Development of postural stability limits: Anteroposterior and mediolateral postural adjustment mechanisms do not follow the same maturation process

Postural Control and Neuromuscular Activation in 11-13-Year-Old Athletic Boy Swimmers

OBJECTIVE

This study compared postural control and neuromuscular activation in athletic swimmers (A-S) and non-athletic swimmers (N-A-S) in older children.

METHODS

Ten A-S and ten N-A-S underwent assessments of center of pressure (CoP) parameters under static and dynamic surfaces in two directions (dynamic mediolateral (DML) and dynamic anteroposterior (DAP)) in eyes-open (EO) and eyes-closed (EC) conditions, and electromyography (EMG) parameters under DAP and DML directions in EO and EC conditions.

RESULTS

Results showed that A-S demonstrated significantly superior postural control (p < 0.05), with smaller CoP area and lower CoP mean velocity compared with N-A-S, particularly in static with EC, DAP with EO and EC, and DML with EO conditions. A-S exhibited significantly larger neuromuscular activation amplitudes (p < 0.05), especially in the AP direction.

CONCLUSIONS

These findings suggested that athletic swimming training may enhance postural control and neuromuscular activation in 11-13-year-old children, emphasizing the potential benefits of incorporating swimming exercises in these children.

Multitasking across the lifespan in different task contexts

We assessed lifespan development of multitasking in a sample of 187 individuals aged 8-82 years. Participants performed a visuo-spatial working memory (VSWM) task together with either postural control or reaction time (RT) tasks. Using criterion-referenced testing we individually adjusted difficulty levels for the VSWM task to control for single-task differences. Age-differences in single-task performances followed U-shaped patterns with young adults outperforming children and older adults. Multitasking manipulations yielded robust performance decrements in VSWM, postural control and RT tasks. Presumably due to our adjustment of VSWM challenges, costs in this task were small and similar across age groups suggesting that age-differential costs found in earlier studies largely reflected differences already present during single-task performance. Age-differences in multitasking costs for concurrent tasks depended on specific combinations. For VSWM and RT task combinations increases in RT were the smallest for children but pronounced in adults highlighting the role of cognitive control processes. Stabilogram diffusion analysis of postural control demonstrated that long-term control mechanisms were affected by concurrent VSWM demands. This interference was pronounced in older adults supporting concepts of compensation or increased cognitive involvement in sensorimotor processes at older age. Our study demonstrates how a lifespan approach can delineate the explanatory scope of models of human multitasking.

Instrumented Balance Error Scoring System in Children and Adolescents-A Cross Sectional Study

Background: The Balance Error Scoring System (BESS) is a commonly used method for clinically evaluating balance after traumatic brain injury. The utilization of force plates, characterized by their cost-effectiveness and portability, facilitates the integration of instrumentation into the BESS protocol. Despite the enhanced precision associated with instrumented measures, there remains a need to determine the clinical significance and feasibility of such measures within pediatric cohorts. Objective: To report a comprehensive set of posturographic measures obtained during instrumented BESS and to examine the concurrent validity, reliability, and feasibility of instrumented BESS in the pediatric point of care setting. Methods: Thirty-seven participants (18 female; aged 13.32 ± 3.31 years) performed BESS while standing on a force plate to simultaneously compute stabilometric measures (instrumented BESS). Ellipse area (EA), path length (PL), and sway velocity (VM) were obtained for each of the six BESS positions and compared with the respective BESS scores. Additionally, the effects of sex and age were explored. A second BESS repetition was performed to evaluate the test-retest reliability. Feedback questionnaires were handed out after testing to evaluate the feasibility of the proposed protocol. Results: The BESS total score was 20.81 ± 6.28. While there was no statistically significant age or sex dependency in the BESS results, instrumented posturography demonstrated an age dependency in EA, VM, and PL. The one-leg stance on a soft surface resulted in the highest BESS score (8.38 ± 1.76), EA (218.78 cm2 ± 168.65), PL (4386.91 mm ± 1859.00), and VM (21.93 mm/s ± 9.29). The Spearman's coefficient displayed moderate to high correlations between the EA (rs = 0.429-0.770, p = 0.001-0.009), PL (rs = 0.451-0.809, p = 0.001-0.006), and VM (rs = 0.451-0.809, p = 0.001-0.006) when compared with the BESS scores for all testing positions, except for the one-leg stance on a soft surface. The BESS total score significantly correlated during the first and second repetition (rs = 0.734, p ≤ 0.001), as did errors during the different testing positions (rs = 0.489-0.799, p ≤ 0.001-0.002), except during the two-legged stance on a soft surface. VM and PL correlated significantly in all testing positions (rs = 0.465-0.675, p ≤ 0.001-0.004; (rs = 0.465-0.675, p ≤ 0.001-0.004), as did EA for all positions except for the two-legged stance on a soft surface (rs = 0.392-0.581, p ≤ 0.001-0.016). A total of 92% of participants stated that the instructions for the testing procedure were very well-explained, while 78% of participants enjoyed the balance testing, and 61% of participants could not decide whether the testing was easy or hard to perform. Conclusions: Instrumented posturography may complement clinical assessment in investigating postural control in children and adolescents. While the BESS score only allows for the consideration of a total score approximating postural control, instrumented posturography offers several parameters representing the responsiveness and magnitude of body sway as well as a more differentiated analysis of movement trajectory. Concise instrumented posturography protocols should be developed to augment neuropediatric assessments in cases where a deficiency in postural control is suspected, potentially stemming from disruptions in the processing of visual, proprioceptive, and/or vestibular information.

Clubfoot patients show more anterior-posterior displacement during one-leg-standing and less ankle power and plantarflexor moment during one-leg-hopping than typically developing children

BACKGROUND

Clubfoot patients show good-to-excellent foot correction after the Ponseti method. Nevertheless, underlying functional problems that limit motor abilities such as one-leg-standing and one-leg-hopping still persist. These restrictions have been proposed to arise due to problems with maintaining balance and the limited force-generating capacity of clubfoot patients. More insight is needed to understand the underlying limiting factors to improve overall motor ability in clubfoot patients.

RESEARCH QUESTION

The aim of this study was to determine the differences between clubfoot patients and typically developing children (TDC) in force and balance parameters during walking, one-leg-standing and hopping.

METHODS

Three-dimensional motion analysis was performed in 19 TDC and 16 idiopathic Ponseti-treated clubfoot patients between 5-9 years old. Kinematic and kinetic parameters were calculated during walking and one-leg-hopping. To describe the balance parameters, center of pressure (CoP) data was assessed during walking, one-leg-hopping and one-leg-standing. Mean group values were calculated and compared using nonparametric statistical tests. A general linear model with repeated measures was used to determine which activity showed the largest group differences.

RESULTS

Clubfoot patients showed lower peak plantarflexor moment and peak ankle power absorption and generation during one-leg-hopping compared to TDC. Furthermore, clubfoot patients showed a lower hop length and velocity than TDC. The difference in peak plantarflexor moment and ankle power between the study groups was larger during one-leg-hopping than during walking. Finally, clubfoot patients showed a higher anterior-posterior CoP range during one-leg-standing.

SIGNIFICANCE

Deviations in force parameters seemed to limit one-leg-hopping in clubfoot patients, and impaired anterior-posterior static balance was thought to be the underlying cause of problems with one-leg-standing. Furthermore, one-leg-hopping was more sensitive to distinguish between clubfoot patients and TDC than walking. Individualized physiotherapy targeting static balance and force parameters, with extra emphasis on including eccentric contractions, might improve the overall motor abilities of clubfoot patients.

Can Stereotype Threat and Lift Visual Messages Affect Subsequent Physical Activity? Evidence from a Controlled Experiment Using Accelerometers

This study investigated how visual messages conveying stereotype threat or lift influenced physical activity performance. Participants (N = 380) were exposed to a stereotype threat, lift, or control condition image and then engaged in a running task. Accelerometers recorded forward-backward movement, upward-downward movement, and sideways balance. Stereotype threat exposure increased state anxiety relative to the control condition. In addition, forward-backward movement was linked to state anxiety and participants' sex. Moreover, women exposed to stereotype threat who experienced increased state anxiety showed reduced forward-backward movement. Men exposed to stereotype lift displayed higher forward-backward movement. Additionally, stereotype threat visual message exposure increased sideways balance activity for women but not for men. Upward-downward movement was unaffected by stereotype threat or lift. We discuss theoretical and practical implications of how exposure to visual stereotypes can influence physical activity performance.

Mediolateral Postural Control Mechanisms and Proprioception Improve With Kicking Sports Training During Adolescence

Sensorimotor stimulation during the sensitive period is crucial for proper brain development. Kicking sports (KS) training stimulates these sensorimotor functions. The purpose of this study was to investigate if incorporating specific sensorimotor stimulation in mediolateral axis and proprioceptive inputs during KS training will improve the specific sensorimotor performance in adolescents. We assessed stability limits in 13 KS practitioners and 20 control participants. Starting from an upright position, subjects were asked to lean as far as possible (forward, backward, rightward, and leftward). Three sensory conditions were tested: (1) eyes open, (2) eyes closed, and (3) eyes closed while standing on a foam mat. We analyzed the maximal center of pressure excursion and the root means square of the center of pressure displacements. Results showed that KS group had smaller root means square and larger maximal center of pressure excursions than those of control participants in mediolateral axis in all sensory conditions. Furthermore, the results also revealed a significant smaller root means square excursion in KS group under foam mat condition compared to control group ML axis. This study provides evidence that KS training improved the lateral balance control and proprioceptive integration.

Community-based postural control assessment in autistic individuals indicates a similar but delayed trajectory compared to neurotypical individuals

Autistic individuals exhibit significant sensorimotor differences. Postural stability and control are foundational motor skills for successfully performing many activities of daily living. In neurotypical development, postural stability and control develop throughout childhood and adolescence. In autistic development, previous studies have focused primarily on individual age groups (e.g., childhood, adolescence, adulthood) or only controlled for age using age-matching. Here, we examined the age trajectories of postural stability and control in autism from childhood through adolescents using standardized clinical assessments. In study 1, we tested the postural stability of autistic (n = 27) and neurotypical (n = 41) children, adolescents, and young adults aged 7-20 years during quiet standing on a force plate in three visual conditions: eyes open (EO), eyes closed (EC), and eyes open with the head in a translucent dome (Dome). Postural sway variability decreased as age increased for both groups, but autistic participants showed greater variability than neurotypical participants across age. In study 2, we tested autistic (n = 21) and neurotypical (n = 32) children and adolescents aged 7-16 years during a dynamic postural control task with nine targets. Postural control efficiency increased as age increased for both groups, but autistic participants were less efficient compared to neurotypical participants across age. Together, these results indicate that autistic individuals have a similar age trajectory for postural stability and control compared to neurotypical individuals, but have lower postural stability and control overall.

Neurological soft signs are associated with reduced medial-lateral postural control in adolescent athletes

INTRODUCTION

Neurological soft signs (NSS) are minor deviations from the norm in motor performance that are commonly assessed using neurological examinations. NSS may be of clinical relevance for evaluating the developmental status of adolescents. Here we investigate whether quantitative force plate measures may add relevant information to observer-based neurological examinations.

METHODS

Male adolescent athletes (n = 141) aged 13-16 years from three European sites underwent a neurological examination including 28 tests grouped into six functional clusters. The performance of tests and functional clusters was rated as optimal/non-optimal resulting in NSS+/NSS- groups and a continuous total NSS score. Participants performed a postural control task on a Balance Tracking System measured as path length, root mean square and sway area. ANCOVAs were applied to test for group differences in postural control between the NSS+ and NSS- group, and between optimal/non-optimal performance on a cluster- and test-level. Moreover, we tested for correlations between the total NSS score and postural control variables.

RESULTS

There was no significant overall difference between the NSS+ and NSS- group in postural control. However, non-optimal performing participants in the diadochokinesis test swayed significantly more in the medial-lateral direction than optimal performing participants. Moreover, a lower total NSS score was associated with reduced postural control in the medial-lateral direction.

CONCLUSION

Our findings demonstrate that NSS are related to postural control in adolescent athletes. Thus, force plate measures may add a quantitative, objective measurement of postural control to observer-based qualitative assessments, and thus, may complement clinical testing.

Posturographic Standards for Optimal Control of Human Standing Posture

Static posturography is a simple non-invasive technique commonly used in contemporary labs and clinics to quantify the central nervous system adaptive mechanisms involved in the control of posture and balance. Its diagnostic value, however, is quite limited due to the lack of posturographic standards for stable posture. To solve this problem, in this research, we aimed to establish reference values for the stable human posture using our novel parameters of static posturography including the sway anteroposterior directional index (DIAP), the mediolateral directional index (DIML), the stability vector amplitude (SVamp), and the stability vector azimuth (SVaz). Towards this end, in a population of young (mean age 22 yrs), healthy able-bodied volunteers (50 males and 50 females), trajectories of postural sway, based upon the center-of-pressure (COP), were assessed. The experiment consisted of ten 60s trials that were carried out 5 times while subjects were standing quietly on the force plate with eyes open (EO test) and 5 times with eyes closed (EC test). Results showed that in young healthy subjects, regardless of gender, the basic variables of COP remained at the following levels: SVamp = 9.2 ± 1.6 mm/s, SVaz = 0.9 ± 0.1 rad, and directional indices DIAP = 0.7 ± 0.05, DIML = 0.56 ± 0.06. Some of the measures were sensitive to visual input (EC trials) and showed a weak to moderate correlation with anthropometric features. These measures can be recommended as reference values that characterize the most stable erect posture.

Changes in joint kinematics and dynamic postural stability with free and restricted arm movements in children

BACKGROUND

Arm movements make a substantial and functionally relevant contribution to quiet standing and dynamic balance tasks. The impact of restricted arm movements on balance control is particularly important for children as their postural control system is not fully matured.

RESEARCH QUESTION

This study investigated the effects of arm movements on lower body joint kinematics and dynamic postural stability during anterior and lateral dynamic movements in children.

METHODS

Eighteen boys (age, 10.1 ± 1.6 years) completed an anterior and a lateral jump-landing task under two different verbally conveyed instructions of arm position; (1) arms placed flat across the chest touching the contralateral shoulder (i.e., restricted arm movement) and (2) arm movement without restriction. Lower body joint kinematics were recorded and used to calculate mean joint position, joint range of motion (ROM) and joint movement variability.

RESULTS

Restricting arm movements resulted in a reduction of joint movement variability and joint ROM of the pelvis during the lateral jump (p <0.05), but increased joint movement variability and joint ROM of the pelvis during the anterior jump (p <0.05).

SIGNIFICANCE

The reduced joint movement variability and joint ROM with restricted arm movements during the lateral jump may represent a potential compensatory 'stiffenin strategy', whilst the increase during the anterior jump suggest an exploratory strategy. These novel findings highlight that it is important for children to be introduced to different dynamic task constraints so that they can learn to control and organise the motor system degrees of freedom appropriately.

Energy spectral density as valid parameter to compare postural control between subjects with nonspecific chronic low back pain vs healthy subjects: A case-control study

BACKGROUND

Nonspecific chronic low back pain (NSCLBP) is one of the most common and frequent health problems. OBJETIVE: to compare postural control (i.e. center of pressure (CoP) displacement and energy spectral density (ESD)) using technological devices (accelerometers and pressure platform) between subjects with NSCLBP and healthy subjects.

METHODS

A cross-sectional case-control study was conducted. Observational study (STROBE). The final sample consisted of 60 subjects (30 NSCLBP subjects and 30 healthy subjects). Triaxial accelerometer and pressure platform were used in order to obtain ESD and CoP displacement measurements during four balance tasks (i.e. with and without vision and on stable versus unstable surface). Independent t tests were used to compare participants with NSCLBP and healthy controls in the two clinical measurements (i.e., CoP displacement and ESD) for the four balance tests. A multivariate analysis of variance (MANOVA) together with a Fisher's linear discrimination was applied in order to categorize NSPLBP.

RESULTS

Patients with NSCLBP showed greater CoP migration in the positions eyes open, stable surface on the anteroposterior axis (p = 0.012), eyes closed, stable surface on the mediolateral axis (p = 0.025), eyes closed, stable surface on the anteroposterior axis (p = 0.001), eyes open, unstable surface on the anteroposterior axis (p = 0.040), eyes closed, unstable surface on the anteroposterior axis (p = 0.015). Also the ESD was significantly greater for the four situations described (p ≤ 0.01) in subjects with NSCLBP.

CONCLUSIONS

Accelerometer appears to be a technological device that could offer a potential benefit within the battery of tests on physical performance among subjects with NSCLBP and healthy subjects.

Maturation of the postural control in adolescent girls: A 3-year follow-up study

BACKGROUND

Stable posture is a manifestation of the appropriate functioning of the neuromuscular system that is essential for proper motor development and control. Balance and stability of the erect posture are shaped during the entire childhood to culminate in its full efficiency in adolescent subjects.

METHODS

In this 3-year follow-up study, the process of the postural control maturation has been assessed in a group of 18 girls at the transition period between childhood to adolescence. Their balance and postural stability control were assessed using standard static posturography supplemented by two postural stability tests: the rising-on-toes (ROT), and the maximum forward lean (MFL), all performed with (EO) and without vision (EC). Balance control was analyzed with the sway vector (SV) and sway directional indices, whereas the anteroposterior trajectories of the center-of- pressure (COP) during forward-leaning and the raise-on-toes tests were used to determine changes in postural stability control.

RESULTS

The study documented that stability control in girls aged 11-13 is shaped according to their own pace of development. Their postural sway was characterized by the lower COP velocity but very sensitive to visual input. The directional sway measures remained at the same level for the entire period of observation. MFL and ROT tests provided similar information on postural stability and its dependence on visual input. These tests allow for more thorough assessment of postural stability to compare with quiet stance testing.

SIGNIFICANCE

Subtle changes in postural control in adolescents could be assessed based on the results of combined static and dynamic tests. In particular, the ROT test can be recommended for the assessment of postural stability.

Development of temporal and spatial characteristics of anticipatory postural adjustments during gait initiation in children aged 3-10 years

This study aimed to analyze the development of direction specificities of temporal and spatial control and the coordination pattern of anticipatory postural adjustment (APA) along the anteroposterior (AP) and mediolateral (ML) directions during gait initiation (GI) in children aged 3-10 years. This study included 72 healthy children aged 3-10 years and 14 young adults. The child population was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10 years. The GI task included GI using the dominant limb. The peak center of feet pressure (COP) shifts during APAs (APA_peak), initiation time of COP shifts (APA_onset), and the COP vectors in the horizontal plane were calculated to evaluate the direction specificity of spatial, temporal, and coordination control, respectively. A difference in direction specificity development was found for the APA_peak. The APA_peak in the mediolateral axis, but not in the anteroposterior axis, was significantly higher in the 7-8 years age group than in other groups. Although APA_onset was not found for direction specificity, a significant difference between the adult and children groups (5-6 years, 7-8 years, and 9-10 years) was observed in the direction of the COP vector. In conclusion, the developmental process of the spatial, temporal, and coordination control of APAs during GI varied with age. Furthermore, the spatial control and coordination pattern of APAs was found to be direction specific. All components of APAs, namely temporal and spatial control, coordination pattern, and direction specificities, should be analyzed to capture the developmental process of anticipatory postural control.

Step Response of Human Motor System as a Measure of Postural Stability in Children

Postural sway is a product of the neuromuscular system that is commonly used in contemporary labs and clinics for the assessment of postural stability. In this study, we analyzed the transient responses of the neuromuscular system during the rise-on-toes (ROT) movement in eighteen 11 yrs old girls. Their center of pressure (COP) trajectories were recorded with standard force-platform during the transition from quiet stance to standing on toes. To assess the robustness of children's postural stability, we compared the ROT trajectories while the movement was performed with and without vision. Our results confirmed that the dynamic characteristics of the COP step response were significantly modified by visual feedback. In particular, the ROT test performed with eyes closed (EC) was characterized by a four-fold increase of COP chaotic oscillations at the target (tiptoe) position. This resulted in a substantial increase in the movement's index of difficulty (ID) thus to achieve adequate accuracy of the target-oriented movement the COP velocity was decreased accordingly. This inherent strategy of the brain controller allowed for precise positioning of the COP within the reduced size of the target. In conclusion, the dynamics of the ROT movement is always precisely adjusted to the stability of the upright posture, and thus, the dynamic characteristics of the COP step response are also sensitive measures of postural stability and the ROT can be recommended as a useful test for this assessment in the general population.