Dynamic Postural Stability Testing Research Articles

Predictors of static and dynamic balance control in kidney transplant recipients.

We aimed to evaluate balance control and lower extremity muscle strength in kidney transplant recipients (KTRs) including acomparison to ahealthy control group and determine the predictors of static and dynamic balance control after kidney transplantation. In this study 40 KTRs and 40healthy controls were included. Balance control was assessed using the Biodex balance system. The static postural stability test (SPST) and clinical test of sensory integration and balance (CTSIB) were used to assess static balance control whereas the dynamic postural stability test (DPST) and limits of stability test (LOST) were used for dynamic balance control. Lower extremity muscle strength was measured with ahand-held dynamometer. Renal functions and laboratory findings of KTRs were recorded. All the stability index scores of SPST and sway index in CTSIB were significantly higher in KTRs compared to healthy controls. The right anteroposterior stability index score in DPST and the reaction time in LOST were significantly higher whereas overall score in LOST and lower extremity muscle strength were significantly lower in KTRs. The linear regression analysis revealed that hemoglobin was the predictor of static balance control accounting for 11% of the variance and body weight was the predictor of dynamic balance control accounting for 34% of the variance. Balance control, both static and dynamic, are impaired in KTRs as well as lower extremity muscle strength. Hemoglobin level is apredictor of static balance control whereas body weight is apredictor of dynamic balance control after kidney transplantation.

Isometric Knee Strength is Greater in Individuals Who Score Higher on Psychological Readiness to Return to Sport After Primary Anterior Cruciate Ligament Reconstruction.

Anterior cruciate ligament (ACL) injury is extremely common among athletes. Rate of second ACL injury due to surgical graft rupture or contralateral limb ACL injury is approximately 15-32%. Psychological readiness to return to sport (RTS) may be an important predictor of successful RTS outcomes. Psychological readiness can be quantified using the ACL Return to Sport after Injury (ACL-RSI) questionnaire, with higher scores demonstrating greater psychological readiness. The purpose of this study was to investigate differences in functional performance and psychological readiness to return to sport among athletes who have undergone primary ACL reconstruction (ACLR). Descriptive cohort study. Eighteen athletes who had undergone primary ACLR were tested at time of RTS clearance. The cohort was divided into two groups, high score (HS) and low score (LS), based on median ACL-RSI score, and performance on static and dynamic postural stability testing, lower extremity isokinetic and isometric strength testing, and single leg hop testing was compared between the groups using an independent samples t-test. The median ACL-RSI score was 74.17. The average ACL-RSI score was 83.1±6.2 for the HS group and 61.8±8.0 for the LS group. High scorers on the ACL-RSI performed significantly better on isometric knee flexion as measured via handheld dynamometry (22.61% ±6.01 vs.12.12% ±4.88, p=0.001) than the low score group. The findings suggest that increased knee flexion strength may be important for psychological readiness to RTS after primary ACLR. Further research is indicated to explore this relationship, however, a continued emphasis on improving hamstring strength may be appropriate during rehabilitation following ACLR to positively impact psychological readiness for RTS. III.

Reliability of a novel dynamic test of postural stability in high-level soccer players

Postural stability of athletes is commonly tested with single-leg stance (SLS) tests. However, for this population, these tests are insufficiently challenging to achieve high sensitivity. Therefore, a new dynamic SLS test based on standardized translational surface perturbations was developed. This study aimed to assess reliability, sensitivity to learning effects, and internal and concurrent validity of this novel test.Healthy soccer players (21 females, 21 males) performed 2 test sessions. Each session consisted of 2 trials. For one trial, the participant performed a 30-seconds, unperturbed SLS on each leg, followed by 12 platform perturbations per leg.Intraclass Correlation Coefficients (ICC) and correlations between outcomes were calculated for the Center of Pressure speed (CoPs) and Time To Stabilization (TTS). ANOVA was used to assess learning effects. CoPs and TTS showed a fair reliability between sessions (ICC = 0.73–0.76). All variables showed improvement over time within and between sessions (all p < 0.01) and were moderately correlated with CoPs during unperturbed SLS (r = 0.39–0.56).Single-leg dynamic postural stability testing through standardized horizontal platform perturbations yielded sufficiently reliable CoPs and TTS outcome measures in soccer players. The moderate correlations with unperturbed SLS support concurrent validity, but also indicates that the new test captures aspects of postural stability that differ from the conventional, unperturbed SLS test.

Poorer dynamic postural stability in patients with anterior cruciate ligament rupture combined with lateral meniscus tear than in those with medial meniscus tear

BackgroundOnly limited data are available regarding postural stability between anterior cruciate ligament (ACL)-injured patients with medial meniscus (MM) tear and those with lateral meniscus (LM) tear. The purpose of this study was to compare preoperative postural stability for both involved and uninvolved knees in ACL rupture combined with MM and LM tears. It was hypothesized that there would be a significant difference in postural stability between these two groups.MethodsNinety-three ACL-injured patients (53 combined with MM tears vs. 40 combined with LM tears) were included. Static and dynamic postural stability were evaluated with the overall stability index (OSI), anterior–posterior stability index (APSI), and medial–lateral stability index (MLSI) using stabilometry. Knee muscle strength was evaluated using an isokinetic testing device.ResultsIn the static postural stability test, none of the stability indices showed significant differences between the two groups for both knees (p > 0.05). In the dynamic postural stability test for involved side knees, the OSI and APSI were significantly higher in the LM tear group compared to the MM tear group (OSI: 2.0 ± 0.8 vs. 1.6 ± 0.5, p = 0.001; APSI: 1.5 ± 0.6 vs. 1.3 ± 0.5, p = 0.023), but not the MLSI (p > 0.05). In the static and dynamic postural stability tests in each group, there were no significant differences between the involved and uninvolved side knees (p > 0.05). There was no significant difference in the knee muscle strength between the two groups (p > 0.05). All postural stability showed no significant correlation with knee muscle strength (p > 0.05).ConclusionDynamic postural stability was poorer in patients with ACL rupture combined with LM tear than in those with MM tear. Therefore, close monitoring for postural stability would be necessary during preoperative and postoperative rehabilitation, especially for patients with ACL rupture combined with LM tear.Level of evidence: Level III

Decreased Postural Control in Patients Undergoing Anterior Cruciate Ligament Reconstruction Compared to Healthy Controls.

Patients with anterior cruciate ligament (ACL) tears are likely to have deficient dynamic postural stability compared with healthy sex- and age-matched controls. To test the hypothesis that patients undergoing ACL reconstruction have decreased dynamic postural stability compared with matched healthy controls. Prospective case-control study. Orthopedic sports medicine and physical therapy clinics. Patients aged 20 years and younger with an ACL tear scheduled for reconstruction were enrolled prospectively. Controls were recruited from local high schools and colleges via flyers. Patients underwent double-stance dynamic postural stability testing prior to surgery, recording time to failure and dynamic motion analysis (DMA) scores. Patients were then matched with healthy controls. Demographics, time to failure, and DMA scores were compared between groups. A total of 19 females and 12 males with ACL tears were matched with controls. Individuals with ACL tears were more active (Marx activity score: 15.7 [1.0] vs 10.8 [4.9], P < .001); had shorter times until test failure (84.4 [15.8] vs 99.5 [14.5]s, P < .001); and had higher (worse) DMA scores (627 [147] vs 481 [132], P < .001), indicating less dynamic postural stability. Six patients with ACL deficiency (1 male and 5 females) demonstrated lower (better) DMA scores than their controls, and another 7 (4 males and 3 females) were within 20% of controls. Patients undergoing ACL reconstruction had worse global dynamic postural stability compared with well-matched controls. This may represent the effect of the ACL injury or preexisting deficits that contributed to the injury itself. These differences should be studied further to evaluate their relevance to ACL injury risk, rehabilitation, and return to play.

Modified Broström procedure in patients with chronic ankle instability is superior to conservative treatment in terms of muscle endurance and postural stability.

To compare muscle strength, muscle endurance, and postural stability in both the affected and unaffected ankles between patients with chronic ankle instability (CAI) who underwent conservative treatment and those who underwent the modified Broström procedure (MBP). A total of 67 patients (37, conservative treatment; 30, MBP) participated. Muscle strength and muscle endurance were measured using an isokinetic device, and postural stability was tested using a postural stabilometry system. We used the independent t test for continuous variables with a normal distribution and Fisher's exact test for categorical variables. There was no difference in the muscle strengths of the affected and unaffected ankles between the groups. The muscle endurance of plantarflexion and inversion muscles was significantly lower in the affected ankles of the conservative treatment group than in those of the MBP group (plantarflexion: 209 ± 103.1 vs. 318 ± 162.2, p = 0.001; inversion: 93 ± 58.7 vs. 154 ± 65.9, p < 0.001). Static postural stability testing showed no significant differences between the affected and unaffected ankles of the two groups. In the dynamic postural stability test, the overall, anterior-posterior, and medial-lateral stability indices were all significantly higher in the affected ankles of the conservative treatment group than in those of the MBP group (p < 0.001, p = 0.004, p = 0.004, respectively), with no differences observed in the unaffected ankles. The MBP may significantly improve muscle endurance and dynamic postural stability in CAI patients in whom conservative treatment has failed. Therefore, clinicians should consider using MBP instead of conservative treatment when patients show severe muscle weakness or dynamic postural instability. Case-control study, Level III.

Postural Stability Under Dual-Task Conditions: Development of a Post-Concussion Assessment for Lower-Extremity Injury Risk.

Concussions are consequence of sports participation. Recent reports indicate there is an increased risk of lower-extremity musculoskeletal injury when returning to sport after concussion suggesting that achieving "normal" balance may not fully indicate the athlete is ready for competition. The increased risk of injury may indicate the need to refine a screening tool for clearance. Assess the between-session reliability and the effects of adding a cognitive task to static and dynamic postural stability testing in a healthy population. Clinical laboratory. Twelve healthy subjects (6 women; age 22.3 [2.9]y, height 174.4 [7.5]cm, weight 70.1 [12.7]kg) participated in this study. Subjects underwent static and dynamic postural stability testing with and without the addition of a cognitive task (Stroop test). Test battery was repeated 10 days later. Dynamic postural stability testing consisted of a forward jump over a hurdle with a 1-legged landing. A stability index was calculated. Static postural stability was also assessed with and without the cognitive task during single-leg balance. Variability of each ground reaction force component was averaged. Interclass correlation coefficients (ICC2,1) were computed to determine the reliability. Standard error of measure, mean standard error, mean detectable change, and 95% confidence interval were all calculated. Mean differences between sessions were low, with the majority of variables having moderate to excellent reliability (static .583-.877, dynamic .581-.939). The addition of the dual task did not have any significant effect on reliability of the task; however, generally, the ICC values improved (eyes open .583-.770, dual task .741-.808). The addition of a cognitive load to postural stability assessments had moderate to excellent reliability in a healthy population. These results provide initial evidence on the feasibility of dual-task postural stability testing when examining risk of lower-extremity musculoskeletal injury following return to sport in a concussed population.

Moderate treadmill run worsened static but not dynamic postural stability of healthy individuals.

Running has been demonstrated to be one of the most relevant exercise in altering static postural stability, while limiting attention has been paid to its effects on dynamic postural stability. The aim of the present study was to investigate if 25min of moderate running on a treadmill altered static and dynamic postural stability in healthy subjects. Eight female and six male participants (age 27.7 ± 8.3 years, height 170.9 ± 12.2cm, weight 63.9 ± 15.6kg) took part in the study. Before and after the run static postural stability was evaluated on a stabilometric platform (10 trials of 30s each), while dynamic postural stability was assessed on an instrumented unstable platform (2 trials of 30s each). After the treadmill run the area of the confident ellipse (from 67.97 ± 34.56 to 93.08 ± 50.00mm2), sway path velocity (from 6.92 ± 1.85 to 7.83 ± 2.57mm/s), sway area velocity (from 6.88 ± 3.27 to 9.54 ± 5.36mm2/s), and medio-lateral maximal oscillation (from 9.48 ± 2.80 to 11.44 ± 3.64mm) significantly increased. Stabilogram diffusion analysis showed no statistically significant difference in the diffusion coefficients, both short and long term. No statistically significant differences were reported in all the parameters of the dynamic postural stability test. The contrasting results of the static and dynamic postural stability tests raise the question of which are the more selective tests to assess the acute effect of physical exercise on postural stability among healthy individuals. The proper interaction of both static and dynamic postural evaluations could represent the next challenge in the postural stability assessment.

Subjective and Objective Evaluation of the Functional Condition after a Single Lateral Sprain of the Ankle in Athletes.

Ankle sprains can lead to functional deficits. However, few papers have investigated deficits following a single lateral ankle sprain as either assessed subjectively by the patient (e.g., with questionnaires) or measured objectively (e.g., by evaluation of postural stability). This paper aims to provide subjective and objective assessment of functional status in athletes after a single lateral ankle sprain. A lateral ankle sprain group (LAS) consisted of 20 athletes after a single lateral ankle sprain (mean age 23 ± 1.78 years). A control group (CTRL) comprised 20 athletes with no history of injury (mean age 22.5 ± 2.67 years). Subjective assessment was based on the Foot and Ankle Disability Index questionnaire (FADI-Q). A Biodex Balance System SD dynamic platform was used to assess postural stability. Static and dynamic testing was performed in single-leg stance. Statistically significant differences were noted during the comparison of the LAS and CTRL groups in FADI-Q in the following parts: FADI (p=0,017) and FADI TOTAL (p=0,049). Moreover, statistically significant differences were noted in the LAS group between subjects with instability (N-STAB) and without instability (STAB) of the ankle in the parts FADI (p=0,006), FADI SPORT (p=0,011) and FADI TOTAL (p=0,002). During static and dynamic postural stability testing, no significant differences were found between sprained and healthy limbs, between the LAS and CTRL groups, or between the STAB and N-STAB groups. 1. Athletes after ankle sprain assessed their functio-nal status as worse compared to the control group. Moreover, deterioration in functional status was perceived by athletes with an unstable ankle joint compared to participants with a stable ankle joint. 2. The study indicates that a single ankle sprain is associated with a high risk of developing functio-nal instability. 3. The process of maintaining postural stability was similar in athletes after a single ankle sprain and in those without a history of ankle injury.

Reliability and Performance Changes with the Addition of a Cognitive Task to Static and Dynamic Postural Stability Testing

Concussions are an unfortunate consequence of sports participation. They affect motor control, neurocognitive performance, and recent reports indicate they increase the risk of lower extremity musculoskeletal injury (LEMI) upon return to sport. The increased risk of secondary LEMI may indicate the need to establish a test that is predictive of LEMI risk following return to sport. PURPOSE: Assess the between-session reliability and the effects of adding a cognitive task to static and dynamic postural stability testing. METHODS: Twelve healthy, physically active subjects (Age: 22.3 ± 2.9 years, Height: 174.4 ± 7.5 cm, Weight: 154.5 ± 28.0 lbs) participated. Subjects underwent static and dynamic postural stability testing with and without the addition of a cognitive task (Stroop task) on two separate days. Static postural stability was assessed with a single-leg balance task under eyes open (with and without the addition of the Stroop task) and eyes closed conditions. Variability of each ground reaction force component was averaged across three trials for each of the static postural stability conditions. Dynamic postural stability testing consisted of forward jump over a hurdle with a one-legged landing performed with and without the addition of the Stroop task. A stability index was calculated based on the resultant ground reaction force and each of its components. Interclass correlation coefficients (ICC, 2,1) were calculated to determine the between-session reliability of each testing condition. Comparisons were made across the static conditions and between the dynamic postural stability tasks. RESULTS: The addition of a cognitive load proved to have moderate to excellent between-session reliability for the majority of variables calculated during static (ICC values 0.74 – 0.81) and dynamic postural stability testing (ICC values 0.77 – 0.80; ML=0.800, V=0.774, DPSI=0.781). No significant differences were observed between the postural stability tasks (with or without the Stroop task). CONCLUSION: Postural stability tasks with the addition of a cognitive load prove to have moderate to excellent reliability in a healthy population. These results provide new evidence on the feasibility of dual-task postural stability testing when examining risk of LEMI following return to sport.

Static and Dynamic Postural Changes after a Mountain Ultra-Marathon of 80 km and 5500 D.

The study aimed to investigate the effect of fatigue on static and dynamic postural stability after completing a mountain ultra-marathon. Twelve male athletes participated in the study. Postural stability was assessed before and immediately after the race. Static postural stability was evaluated on a dynamometric platform with eyes opened (OE) and closed (CE). Dynamic postural stability was assessed with OE on an instrumented plate which allowed medio-lateral oscillations. Stabilometric data were affected by fatigue in the OE condition, concerning sway path velocity (p = 0.0006), sway area velocity (p = 0.0006), area of the confidence ellipse (p = 0.0016), maximal anterior-posterior (AP) (p = 0.0017) and medio-lateral (ML) (p = 0.0039) oscillations. In the CE condition the sway path velocity (p = 0.0334), the maximal ML oscillations (p = 0.0161) and the area of the confident ellipse (p = 0.0180) were also negatively influenced. Stabilogram diffusion analysis showed in the OE condition an increase of short-term diffusion coefficients considering the anterior-posterior direction (Dfys; p = 0.0023) and the combination of the two (Dfr2s; p = 0.0032). Equally, long term diffusion coefficients increased considering the anterior-posterior direction (Dfyl; p = 0.0093) and the combination of the two (Dfr2l; p = 0.0086). In CE condition greater values were detected for medio-lateral direction (Dfxl; p = 0.033), anterior-posterior direction (Dfyl; p = 0.0459) and the combination of the two (Dfr2l; p = 0.0048). The dynamic postural stability test showed an increase of the time spent with the edges of the plate on the floor (p = 0.0152). Our results showed that mountain ultra-marathon altered static stability more than dynamic stability. An involvement of cognitive resources to monitor postural stability after fatiguing could be the explanation of the worsening in the automatic task (quiet standing) and of the positive compensation in the less automatic task (dynamic standing on the instrumented plate).

Young Females Exhibit Decreased Coronal Plane Postural Stability Compared to Young Males.

Female athletes are at significantly higher risk of noncontact ACL injury than males, particularly in pivoting sports such as soccer and basketball. Sex-based differences in proprioception and core stability may contribute to this elevated risk. This study evaluates a novel method of assessing dynamic stability to test the hypothesis that healthy adolescent controls have sex-based differences in postural stability. Seventy-nine male and 72 female subjects completed three rounds of dynamic postural stability testing. During the assessment, subjects attempted to stabilize their torso and upper body in response to random movements of the platform. The total time a subject lasted on the platform and dynamic motion analysis (DMA) score, a summation of motion in five planes throughout testing, was calculated for each subject. The average score for each subject was included in the analysis. Males lasted longer on the platform (98 ± 14s) than females (94 ± 13s) (p = 0.04). Coronal plane and rotation stability differed significantly between genders (323 ± 126 vs. 365 ± 128, p = 0.04) and (318 ± 82 vs. 403 ± 153, p = 0.0002), respectively. No statistically significant difference was seen in the other planes of motion. Females have less dynamic postural stability than their male counterparts in the coronal plane based on a novel assessment tool. This finding may contribute to better understanding of sex-based differences in rates of injury such as noncontact ACL tears.

Vitamin D and muscle strength, functional ability and balance in peritoneal dialysis patients with vitamin D deficiency

25(OH)D deficiency has been associated with significantly worse physical performance in individuals with normal renal function. We examined the physical function, muscle strength and balance in age- and gender-matched 25 Stage 3 - 4 CKD patients and 47 Stage 5 CKD patients on peritoneal dialysis (PD) with vitamin D deficiency by objective methods and evaluated the effect of vitamin D replacement on physical performance tests: the "timed up and go" (TUG) test, gait velocity test, timed chair stand test, stair climb test, dynamic balance tests (TUG test, dynamic postural stability test), static balance test (functional reach test) and muscle strength in these two groups. At baseline 25(OH)D in the Stage 3 - 4 CKD patients and patients on PD were 6.9 ± 3.5 ng/ ml (17.2 ± 8.7 nmol/l) and 5.7 ± 3.3 ng/ml (14.2 ± 8.2 nmol/l), respectively (p > 0.05). Mean (± SD) 25(OH)D in Stage 3 - 4 CKD patients and those on PD were 52.0 ± 40.9 ng/ml (129.7 ± 102.2 nmol/l) and 41.9 ± 21, ng/ml (104,5 ± 52,6 nmol/l) respectively after vitamin D replacement (p > 0.05). When both Stage 3 - 4 CKD and dialysis patients became vitamin D-sufficient after vitamin D replacement, they took a significantly shorter time to complete the TUG test, gait velocity test, the timed chair stand test and stair climb test. Results of physical performance tests, static and dynamic balance tests and isometric strength tests improved in both groups after the treatment (p < 0.05). In conclusion, our results show that vitamin D supplementation improves muscle strength, functional ability and balance in both CKD and dialysis patients.

Comparison of Remnant Preserved versus Conventional Anterior Cruciate Ligament Reconstruction

PURPOSE: Surgical reconstruction of the anterior cruciate ligament (ACL) may reduces knee instability. It has been suggested that the lack of full recovery of knee function following ACL reconstruction is partially the result of a sensory deficit. The remnant preserving technique was developed to preserve the prorioception and to enhance the revasularzation of the reconstructed ACL. Therefore, the purpose of this study was to analyze the clinical results of comparing the remnant preserving technique with the conventional ACL reconstruction. METHODS: We have tested 40 patients ACL reconstruction by auto graft-hamstring tendon, by dividing the subjects into 2 different groups; Trial group (preservation of remnant, Group 1) and control group (no remnant, Group 2). We measured concentric peak torque measurements of the knee extensors and flexors at 60°/sec and 180°/sec on an Isokinetic dynamometry. Proprioceptive functions has been assessed using Joint position sense (JPS) and threshold to detection of passive motion (TDPM). Dynamic postural stability was measured as a stability index in the anterior-posterior and medial-lateral planes with the Biodex Stability System. All tests were measured postoperative 1year. For statistical analysis, we used an independent-sample t test and Pearson correlation and found the results to be statistically significant at p<.05. RESULTS: A significant difference was detected in proprioception. we found significant difference between the group 1 and group 2 for Joint position sense (1.79±0.63° vs 3.14±0.95°. p=0.012) and threshold to detect passive motion (1.73±0.68° vs 2.73±1.15°. p=0.007). In dynamic postural stability test, group 1 showed a significantly improved instability of 10.7±8.5% whereas group 2 resulted that of 17.5±8.8%(p=0.037). But, we found no significant difference between the groups for the test results of knee strength. CONCLUSIONS: We thought that the presence of the proprioceptive nerve fibers in the remnant of the ACL may provide a source for the reinnervation of the graft and restoration of normal proprioception. Therefore, preservation of the remnant ACL reconstruction is helpful in preserving the proprioception and function to stabilize the knee.