p < 0.05, d = 0.83) in the EO condition. In contrast, C-tDCS over the left hemisphere significantly increased the L/A in both the EC and EO condition (EO; p < 0.05, d = 0.67, EC; p < 0.05, d = 0.57).ConclusionThese results suggest that the right parietal region contributes to static standing balance through chiefly visual information processing during the EO condition. On the other hand, L/A increase during EC and EO by tDCS over the left parietal region depends more on somatosensory information to maintain static standing balance during the EC condition.

Does Alteration of Balance Control After Ankle Muscle Fatigue in National Judo Athletes Depend on Postural Task Difficulty?

Background: The purpose of the present study was to assess the impacts of plantar-flexors and dorsi-flexors fatigue following isokinetic contractions on postural control in nine young healthy national level judo athletes. Methods: Participants were required to stand still on a force plate with opened and closed eyes in feet together (FT) and single leg (SL) stance before (PRE) and after (POST) an isokinetic fatigue protocol. Mediolateral sway (ML sway), anteroposterior sway (AP sway), and velocity sway were calculated and used to assess the postural control. Results: Velocity sway POST was significantly (P &lt; 0.001) higher than PRE in FT stance and SL stance. Velocity sway POST was significantly higher in the SL stance than the FT stance (P = 0.01). During eyes closed, a significant interaction postural task by fatigue for all parameters was found. All parameters increased significantly after fatigue compared to PRE. After fatigue, ML sway, AP sway, and velocity sway were significantly higher for the SL stance than the FT stance. Conclusions: Ankle muscle fatigue led to reduced postural stability during different stances in young healthy judo athletes. This effect was more accentuated when vision was removed and the base of support was reduced. Alteration of postural control depended on the difficulty of the postural stance.

Pain, balance, and mobility in people 1 year after total knee arthroplasty: a non-randomized cross-sectional pilot study contrasting posterior-stabilized and medial-pivot designs

BackgroundTotal knee arthroplasty (TKA) is a common treatment for severe knee osteoarthritis. Medial-pivot TKA systems (MP-TKA) are theoretically better than posterior-stabilized TKA systems (PS-TKA) in improving static and dynamic balance of patients although it is difficult to objectively quantify these balance parameters in a clinical setting.Therefore, this pilot study aimed to evaluate the feasibility of using wearable devices in a clinical setting to examine whether people with MP-TKA have better postoperative outcomes than PS-TKA, and their balance control is more akin to age-matched asymptomatic controls.MethodsThe current cross-sectional pilot study recruited 57 participants with 2 different prosthesis designs (20 PS-TKA, 18 MP-TKA) and 19 asymptomatic controls. At 1-year post-TKA, pain, knee stiffness, and physical function were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Static balance, mobility, and gait stability of the participants were evaluated based on data collected from wearable motion sensors during the near tandem stance, timed-up-and-go, and 6-min walk tests.ResultsCompared to asymptomatic controls, both TKA groups reported significantly more pain and stiffness and demonstrated reduced functional mobility, increased stride-time-variability, and impaired balance. After Bonferroni adjustment, no significant differences in pain, balance, and mobility performance were observed between PS-TKA and MP-TKA participants 1 year after surgery. However, there was a trend for increased anteroposterior sway of the lumbar and head regions in the MP-TKA participants when undertaking the near tandem stance test. The wearable motion sensors were easy to use without any adverse effects.ConclusionsIt is feasible to use wearable motion sensors in a clinical setting to compare balance and mobility performance of patients with different TKA prothesis designs. Since this was a pilot study and no definite conclusions could be drawn, future clinical trials should determine the impacts of different TKA prosthesis designs on post-operative outcomes over a longer follow-up period.

Impact of Gender, Change of Base of Support, and Visual Deprivation on Postural Balance Control in Young, Healthy Subjects

Background: Vision, vestibular sense, proprioception and muscle strength are required to maintain balance. However, gender could also play a crucial role in postural sway. Objectives: This study was used to examine (i) the impact of gender, surface type, and vision on postural sway; (ii) the effects of gender and vision on the limb symmetry of postural sway; and (iii) to understand the effects of gender, stance, surface type and vision on the alterations of dynamic postural sway alterations. Methods: This was a cross-sectional study in which young, healthy men (n = 15) and women (n = 12) underwent a balance control assessment using a force plate (SATEL, 40 Hz). Postural stances were evaluated in different conditions: Opened eyes (EO) and closed eyes (EC), on different surface foam vs. firm, a dominant leg stance (DL) vs. a non-dominant leg stance (NDL), and a mediolateral stance (ML) vs. an anteroposterior stance (AP). The mediolateral sway (ML sway), anteroposterior sway (AP sway), and sway area were calculated from the centre of pressure displacements. Results: ML sway, AP sway and sway area increased when eyes were closed (P &lt; 0.000). Foam surface perturbs balance control more than firm surface under EO and EC conditions for both genders, as observed in the AP sway curve (P &lt; 0.000). A functional symmetry exists between the DL and NDL for all sway parameters: The ML sway, AP sway, and sway area (P = 0.720; P = 0.292; P = 0.954). The AP stance is more stable for the ML sway than the ML stance for both genders (P &lt; 0.001). For the AP sway, the ML stance is more stable than the AP sway AP direction stance for both genders (P &lt; 0.001). Women were significantly more stable than men in the ML stance when vision was absent (P &lt; 0.01). Conclusions: Postural sway was altered more significantly on a foam surface than on a firm surface and symmetry between the DL and NDL was observed. Furthermore, we concluded that women have better dynamic balance control than men.

Vestibular Function Predicts Balance and Fall Risk in Patients with Alzheimer's Disease.

Patients with Alzheimer's disease (AD) are at high risk for falls. Vestibular dysfunction predicts balance impairment in healthy adults; however, its contribution to falls in patients with AD is not well known. The objective of this study was to assess whether vestibular function contributes to balance and fall risk in patients with AD. In this prospective observational study, we assessed vestibular function using measures of semicircular canal (vestibulo-ocular reflex (VOR) gain) and saccular function (cervical vestibular-evoked myogenic (cVEMP) response), and we assessed balance function using the Berg Balance Scale and quantitative posturography. We evaluated falls incidence for a mean 1-year follow-up period (range 3-21 months) in 48 patients with mild-moderate AD. Relative to matched controls, AD patients exhibited increased medio-lateral (ML) sway in eyes-open (0.89 cm versus 0.69 cm; p = 0.033) and eyes-closed (0.86 cm versus 0.65 cm; p = 0.042) conditions. Among AD patients, better semicircular canal function was associated with lower ML sway and antero-posterior (AP) sway in the eyes-closed condition (β= -2.42, 95% CI (-3.89, -0.95), p = 0.002; β= -2.38, 95% CI (-4.43, -0.32), p = 0.025, respectively). Additionally, better saccular function was associated with lower sway velocity (β= -0.18, 95% CI (-0.28, -0.08); p = 0.001). Finally, we observed that better semicircular canal function was significantly associated with lower likelihood of falls when adjusted for age, sex, and MMSE score (HR = 0.65; p = 0.009). These results support the vestibular system as an important contributor to balance and fall risk in AD patients and suggest a role for vestibular therapy.

AGE-RELATED DIFFERENCES IN STATIC POSTURAL BALANCE IN KOREAN ELDERLY ADULTS

Poor postural balance has been related to falls in older people. Although fall rates increase with age, age-related declines in postural balance of older people are still unclear. The goal of this study was to investigate age-related changes in the static postural balance ability of Korean elderly adults. Three hundred and eighty-nine normal elderly adults with ages ranging from 57 years to 87 years participated in this study. All elderly adults were instructed to stand in their preferred natural stance on a self-developed force platform. As postural sway variables, peak frequency, mean frequency, mean velocity, and mean distance were calculated from the center of pressure (COP) trajectories in both the medio-lateral (ML) and antero-posterior (AP) directions. The mean velocity in the older-elderly was significantly faster compared to those of the other age groups particularly in the AP direction ([Formula: see text]). In both the ML and AP directions, the older-elderly group showed a greater mean distance compared to the other age groups ([Formula: see text]). Conversely, no significant age group differences were found in mean frequency and peak frequency ([Formula: see text]). Our results mean that the older-elderly group showed postural balance with faster AP sway speed and overall sway size. The results of our study help in the understanding of age-related declines in postural balance for the prevention of falls and the development of a regression model for normative postural balance ability in Korean elderly adults.