Postural Stability Index Research Articles

Effects of non-extensible lumbar belts on static and dynamic postural stability

BackgroundPrevious studies have found that increased intra-abdominal pressure helps to reduce spinal loading and improve spine stability. Non-extensible lumbar belts (NEBs) could elevate intra-abdominal pressure and augment spinal stability. NEBs have been used in the healthcare field to help reduce pain and improve spine function for people with low back pain. However, the effect of NEBs on static and dynamic postural stability is not clear.MethodsThis study aimed to investigate whether NEBs affect static and dynamic postural stability. Twenty-eight healthy male subjects were recruited to finish four static postural stability tasks and two dynamic postural stability tests. Center of pressure (COP) values during 30 s of quiet standing, dynamic postural stability index (DPSI) and Y balance test (YBT) score with and without NEBs were analyzed.ResultsNEBs had no significant effect in all COP variables in the static postural tasks. The results of a repeated measure two-way ANOVA indicated the NEBs significantly improved the dynamic postural stability in YBT score and DPSI (F (1,27) = 5.506, p = .027, {{eta }_{p}}^{2}=.169 and F (1,27) = 83.94, p = .000, {{eta }_{p}}^{2}=.757 respectively).ConclusionsThe study results indicate that non-extensible belts improve dynamic stability in healthy male participants, with potential implications for rehabilitation and performance enhancement programs.

Exploring effects of Egoscue versus lumbar stabilisation exercises for lower crossed syndrome on postural stability and hyperlordotic posture correction

Abstract The aim of the study was to evaluate the comparative effectiveness of Egoscue exercises and lumbar stabilisation exercises in individuals with the lower crossed syndrome in terms of hyperlordotic posture correction, postural stability, and patient satisfaction towards treatment. The study was a randomised controlled trial. Through randomisation, 30 participants were allocated into 2 study groups, the Egoscue Exercise (EE) group (n=15) and the lumbar stabilisation exercise (LSE) group (n=15). The outcome measures were the degree of lumbar lordosis, functional disability, and postural stability parameters (risk of fall, stability index, weight distribution, anterior-posterior sway, and lateral sway) and patient satisfaction with treatment assessed at baseline and post-10th session of the intervention. Within group analysis showed significant improvement in the outcome measures, such as Index of Lumbar Lordosis, functional disability, postural stability, and patient satisfaction towards treatment with the groups (P<0.05). Between groups analysis showed that EE group and LSE groups were equally effective in improving lumbar hyperlordosis (P=0.458), functional disability (P=0.545), postural stability (risk of fall P=0.781; stability index P=0.964; weight distribution index P=0.718; anterior-posterior sway P=0.402; lateral sway P=0.212) and patient satisfaction towards treatment (P=0.999). Egoscue exercises and lumbar stabilisation exercises are equally effective in correcting lumbar hyper lordotic posture, postural stability, pain, and functional disability in low back pain individuals with the lower crossed syndrome. Clinical Trials Registry – India (CTRI): CTRI/2021/09/036733

Correlation between the Severity of Urinary Incontinence with Postural Stability Indices and Disability Due to Low Back Pain in Women with Stress Urinary Incontinence: A Cross-sectional Study

Correlation between the Severity of Urinary Incontinence with Postural Stability Indices and Disability Due to Low Back Pain in Women with Stress Urinary Incontinence: A Cross-sectional Study

Relationship between postural stability and fall risk in young adult after lower limb muscle fatigue


 Introduction: Muscle fatigue can reduce body balance and activity of daily living tasks. Therefore, this study aims to identify the correlation between postural stability and fall risk due to muscle fatigue. The components in postural stability include Overall Stability Index (OSI), Anterior-Posterior Stability Index (APSI), and Mediolateral Stability Index (MLSI).
 
 
 Design and Methods: A total of seven healthy adults aged 31.1±7.4 years were recruited in this study. The sit-to-stand (STS) protocol was used to induce lower limb muscle fatigue, while postural stability and fall risk were assessed using the Biodex Balance System (BBS) before and after muscle fatigue. 
 
 
 Result: The result showed a significant increase in postural stability index after fatigue only for OSI with p<0.05, while no significant difference was found on APSI and MLSI with p=0.157 and p=0.109 respectively. However, the mean score for the postural stability index showed an increase in percentage with 47.8% in OSI, 26.3% in APSI and 46.8% in MLSI. Furthermore,fall risk showed no significant differences with p=0.149, but the mean score data increased by 16.7% after fatigue. The correlation between fall risk and OSI was significant with p<0.05, while MLSI had a significant negative correlation with APSI (p<0.05). 
 
 
 Conclusions: Based on the results, the young adults had reduced overall postural stability but were less affected by fall risk after muscle fatigue. The positive correlation between OSI and fall risk indicated that their overall postural stability can induce the fall risk after muscle fatigue. Therefore, young adults need to be aware of their fatigue symptoms during prolonged exercise that can increase fall risk potential.

Relationship between hippocampal subfields volume and balance function in healthy older adults

BackgroundThe volume of the hippocampus and its subfields is known to be affected by aging, disease, and physical training. In regard to training, the differential effects of aerobic exercise and dance training on the subfield volume suggest that balance function may be involved. However, the relationship between balance function and the volume of the hippocampus and its subfields remains unclear. MethodsSubjects were 30 cognitively intact individuals. They underwent balance tests, cognitive tests and structural MRI scans. The balance index measured was the index of postural stability (IPS) under a visual block condition and/or a proprioception block condition. MR images acquired using a 3-tesla system and three-dimensional T1-weighted images were segmented in the hippocampal subfield with Freesurfer 6.0.0. The relationship between the IPS and hippocampal volume was evaluated. ResultsA positive correlation was observed only between the IPS closed eyes/soft surface condition and whole hippocampal volume ratio. In the subfields, positive correlations were found between the IPS and molecular layer of the hippocampus, granule cell layer of the dentate gyrus (GC-ML-DG), and cornu ammonis areas (CA)3 and CA4. These correlations were stronger under the closed eyes/soft surface condition than under the other conditions. ConclusionsA correlation between balance function and the volume of the hippocampus and subfields was found in healthy elderly subjects. The balance function may be involved in the volume of the whole hippocampus and specific subfields. The IPS closed eyes/soft surface condition is considered to reflect vestibular function. Thus, IPS may be useful in evaluations of the relationship between the vestibular system function via the hippocampus and balance.

New balance capability index as a screening tool for mild cognitive impairment

BackgroundMild cognitive impairment (MCI) is not just a prodrome to dementia, but a very important intervention point to prevent dementia caused by Alzheimer's disease (AD). It has long been known that people with AD have a higher frequency of falls with some gait instability. Recent evidence suggests that vestibular impairment is disproportionately prevalent among individuals with MCI and dementia due to AD. Therefore, we hypothesized that the measurement of balance capability is helpful to identify individuals with MCI.MethodsFirst, we developed a useful method to evaluate balance capability as well as vestibular function using Nintendo Wii balance board as a stabilometer and foam rubber on it. Then, 49 healthy volunteers aged from 56 to 75 with no clinically apparent cognitive impairment were recruited and the association between their balance capability and cognitive function was examined. Cognitive functions were assessed by MoCA, MMSE, CDR, and TMT-A and -B tests.ResultsThe new balance capability indicator, termed visual dependency index of postural stability (VPS), was highly associated with cognitive impairment assessed by MoCA, and the area under the receiver operating characteristic (ROC) curve was more than 0.8, demonstrating high sensitivity and specificity (app. 80% and 60%, respectively).ConclusionsEarly evidence suggests that VPS measured using Nintendo Wii balance board as a stabilometer helps identify individuals with MCI at an early and preclinical stage with high sensitivity, establishing a useful method to screen MCI.

Effect of Hamstring Tightness and Fatigue on Dynamic Stability and Agility in Physically Active Young Men.

Hamstring extensibility has been defined as a factor to diminished dynamic stability and therefore increased risk of injury. The purpose of this study was to analyse the effects of hamstring tightness and fatigue on dynamic stability and agility. Nineteen participants were divided between the normal extensibility group (NEG) (n = 9, 82.2° ± 12.4°) and hamstrings tightness group (HTG) (n = 10, 64° ± 4.9°) using the passive straight leg raise test. To analyse dynamic stability and agility, they performed the modified Star Excursion Balance Test (mSEBT) and Dynamic Postural Stability Index (DPSI), and hexagon agility test, respectively, before and after a fatigue protocol. A two-way repeated measures ANOVA was used to determine differences among conditions: NEG vs. HTG, and rested vs. fatigued. HTG showed a significantly lower reach in the anterior direction in the mSEBT in pre- and post-fatigue than NEG. Participants in the NEG showed poor stability after landing in the mediolateral direction on DPSI post-fatigue. No significant changes were found in agility related with the group nor fatigue state. Participants with hamstring extensibility reduction has no differences in dynamic stability after landing nor agility after fatigue test, but significantly affects reaching distances during one-leg balance. As a conclusion, a reduction in range of motion in HTG was observed, but no other effects were observed on performance and dynamic stability after a local fatigue protocol depending on hamstring extensibility.

Relationship between toe grip strength and dynamic balance in older adult patients with femoral neck fracture.

[Purpose] Femoral neck fractures are a common problem resulting from balance impairment. Toe grip strength is related to balance function. This study aimed to confirm the type of balance function that is highly related to toe grip strength. [Participants and Methods] The participants included 15 patients who were examined for differences in toe grip strength between the affected and nonaffected side. The relationship between toe grip strength and functional balance scale (FBS) and index of postural stability (IPS) was analyzed. [Results] The result showed no significant difference between the nonaffected and affected sides. A correlation exists between toe grip strength and FBS and IPS. In addition, the data from the center-of-gravity sway meter showed a correlation only between the toe grip strength and anteroposterior diameter of the stable area but not between the right and left diameters of the stable area and anterior and posterior trajectory lengths. [Conclusion] No significant difference was found between the affected and nonaffected sides. The results suggest that toe grip strength is related to the ability to move the center of gravity forward and backward rather than to sustain the center of gravity.

Quantification of Gait Stability During Incline and Decline Walking: The Responses of Required Coefficient of Friction and Dynamic Postural Index.

This study aims to investigate the gait stability response during incline and decline walking for various surface inclination angles in terms of the required coefficient of friction (RCOF), postural stability index (PSI), and center of pressure (COP)–center of mass (COM) distance. A customized platform with different surface inclinations (0°, 5°, 7.5°, and 10°) was designed. Twenty-three male volunteers participated by walking on an inclined platform for each inclination. The process was then repeated for declined platform as well. Qualysis motion capture system was used to capture and collect the trajectories motion of ten reflective markers that attached to the subjects before being exported to a visual three-dimensional (3D) software and executed in Matlab to obtain the RCOF, PSI, as well as dynamic PSI (DPSI) and COP-COM distance parameters. According to the result for incline walking, during initial contact, the RCOF was not affected to inclination. However, it was affected during peak ground reaction force (GRF) starting at 7.5° towards 10° for both walking conditions. The most affected PSI was found at anterior-posterior PSI (APSI) even as low as 5° inclination during both incline and decline walking. On the other hand, DPSI was not affected during both walking conditions. Furthermore, COP-COM distance was most affected during decline walking in anterior-posterior direction. The findings of this research indicate that in order to decrease the risk of falling and manage the inclination demand, a suitable walking strategy and improved safety measures should be applied during slope walking, particularly for decline and anterior-posterior orientations. This study also provides additional understanding on the best incline walking technique for secure and practical incline locomotion.

Validity of the frame subtraction method in dynamic postural stability.

BackgroundThe movement of targeted subjects can be calculated using the frame subtraction method. However, the validity of this evaluation method of dynamic postural stability has not been clarified yet. This study aimed to verify the validity of the evaluation method for jump landing using the frame subtraction score based on the ground reaction force (GRF).MethodsTwenty subjects performed single-leg jump landing, and their dynamic postural stability index (DPSI), medial‒lateral stability index (MLSI), anterior‒posterior stability index, and vertical stability index (VSI) were calculated from the GRF. Simultaneously, motion images were captured using digital video cameras in the sagittal and frontal planes. After the motion images were analyzed using the frame subtraction method, the frame subtraction scores in the frontal, sagittal, and combined planes were calculated. To confirm its validity, the relationship between the frame subtraction scores and GRF parameters was investigated using Pearson's correlation analysis.ResultsThe frame subtraction scores in the frontal and combined planes were significantly correlated with the DPSI, MLSI, and VSI (r = 0.46–0.75, P < 0.05).ConclusionsTherefore, the frame subtraction method could be applied to the evaluation of dynamic postural stability. Markerless systems are deemed useful in clinical practice.

Effects of Transcranial Direct Current Stimulation over the Primary Motor Cortex in Improving Postural Stability in Healthy Young Adults.

Simple SummaryTranscranial direct current stimulation (tDCS) is used as an adjuvant rehabilitation treatment to improve postural control and lower limb function. This study explored the effects of sham and anodal tDCS over the leg region of M1 on static and dynamic postural stability in healthy young adults. Jump-landing tasks were used to examine dynamic postural stability. Static postural stability was assessed by a single-leg stand on force plates with open eyes. Anodal tDCS had an immediate improving effect on static and dynamic postural stability, and might evolve as an adjuvant rehabilitation treatment to enhance postural deficits in the future.Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) is of increasing interest to improve motor performance in healthy adults and patients with respective deficits. This study aimed to examine whether tDCS over M1 can improve static and dynamic postural stability in young healthy adults. Seventeen healthy participants (mean age = 25.14 ± 2.50 (standard deviation, SD) years) received sham and anodal tDCS (2 mA) over the vertex at the Cz electrode position for 15 min. Static and dynamic postural stability were evaluated before and immediately after tDCS. The center of pressure (COP) sway area (COPSA) and COP maximum displacements to medio-lateral (COPML) and antero-posterior directions (COPAP) were used to evaluate static postural stability. The anterior–posterior stability index (APSI), medial–lateral stability index (MLSI), vertical stability index (VSI), dynamic postural stability index (DPSI), and time to stabilization (TTS) in forward (FL), 45° anterior lateral (LL), and 45° anterior medial (ML) direction landing, as well as the Y-balance composite score (YBTCS) were used to assess dynamic postural stability. The results showed that the LL-TTS (p = 0.044), non-dominant leg COPSA (p = 0.015), and YBTCS (p < 0.0001) were significantly improved in the real stimulation as compared with the sham stimulation session, and anodal tDCS significantly changed dominant leg COPAP (p = 0.021), FL-APSI (p < 0.0001), FL-TTS (p = 0.008), ML-TTS (p = 0.002), non-dominant leg YBTCS (p < 0.0001), and dominant leg YBTCS (p = 0.014). There were no significant differences in all obtained balance values in the sham stimulation session, except for non-dominant leg YBTCS (p = 0.049). We conclude that anodal tDCS over M1 has an immediate improving effect on static postural stability and dynamic performance in young healthy adults. This makes tDCS a promising adjuvant rehabilitation treatment to enhance postural stability deficits in the future.

The effects of footwear on dynamic stability and impact loading in jump landing

ABSTRACT Research into the effect of footwear on dynamic stability and impact loading is still in its infancy. The aim of this study was to determine whether cushioned footwear influenced dynamic stability (dynamic postural stability index (DPSI) and time to stabilisation (TTS)) or impact loading (peak ground reaction force (pGRF) and loading rate (LR)) through a series of single-leg jump landings when compared to barefoot and minimalist shoes. Fourteen healthy, active participants (9 males, 5 females, Age: 21 ± 1 years; height: 174 ± 9.87 cm; weight: 75 ± 15.40 kg) were recruited to undergo a series of single-leg jump landings. Each participant randomly performed three jumps in each footwear condition. Repeated measures ANOVA was conducted to determine whether any differences occurred between condition. No statistically significant difference was observed for DPSI (p = 0.300, pη2 = 0.083) between footwear types. A statistically significant difference was determined between footwear condition for TTS (p = 0.001, pη2 = 0.52), and also for pGRF (p = 0.003, pη2 = 0.39), and LR (p ≤ 0.001, pη2 = 0.53). For TTS, pGRF, and LR, no differences were noted between minimalist and barefoot, but were worse in the cushioned shoe vs. both other conditions. Overall, this study determined that cushioned footwear can negatively influence both TTS and impact loading, but not DPSI.

The Relationship Between Edema and Body Functions in Patients With Chronic Kidney Disease: A Preliminary Study.

Introduction: Chronic kidney disease (CKD) is known to be a risk factor for falls. In addition, numerous factors such as impaired body balance and loss of muscle mass were reported as risk factors for falls. Patients with CKD often have edema in their lower extremes. In Japan, edema, as well as physical factors, are listed as fall assessment items. Little is known about the relation between body functions and edema in patients with CKD. Thus, we conducted a multivariate regression analysis to investigate the factors related to knee extension muscle strength and dynamic balance in motion (TUG).Materials and methods: Thirty patients with CKD participated in this study. The basic characteristics were sex, age, blood pressure, body mass index (BMI), and medications. The laboratory data were estimated glomerular filtration rate (eGFR), hemoglobin (Hb), and C-reactive protein (CRP). Edema and muscle mass was measured by using InBody S10 (Inbody Japan Inc., Tokyo, Japan). The balance function while standing at rest and motion was measured as the total trajectory length of the center of gravity and the index of postural stability (IPS) using a kinetogravicorder 7100 (Anima Inc., Tokyo, Japan). Dynamic balance was assessed by the timed up & go (TUG) test. Knee extension muscle strength was measured by the Micro Total Analysis System (μ-Tas) F-1 (Anima Inc., Tokyo, Japan) test. Nutritional assessment was measured by the geriatric nutritional risk index (GNRI). Activities of daily living were measured using the functional independence measure (FIM). We conducted a multivariate regression analysis to investigate the factors related to knee extension muscle strength and dynamic balance in motion.Results: Extracellular water/total body water (ECW/TBW) was not significantly correlated with balance at rest and IPS. The ECW/TBW was associated with knee extension muscle strength, TUG, albumin (Alb), Hb, and GNRI with statistical significance. After adjusting for sex and age, knee extension muscle strength was associated with ECW/TBW and TUG (p=0.044). The TUG was also associated with ECW/TBW after being adjusted for age and sex (p=0.046). Conclusion: Patients with CKD who have edema may have decreased knee extensor strength and body balance function. Investigation of knee extension muscle strength and the body balance test in addition to the presence of leg edema at the time of physical examination may help predict a functional decline in CKD patients.

Postural stability, fall risk and sensory integration of balance in discogenic low back pain

BACKGROUND: Even though studies have reported impaired postural stability (PS) and risk of fall in non-specific low back pain (LBP), evidence is relatively scarce in terms of discogenic LBP or in persons with degenerative disc disorders of the lumbar spine. OBJECTIVE: To determine the differences in terms of PS, fall risk and sensory integration of balance in persons with discogenic LBP as compared to healthy controls. METHODS: A cross sectional comparative study was conducted on 60 participants, out of which 30 had discogenic LBP and 30 were healthy controls. The variables of interest included PS, fall risk score (FRS) and clinical test of sensory integration of balance (CTSIB), and the data was collected using Biodex Balance SystemTM SD, with higher scores signifying poorer outcomes. RESULTS: Persons with discogenic LBP scored significantly (p &lt; 0.05) higher in terms of overall PS index [Mean difference = 2.33 (95% CI 1.38, 3.28)], anteroposterior PS index [Mean difference = 1.87 (95% CI 0.84, 2.90)] and mediolateral PS index [Mean difference = 0.82 (95% CI 0.43, 1.21)], FRS [Mean difference = 2.92 (95% CI 2.36, 4.8)] and CTSIB [Mean difference = 1.67 (95% CI 1.28, 2.06)] as compared to healthy controls. Both healthy controls and persons with discogenic LBP revealed higher anteroposterior postural stability index as compared to mediolateral postural stability index (p &lt; 0.001). CONCLUSIONS: Persons with discogenic low back pain exhibit greater risk of fall and poorer postural stability and sensory integration of balance as compared to healthy controls. It is suggested that fall risk, postural stability and sensory integration of balance should be considered as outcome measures in clinical management of such patients.

A randomized controlled study of the effect of functional exercises on postural kyphosis: Schroth-based three-dimensional exercises versus postural corrective exercises

Purpose To compare the effects of postural corrective and Schroth-based three-dimensional exercises on thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), balance and quality of life (QoL) in individuals with postural kyphosis. Methods This was a single-blind randomized controlled clinical trial with a total of 63 subjects (57 women, 6 men) with TKA of 40°. Subjects were separated into three groups: postural corrective exercise group (PCEG), Schroth-based three-dimensional exercise group (SBEG) and control group (CG). Participants in the exercise groups participated in the exercise program twice a week for eight weeks under the supervision of a physiotherapist: CG performed no exercise but was generally informed. The primary outcome variable was TKA. Secondary outcome variables were LLA, balance and QoL. Results After the functional exercise programs, TKA (mean change for PCEG, SBEG: −9.71, −14.76, p < 0.001), static postural stability index overall (−0.22, −0.40, p < 0.05), and QoL (−0.41, −0.37, p < 0.001) significantly improved in both training groups compared with CG. The LLA (−3.95, p = 0.003) was significantly lower in the SBEG group than in CG. Conclusion This study demonstrated that Schroth-based three-dimensional exercises are an effective treatment for individuals with postural kyphosis and have a large effect size that improves TKA, LLA, balance and QoL. Clinical trial registration number: NCT03706495 Implications for rehabilitation Eight weeks of postural corrective or Schroth-based three-dimensional functional exercise programs are effective in addressing thoracic kyphosis angle (TKA), balance, and quality of life in individuals with postural kyphosis. An eight-week Schroth-based three-dimensional exercise program was more effective than postural corrective exercises in improving TKA, lumbar lordosis angle, and balance for patients with postural kyphosis. Schroth-based three-dimensional exercise programs could promote balance and spinal health in young adults with thoracic kyphosis.

Comparison of two periods of Schroth exercises for improving postural stability indices and Cobb angle in adolescent idiopathic scoliosis

Adolescents with idiopathic scoliosis present postural instability when compared with healthy subjects. Although Schroth exercises therapy (SET) is broadly utilized, its effect on postural stability is still not clear. To compare the two treatment periods of the SET for improving the postural stability indices and Cobb angle, and to examine the correlation between the Cobb angle and stability indices in adolescent idiopathic scoliosis (AIS). Twenty girls aged 10-16 years with AIS (study group) and 20 age-matched girls without AIS (control group) were examined. The Biodex Balance System was used to evaluate the overall stability index (OSI), anteroposterior index (APSI), and mediolateral stability index (MLSI) in the study group before SET and one and three months after the therapy. A plain X-ray was used to measure the Cobb angle before and three months after SET. Stability indices and Cobb angle were measured only once for the control group. One-way repeated-measures ANOVA revealed that the three-month duration of SET was the most effective for improving OSI, APSI, and MLSI (p< 0.001). The significant proximities of OSI, APSI, and MLSI to the normal values post three months of SET were 29.65%, 24.07, and 20% respectively. The MLSI was robust and correlated with the Cobb angle (r= 0.85) three months post intervention. Stability indices and Cobb angles were highly improved after three months of SET compared to one month among AIS patients. The MLSI is the most substantial index correlated with the Cobb angle.

Effect of Antigravity Treadmill Training on Gait and Balance in Patients with Diabetic Polyneuropathy: A Randomized Controlled Trial

Background: Diabetic polyneuropathy (DPN) is the most prevalent consequence of diabetes mellitus, and it has a significant impact on the patient's health. This study aims to evaluate effects of antigravity treadmill training on gait and balance in patients with DPN. Methods: The study included 45 males with type 2 diabetes who were randomly assigned to one of two groups: the experimental group (n=23) or the control group (n=22). For a period of 12 weeks, the experimental group received antigravity treadmill training (75% weight bearing, 30 min per session, three times per week) combined with traditional physical therapy. During the same time period, the control group received only traditional physical therapy. The Biodex Balance System was used to assess postural stability indices, while the GAITRite Walkway System was used to assess spatiotemporal gait parameters. All measurements were obtained before and at the end of the study after 12 weeks of treatment. Results: The mean values of all measured variables improved significantly in both groups (P<0.05), with the experimental group showing significantly greater improvements than the control group. The post-treatment gait parameters ( i.e., step length, step time, double support time, velocity, and cadence) were 61.3 cm, 0.49 sec, 0.25 sec, 83.09 cm/sec, and 99.78 steps/min as well as 56.14 cm, 0.55 sec, 0.29 sec, 75.73 cm/sec, and 88.14 steps/min for the experimental and control group, respectively. The post-treatment overall stability index was 0.32 and 0.70 for the experimental and control group, respectively. Conclusions: Antigravity treadmill training in combination with traditional physical therapy appears to be superior to traditional physical therapy alone in terms of gait and balance training. As a result, the antigravity treadmill has been found to be an effective device for the rehabilitation of DPN patients.

Dominance of Attention Focus and Its Electroencephalogram Activity in Standing Postural Control in Healthy Young Adults.

Attention focus changes performance, and external focus (EF) improves performance compared to internal focus (IF). However, recently, the dominance of attention focus, rather than the effectiveness of unilateral EF, has been examined. Although the positive effects of EF on standing postural control have been reported, the dominance of attention focus has not yet been examined. Therefore, the purpose of this study was to examine the dominance of attention focus and its neural mechanism in standing postural control using electroencephalography (EEG). A standing postural control task under IF and EF conditions was performed on healthy young men. Gravity center sway and cortical activity simultaneously using a stabilometer and an EEG were measured. Participants were classified into IF-dominant and EF-dominant groups according to their index of postural stability. The EEG was analyzed, and cortical activity in the theta-wave band was compared between the IF-dominant and EF-dominant groups. Significant neural activity was observed in the left parietal lobe of the IF-dominant group in the IF condition, and in the left frontal lobe of the EF-dominant group in the EF condition (p < 0.05). Differences in EEG activity between IF-dominant and EF-dominant groups, in standing postural control, were detected. This contributes to the development of training methods that consider attentional focus dominance in postural control.

Prospective Study on Dynamic Postural Stability in Youth Competitive Alpine Skiers: Test-Retest Reliability and Reference Values as a Function of Sex, Age and Biological Maturation.

This study aimed 1) to assess the test-retest reliability of dynamic postural stability index (DPSI) assessments using a ski-specific jump protocol that consists of single-leg landings on a three-dimensional force plate after forward-performed double-leg drop jumps from a box over a hurdle (DJSLLs), 2) to provide reference values for female and male youth competitive alpine skiers; 3) to explore their changes in DPSI over 3 years during adolescence; and 4) to investigate potential associations of DPSI with age and biological maturation. Using three-dimensional force plates, 16 healthy subjects were tested on the same day (test-retest reliability experiment; five test-retest assessments of right leg landings), and 76 youth skiers aged 13–15 years were tested 3 times within 2 years (main experiment; average of two trials per leg each time). The test-retest reliability experiment revealed an ICC(3,1) and 95% CI of 0.86 [0.74, 0.94] for absolute DPSI assessment. The within-subject SEM of absolute DPSI was 16.30 N [13.66 N, 20.65 N], and the standardized typical error was moderate (0.39 [0.33, 0.50]). Both absolute and relative DPSI values were comparable between male and female youth competitive alpine skiers. The mean absolute DPSI in year 1 (195.7 ± 40.9 N), year 2 (196.5 ± 38.9 N) and year 3 (211.5 ± 41.3 N) continuously increased (i.e., worsened) (p < 0.001). Mean relative, i.e. body weight force normalized, DPSI values significantly decreased, i.e., improved, from year 1 to 2 (0.42 ± 0.01 vs. 0.36 ± 0.004; p < 0.001) and year 1 to 3 (0.42 ± 0.01 vs. 0.36 ± 0.01; p < 0.001). Absolute DPSI correlated with age and biological maturation, while no such correlations were found for relative DPSI values. Our findings suggest that DPSI is a reliable and sensitive measure of dynamic postural control during DJSLLs and that relative DPSI improves annually in competitive youth skiers when accounting for body weight. Future work should consider biological maturation testing during the growth spurt, and normalizing to body weight force could be a possible solution.

Does insole hardness affect the dynamic postural stability of basketball athletes during jump landing?

This study aimed to examine the effects of shoe insole hardness on the dynamic postural stability of basketball athletes during jump landing manoeuvres. Twenty college basketball athletes were recruited to complete a single-leg jump landing task on a force plate in three insole conditions (soft-, rigid- and no-insole). Kistler force plate and Pedar-X insole system were used to collect the ground reaction force (GRF) and plantar pressure data. Dynamic Postural Stability Index (DPSI), Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), and Vertical Stability Index (VSI) were then calculated from GRF data. DPSI, APSI, MLSI, and VSI were statistically conducted among the three insole conditions by a one-way ANOVA with repeated measures. MLSI were decreased when wearing soft- and rigid insoles compared with no-insole condition (p &lt; 0.05). However, there were no significant differences in APSI and VSI among the three insole conditions. In the midfoot region, contact areas were increased in the soft- and rigid insole than the no-insole condition (p &lt; 0.0001). Dynamic balance of basketball athletes in the medial-lateral direction could be enhanced by wearing insoles during jump landings tasks. However, the postural stability of basketball athletes did not increase with insole hardness increasing.