Postural Stability Index Research Articles

Effect of 4-week cyclic stretching program on muscle properties and physical performance in healthy adult men.

The short-term effect of cyclic stretching (CS) has been found to decrease muscle hardness and improve physical performance. However, the long-term effect of CS program was unclear. This study investigated the long-term effect of CS program on muscle properties and physical performance. Eighteen healthy men participated in this study. The participants were assigned randomly to either the CS or control group (9 participants in each group) to conduct 2 min CS of the plantar flexor muscles 5 times a week for 4 weeks. Before and after intervention, the gastrocnemius medialis muscle hardness, muscle-tendon joint (MTJ) angle, and MTJ displacement (ΔMTJ) were measured as indices of muscle properties. In addition, the maximum range of motion of ankle dorsiflexion (ROM max), normalized maximum peak torque of plantar flexor (NPT), vertical jump height, and dynamic postural stability, dynamic postural stability index (DPSI) were measured as indices of physical performance. The CS program was found to significantly decrease muscle hardness and increase vertical jump height and ROM max, but not to change the MTJ angle, ΔMTJ, NPT, and DPSI. The results of our study suggested that long-term CS program was effective in decreasing muscle hardness and increasing vertical jump height.

Concurrent postural training and M1 anodal transcranial direct current stimulation improve postural impairment in patients with chronic low back pain

Changes in different regions of the brain due to postural disturbances were found in patients with chronic low back pain (LBP). The aims of the current study were to investigate the short- and long-term enhancing effects of concurrent postural training and primary motor cortex (M1) anodal transcranial direct current stimulation (a-tDCS) on balance, postural stability and pain in chronic LBP patients with postural impairment. In this clinical trial study, thirty eight patients with chronic LBP were randomly assigned to a-tDCS and training, sham a-tDCS and training,and training only groups. All groups received identical postural training for 20 min, three sessions per week for two weeks. The length of stimulation, which used concurrent with postural training in the active a-tDCS group was also 20 min. Before, immediately and one-month after the interventions, postural stability, balance and pain were assessed using Biodex Balance System, Berg Balance Scale (BBS) and Visual Analog Scale (VAS), respectively. The postural stability indices, BBS and VAS scores significantly improved immediately and one-month after the intervention in the a-tDCS and training group (P < 0.001), while there were significant differences between active a-tDCS and other two groups (P < 0.001). Postural stability indices, the BBS and VAS scores were not significantly different between the sham and training only groups after the interventions (P > 0.05). M1 a-tDCS significantly improves the effects of postural training on postural stability, balance and pain in patients with chronic LBP. Two-week postural training alone cannot improve postural impairment in patients with chronic LBP.

The assessment of single-leg drop jump landing performance by means of ground reaction forces: A methodological study

BackgroundTime to stabilization (TTS) and dynamic postural stability index (DPSI) are outcome measures based on ground reaction force (GRF) that are often used to quantify dynamic postural stability performance following a drop jump landing. However, their interrelations, as well as the overlap with other dynamic measures and static single-leg postural sway, are unknown. Research questionWhat is the relation among TTS and DPSI, how are they related to impact forces and dynamic postural sway, and how are all these dynamic measures related to static postural sway? MethodsA sample of 190 elite soccer players performed four single-leg drop jump landings. TTS in three directions (vertical, anteroposterior, and mediolateral), and DPSI were intercorrelated (Pearson’s r), and related to impact forces and the magnitude of horizontal GRF (HGRF) from 0.4 to 2.4 s and 3.0–5.0 s following landing. All these measures were also correlated to HGRF in the static phase (i.e., 5.3–11.7 s). ResultsThe TTS measures were significantly interrelated (r = 0.28-0.53), but were not significantly correlated to DPSI. TTS was more strongly related to HGRF0.4–2.4 s (r = 0.54-0.75) than to HGRF3.0–5.0 s (r = 0.32-0.54) or impact forces (r=-0.28-0.36). Vertical TTS was not significantly related to impact forces. The DPSI was most strongly related to the vertical peak force (r = 0.85), and was not significantly related to HGRF of the dynamic periods. Furthermore, TTS and dynamic HGRF were significantly related to static HGRF (r = 0.34-0.80), while DPSI and impact forces were not. SignificanceTTS and DPSI do not represent similar aspects of single-leg jump landing performance. The ability to stabilize posture seems to be represented by TTS and dynamic postural sway, which partly overlaps with static postural sway. In contrast, DPSI and vertical peak force mainly reflect the kinetic energy absorption during impact. The findings can help to better understand the meaning of the outcome measures, and to translate results to rehabilitation or prevention programs.

Effect of muscle mass asymmetric between upper and lower limbs on the postural stability and shock attenuation during landing.

The aim of the study was to analyze the effect of muscle mass asymmetric between upper and lower limbs on postural stability and shock attenuation during landing. Twenty adults (without lower limb disorders and who could land from a 35-cm height) participated in this study (mean age, 21.85±2.97 years; mean height, 1.68±0.10 m; mean weight: 68.64±17.36 kg). Subjects performed one-leg landing from 36-cm vertical heights. Ground reaction force components and medial-lateral, anterior-posterior, vertical and dynamic postural stability index were obtained from force platform recordings. We found that muscle mass in right limbs more increased than that of left limbs. Medial-lateral force, vertical force, vertical stability index, and dynamic postural stability index in left leg showed higher value than that of right leg during landing. The asymmetry of muscle mass (%) and ground reaction force variables showed a similar correlation, including dynamic postural stability index (r=0.316). These findings allow us to conclude that the factor of muscle mass asymmetric is a contributor to impulse control and dynamic postural stability index asymmetry. Therefore, knowledge of bilateral limbs asymmetry may provide insights into exercise rehabilitation and performance.

Sex differences in lower extremity musculoskeletal and neuromuscular characteristics in intercollegiate soccer athletes

ABSTRACTPurpose: Establishing sex-specific musculoskeletal characteristics promotes specific and effective injury prevention. The purpose was to identify sex differences in musculoskeletal characteristics in soccer athletes.Methods: 80 collegiate male and female soccer athletes participated. Flexibility included: weight-bearing ankle dorsiflexion mobility (DFM), active ankle dorsiflexion (ADF), active knee extension (AKE), and passive hip flexion (PHF). Strength tests included: ankle dorsiflexion/inversion/eversion, knee flexion/extension, hip abduction/adduction/internal/external rotation. LE dynamic postural stability (DPS) was assessed with an accelerometer. DPS was expressed as the Dynamic Postural Stability Index composite (DPSIC) and component scores in the anterior/posterior (APSI), medial/lateral (MLSI), and vertical (VSI) directions. If normally distributed, differences were calculated using a Student’s T-test; if non-normal, a Mann–Whitney U test was utilized.Results: Flexibility tests yielded significant differences for AKE (Dominant:p = 0.008, Non-Dominant:p = 0.040) and PHF (Dominant:p < 0.000,Non-Dominant:p = 0.001). Strength tests yielded significant differences for non-dominant hip internal rotation (p = 0.002). Dynamic postural stability tests yielded significant differences for DPSIC (p = 0.0160) and APSI (p = 0.014).Conclusion: These results implicate that flexibility and DPS may be better linked to sex than strength, suggesting that they may sex-specific musculoskeletal characteristics for the purpose of effective injury prevention.

An Investigation of Factors Affecting Dynamic Postural Stability in Collegiate Cross Country Runners

Injury rates for NCAA cross country runners between 2009 and 2014 were 4.7-5.9/1000 athlete exposures. Prevalence of running-related injuries in the general population has been shown to be between 18-92%. Injury could lead to impaired balance which is a common aspect of return-to-sport rehabilitation programs, and various methods of its assessment have been proposed. The Dynamic Postural Stability Index (DPSI) was introduced to measure variability in tri-axial ground reaction forces during specific tasks. DPSI has been shown to be increased in injured runners and predict athletic performance in soccer players. DPSI has been correlated to ankle range of motion and strength in military personnel. These variables have not been measured in healthy collegiate runners. PURPOSE: To investigate how previous injury affects DPSI and explore relationship between ankle range of motion and strength with DPSI in collegiate runners. METHODS: Twenty-seven Division I collegiate cross country athletes (age: 19.8±1.3 years) participated. Those with an injury in the past 3 years were categorized in the injured group (IG). Athletes jumped over a hurdle on to a force plate and landed on a single leg. Three trials were performed on each leg. DPSI was calculated for the first 3s after landing. Ankle range of motion was assessed via active dorsiflexion and gastrocnemius length measurement. Ankle and hip strength were measured using a handheld dynamometer. An independent samples t-test was used to determine differences in DPSI between IG and uninjured group (UG). Pearson’s correlation coefficient was used to determine relationships between DPSI and other variables. RESULTS: No significant difference was found for DPSI on left (IG: 0.30±0.03 vs. UG: 0.32±0.04) and right (IG: 0.30± 0.03 vs. UG: 0.31±0.03) sides. There was a significant moderate negative correlation between dorsiflexion range of motion and DPSI (right side r= -0.605, p= 0.001; left side r= -0.452, p= 0.001). There were no correlations between strength and DPSI except for right inversion strength and right DPSI (r= 0.446, p=0.020). CONCLUSION: DPSI seems to be influenced to a greater extent by ankle dorsiflexion than strength or previous injury in a collegiate running population; therefore, improving ankle dorsiflexion may be used as a rehabilitation strategy to improve DPSI.

The Effects of Instruction Exercises on Performance and Kinetic Factors Associated With Lower-Extremity Injury in Landing After Volleyball Blocks.

Female volleyball players are more predisposed to anterior cruciate ligament injury in comparison with their male counterparts. Recent research on anterior cruciate ligament injury prevention strategies has shown the positive results of adopting the external focus (EF) of attention in sports. To determine the effect of 6-week EF instruction exercises on performance and kinetic factors associated with lower-extremity injury in landing after the volleyball blocks of female athletes. Pretest and posttest control study. University research laboratory. Thirty-two female volleyball players (18-24y old) from the same team randomly divided into experimental (n = 16) and control (n = 16) groups. The experimental group performed a 6-week exercise program with EF instructions. The control group continued its regular volleyball team schedule. To assess function, single-leg triple hop test for distance was used. A force plate was used to evaluate kinetic variables including vertical ground reaction forces, the rate of loading, and dynamic postural stability index. All data were assessed at baseline and after the intervention. There was a significant increase in single-leg triple hop test (P < .05) and in the first and second peak ground reaction force, rate of loadings, dynamic postural stability index (P < .05). According to the results of this study, anterior cruciate ligament injury prevention programs should incorporate EF instruction exercises to enhance the kinetics and to increase athletes' functional performance.

Development of Postural Stability Index to Distinguish Different Stability States.

A key factor for fall prevention involves understanding the pathophysiology of stability. This study proposes the postural stability index (PSI), which is a novel measure to quantify different stability states on healthy subjects. The results of the x-, y-, and z-axes of the acceleration signals were analyzed from 10 healthy young adults and 10 healthy older adults under three conditions as follows: Normal walking, walking with obstacles, and fall-like motions. The ensemble empirical mode decomposition (EEMD) was used to reconstruct the acceleration signal data. Wearable accelerometers were located on the ankles and knees of the subjects. The PSI indicated a decreasing trend of its values from normal walking to the fall-like motions. Free-walking data were used to determine the stability based on the PSI. The segmented free-walking data indicated changes in the stability states that suggested that the PSI is potentially helpful in quantifying gait stability.

Alterations of static and dynamic balance in patients with lumbar radiculopathy

BackgroundLumbosacral radiculopathy (LR) is strongly associated with delayed recovery and persistent disability. Chronic LR may lead to somatosensory system impairment, resulting in decline of postural balance.PurposeThe aim of the study was to investigate static and dynamic postural balance alterations in individuals with LR owing to lumbar disc herniation.Participants and methodsIn this case–control study design, 12 patients presenting with unilateral LR were included, whereas 12 normal individuals were randomly selected for control. Static balance was assessed functionally using Functional Reach Test. Dynamic balance was assessed via Biodex Balance System, where postural stability indices and the dynamic limits of stability were evaluated. Dynamic limits of stability parameters were expressed as direction control and time required to complete the test.ResultsThere was significant reduction of mean values of Functional Reach Test in LR group (P<0.0001) when compared with the control. In addition, there was a significant increase of the mean values of overall stability index (P<0.0001) and postural stability indices (P<0.0002) and a significant decrease of the mean values of direction control (P<0.0001) in the LR group.ConclusionPatients with chronic LR have shown to have limited functional abilities and decreased postural balance both statically and dynamically when compared with normal individuals.

Relationship between Sensory Integration, Postural Stability and Fall Risk Assessment Parameters Using Physical Therapy for Individuals after Traumatic Brain Injury

Research background. Equilibrium and posture impairment is a common cause of collapse in individuals experiencing traumatic brain injury, which limits patient autonomy and independence in daily activities. Therefore, the recovery of balance is one of the primary goals of rehabilitation for individuals following the traumatic brain injury (Llorens et al., 2013). The aim was to determine the relationship between sensory integration, postural stability and fall risk assessment parameters using physiotherapy for individuals with traumatic brain injury. Methods. The study involved 16 people with traumatic brain injury. The subjects were divided into two groups – the frst one (n = 8) and the second one (n = 8). The frst group was taking 30 minutes regular physiotherapy and 30 minutes balance training with Biodex Balance System, second group – 30 min. regular physiotherapy and 30 minutes regular exercises for balance. Results. Changes in the postural stability index, anterior /posterior and medial/ lateral fluctuation indexes, fall risk stability index and clinical sensory integration test index in both groups did not change statistically signifcant (p &gt; 0.05). A strong, statistically signifcant direct relationship was found in the frst study group between the postural stability index and the fluctuation of the anterior /posterior index changes (r = 0.922; p = 0.001). Conclusions. Physiotherapy using the Biodex Balance System and the usual physiotherapy is equally effective in developing postural stability, sensory integration, and fall risk. The link between many of the studied indicators shows that postural stability, sensory integration and the risk of falls are related.Keywords: traumatic brain injury, sensory integration, postural stability, fall risk, physiotherapy.

Comparison and Correlation of Dynamic Postural Stability Indices Obtained during Different Dynamic Landing Tasks and Footwear Conditions

Objectives: To compare the dynamic postural stability indices (DPSI) from two different landing protocols with normalized jump distance (NDP) and jump height (RWDP) and footwear conditions (barefoot and shod).Design: Cross-sectional.Setting: Research laboratory.Participants: Twenty-five physically active adults (13 males/12 females, age: 22.1±4.2yrs, height: 178.3±11.1cm, weight: 75.6±19.4kg).Main Outcome Measures: Subjects jumped off two feet and landed with their preferred foot on a force-plate. From the ground reaction forces, the DPSI scores in the anterior-posterior, medial-lateral, and vertical directions, and the cumulative scores (DPSI) were calculated under two protocols and footwear conditions. Based on normality of data distribution, paired t-tests/Wilcoxon signed rank tests and Pearson/Spearman correlation coefficients were used to compare, and measure the relationship between the two protocols under two footwear conditions (p&lt;0.05).Results: There were mixed results for DPSI scores when comparing the two protocols. There were significant differences (p=0.001–0.039) and positive correlations (r=0.660–0.870, p&lt;0.001) on the DPSI scores between footwear conditions during the NDP protocol while the RWDP showed no significant differences.Conclusions: Different protocols and footwear conditions may impact DPSI scores. Therefore, a standardized protocol and footwear condition should be established for future studies examining dynamic postural stability.

Dynamic Postural Control in Children: Do the Arms Lend the Legs a Helping Hand?

There is growing empirical evidence lending support to the existence of an “upper body strategy” to extend the ankle and hip strategies in maintaining upright postural stability among adults. Both postural stability and arm movement functions are still developing in children. Therefore, enquiry concerning arm contribution to postural stability among children is needed. This proof of concept study seeks to determine whether the arms play a functionally relevant role in dynamic postural control among children. Twenty-nine children (girls, n = 15; age, 10.6 ± 0.5 years; height, 1.48 ± 0.08 m; mass, 42.8 ± 11.4 kg; BMI, 19.2 ± 3.7 kg/m2) completed three dynamic balance tests; (1) Y Balance test®, (2) timed balance beam walking test, (3) transition from dynamic to static balance using the dynamic postural stability index (DPSI). Each test was performed with free and restricted arm movement. Restricting arm movements elicited a marked degradation in the Y Balance reach distance (all directions, P ≤ 0.001, d = -0.85 to -1.13) and timed balance beam walking test (P ≤ 0.001, d = 1.01), while the DPSI was the only metric that was not different between free and restricted arm movements (P = 0.335, d = -0.08). This study provides direct evidence that the arms play a functionally relevant role in dynamic balance performance among children. These findings may provide the impetus to develop training interventions to improve the use of the arms in activities of daily living.

드롭랜딩 시 만성적인 발목관절 불안정성에 대한 운동역학적 특성 비교

The purpose of this study was to compare the kinetic variables between both legs during drop landing in chronic ankle instability individuals. Fifteen individuals with chronic ankle instability(right leg) performed five repetitions of a single leg landing task. Furthermore, the analyzed variables included the peak vertical force(PVF), elapsed time, and the dynamic postural stability index (DPSI; medial-lateral [ML], anterior-posterior [AP], and vertical [V]) in the initial contact phase. Paired t-tests were used to compare variables between both legs. The Elapsed time to the PVF in CAI leg(right) showed more less time than that of the normal leg(left). Also, PVF showed increased higher force at CAI than that of normal leg. MLSI, APSI, and DPSI showed higher index at CAI than that of normal leg during drop landing. It is understandable to protect tissues from mechanical injuries by the sacrifice of certain postural stability in CAI leg. Identifying these potential differences may enable clinicians to assess chronic ankle instability and design rehabilitation protocols specific to the impairment.

Dynamic postural stability, is associated with competitive level, in youth league soccer players

ObjectivesTo assess the effect of competitive level on dynamic postural stability in young elite and sub-elite soccer players. DesignCross-sectional study. SettingLaboratory. ParticipantsFifty-four male soccer players of Under 16 and Under 17 categories (mean age 15.9 ± 0.6), divided into two groups who regularly compete at national (n = 28) and regional (n = 26) levels. Main outcome measuresDynamic Postural Stability Index (DPSI) and vertical Time to Stabilization (vTTS) for a forward-jump landing. Static postural sway was calculated on the basis of center-of-pressure trajectories for a 20 s one-legged stance. ResultsPlayers at national level exhibit better dynamic postural control than those at regional level, as indicated by the significantly lower DPSI (0.327 vs. 0.373, p < 0.001) and vTTS (0.887 vs. 1.158 s, p = 0.003). In contrast, no differences between groups were found in any of the postural sway parameters for the static test. ConclusionsYoung soccer players at national level are characterized by better balance performance in terms of faster and more efficient stabilization after a forward jump, while one-leg static standing tests appear not challenging enough to reveal differences in balance abilities associated with the combination of superior technical and physical features.

Do Squat Exercises With Weight Shift During Pregnancy Improve Postural Control?

Objectives: The present study aimed to investigate the effect of squat exercises with weight shift on muscle strength and postural control during pregnancy. Materials and Methods: The squat group comprised 21 pregnant women in their 20s and 30s with no exercise habits while the control group consisted of 20 randomly selected pregnant women in their 20s and 30s with no exercise habits. The squat group was instructed to perform two sets of daily squat exercises with weight shift in the anterior, posterior, right, and left directions, with 10 repetitions counted as one set, for 10 weeks. The stabilometer was used to measure postural control ability in the second and third trimesters. Meanwhile, muscular strength was taken as the toe grip force and quadriceps muscle strength before and after the intervention. Results: In the squat group, significant increases were observed in the index of postural stability and the stability area. Conversely, however, significant decreases were detected in the average rectangular area. In addition, in the intervention group, significant declines were observed in the rectangular area in the posterior, right, and left directions. However, a considerable increase in muscular strength was only seen after the intervention in toe grip force. Conclusions: Based on the results, it was concluded that everyday squat exercises which were performed during pregnancy improved postural control. The improvement of postural control during squat movements was thought to have a greater impact on plantar sensation than on muscle strength. These findings suggest that squat exercises with weight shift may promote fall prevention.

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.

The relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy

BackgroundPatellar tendinopathy is a common condition resulting in persistent pain, frequently reported during physical activity. The relationship between dynamic postural stability and pain in these individuals is unclear and how it may affect postural stability. Research QuestionIs there a relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy? MethodsTwenty-two recreationally active individuals with patellar tendinopathy participated. Participants performed a two-legged jump and landed on a single test-limb on a force platform. They completed 100 mm visual analogue scales (VAS) before and after landing trials. Anterior-posterior (APSI), medial-lateral (MLSI), vertical (VSI), and composite (DPSI) stability indices were calculated from ground reaction force data. The relationship between stability indices and VAS for pain as well as pain change scores were assessed via non-parametric Spearman’s rho (ρ) rank correlations (p≤.05). ResultsBaseline pain was not significantly correlated with any stability indices. Post-landing pain was significantly correlated with MLSI (ρ = 0.540, p = 0.004) while, VSI (ρ = 0.353, p = 0.053) and DPSI (ρ = 0.347, p = 0.057) had moderate, yet insignificant correlations. Pain change scores demonstrated a large correlation with MLSI (ρ = 0.598, p = 0.002). SignificanceAs pain increased in individuals with patellar tendinopathy, dynamic postural stability indices values increased, indicating more difficulty transitioning from a dynamic to static state. Although balance deficits are not typically associated with patellar tendinopathy, it appears pain and dynamic postural stability may be related in these individuals.

Multi-session anodal tDCS enhances the effects of postural training on balance and postural stability in older adults with high fall risk: Primary motor cortex versus cerebellar stimulation

BackgroundPostural control impairment is a key target for rehabilitation of older adults with high fall risk. ObjectiveTo investigate whether anodal transcranial direct current stimulation (a-tDCS) over primary motor cortex (M1) or cerebellum can enhance the positive effects of postural training on balance and postural stability in older adults with high fall risk. MethodIn this randomised, double-blinded sham-controlled study, 65 participants were randomly assigned into five groups; M1 a-tDCS with postural training, bilateral cerebellar a-tDCS with postural training, sham a-tDCS with postural training, postural training alone and cerebellar a-tDCS alone. Participants in the first two a-tDCS groups received 2 mA stimulation for 20 min concurrently with postural training. Postural training was conducted for three sessions of 20 min per week for two weeks. The Berg Balance Score (BBS) and the stability indices at both static and dynamic levels of the Biodex Balance System were evaluated before and after intervention. A general linear model repeated measure ANOVA was used to assess the effects of variables among groups. ResultSimultaneous postural training with M1 or bilateral cerebellar a-tDCS significantly improved postural stability indices (p < 0.05) and BBS scores (p < 0.05). Besides, the effects of bilateral cerebellar a-tDCS were significantly higher than that of M1 stimulation on these indices (p < 0.05). Moreover, two weeks postural training alone or cerebellar a-tDCS alone is not an adequate intervention to improve the postural stability indices (p > 0.05). ConclusionPostural training with M1 or bilateral cerebellar a-tDCS, especially bilateral cerebellar a-tDCS, can significantly improve postural control or balance in older adults with high fall risk, while two weeks of postural training alone or two weeks cerebellar a-tDCS alone is not a sufficient intervention.

The Sensitivity of Thresholds by Ground Reaction Force and Postural Stability in Subjects With and Without Navicular Drop

Understanding plantar pressure changes is an important component of the functional evaluation of subjects with flat foot. However, the altered postural control determined by the threshold from the vertical ground reaction force (GRF) requires clarification. The purpose of our study was to investigate the various GRF thresholds in subjects with and without flat foot during 1-leg standing. We included 34 control subjects and 30 subjects with flat foot in the present study. They performed the 1-leg standing test for 30 seconds, with the contralateral hip and knee flexed approximately 90°. The sensitivity of the various GRF thresholds (3, 7, 15, 50, and 100 N) for the postural stability index was analyzed with and without visual input. The standing times for the control and flat foot groups were 23.76 ± 4.42 and 21.78 ± 6.59 seconds, respectively, with no significant differences (t = 1.23; p = .22). The 2 groups demonstrated a significant interaction between the visual condition and the threshold levels (F = 11.40; p = .001). The postural stability index was significantly different in the eyes-open condition (0.95 ± 0.08 for the control group versus 0.84 ± 0.23 for the flat foot group; t = 2.29; p = .02). However, no difference was found in the eyes-closed condition (0.94 ± 0.10 for the control group versus 0.81 ± 0.30 for the flat foot group; t = 1.45; p = .15). These results indicate that GRF thresholds less than the 15N setting are sensitive to detect postural stability between groups, especially in the eyes-open condition. The GRF threshold setting, in addition to the visual condition, could alter the outcomes of sensitive plantar pressure changes in subjects with flat foot.

Age-dependent changes in dynamic standing-balance ability evaluated quantitatively using a stabilometer.

[Purpose] The efficacy of a stabilometer-based index of postural stability (IPS) as an indicator of dynamic balance ability was investigated. [Subjects and Methods] Using a stabilometer, we calculated the IPS in 583 healthy subjects (178 males, 405 females) under two conditions (open eyes/hard surface, OE/HS; closed eyes/soft surface, CE/SS). [Results] Results revealed a negative relation between IPS and age. IPS (OE/HS) began to decrease at middle-age (40–60 years old), and then decreased more rapidly during elderly ages (>60 years old). On the other hand, IPS (CE/SS) decreased linearly with increasing age. There was no gender difference between the two IPSs. [Conclusion] These results suggest that IPS can evaluate balance ability quantitatively and without a ceiling effect. It was concluded that IPS (OE/HS) indicates comprehensive balance ability, while IPS (CE/SS) reveals balance ability without compensation by visual acuity and plantar superficial sense.