Dynamic Postural Stability Research Articles

Effects of four weeks intervention combining high-definition transcranial direct current stimulation and foot core exercise on dynamic postural stability

This study aimed to evaluate the effect of combining high-definition transcranial direct current stimulation (HD-tDCS) with foot core exercise (FCE) on dynamic postural stability and to determine whether the improvement achieved through this mix-type intervention outperforms the intervention of HD-tDCS and FCE alone. Sixty healthy males were recruited and randomly divided into four groups: (1) HD-tDCS + FCE group (HD-tDCS combined with FCE intervention); (2) s-tDCS + FCE (sham tDCS combined with FCE intervention); (3) HD-tDCS group which only received HD-tDCS; (4) FCE group which only performed FCE. All participants received a four-week intervention (3 times a week, 20 min each time). The Y-balance task was completed before and after the intervention. The maximum reaching distance was recorded, and the data of the center of pressure (COP) were collected by a three-dimensional force plate to calculate COP displacement and velocity. No significant change in COP displacement was found among the four groups. However, the COP velocity decreased significantly in the posteromedial direction after HD-tDCS + FCE intervention compared with the baseline. The maximum reach distance was significantly increased after HD-tDCS + FCE intervention in the posteromedial (p < 0.001) and posterolateral (p < 0.001) directions of the Y balance task compared with the baseline, and the extent of increase was greater than that in the three other groups. The intervention of HD-tDCS combined with FCE may exert a synergistic effect and more effectively improve dynamic postural stability.

The Influence of high kinesiophobia on dynamic postural stability among females with patellofemoral pain syndrome during a single-leg squat test

Objective. The purpose of this study was to examine the effect of Kinesiophobia level on postural stability during Single Leg Squat Test (SLST) in females with patellofemoral pain syndrome (PFPS). Methods. Forty women with PFPS were divided into a High Kinesiophobia level group (HK), a Low Kinesiophobia level group (LK), and a pain-free control group of twenty participants. Postural stability was measured during the performance of the Single Leg Squat Test (SLST) on a force platform. The centre of pressure (COP) excursion and velocity were recorded. Results. The HK group had a significantly higher mean medial–lateral and anterior-posterior COP displacement compared to the LK and control groups. However, the results showed no significant differences in COP variables (velocity and displacement) between LK and healthy subjects. Muscle strength of participants with PFPS presented a significant deficit compared to healthy control group. Conclusions. High Kinesiophobia negatively affects postural stability during the SLST. Kinesiophobia should be considered during the assessment and management of PFPS.

Effects of Different Auditory Stimuli and Cognitive Tasks on Balance in Healthy Young Adults

Introduction: This study investigated the effect of different auditory stimuli and cognitive tasks on balance in healthy young adults. Methods: Thirty-three participants, aged 23.33 ± 2.43 years, were included in the study. The hearing levels of the participants were determined. Static and dynamic postural stability and limits of stability (LOS) tests were performed in the absence of auditory stimuli, in the presence of spondee word lists at 70 dB(A) and in the presence of spondee+white noise (−6 dB signal-to-noise ratio [SNR]), while auditory stimuli were presented bilaterally with supra-aural headphones. Participants were asked to repeat the words they listened to while performing balance-related tasks. Results: No significant differences between the three conditions were observed in the postural stability and LOS results. Increase in total repetition error was observed as the listening task became more difficult. Conclusion: The presence of auditory stimuli and the cognitive tasks did not cause any changes in the participants’ balance.

Correlation between the biomechanical characteristics and stability of the 143D movement during the balance phase in competitive Tai Chi.

To explore the biomechanical factors affecting the stability of athletes in the 143D balance phase of competitive Tai Chi. The Vicon 3D motion capture system, Kistler 3D force platform, and Noraxon surface electromyography (sEMG) system were used to measure the joint angle, joint moment, center of gravity, ground reaction force, and sEMG data of athletes. The stability index was then calculated according to the formula. Pearson's or Spearman's correlation tests were used to analyze the associations between the biomechanical factors and stability index. (1) Medial lateral stability index (MLSI): A significant negative correlation was found between the ankle inversion angle of the supporting leg (SL) and MLSI (p < 0.05). (2) Anterior posterior stability index (APSI): Significant negative correlations were observed between the ankle intorsion angle, integrated electromyography (iEMG) of the gastrocnemius, and muscle contribution rates of the tibialis anterior, external oblique, and gastrocnemius of the non-supporting leg (NL) with the APSI (p < 0.05). The ankle dorsiflexion moment, iEMG of the rectus femoris and tibialis anterior, muscle contribution rate of the biceps femoris, and root mean-squared (RMS) amplitude of the gluteus maximus of the SL also showed significant negative correlations with the APSI (p < 0.05). Strong and significant negative correlations were also identified between the hip intorsion angle, iEMG of the tibialis anterior, and RMS amplitude of the rectus femoris of the NL with the APSI (p < 0.01). Further strong and significant negative correlation was also found between the RMS amplitude of the biceps femoris of the SL and APSI (p < 0.01). The knee extorsion angle of the NL was positively correlated with the APSI (p < 0.05). (3) Dynamic postural stability index (DPSI): The knee adduction angle, iEMG of the tibialis anterior, and RMS amplitude of the erector spinae of the NL were significantly positively correlated with the DPSI (p < 0.05). The knee abduction and hip extension moments of the SL were also significantly positively correlated with the DPSI (p < 0.05). The ankle inversion angle of the SL impacts left-right stability, while the NL's hip and ankle intorsion angles, knee extorsion angle, and exertion on the core muscle and SL's main muscles, as well as exertion of specific muscles of the NL affect anterior-posterior stability. The hip extension and knee abduction moments of the SL, knee adduction angle, exertion on the tibialis anterior, and activation of the erector spinae of the NL significantly affect the overall stability of an athlete.

Correlations of Postural Stability to Proprioception, Tactile Sensation, and Strength Among People With Chronic Ankle Instability.

The static and dynamic correlations of postural stability to its three potential contributors, namely, proprioception, tactile sensation, and strength remain unclear among people with chronic ankle instability (CAI). This study aimed to compare static and dynamic postural stability, along with proprioception, tactile sensation, and strength between people with and without CAI and explore their correlations. Sixty-seven participants with CAI and 67 participants without CAI were enrolled in this study. Ankle proprioception, plantar tactile sensation, and lower limb strength were measured by a proprioception test device, a set of monofilaments, and a strength testing system, respectively. Static and dynamic postural stability were measured during standing and jump landing on a force plate and indicated by the root mean square of center of pressure and time to stability. Compared to people without CAI, people with CAI had poorer postural stability, proprioception, tactile sensation, and strength. Both groups demonstrated correlation between proprioception and static postural stability, but only people without CAI showed correlation between proprioception and dynamic postural stability. Both groups demonstrated a correlation between tactile sensation and static postural stability, but not with dynamic stability. Both groups demonstrated a correlation between strength and both static and dynamic postural stability. People with CAI had deficits in static and dynamic postural stability, proprioception, tactile sensation, and strength. Among people with CAI, proprioception, tactile sensation, and strength can help maintain static postural stability; strength can help maintain dynamic postural stability, whereas proprioception may not provide sufficient information for dynamic postural stability.

Subtalar joint pronation: Who is the real enemy, presence or severity: A cross-sectional study?

The study aims to compare static and dynamic postural stability, navicular drop, dorsiflexion range of motion, and jumping performance of individuals with neutral, prone, and hyperprone foot postures. Forty-eight participants between the ages of 18 and 40, were categorized into neutral (n=16), prone (n=16), and hyperprone (n=16) according to foot posture index (FPI). Static and dynamic postural control evaluations (with the Biodex Balance System SD), navicular drop test (NDT) weight-bearing lunge test, countermovement jump test without arm swing, and drop vertical jump tests have been completed. In the results, the average age of participants in the NG, PG, and HPG are 22.31 ± 2.75, 23.87± 3.72, and 22.37 ± 1.28 years and BMI are 22.6 ± 3, 23.4 ± 3.8, and 21.4 ± 2.24 (kg/m²), respectively. The demographic data of the participants showed a homogeneous distribution. There were no significant differences in none of the outcomes except the NDT. Navicular drop amount is positively correlated by the subtalar joint pronation. An increase in subtalar joint pronation does not have a significant effect on static and dynamic stability, jump performance, or dorsiflexion range of motion in healthy individuals.

Stair-Climbing Training with Interferential Electrotherapy Improves Knee Muscle Strength, Dynamic Postural Stability, Pain Score, and Physical Activity in Patients with Knee Osteoarthritis.

Background/Objective: This study aimed to compare the functional outcomes, such as knee muscle strength, dynamic postural stability, pain scores, and physical activity, in patients with knee osteoarthritis (OA) on stair climbing training with and without interferential electrotherapy (IFE) for 12 weeks. Methods: A total of 40 knee OA patients with Kellgren-Lawrence (K-L) grade ≤ 2 were enrolled (20 stair-climbing training with IFE vs. 20 stair-climbing training without IFE). The knee quadriceps and hamstring muscle strengths were measured using an isokinetic device. The dynamic postural stability was assessed using postural stabilometry. The pain score was evaluated using the visual analog scale (VAS). Physical activity was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results: The WOMAC score was significantly different (p < 0.019) between stair-climbing training with and without IFE in patients with knee OA, while knee muscle strength, dynamic postural stability, or pain score were not (all p > 0.05). Conclusion: Stair-climbing training with IFE was more beneficial for physical activity recovery than stair-climbing training without IFE. Therefore, clinicians and therapists should be aware that stair climbing, which can be practiced in daily life for the management of patients with knee OA, and the addition of IFE may improve physical activity.

Relationship between Kinesiophobia and Dynamic Postural Stability after Anterior Cruciate Ligament Reconstruction: A Prospective Cohort Study.

Anterior cruciate ligament (ACL) injuries in young, active patients generally require ACL reconstruction (ACLR) to restore mechanical and postural stability. The fear of movement or reinjury (kinesiophobia) has become increasingly recognized in the post-ACLR population; however, the association between restoration of postural stability and kinesiophobia remains largely unknown. The purpose of this study was to investigate changes in mean Tampa Scale of Kinesiophobia-11 (TSK-11), dynamic motion analysis (DMA) scores, and time on the testing platform, as well as any correlation between TSK-11 and mean overall and individual translational and rotational DMA scores during the first 12 months following ACLR. Cohort study. Patients undergoing ACLR were prospectively enrolled and dynamic postural stability and kinesiophobia based on the TSK-11 were collected within 2 days prior to surgery and at 6 and 12 months following ACLR. Dynamic postural stability was quantified by calculating a DMA score, with score calculated in three translational (anterior/posterior [AP], up/down [UD], medial/lateral [ML]) and three rotational (left/right [LR], flexion/extension, and internal/external rotation) independent planes of motions. Correlations between DMA and TSK-11 scores at each time point were analyzed. A total of 25 patients meeting inclusion criteria were analyzed. Mean overall DMA and TSK-11 scores increased with each successive testing interval. At 6-month follow-up, a weakly positive association between TSK-11 and DMA scores was appreciated based on overall DMA, AP, UD, ML, and LR. At 12 months, a moderately positive correlation was appreciated between TSK-11 and the translational, but not rotational, planes of motion. Following ACLR, lower level of kinesiophobia were found to be moderately associated with improved dynamic stability, especially in the translation planes of motion.

Analysing lower limb motion and muscle activation in athletes with ankle instability during dual-task drop-jump

ABSTRACT This study investigates the impact of chronic ankle instability (CAI) on athletes’ lower extremity mechanics during bounce drop-jump landings with divided attention. Thirty Division I physical education voluntarily participated in the study. They performed two sets of bounce drop jumps: one set with a divided attention task and the other without. The obtained data were analysed using a paired t-test to compare the outcomes between the divided attention (DA) and non-divided attention (NDA) tasks. Athletes with CAI, during the DA task, displayed higher vertical landing forces, increased ankle inversion velocity, and greater range of motion of the ankle, knee, and hip in the frontal and transverse planes. They also exhibited insufficient neuromuscular preparation of the rectus femoris muscle. Notably, distinct kinematic alterations were observed in the ankle, knee, and hip joints regarding frontal and transverse lower-extremity kinematics. The findings suggest that athletes with CAI experience decreased activation of the rectus femoris muscle, which may impact their dynamic postural stability from pre-landing to ascending phases. Furthermore, the results indicate that individuals with CAI closely replicate the injury mechanisms encountered during a drop-jump landing task with divided attention. These insights offer valuable information about the real-time challenges faced by athletes with CAI.

Impact of Duration of Type 2 Diabetes Mellitus on Dynamic Postural Stability

Introduction Diabetes mellitus (DM) is the most common endocrine disorder, affecting over 100 million people globally. Type 2 diabetes mellitus (T2DM) is particularly prevalent, with projections indicating a rise in global prevalence from 8.8% in 2017 to 9.9% by 2045. India, in particular, has the highest number of diabetic patients. T2DM patients often experience peripheral neuropathy and muscle weakness, leading to postural instability and gait issues. This study aims to assess the dynamic postural stability in T2DM patients and its correlation with the duration of diabetes.  Methods An observational study was conducted from February 2024 to June 2024 at the University College of Physiotherapy and the Department of Medicine, Guru Gobind Singh Medical College and Hospital, Faridkot. Thirty patients with T2DM, aged 40-60, were enrolled. The Y-Balance Test (YBT) was used to evaluate dynamic postural stability. Patients performed reach tests in three directions: anterior (AN), posteromedial (PM), and posterolateral (PL). The composite reach distance was calculated for each leg, and the composite percentage was determined.  Results The study included 16 males and 14 females with a mean age of 53.2 years and an average diabetes duration of 5.723 years. The composite reach percentages for the left and right legs were 68.43% and 68.37%, respectively. Significant correlations were found between the reach distances of both legs, particularly in the AN, PM, and PL directions. A negative correlation was observed between diabetes duration and composite reach percentages, indicating that longer diabetes duration is associated with greater impairment in dynamic postural stability.  Discussion The findings suggest that patients with longer durations of T2DM have compromised dynamic postural control, increasing their risk of falls and lower limb injuries. The YBT, derived from the Star Excursion Balance Test (SEBT), is effective in assessing these deficits. The results align with previous studies, confirming the impact of diabetes on postural stability.  Conclusion Dynamic postural stability declines with the increasing duration of T2DM, regardless of the presence of diabetic complications. Regular assessment using the YBT can help in early identification and management of postural instability in T2DM patients, potentially reducing fall risk and associated injuries.

Enhancing Dynamic Balance and Postural Stability in Stroke Patients: The Impact of Immersive Virtual Reality Training.

Introduction Stroke is a major neurological event resulting from reduced or blocked blood flow to the brain, leading to significant morbidity. Immediate medical attention is essential to minimize brain damage and improve outcomes since it leads to many clinical deficits like locomotor impairment, instability in postural control, tonic alterations of the affected musculature, and an array of neurological dysfunctions if left unnoticed. Immersive virtual reality (VR) has emerged as a novel therapeutic tool in stroke rehabilitation, offering engaging and realistic environments for therapy. This study aims to evaluate the effectiveness of immersive VR training combined with functional gait exercises in improving dynamic balance and postural stability in stroke patients, compared to VR training alone. Methods This comparative study included 30 subjects from Madha Medical College and Hospital, Chennai, Tamil Nadu, India, divided into two groups. Group A (n=15) received immersive VR combined with functional gait exercises, while Group B (n=15) received immersive VR alone. Subjects were aged 40-60 years with stable blood pressure and a stroke duration of two weeks to six months. The study spanned 12 weeks, with 30-minute sessions on alternate days. Dynamic balance and postural stability were assessed using the Functional Gait Assessment (FGA) and Falls Efficacy Scale (FES). Pre-test and post-test scores were evaluated using parametric tests. Results Post-test mean values showed significant improvements in both groups. Group A demonstrated greater effectiveness, with lower FES scores (mean 36.66 ± 11.12) than Group B (mean 46.66 ± 9.75). FGA scores were higher in Group A (mean 28.00 ± 0.925) compared to Group B (mean 26.06 ± 1.66). Significant differences were observed in pre-test and post-test values within each group, supporting the hypothesis that combined VR and gait exercises offer superior rehabilitation outcomes. Conclusions Immersive VR combined with functional gait exercises significantly improves dynamic balance and postural stability in stroke patients compared to VR alone. This integrated approach can enhance motor function recovery, increase independence, and improve the quality of life. VR's capability to simulate real-life activities and provide immediate feedback allows for personalized rehabilitation programs. Further research is required to validate these findings and optimize VR-based rehabilitation protocols.

The effect of different subtalar joint pronation amounts on postural stability, function and lower extremity alignment in healthy individuals

IntroductionThe prone foot posture has a negative effect on postural stability, function, and knee valgus, but to our knowledge, the contribution of the degree of pronation has not been examined. Methods39 participants aged 18–40, with Foot Posture Index (FPI) scores between 6–12 and without any pain complaints were included. Participants with 6–9 points were included in the pronation group (PG) (n = 19), and participants with 10–12 points were included in the hyperpronation group (HPG) (n = 20). Static and dynamic postural stability, Foot and Ankle Ability Measure (FAAM), and frontal plane projection angles (FPPA) were measured for all participants. ResultsThe initial data of the participants are distributed homogeneously. In the intergroup evaluation only FPI-1 (p = 0.001; p < 0.05), FPI-4 (p = 0.00; p < 0.05), FPI-5 (p = 0.00; p < 0.05) and FPI-T (p = 0.000; p < 0.05) scores were found significantly different. ConclusionPronation and hyperpronation of the subtalar joint did not lead to a difference in postural stability, function, and knee valgus in healthy individuals. It may be more beneficial to focus on the prone posture rather than the degree of pronation.

Virtual reality and functional training effect on contractile properties of lower leg muscles and postural stability

Purpose. Tensiomyography is a noninvasive and reliable method to identify the differences in skeletal muscle responses. Poor lower leg muscles cause poor postural stability, leading to the risk of injury in athletes. The study aims to investigate the aftereffect of a six-week virtual reality environment and functional training program on the contractile properties of lower-leg muscles and postural stability index. Material and methods. A comparative pre-test and post-test study design was selected for this study. Twenty-four male athletes were taken part in the study. The participants were randomly divided into a virtual reality intervention-training group (n=12) or a functional training group (n=12). The virtual reality environment training was provided using the CAREN integrated virtual reality system with a D-flow application from Motek. Functional training for static and dynamic postural stability was performed with various open and closed-eye exercises in the physical therapy lab. The contractile properties of lower-leg muscles were measured using tensiomyography. The postural stability index was assessed using a stadiometer. The assessments were performed before and after six weeks of training. A paired sample t-test was used to determine differences between pretest and posttest intervention outcome measures, and sample t-test was also applied to determine differences between groups after six weeks of training. Results. Results indicated significant differences between pretest and posttest measurement in virtual reality training group for displacement (t=2.81, p=.043), (t=-6.92, p=&lt;.001) in gastrocnemius lateral and medial muscle respectively, and sustain time (t=2.29, p=.042) in souls muscle. The postural stability with close eye was significant (t=2.61, p=.024). The functional training group showed significant differences for sustain time (t=-18.86, p=&lt;.001) in gastrocnemius lateral, and relaxation time (=3.24, p=.008), delay time (t=3.07, p=.011), and sustain time (t=-19.74, p=&lt;.001) in gastrocnemius medial, and sustain time (t=3.17, p=.009) in souls muscle. The postural stability was having insignificant differences. Conclusion. The virtual reality environment and functional training, help to improve performance, and tensiomyography could be used to assess and evaluate the parameters that could be helpful for optimizing training load in the performance enhancement process of athletes.

Role of Sport Vision in Performance: Systematic Review.

Sport Vision is a speciality of multidisciplinary interest aimed at improving the performance of the visual system to achieve benefits in practiced sports, as well as in daily life and in preventive care. The type of training practiced by the athlete, his or her physical condition, cognitive level, and level of fatigue condition affects the speed of the reaction time and, consequently, the speed of motor response. Specific orthoptic exercises, the use of technological devices, the recovery of static and dynamic postural stability by using unstable platforms and the dual-task paradigm can help to achieve the expected results. The aim of this systematic review of Sport Vision was to assess the overall existing literature on Sport Vision, paying particular attention to the effects of visual training and its application in different sports and in rehabilitation and preventive settings. We analysed published English language studies about the role of sport vision in athletic performance from 1950 to 2023. We searched through the Medline database. The PRISMA 2020 checklist was used to assess the transparency and reproducibility of this review. The enrolled papers were evaluated with the Jadad Scale, Amstar 2 Scale and Newcastle-Ottawa Scale. 25 (16 studies, 5 reviews, 2 comments, 1 editorial, 1 descriptive paper) out of 476 studies met the inclusion criteria. Due to the variability in the age of the samples, the different techniques, the treatments among the participants in the studies and the finding of non-evaluable articles, a meta-analysis was not conducted. The limitations of this review are the single database research, the studies analyzed contain a non-statistically representative sample size and the lack of a control group. There is no standardized test to measure performance. It was shown that the development of visual skills can benefit athletes in injury prevention, and can lead to improved sports performance and motor function at any age, acquiring adaptive motor behaviour even when the visual system is impaired, due to task repetition and familiarity of the gesture. We intended to identify a multidisciplinary approach and a manual treatment scheme to optimize the circuitry involved in sport vision in order to increase the results that are achieved, but further studies will be needed to this end.

Addition of anterolateral ligament reconstruction to primary anterior cruciate ligament reconstruction could benefit recovery of functional outcomes

This study aimed to compare functional outcomes sequentially up to 1 year after combined anterior cruciate ligament reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) and isolated ACLR. Fifty patients who underwent ACLR with versus without ALLR were analyzed at four different time points (preoperatively and 3, 6, and 12 months postoperatively). For the functional outcomes, muscle strength and acceleration time (AT) were measured using an isokinetic dynamometer. Proprioception was evaluated using joint position sense and dynamic postural stability. Patient-reported outcomes were measured using the Tampa Scale for Kinesiophobia (TSK-11) scores. Functional performance was assessed using single-leg hop distance (SLHD) and Limb Symmetry Index. In the operated knees, quadriceps (at 6 months postoperatively, p = 0.003) and hamstring (at 6 and 12 months postoperatively, p < 0.001) strength were significantly higher in the combined ACLR and ALLR group than the isolated ACLR group. The TSK-11 (at 6 and 12 months postoperatively, p < 0.001) was significantly lower in the combined ACLR and ALLR group than the isolated ACLR group. SLHD was significantly higher in the combined ACLR and ALLR group than the isolated ACLR group (at 6 months, p = 0.022 and at 12 months, p = 0.024). The addition of ALLR to primary ACLR yielded better muscle performance, fear of movement, and functional performance than isolated ACLR.

The Effect of Sportsmetrics Program on Dynamic Knee Valgus, Core Endurance, and Postural Stability in Soccer Female Athletes With Dynamic Knee Valgus

Background and Aims The most important risk factors for knee injuries include weakness in core stability, poor postural stability, and excessive dynamic valgus of the knee. One of the most successful protocols for preventing knee injuries in female athletes is specialized sportsmetrics soccer training. It seems that the effect of this protocol on the core stability of female soccer players with knee valgus has not been studied. Methods In the present study, 24 footballers with knee valgus in the training (12 people) and the control (12 people) groups participated in specialized sportsmetrics soccer training and regular pre-season exercises for six weeks, respectively. The tests consisted of a core stability test (trunk flexor, trunk extensor, right side bridge, and left side bridge), postural stability (Y balance), and dynamic knee valgus (during the scoring of landing error test). Results Analysis of covariance was used to analyze the data (P≤0.05) in SPSS software, version 25. The results showed a significant improvement (P=0.01) in postural stability (from 105.2 to 116.7 cm), core stability (from 38.2 to 41.1 s), and knee valgus (from 25.3 to 12.4 degrees). Conclusion According to the results of the study, the present protocol, which is designed to prevent knee injuries in female soccer players, modifies all three risk factors for knee injuries (weakness in core stability, poor postural stability, and knee valgus). Therefore, this protocol is recommended for all female soccer players with dynamic knee valgus.

The Effect of Acute Focus of Attention Instructions on Biomechanical Indexes Associated With Anterior Cruciate Ligament Injury Prevention

Background and Aims Anterior cruciate ligament (ACL) injury is one of the most common and serious injuries of the knee joint, which accounts for 80% of all knee ligament surgeries. Studies have shown that a significant percentage of this injury (70%) occurs in a non-contact form, usually during activities like deceleration, landing, or side cutting. Studies have shown that focus instructions could improve and promote performance. This study aimed to investigate the acute effect of focus instructions on biomechanical indexes associated with ACL injury prevention. Methods In this research, 24 young football players from the two clubs of the Tehran Premier League, Tehran City, Iran, were randomly divided into two groups: external focus attention (n=12) and internal focus attention (n=12). First, the dynamic postural stability index (DPSI), the peak of vertical, anteroposterior, and mediolateral GRF components, and the rate of loading during the jump-landing movement from a box with 30 cm height were calculated using a force plate with a sampling frequency of 1000 Hz. Then, the internal and external focus instructions were taught to the participants, and the two groups performed a posttest to examine the changes. Statistical methods of repeated measures analysis of variance and paired t test were used to evaluate the changes. Results The results showed significant changes in the vertical component and rate of loading variables in both groups of internal and external focus attention (P≤0.05). However, no significant difference was observed between the two groups in the DPSI, anteroposterior and mediolateral GRF. Conclusion The results of this study showed that acute instructions of both internal and external focus attention can improve landing mechanics and landing-related kinetic variables. It seems that the external focus instructions have increased the motor control of the limb, leading to a further reduction of vertical GRF and the load applied to the lower limb compared to the instructions of internal focus, thus reducing the risk of ACL injury.

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.

Dynamic Stability, Symmetry, and Smoothness of Gait in People with Neurological Health Conditions.

Neurological disorders such as stroke, Parkinson's disease (PD), and severe traumatic brain injury (sTBI) are leading global causes of disability and mortality. This study aimed to assess the ability to walk of patients with sTBI, stroke, and PD, identifying the differences in dynamic postural stability, symmetry, and smoothness during various dynamic motor tasks. Sixty people with neurological disorders and 20 healthy participants were recruited. Inertial measurement unit (IMU) sensors were employed to measure spatiotemporal parameters and gait quality indices during different motor tasks. The Mini-BESTest, Berg Balance Scale, and Dynamic Gait Index Scoring were also used to evaluate balance and gait. People with stroke exhibited the most compromised biomechanical patterns, with lower walking speed, increased stride duration, and decreased stride frequency. They also showed higher upper body instability and greater variability in gait stability indices, as well as less gait symmetry and smoothness. PD and sTBI patients displayed significantly different temporal parameters and differences in stability parameters only at the pelvis level and in the smoothness index during both linear and curved paths. This study provides a biomechanical characterization of dynamic stability, symmetry, and smoothness in people with stroke, sTBI, and PD using an IMU-based ecological assessment.

Repetitive temporal interference stimulation improves jump performance but not the postural stability in young healthy males: a randomized controlled trial

BackgroundTemporal interference (TI) stimulation, an innovative non-invasive brain stimulation technique, has the potential to activate neurons in deep brain regions. The objective of this study was to evaluate the effects of repetitive TI stimulation targeting the lower limb motor control area (i.e., the M1 leg area) on lower limb motor function in healthy individuals, which could provide evidence for further translational application of non-invasive deep brain stimulation.MethodsIn this randomized, double-blinded, parallel-controlled trial, 46 healthy male adults were randomly divided into the TI or sham group. The TI group received 2 mA (peak-to-peak) TI stimulation targeting the M1 leg area with a 20 Hz frequency difference (2 kHz and 2.02 kHz). Stimulation parameters of the sham group were consistent with those of the TI group but the current input lasted only 1 min (30 s ramp-up and ramp-down). Both groups received stimulation twice daily for five consecutive days. The vertical jump test (countermovement jump [CMJ], squat jump [SJ], and continuous jump [CJ]) and Y-balance test were performed before and after the total intervention session. Two-way repeated measures ANOVA (group × time) was performed to evaluate the effects of TI stimulation on lower limb motor function.ResultsForty participants completed all scheduled study visits. Two-way repeated measures ANOVA showed significant group × time interaction effects for CMJ height (F = 8.858, p = 0.005) and SJ height (F = 6.523, p = 0.015). The interaction effect of the average CJ height of the first 15 s was marginally significant (F = 3.550, p = 0.067). However, there was no significant interaction effect on the Y balance (p > 0.05). Further within-group comparisons showed a significant post-intervention increase in the height of the CMJ (p = 0.004), SJ (p = 0.010) and the average CJ height of the first 15 s (p = 0.004) in the TI group.ConclusionRepetitive TI stimulation targeting the lower limb motor control area effectively increased vertical jump height in healthy adult males but had no significant effect on dynamic postural stability.