Investigation of the functional and biomechanical effect of instrument-assisted soft tissue mobilization technique in individuals with asymptomatic dynamic knee valgus - Randomized controlled trial.

Although there are studies showing that myofascial release will increase muscle force production, the contribution of its application alone to muscle force production has not been examined. Aim of the study is to investigate the effect of instrument-assisted soft tissue mobilization (IASTM) on eccentric strength, frontal plane projection angle (FPPA), dynamic (DPS), and static postural stability (SPS), femoral internal rotation (FIR) angle in females with dynamic knee valgus (DKV). A total of 44 recreationally active females with asymptomatic DKV (age: 21,39 ± 1,79, body mass index: 20,09 ± 2,45) participated and were randomly assigned to either control group (CG) or IASTM group (IASTMG). Participants' eccentric contraction strength, FPPA, DPS, SPS, and FIR on the involved leg were measured pre- and post. IASTM application was applied to IASTMG for 6 weeks, twice a week, for 5 min, using Graston Technique® instruments on gluteus medius. CG received no intervention. In comparison of ECS difference values, change in IASTMG was found to be statistically significantly higher than CG (p = .004; p < .01). There was no statistical difference in comparison of FIR and FPPA values (respectively p = .213, p = .360; p < .05). In SPS and DPS evaluation, a statistically significant improvement was observed in favor of IASTMG in comparison of both intergroup and difference values (p < .05 for all). Strength gain without exercise can increase postural stability, but it isn't sufficient to correct faulty movement patterns. We recommend adding IASTM to injury prevention programs, but there is a need to investigate the effect of IASTM with technique correction feedback.

Intersession reliability of center of pressure measurement during bipedal standing with different foot placement angles.

INTRODUCTION: The foot placement is a determinant of the base of support and influences standing balance. The reliability of postural stability tests with different foot placement angles is unclear. RESEARCH QUESTION: To determine and compare the intra- and inter-day reliability of the center of pressure-based postural stability while standing with different foot placement angles. METHOD: Twenty-five healthy adults (16 females and 9 males; age: 29 ± 6 years) completed 70 s trials of eyes open and eyes closed stability tests with 0°, 15°, 30°, and 45° angles between the feet while standing on a forceplate in three sessions: two sessions were in the same day, and the third session was one-week apart. The repeatability of measurements was tested using analysis of variance, interclass correlation, and standard error of measurements. RESULT: Throughout the three study sessions, there was no difference in postural stability while participants stood with different foot placement angles. The interclass correlation scores ranged from 0.71 to 0.96, the standard error of measurements ranged from 2.1% to 12.9%, and no significant systematic changes (p < 0.05) occurred between the testing sessions for any foot placements. Standing with a 45° angle between the feet with closed eyes showed higher reliability values than other conditions. The intra-day reliability scores were greater than inter-day reliability. DISCUSSION: The relative reliability of postural stability could be impacted by foot placement angles, which might alter ankle mobility and base of support dimensions. The advantages of larger foot placement angles on improving the relative reliability of postural stability could be better demonstrated in healthy people under challenging conditions such as standing with closed eyes. CONCLUSION: Standing with foot placement angles between 0° and 45° are reliable and a quantitative assessment of the center of pressure could be used to monitor the changes in postural stability between sessions.

Postural Stability and Pedobarography After Reconstruction of Peroneus Brevis Tendon Split Lesion.

PURPOSE: Lesions of the peroneal tendons are frequently overseen after ankle sprain. The symptoms consist of stress-dependent pain that extends from the inframalleolar to the proximal part along the course of the peroneal tendons as well as ankle instability and soft-tissue swelling. In case of unsuccessful conservative treatment, surgical therapy is recommended. The aim of the study was to evaluate the clinical and functional outcome after open reconstruction of the peroneus brevis tendon. METHODS: 13 patients were included in this retrospective study. All of them received a single reconstruction of the peroneus brevis tendon in open technique. Postoperative results were evaluated with the AOFAS score, a functional and perdobargraphic analysis as well as measuring postural stability with the Biodex balance system. The participants were matched with a healthy control group according to age, sex and BMI. RESULTS: The results of the AOFAS score showed significantly convincing results in all subscores postoperatively. A bilateral comparison of the postural stability showed that the affected side had become functionally similar to the healthy side. No statistical significant difference was detected concerning both one-legged and two-legged standing with the control group. Pedobarographic results revealed no difference between the affected and contralateral side, as well as between the patients and the healthy control group. CONCLUSION: Open reconstruction of the peroneus brevis tendon leads to significant better postoperative results and can be recommended after unsuccessful conservative treatment as promising option.

A study on the effects of visual condition on postural stability in adults with and without chronic low back pain.

This study was conducted to compare postural stability during repeated unilateral standing tasks between adults with and without chronic low back pain (LBP) while considering visual input. The study involved 26 participants with LBP and 39 control participants. Each participant performed three trials of standing tasks on the dominant limb using a stable platform. The Falls Efficacy Scale was utilized to assess fall-related self-efficacy and fear of falling due to potential physical frailty. The center of pressure (COP) sway excursion was analyzed at 10 mm and 20 mm thresholds for the time-in-boundary (TIB). The results indicated a significant fear of falling difference in the LBP group compared to the control group (t = 3.27, p = 0.001). The LBP group demonstrated a significant interaction between visual condition and TIB (F = 8.45, p = 0.01), particularly in the LBP group, which demonstrated a notable decrease in TIB at 10 mm (54.02 % compared to the control group's 70.40 %) and 20 mm (70.93 % compared to the control group's 85.92 %) thresholds during the second trial and at 10 mm (59.73 % compared to the control group's 73.84 %) during the third trial in the eyes open condition. Overall, visual condition demonstrated significant interactions on thresholds (F = 15.80, p = 0.001, η2p = 0.21) as well as trials  ×  thresholds (F = 4.21, p = 0.04, η2p = 0.07). These findings indicate a potential adaptation in postural control among the LBP group with visual feedback. Further research is warranted to explore group differences when considering visual conditions and sway excursion thresholds.

Trend change analysis of postural balance in Parkinson's disease discriminates between medication state.

BACKGROUND: Maintaining static balance is relevant and common in everyday life and it depends on a correct intersegmental coordination. A change or reduction in postural capacity has been linked to increased risk of falls. People with Parkinson's disease (pwPD) experience motor symptoms affecting the maintenance of a stable posture. The aim of the study is to understand the intersegmental changes in postural sway and to apply a trend change analysis to uncover different movement strategies between pwPD and healthy adults. METHODS: In total, 61 healthy participants, 40 young (YO), 21 old participants (OP), and 29 pwPD (13 during medication off, PDoff; 23 during medication on, PDon) were included. Participants stood quietly for 10 s as part of the Short Physical Performance Battery. Inertial measurement units (IMU) at the head, sternum, and lumbar region were used to extract postural parameters and a trend change analysis (TCA) was performed to compare between groups. OBJECTIVE: This study aims to explore the potential application of TCA for the assessment of postural stability using IMUs, and secondly, to employ this analysis within the context of neurological diseases, specifically Parkinson's disease. RESULTS: Comparison of sensors locations revealed significant differences between head, sternum and pelvis for almost all parameters and cohorts. When comparing PDon and PDoff, the TCA revealed differences that were not seen by any other parameter. CONCLUSIONS: While all parameters could differentiate between sensor locations, no group differences could be uncovered except for the TCA that allowed to distinguish between the PD on/off. The potential of the TCA to assess disease progression, response to treatment or even the prodromal PD phase should be explored in future studies. TRIAL REGISTRATION: The research procedure was approved by the ethical committee of the Medical Faculty of Kiel University (D438/18). The study is registered in the German Clinical Trials Register (DRKS00022998).

The effect of stroboscopic visual disruption on static stability measures in anterior cruciate ligament reconstructed individuals.

BACKGROUND: Those who undergo ACL reconstruction are at an increased risk of suffering a second ACL injury. A suggested rationale for the increased injury risk is sensory reweighting to the visual system to compensate for a lack of somatosensory information from the knee. Understanding this proposed visual reliance may help clinicians improve return to sport outcomes and reduce the risk of a subsequent ACL injury. METHODS: Thirteen ACL reconstructed individuals and thirteen matched controls completed two common static postural control assessments under three different visual conditions; eyes open, low visual disruption, and high visual disruption. Center of pressure data was collected for 30 s using force plates. Static postural stability was evaluated using the following: 1) root mean square distance, 2) mean velocity, 3) sway area, and 4) mean frequency. FINDINGS: No significant interactions between group and vision were observed. Significant differences between groups were observed for mean frequency in the double-limb stance (p < .05). Additionally, significant differences were observed for visual conditions in both double-limb (mean velocity; p < .05) and single-limb stances (root mean square distance, mean velocity, sway area, and mean frequency; p < .05). INTERPRETATION: The findings of the current study suggest that ACL reconstructed individuals, who are at least two years removed from surgery, do not rely on visual information to a greater extent than controls during static postural stability assessments. Stroboscopic glasses may be a cost-effective alternative for rehabilitation purposes compared to the traditional binary eyes open vs. eyes closed methods.

Characterizing Longitudinal Alterations in Postural Control Following Lower Limb Injury in Professional Rugby Union Players.

Assessment of player's postural control following a lower limb injury is of interest to sports medicine practitioners due to its fundamental role in daily tasks and sporting activities. The aim was to longitudinally monitor professional rugby union players' postural control during each phase of the rehabilitation program (acute, middle, and late) following a lower limb injury. Seven male rugby union players (height 1.80 [0.02] m; mass 100.3 [11.4] kg; age 24 [4] y) sustained a time loss, noncontact lower limb injury. Static postural control was assessed via sway path (in meters), and dynamic postural control was assessed via vertical postural stability index. Group differences (P < .05) were reported across the acute, middle, and late phase. Smaller magnitudes of sway path were observed for eyes-open sway path, and for the middle and late phase smaller magnitudes of vertical postural stability index (P < .05) at the end session compared with first session. Whereas larger magnitudes of vertical postural stability index were found between baseline and the last session (P < .05). Large interindividual and intraindividual variation was apparent across the 3 phases of rehabilitation. Postural control improvements were identified during rehabilitation. However, postural control did not return to baseline, with altered kinetics throughout each rehabilitation phase.

Age-Related Reduction of Foot Intrinsic Muscle Function and the Relationship with Postural Stability in Old Adults.

Introduction: The risk of falls among the elderly significantly increases, which has become a serious public health concern. Falls can not only lead to serious complications such as fractures and brain injuries but also limit their mobility function, reducing quality of life. Foot intrinsic muscles (FIMs) are an essential part of foot core stability even overall postural stability. This study aimed to investigate the effects of aging on the function of FIMs and to explore the influence of FIMs on postural control in the elderly. Materials and Methods: 56 healthy old participants (60-75 years) and 57 healthy young participants (18-29 years) joined this study. An ergoFet dynamometer was used to determine foot muscle strength (Doming, T1, T23 and T2345), and ankle muscle strength (plantarflexion and dorsiflexion). The morphology of FIMs and extrinsic foot muscle was determined using a Doppler ultrasound system, whereas the postural stability was assessed through Limits of Stability test. Independent samples t-test was used to determine the differences in strength and morphological parameters and Spearman correlation analysis was used to determine whether an association existed between muscle strength and postural stability parameters in the elderly. Results: Compared with young adults, foot muscle strength and ankle muscle strength (Doming, T1, T23, T2345, dorsiflexion, and plantarflexion, all p <0.05) and the morphology of foot muscles (all p <0.05) were significantly reduced in the elderly. The strength of FIMs and the limit of stability (r = 0.302-0.424, all p <0.05) were significantly correlated in the elderly. Conclusion: Compared with young adults, the weakness of strength as well as the morphological decline of the intrinsic and extrinsic foot muscles were found in the elderly. In addition, a correlation was observed between FIM's strength and postural stability in the elderly, suggesting their potential role in posture stability.

How virtual reality is impacting balance: An examination of postural stability.

BACKGROUND: The interest in virtual reality (VR) applications has been on the rise in recent years. However, the impact of VR on postural stability remains unclear. RESEARCH QUESTION: The study has two primary objectives: first, to compare postural stability in a 3D-immersed virtual reality environment (VE) and a real environment (RE), and second, to investigate the effect of positive and negative visual feedback, which are subconditions of VE on postural stability. METHODS: The observational study recruited 20 healthy adults (10 male, 10 female, 22.8 ± 1.8 years) who underwent postural stability assessments in both RE and VE. In VE, participants received visual stimuli in three different ways: without visual feedback, with positive and negative visual feedback that they would consider themselves to be directed towards postural stability outcomes. The RE included two conditions: eyes open (EO) and eyes closed (EC). Postural stability was evaluated with sway velocity, sway area, and perimeter variables obtained from a force platform. RESULTS: All postural stability variables were significantly lower in the RE than in the VE (p < 0.05). There was no significant difference between the VE and EC in terms of sway velocity and sway area (p > 0.05). The visual feedback in the VE did not affect participants' postural stability (p > 0.05). VE may cause an increase in postural sway variables compared to RE and postural requirements may be higher in VE compared to RE. SIGNIFICANCE: This is the first and only study examining the effect of different visual feedback on postural stability in VE.

The Impact of Resistance Training on Equilibrium Abilities and Quality of Life in Older Adults after SARS-CoV-2 Survival.

Background: The scientific literature on COVID-19 and its long-term impacts on all-body systems and their treatments is still limited. The aim of the study was to create a safe protocol-based intervention to improve functional and equilibrium abilities in older adults impacted by COVID-19. Methods: This study used a sample of 46 people (intervention group: n = 26; control group: n = 20). Resistance training (RT) was held twice a week, with 60 min per session for 8 weeks. The postural stability and quality of life questionnaire (WHQOOL) was completed during pre- and post-testing. Results: The results indicated significant differences in overall stability index (OSI) with eyes open (EO), anterior-posterior stability index (APSI) EO, fall-risk index 6-2 (FRI6-2) values in males (p < 0.05), and APSI EO (p < 0.05) values in females compared to control groups, respectively. In the training, a significant improvement was reported in OSI EO and APSI EO (p < 0.05) female groups compared to baseline results and in FRI6-2 values in both gender groups (p < 0.01-men, p < 0.05-women). The effect of the intervention was recorded in the intervention group in the OSI EO (Z = -3.12, p < 0.01, R = 0.533) and FRI6-2 (Z = -2.06, p < 0.05, R = 0.354). Additionally, significantly different reactions between the groups were observed in the psychological domain (DOM2) (Z = 2.194, p < 0.028, R = 0.389), social relationship domain (DOM3) (Z = 2.051, p < 0.0403, R = 0.361), and in question 2 concerning general health (Z = 3.309, p < 0.0009, R = 0.535). Conclusions: The findings indicate that RT had a positive effect on older adults affected by COVID-19, led to a significant improvement in their postural stability, and had a significant impact on elements of psychological well-being and quality of life.

Accuracy to identify young adults with chronic ankle instability using a virtual reality - Balance error scoring system: A cross-sectional study.

INTRODUCTION: The Balance Error Scoring System (BESS) assesses the ability to control postural stability by performing 3 different stances on two-type surfaces during closed eyes. Virtual reality technology combined with the BESS test (VR-BESS) may be used to disrupt visual inputs instead of closing the eyes, which may improve the sensitivity of diagnosing patients with chronic ankle instability (CAI). OBJECTIVE: This study aimed to evaluate the accuracy to identify individuals with CAI of the VR-BESS test comparing with the original BESS test. METHODS: The BESS and VR-BESS tests were administered to 68 young adults (34 participants with CAI and 34 without CAI). Frontal and lateral video views were used to measure the participant's performance errors. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was computed to determine the diagnostic test's overall accuracy. RESULTS: The total score of the BESS test and the VR-BESS test were statistically significant in comparison to the AUC of no discrimination at 0.5, with AUC values of 0.63 and 0.64, respectively. The cut-off scores for the BESS and VR-BESS tests were 12 and 15, respectively. There was no significant difference between the ROC curves of the BESS and the VR-BESS test for identifying individuals with CAI. CONCLUSION: The BESS and VR-BESS tests may be utilized interchangeably to identify individuals with CAI.

Comparative analysis of postural stability and risk of falling and developing disability among overweight and obese women over 40 years.

BACKGROUND: Increased body mass index (BMI) adversely affects the mechanics of the musculoskeletal system. It is known that obese people have poorer postural stability and mobility-related outcomes compared to normal weight people, but there is limited research comparing overweight and class 1 obese people, two consecutive and prevalent BMI categories. AIMS: To compare postural stability, functional mobility, and risk of falling and developing disability between overweight and obese women, and to investigate the relationship of BMI and body weight with the outcomes. METHODS: Thirty women with class 1 obesity and 30 overweight women were included. Standing postural stability with eyes-open and eyes-closed and stability limits were assessed using the Prokin system. The Timed Up and Go Test (TUG) was used to assess functional mobility and risk of falling (≥11 s) and developing disability (≥9 s). RESULTS: The average center of pressure displacements on the y-axis (COPY) obtained during quiet standing with both eyes-open and eyes-closed were higher in obese women than overweight women (p < 0.05) and the effect sizes were moderate for the results. The COPY values in the eyes-open and eyes-closed conditions were correlated with BMI (r = 0.295 and r = 0.285, p < 0.05). Furthermore, the COPX value in the eyes-open condition and the TUG score were correlated with body weight (r = 0.274 and r = 0.257, p < 0.05). CONCLUSIONS: Obese women had poorer static standing stability in the anteroposterior direction than overweight women, while functional mobility and risk of falling and developing disability did not differ. Furthermore, BMI and body weight were related to poorer static standing stability.

Postural Control and Muscle Activity during Dual-Task in Young Adults.

In everyday life, we recurrently perform two tasks simultaneously, which is called dual-tasking. A common dual task is smartphone use while standing or walking. According to previous studies, this task can compromise postural stability. However, few studies have analyzed lower limb muscle activity during dual-tasking using smartphones. This study aimed to assess the postural sway and muscle activity during dual-tasking in young adults. Thirty-six healthy young adults (23.08 ± 3.92 years) participated in this study. They performed a single task (ST: keeping a quiet standing posture) and a dual task (DT: keeping the ST while simultaneously performing a cognitive task on their smartphone). Postural sway was assessed through the center of pressure (CoP) analysis using a force platform: total CoP displacement, CoP displacement in the anterior-posterior and medial-lateral directions, mean total velocity of the CoP, mean velocity of the CoP in the anterior-posterior and medial-lateral directions, and 95% confidence ellipse sway area. A surface electromyography system recorded the muscle activity of the lumbar spinal erector and five muscles of the lower limb (bilaterally). The results showed an increase in postural sway from the ST to the DT in all CoP variables (p < 0.05), and muscle activity in most muscles analyzed decreased from the ST to the DT (p < 0.05). In conclusion, our results reflect a decentralization of attention from motor performance once postural sway increased and muscle activity decreased in dual-task conditions.

The influence of smoothness and speed of stand-to-sit movement on joint kinematics, kinetics, and muscle activation patterns.

Background: Stand-to-sit (StandTS) is an important daily activity widely used in rehabilitation settings to improve strength, postural stability, and mobility. Modifications in movement smoothness and speed significantly influence the kinematics, kinetics, and muscle activation patterns of the movement. Understanding the impact of StandTS speed and smoothness on movement control can provide valuable insights for designing effective and personalized rehabilitation training programs. Research question: How do the smoothness and speed of StandTS movement affect joint kinematics, kinetics, muscle activation patterns, and postural stability during StandTS? Methods: Twelve healthy younger adults participated in this study. There were two StandTS conditions. In the reference condition, participants stood in an upright position with their feet positioned shoulder-width apart on the force plate. Upon receiving a visual cue, participants performed StandTS at their preferred speed. In the smooth condition, participants were instructed to perform StandTS as smoothly as possible, aiming to minimize contact pressure on the seat. Lower leg kinetics, kinematics, and coordination patterns of muscle activation during StandTS were measured: (1) angular displacement of the trunk, knee, and hip flexion; (2) knee and hip extensor eccentric work; (3) muscle synergy pattern derived from electromyography (EMG) activity of the leg muscles; and (4) postural sway in the anterior-posterior (A-P), medio-lateral (M-L), and vertical directions. Results: Compared to the reference condition, the smooth condition demonstrated greater eccentric knee extensor flexion and increased joint work in both the knee and hip joints. Analysis of specific muscle synergy from EMG activity revealed a significant increase in the relative contribution of hip joint muscles during the smooth condition. Additionally, a negative correlation was observed between knee extensor and vertical postural sway, as well as hip extensor work and M-L postural sway. Conclusion: Smooth StandTS facilitates enhanced knee eccentric control and increased joint work at both the hip and knee joints, along with increased involvement of hip joint muscles to effectively manage falling momentum during StandTS. Furthermore, the increased contributions of knee and hip joint work reduced postural sway in the vertical and M-L directions, respectively. These findings provide valuable insights for the development of targeted StandTS rehabilitation training.

A machine learning approach to evaluate the impact of virtual balance/cognitive training on fall risk in older women.

Introduction: Novel technologies based on virtual reality (VR) are creating attractive virtual environments with high ecological value, used both in basic/clinical neuroscience and modern medical practice. The study aimed to evaluate the effects of VR-based training in an elderly population. Materials and methods: The study included 36 women over the age of 60, who were randomly divided into two groups subjected to balance-strength and balance-cognitive training. The research applied both conventional clinical tests, such as (a) the Timed Up and Go test, (b) the five-times sit-to-stand test, and (c) the posturographic exam with the Romberg test with eyes open and closed. Training in both groups was conducted for 10 sessions and embraced exercises on a bicycle ergometer and exercises using non-immersive VR created by the ActivLife platform. Machine learning methods with a k-nearest neighbors classifier, which are very effective and popular, were proposed to statistically evaluate the differences in training effects in the two groups. Results and conclusion: The study showed that training using VR brought beneficial improvement in clinical tests and changes in the pattern of posturographic trajectories were observed. An important finding of the research was a statistically significant reduction in the risk of falls in the study population. The use of virtual environments in exercise/training has great potential in promoting healthy aging and preventing balance loss and falls among seniors.

Research on the Postural Stability of Underwater Bottom Platforms with Different Burial Depths.

The bottom platform is an important underwater sensor that can be used in communications, early warning, monitoring, and other fields. It may be affected by earthquakes, winds, waves, and other loads in the working environment, causing changes in posture and affecting its sensing function. Therefore, it is of practical engineering significance to analyze the force conditions and posture changes in the bottom platform. In order to solve the problem of postural stability of the underwater bottom platform, this paper establishes a fluid and structural simulation model of the underwater bottom platform. First, computational fluid dynamics (CFD) technology is used to solve the velocity distribution and forces in the watershed around the bottom platform under a 3 kn ocean current, where the finite element method (FEM) numerical calculation method is used to solve the initial equilibrium state of the bottom platform after it is buried. On this basis, this paper calculates the forces on the bottom platform and the posture of the bottom platform at different burial depths under the action of ocean currents. Additionally, the effects of different burial depths on the maximum displacement, deflection angle, and postural stability of the bottom platform are studied. The calculation results show that when the burial depth is greater than 0.6 m, and the deflection angle of the bottom platform under the action of the 3 kn sea current is less than 5°, the bottom platform can maintain a stable posture. This paper could be used to characterize the postural stability of underwater bottom platforms at different burial depths for the application of underwater sensors in ocean engineering.

Comparison of Functional Outcomes after Anterior Cruciate Ligament Reconstruction with Meniscal Repair for Unstable versus Stable Meniscal Tears.

This study aimed to compare functional outcomes including knee muscle strength in the quadriceps and hamstrings, and proprioception, assessed through dynamic postural stability (overall stability index [OSI]) and self-reported outcomes in the operated and non-operated knees between anterior cruciate ligament reconstruction (ACLR) with meniscal repair for unstable (root and radial tears) and stable (longitudinal, horizontal, and bucket handle tears) meniscal tears. A total of 76 patients were randomly selected (41 with ACLR with meniscal repair for unstable meniscal tears and 35 with ACLR with meniscal repair for stable meniscal tears) at three different time points (preoperative, 6 months, and 12 months). Repeated measures analysis of variance was used to investigate the differences in outcomes for between-subject and within-subject factors. In the operated knees, there were no significant differences for functional outcomes between the two groups (all p > 0.05). In the non-operated knees, a significant difference was observed for the OSI between the two groups, which was significantly higher in ACLR with meniscal repair for unstable meniscal tears than for stable meniscal tears at 6 months (p < 0.001). Multiple linear regression analysis showed that age (p = 0.027), preoperative OSI in the operated knees (p = 0.005), and postoperative OSI in the operated knees at 6 months (p = 0.002) were significant and independent predictors for OSI in the non-operated knees at 6 months postoperatively. Therefore, while no differences were observed in functional outcomes between the two groups in the operated knees, dynamic postural stability was poorer at 6 months postoperatively in the non-operated knees of patients with ACLR with meniscal repair for unstable meniscal tears. Furthermore, a significant correlation was observed between preoperative/postoperative dynamic postural stability in the operated knees and postoperative dynamic postural stability in the non-operated knees. Hence, we recommend incorporating balance exercises for both knees in post-surgical rehabilitation, particularly for patients with unstable meniscal tears.

Different montages of transcranial direct current stimulation on postural stability in chronic low back pain patients: A randomized sham-controlled study.

BACKGROUND: Impairment in both the motor and cognitive aspects of postural control is a critical issue in patients with chronic low back pain (CLBP) who experience high pain anxiety (HPA). OBJECTIVE: This study aimed to compare the effects of cathodal and anodal transcranial direct current stimulation (c-tDCS and a-tDCS) over the dorsolateral prefrontal cortex (DLPFC) on postural control during cognitive postural tasks in CLBP patients with HPA. METHODS: This study included 66 patients randomly assigned to three groups: DLPFC a-tDCS, DLPFC c-tDCS, and sham tDCS. All groups received 20 minutes of tDCS, but the stimulation was gradually turned off in the sham group. Postural stability indices were assessed using the Biodex Balance System. RESULTS: Both the a-tDCS and c-tDCS groups showed a significant reduction in most postural stability indices at static and dynamic levels after the interventions (immediately, 24 hours, and one-week follow-up) during the cognitive postural task (P< 0.01). Additionally, there was a significant improvement in postural balance in the a-tDCS and c-tDCS groups compared to the sham tDCS group (P< 0.01). Furthermore, the a-tDCS group showed significantly greater improvement than the c-tDCS group (P< 0.01). CONCLUSION: Based on the results, both a-tDCS and c-tDCS over the DLPFC had positive effects on postural control during cognitive postural tasks in CLBP patients with HPA.

Turns while walking among individuals with Parkinson's disease following overground locomotor training: A pilot study.

BACKGROUND: Individuals with Parkinson's disease are challenged in making turns while walking, evidenced by reduced intersegmental coordination and reduced dynamic postural stability. Although overground locomotor training previously improved ambulation among people with Parkinson's disease, its effect on walking turns remained unknown. We sought to understand the effects of overground locomotor training on walking turns among individuals with mild-Parkinson's disease. METHODS: Twelve participants with Parkinson's (7 Males/5 Females; Age: 68.5 ± 6.4 years) completed twenty-four sessions lasting approximately 60 min and over 12-15 weeks. Baseline and follow-up assessments included the ten-minute walk test using wearable sensors. Primary outcomes included changes to intersegmental coordination, measured by peak rotation and normalized peak rotation, and dynamic postural stability, measured by peak turn velocities in the frontal and transverse planes. Statistical analysis included one-tailed paired t-tests and Cohen's d effect sizes with α = 0.05. FINDINGS: No effects of overground locomotor training on mean peak thoracic rotation (+0.23 ± 4.24°; Cohen's d = 0.05; P = 0.45) or mean normalized peak thoracic rotation (-0.59 ± 5.52 (unitless); Cohen's d = 0.10; P = 0.45) were observed. Moderate and small effects of overground locomotor training were observed on mean peak turn velocities in the frontal (+1.59 ± 2.18°/s; Cohen's d = 0.43; P = 0.01) and transverse planes (+0.88 ± 3.18°/s; Cohen's d = 0.25; P = 0.18). INTERPRETATION: This pilot study provides preliminary evidence suggesting that individuals with mild-Parkinson's moderately improved frontal plane dynamic postural stability after overground locomotor training, likely attenuating the perturbations experienced while turning. CLINICAL TRIAL REGISTRATION: NCT03864393.

How do features of dynamic postural stability change with age during quiet standing, gait, and obstacle crossing?

Previous research has reported mixed findings regarding age-related changes in dynamic postural stability, quantified by margin of stability (MOS), during gait. However, age-related changes in MOS may be better elicited by tasks imposing greater challenges to the postural control system. Older adults' MOS during obstacle crossing, a destabilizing task, has previously been characterized, although studies comparing MOS during this task between younger and older adults remain sparse. This study investigated age-related changes in dynamic postural stability during quiet standing, gait, and obstacle crossing. Participants aged 20-30 (n = 20), 60-69 (n = 18), 70-79 (n = 15), and 80+ (n = 7; not analyzed statistically) years old performed these tasks while whole-body motion was tracked using motion capture. MOS in each direction was estimated throughout each trial, and integrals, transient ranges, and trial minima were extracted (as applicable). MOS time series were also ensemble averaged across age groups. No age-related differences were identified for quiet standing or gait. However, obstacle crossing metrics revealed greater stability (i.e., more positive MOS) and less instability (i.e., less negative MOS) in older adults, and reduced ranges during transients. These findings potentially arise from shorter step lengths, which may be the result of age-related physical declines; or may reflect a cautious strategy in older adults, which maximizes postural stability in the direction with the greatest consequences for foot-obstacle contact, as it changes throughout the task. This study supports the use of tasks imposing physical challenges and/or voluntary perturbations to study age-related changes in dynamic postural stability. Findings also contribute to our theoretical understanding of the time course of dynamic postural stability during functional tasks in relation to periods of transition in the base of support, and task-specific strategies adopted for obstacle crossing by older adults to maintain dynamic postural stability and mitigate fall risk.