Is Young Age a Limiting Factor When Training Balance? Effects of Child-Oriented Balance Training in Children and Adolescents

Factors Affecting Balance Performance in Adolescents

(1) Background: The influence of different factors on balance in adolescence is assessed by conducting functional balance tests that examine its different components. (2) Materials and methods: The study sample comprised 110 healthy adolescents of both sexes, aged 12-18 years. Single Leg Stance with Eyes Open (SLS-EO) and Eyes Closed (SLS-EC) tests were conducted to evaluate static balance, whereas the Functional Reach Test (FRT) and Lateral Reach Test (LRT) were performed to establish functional stability limits. The influence of sex, age, demographic factors, anthropometric characteristics, participation in sports activities, and trunk extensor muscle endurance (Biering-Sorensen test) on balance performance was determined through correlational and univariate linear regression analyses. (3) Results: Older age (Beta [β] = 0.247; 95% CI [0.75, 5.20]; p < 0.01) and better trunk extensor muscle endurance (β = 0.224; 95% CI [0.015, 0.13]; p < 0.05) were significant predictors of the SLS-EO results, while younger age (β = -0.219; 95% CI [-1.32, -0.11]; p < 0.05) and higher muscle percentage (β = 0.237; 95% CI [0.06, 0.48]; p < 0.05) emerged as significant predictors of LRT performance, and greater bone mass was a significant predictor of FRT results (β = 0.444; 95% CI [3.62, 8.17]; p < 0.01). However, none of the independent variables was a statistically significant predictor of the SLS-EC results. (4) Conclusions: The current study found that age, trunk extensor muscle endurance, muscle percentage, and bone mass are significant predictors of different balance components, suggesting that balance is task-specific.

Time-course of balance training-related changes on static and dynamic balance performance in healthy children

OBJECTIVE

In healthy children, there is evidence of improvements in static and dynamic balance performance following balance training. However, the time-course of balance training-related changes is unknown. Thus, we determined the effects of balance training after one, three, and six weeks of exercise on measures of static and dynamic balance in healthy children (N = 44, 20 females, mean age: 9.6 ± 0.5 years, age range: 9-11 years).

RESULTS

Participants in the intervention group (2 × 25 min balance exercises per week) compared to those in the control group (2 × 25 min track and field exercises and soccer practice per week) significantly improved their static (i.e., by measuring stance time in the One-Legged Stance test) and dynamic (i.e., by counting step number in the 3-m Beam Walking Backward test) balance performance. Late effects (after 6 weeks) occurred most frequently followed by mid-term effects (after 3 weeks) and then early effects (after 1 week). These findings imply that balance training is effective to improve static and dynamic measures of balance in healthy children, whereby the effectiveness increases with increasing training period.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16518737 (retrospectively registered at 24th August, 2023).

Effect of Swiss Ball Stabilization Training on Trunk Control, Abdominal Muscle Thickness, Balance, and Motor Skills of Children With Spastic Cerebral Palsy: A Randomized, Superiority Trial

OBJECTIVES

To compare the effects of Swiss ball stabilization training (SBST) and stable surface stabilization training (SSST) on the trunk control, abdominal muscle thickness, balance, and motor skills of children with spastic cerebral palsy (CWSCP).

DESIGN

Single-blind, randomized superiority trial.

SETTING

General Community and Referral Center.

PARTICIPANTS

Thirty CWSCP, aged 6-12 years, with Gross Motor Function Classification System levels I-III were randomly assigned to the SBST and SSST groups (N=30).

INTERVENTIONS

The participants were randomized to receive either SBST or SSST for 5 weeks, 3 days a week.

OUTCOME MEASURES

The Trunk Control Measurement Scale (TCMS), abdominal muscle thickness, Pediatric Balance Scale (PBS), standing and walking sections of Gross Motor Function Measure (GMFM-88), and mobility section of the Pediatric Evaluation of Disability Inventory (PEDI) were assessed.

RESULTS

After 5 weeks of the intervention and 9 weeks of follow-up, the SBST group showed statistically significant improvements in the TCMS, GMFM-88, PEDI, thickness of the internal oblique muscle at rest and contraction, and thickness of the transverse abdominis muscle at rest and contraction compared with the SSST group (P<.0001). Contrarily, the thickness of the external oblique muscle increased statistically significantly in the SSST group compared with the SBST group after 5 weeks of the intervention and 9 weeks of follow-up both at rest (P<.0001 and P=.0001, respectively) and contraction (P=.015 and P=.017, respectively). No statistically significant difference was found between the groups regarding the PBS score after 5 weeks of intervention.

CONCLUSION

The SBST could improve the trunk control, balance, and motor skills of CWSCP and increase the thickness of local abdominal muscles. Also, SBST was more effective than SSST for CWSCP.

Frequency-dependent tuning of the human vestibular "sixth sense" by transcranial oscillatory currents

OBJECTIVE

The vestibular cortex is a multisensory associative region that, in neuroimaging investigations, is activated by slow-frequency (1-2 Hz) galvanic stimulation of peripheral receptors. We aimed to directly activate the vestibular cortex with biophysically modeled transcranial oscillatory current stimulation (tACS) in the same frequency range.

METHODS

Thirty healthy subjects and one rare patient with chronic bilateral vestibular deafferentation underwent, in a randomized, double-blind, controlled trial, to tACS at slow (1 or 2 Hz) or higher (10 Hz) frequency and sham stimulations, over the Parieto-Insular Vestibular Cortex (PIVC), while standing on a stabilometric platform. Subjective symptoms of motion sickness were scored by Simulator Sickness Questionnaire and subjects' postural sways were monitored on the platform.

RESULTS

tACS at 1 and 2 Hz induced symptoms of motion sickness, oscillopsia and postural instability, that were supported by posturographic sway recordings. Both 10 Hz-tACS and sham stimulation on the vestibular cortex did not affect vestibular function. As these effects persisted in a rare patient with bilateral peripheral vestibular areflexia documented by the absence of the Vestibular-Ocular Reflex, the possibility of a current spread toward peripheral afferents is unlikely. Conversely, the 10 Hz-tACS significantly reduced his chronic vestibular symptoms in this patient.

CONCLUSIONS

Weak electrical oscillations in a frequency range corresponding to the physiological cortical activity of the vestibular system may generate motion sickness and postural sways, both in healthy subjects and in the case of bilateral vestibular deafferentation.

SIGNIFICANCE

This should be taken into account as a new side effect of tACS in future studies addressing cognitive functions. Higher frequencies of stimulation applied to the vestibular cortex may represent a new interventional option to reduce motion sickness in different scenarios.

Physical Function of Japanese Preadolescents during the COVID-19 Pandemic

Children's exercise habits have changed during the COVID-19 pandemic. This study aimed to examine the physical function and physical activity of preadolescent children before and during the COVID-19 pandemic. This cross-sectional study compared time spent in moderate-to-vigorous physical activity (MVPA), grip strength, single-leg standing time, and two-step tests of healthy children aged 10 to 12 years, enrolled from January 2018 to January 2020 (pre-COVID-19 group, n = 177) and from January 2021 to September 2022 (during-COVID-19 group, n = 69). The during-COVID-19 group had weaker grip strength (median: 14.4 vs. 15.8 kg; p = 0.012), worse performance on the two-step test (mean: 1.56 vs. 1.60; p = 0.013), and less MVPA (median: 4 vs. 7 h per week; p = 0.004). Logistic regression showed that the during-COVID-19 group was significantly related to weaker grip strength (odds ratio: 0.904, 95% CI: 0.829-0.986; p = 0.022) and worse performance in the two-step test (odds ratio: 0.976, 95% CI: 0.955-0.997; p = 0.028). The COVID-19 pandemic decreased exercise opportunities for preadolescent children, which may have had a negative impact on muscle strength and balance. It is essential to increase the amount of MVPA among preadolescent children.

No sex-specific effects of balance training on dynamic balance performance in healthy children

Background

Cross-sectional studies in children reported better balance performance for girls than for boys. Thus, balance trainability might be different between female and male children. The aim of the present study was to examine the effects of balance training (BT) on dynamic balance performance in girls compared to boys.

Methods

Seventeen girls (age: 11.1 ± 0.7 years) and 22 boys (age: 11.1 ± 0.8 years) were assigned to either a BT-group or an active control (CON) group. BT was conducted over eight weeks (two sessions/week) while the CON-groups received their regular physical education lessons during the same period. Before and after treatment, dynamic balance performance was assessed by using the Lower Quarter Y-Balance (YBT-LQ) test. A series of three-way analyses of covariance (ANCOVA) were undertaken to test for within-between effects of Test [×2 (pretest vs. posttest)], Group [×2 (BT-group vs. CON-group)] and Sex [×2 (boys vs. girls)].

Results

The three-way ANCOVA yielded a significant main effect of Test (p = 0.002-0.043, η p 2 = 0.122-0.262) and of Group (all p < 0.001, η p 2 = 0.330-0.651) but not of sex for all YBT-LQ reach directions and the composite score. Further, there were significant Test × Group interactions (all p < 0.001, η p 2 = 0.330-0.651) in favor of both BT-groups but neither Test × Sex nor Test × Group × Sex interactions were detected.

Conclusions

We conclude that BT is an effective treatment to improve dynamic balance performance in healthy children regardless of their sex. Consequently, girls and boys can be provided with the same BT regime to enhance their postural control.

Effect of practice on learning a balance task in children, adolescents, and young adults

Background

A lower developmental stage of the postural control system in childhood compared to adolescence and adulthood was reported in numerous studies and suggests differences (i.e., less improvements in children than in adolescents and young adults due to the immature postural control system) during learning a balance task. Therefore, the present study examined the effect practice on learning (i.e., retention and transfer) a balance task in healthy children, adolescents, and young adults.

Methods

Healthy children (n = 32, 8.5 ± 0.5 years), adolescents (n = 30, 14.6 ± 0.6 years), and young adults (n = 28, 24.3 ± 3.3 years) practiced balancing on a stabilometer (i.e., to keep the platform as close to horizontal as possible) for 2 days. On the third day, learning was assessed using a retention (i.e., balance task only) and a transfer (i.e., balance task plus concurrent motor interference task) test. The root-mean-square-error (RMSE) was calculated and used as outcome measures.

Results

Over the course of practice, significant improvements (p < 0.001) were detected in favor of children and young adults. However, neither the retention nor the transfer test showed significant group differences.

Conclusion

Our findings indicate that learning a balance task did not seem to be influenced by the developmental stage of the postural control system.

Balance performance analysis after the COVID-19 quarantine in children aged between 8 and 12 years old: Longitudinal study

BACKGROUND

Corona Virus Disease 2019 (COVID-19) has caused great changes in daily activities, especially in children. In Spain, to avoid infections, a home quarantine was declared, which caused a drastic reduction in daily or weekly physical activity in children.

OBJECTIVE

to analyse the balance performance after the COVID-19-induced quarantine on children's balance, through the use of balance tests, considering the type of sport practiced.

METHODS

an observational and longitudinal study was carried out with a sample size of 150 healthy children (69 boys and 81 girls) with a mean age of 10.02 ± 1.15 years. Postural control was evaluated under different equilibrium conditions before and after the quarantine period. Two data collections using the Gyko system were compared, with a difference of 8 months between them. In addition, the influence of foot type and physical activity was analysed.

RESULTS

After the quarantine, statistically significant differences were found in terms of balance results, which were worse than before (p < 0.05). Postural control was not influenced by the type of sport practiced (i.e., individual, collective and / or not practicing sport), nor by the surface which the test was performed (p > 0.05). Physically active children (i.e., individual and / or collective sport) presented worse results than physically inactive children. A statistically significant impairment in terms of balance was demonstrated in children who performed high and moderate physical activity (p < 0.05).

CONCLUSIONS

After the quarantine period, a significant reduction in balance performance was found in children. The findings suggest that regular physical activity benefits postural control. Loss of balance does not differ in postural stability by the type of sport practised. Postural stability is not influenced by the type of footprint after the period of physical inactivity. Postural control is influenced in children with a great level of physical activity.

Brain Activation During Active Balancing and Its Behavioral Relevance in Younger and Older Adults: A Functional Near-Infrared Spectroscopy (fNIRS) Study

Age-related deterioration of balance control is widely regarded as an important phenomenon influencing quality of life and longevity, such that a more comprehensive understanding of the neural mechanisms underlying this process is warranted. Specifically, previous studies have reported that older adults typically show higher neural activity during balancing as compared to younger counterparts, but the implications of this finding on balance performance remain largely unclear. Using functional near-infrared spectroscopy (fNIRS), differences in the cortical control of balance between healthy younger (n = 27) and older (n = 35) adults were explored. More specifically, the association between cortical functional activity and balance performance across and within age groups was investigated. To this end, we measured hemodynamic responses (i.e., changes in oxygenated and deoxygenated hemoglobin) while participants balanced on an unstable device. As criterion variables for brain-behavior-correlations, we also assessed postural sway while standing on a free-swinging platform and while balancing on wobble boards with different levels of difficulty. We found that older compared to younger participants had higher activity in prefrontal and lower activity in postcentral regions. Subsequent robust regression analyses revealed that lower prefrontal brain activity was related to improved balance performance across age groups, indicating that higher activity of the prefrontal cortex during balancing reflects neural inefficiency. We also present evidence supporting that age serves as a moderator in the relationship between brain activity and balance, i.e., cortical hemodynamics generally appears to be a more important predictor of balance performance in the older than in the younger. Strikingly, we found that age differences in balance performance are mediated by balancing-induced activation of the superior frontal gyrus, thus suggesting that differential activation of this region reflects a mechanism involved in the aging process of the neural control of balance. Our study suggests that differences in functional brain activity between age groups are not a mere by-product of aging, but instead of direct behavioral relevance for balance performance. Potential implications of these findings in terms of early detection of fall-prone individuals and intervention strategies targeting balance and healthy aging are discussed.

Balance on different unstable supports: a complementary approach based on linear and non-linear analyses

Maintenance of postural control is a complex task that requires the integration of different sensory-motor processes. To improve postural control, balance training is often implemented using unstable surfaces. Little is known, however, about how different surfaces compare in terms of postural control strategy. Non-linear dynamical system analysis, like recurrent quantification analysis (RQA) applied to the center of pressure (CoP) trajectory, represents a useful tool in this respect. The aim of this study is to investigate the effects of different unstable supports on the CoP trajectory through a complementary approach based on linear and non-linear analyses. Seventeen healthy adults performed barefoot single-leg balance trials on a force plate and on three different balance training devices (soft disc, foam pad, and pillow). Sets of parameters were extracted from the CoP trajectories using classical stabilometric analysis (sway path, mean velocity, root mean square) and RQA (percent recurrence and determinism, maximum line length, entropy). Both classical and RQA analyses highlighted significant differences between stable (force plate) and unstable conditions (p < 0.001). Conversely, only classical stabilometric parameters showed significant differences among the considered balance training devices, indicating that the different characteristics of the devices do not influence the dynamic/temporal structure of the CoP trajectory. Analysis of the center of pressure trajectory during single-leg standing on three different balance training devices and on a rigid surface using both linear and non-linear techniques.

Effects of Short-Term Dynamic Balance Training on Postural Stability in School-Aged Football Players and Gymnasts

Static and dynamic balance abilities enable simple and complex movements and are determinants of top athletic performance. Balance abilities and their proficiency differ fundamentally with respect to age, gender, type of balance intervention, and type of sport. With this study, we aim to investigate whether 4weeks of dynamic balance training (DBT) improves static balance performance in school-aged gymnasts and football players. For this purpose, young male gymnasts (n=21) and male football players (n=20) completed an initial static balance assessment consisting of two one-legged stance (left and right foot) and two two-legged stance (eyes open and eyes closed) tasks. Subsequently, all participants underwent a 4-week intervention. DBT consisting of nine individual tasks was performed two times per week. Another static balance assessment followed 1day after the last training session and retention was assessed 2weeks later. Dynamic balance scores and total path length were analyzed via rank-based repeated measures designs using ANOVA-type statistics. The influence of factors GROUP and TIME on the static and dynamic balance performance was examined. Prior to DBT, young gymnasts showed better static balance performance than football players. However, after intervention, both groups improved in both one-legged stance tasks and also had high retention rates in these tasks. No significant improvements were seen in either group in the two-legged balance tests. Both groups improved in the dynamic balance tasks, although no differences in learning rates were evident. Our findings imply an inter-relationship between both static and dynamic balance components. Consequently, training regimes should include both balance components to facilitate early development of balance ability.

Effectiveness of the Mat Pilates on the postural control, plantar pressure and plantar arch of school children: A randomized clinical trial

OBJECTIVE

To evaluate the effectiveness of Mat Pilates on postural control, plantar pressure and plantar arch (ALM) in schoolchildren.

DESIGN AND SETTING

The study was a randomized clinical trial, developed at the Early Childhood Education Institute, Londrina-PR. The participants were randomly assigned to groups: Pilates Group (PG) and Control Group (CG). Patients in the CG did not perform extra physical activity (Interventions).

PARTICIPANTS

43 children (eight to 12 years), no prior knowledge of the Pilates method, and no exercise training in the last six months.

INTERVENTION

The exercise program was based on the Mat Pilates method, twice weekly, 50 min each, 28 sessions.

OUTCOME MEASURES

Static balance (force platform), dynamic balance (the Reach Test), ALM (plantigraphy) and plantar pressure (baropodometry). The assessors were blinded to the allocation of participants.

RESULTS

Three children were excluded before randomization and 40 were randomized (PG n: 20; CG n:20).12 children were excluded during the protocol (PG n:7; CG n:5) and included in the intention to treat analysis. No significant difference between groups was observed for static and dynamic balance and ALM measures. There was a significant difference in the following outcomes for the PG: the plantar pressure on the right hemibody forefoot between pre-test 38.70 ± 14.38 and post-test 42.65 ± 15.63 (ES = 0.66; SRM = 0.50). The plantar pressure on the right hemibody rearfoot between pre-test 61.10 ± 14.18 and post-test 56.85 ± 19.39 (ES = 0.68; SRM = 0.53). No adverse or harmful events were reported in any group.

CONCLUSION

There were no differences in static and dynamic postural control and ALM between PG and CG. However, children GP showed improvement in some results of plantar pressure in relation CG.

CLINICAL TRIAL REGISTRATION NUMBER

Brazilian Registry of Clinical Trials (REBEC) (N_ RBR-8t5p7d).

Neuromuscular Training and Motor Control in Youth Athletes: A Meta-Analysis

Our purpose in this review was to determine the effects of bodyweight-only neuromuscular training (NMT) programs on motor control of movement among youth athletes. We searched three electronic databases (CrossRef, Google Scholar, and PubMed), using the following inclusion criteria for selecting research studies: (a) healthy male and female participants aged 8-18 years who were engaged in organized sports; (b) interventions up to 16-weeks duration; (c) incorporation of a control group; and (d) interventions that utilized only exercises using participants' body mass. We calculated pooled estimates of effect sizes (standardized mean difference) for changes in motor control across nine studies (12 comparisons) using the inverse-variance random effects model for meta-analyses and 95% confidence intervals. Among the nine studies included in our meta-analysis, there was a moderate, significant effect in favor of neuromuscular training programs (0.79 [95% CI: 0.38, 1.20], Z = 3.76 [p = 0.0002]) on motor control. Heterogeneity was high and significant (I²= 77% [p = 0.00001]). Moderator analyses for age and stature revealed NMT programs to be more effective in younger, shorter, and lighter individuals. We found larger effect sizes in males, and for programs >8 weeks in duration. We concluded that the older and heavier an individual is, the less effective bodyweight-only NMT programs became, particularly for female participants. These results reinforce the notion that exercise to enhance motor control should be emphasized during pre-adolescence.

The effects of Pilates training on static and dynamic balance of female deaf students: A randomized controlled trial

INTRODUCTION

To evaluate the effect of Pilates training on static and dynamic balance of deaf female.

METHODS

This study is a randomized, controlled trial with concealed randomization and blinded assessments. 19 female deaf students participated in this study and were randomly assigned into experimental (EXP, n = 9) and control (CON, n = 10) groups. Static balance was examined by Balance Error Scoring System (BESS), and dynamic balance was examined by Y balance test (YBT). The experimental group performed a Pilates training program for 8 weeks (three sessions of 60 min).

RESULTS

The findings showed that experimental group showed a significant change in static balance (with open eye and close eye) and dynamic balance (dominant limb and non-dominant limb) after 8 weeks Pilates training (p < 0.05). The control also showed no significant changes after training duration (p > 0.05).

CONCLUSIONS

This study showed that Pilates training significantly improve balance in female deaf students.

Physical Activity Practice and Optimal Development of Postural Control in School Children: Are They Related?

Background: This study aims to analyze the effect of physical activity practice on the postural control state of school children. If such an effect was detected, the second aim of the study was to identify which specific capacities of postural control benefited the most from physical activity. Methods: A cross-sectional study was performed using a convenience sample of 118 healthy children (54 girls) with a mean age of 10.3 ± 1.2 years. Their weight and height were measured. The accelerometric assessment of balance included four different tests in static balance and walking. Results: Physical activity habit prevalence was 38.9% in girls and 60.9% in boys, and its frequency was 2.3 days per week in girls and 2.8 days in boys. The active children obtained lower accelerations, but the active and sedentary girls showed lower accelerometric values than the active boys. The logistic regression analysis demonstrated the influence of sex on the accelerations of the body (p < 0.001), regardless of the habit of physical activity. Conclusions: Active children have better postural control than sedentary children, although sedentary girls have better balance than active boys. Therefore, physical activity practice seems to favor a more efficient development of postural control, but it cannot level or reverse the effect of the neurophysiological factors that are conditioned by sex.

Effects of Balance Training on Balance Performance in Youth: Are There Age Differences?

Purpose: In youth, cross-sectional studies reported age differences in balance performance that were in favor of adolescents. Thus, trainability of balance performance might be different in children compared to adolescents. The purpose of this study was therefore to compare the effects of balance training (BT) on balance performance between children and adolescents.Method: Thirty children (7.5 ± 0.5 years) and 42 adolescents (14.7 ± 0.5 years) participated in this study and were assigned to either a BT-group or a control (CON) group. In both age groups, BT was conducted over five weeks while the CON-groups received their regular physical education lessons. Pre- and posttests included the assessment of mobility, static steady-state, proactive, and reactive balance.Results: Significant Test × Group × Age interactions were found for static steady-state balance (i.e., CoP displacements during single leg stance) and mobility (i.e., 10-m gait velocity). For both measures, post hoc analysis revealed larger improvements (+16-37%, 0.001 ≤ p ≤ 0.033, 0.65 ≤ d ≤ 2.24) for children compared to adolescents. For proxies of proactive and reactive balance, we could not detect significant Test × Group × Age interactions.Conclusions: We conclude that trainability of static steady-state balance and mobility seems to be higher in children than in adolescents indicating larger adaptive reserves in children compared to adolescents. However, there were no age differences in adaptations to BT with respect to proactive and reactive balance.

Reliability of accelerometric assessment of balance in children aged 6-12 years

BACKGROUND

Development and evaluation of an accelerometers technique for collecting data for asses balance had reported difficulty due to equilibrium reactions and continuous bursts. The aim of this study is to determine the reliability and internal consistency of accelerometric measurements, related to static equilibrium and gait in children aged 6 to 12 years.

METHODS

This descriptive and cross-sectional study involved 70 healthy children (50% girls) with a mean age of 9 years old. At the height of the 4th lumbar vertebra and directly on the skin, an accelerometer was placed on each participant. All of them had to complete four trials three times: balancing on one leg with eyes closed and eyes open, dynamic balancing on one leg on a foam mat, and normal gait.

RESULTS

Results show that tests performed in older children had higher internal consistency than those performed in younger children (vertical axis r = 0.82, sagittal axis r = 0.77, and perpendicular axis r = 0.74). Tests performed in children aged 8 years or older presented a strong correlation between trials (r > 0.71). The three static equilibrium tests obtained reliability values between 0.76 y 0.84. On the contrary, gait test obtained inferior and poorer results (0.6 < r < 0.71).

CONCLUSIONS

This method of assessment obtained positive results as an instrument for the quantitative assessment of balance in school-aged children. Values obtained for the three one-leg balance and static tests,were more strongly correlated than the normal gait test for all axes.

Effects and Dose-Response Relationship of Balance Training on Balance Performance in Youth: A Systematic Review and Meta-Analysis

BACKGROUND

Effects and dose-response relationships of balance training on measures of balance are well-documented for healthy young and old adults. However, this has not been systematically studied in youth.

OBJECTIVES

The objectives of this systematic review and meta-analysis were to quantify effects of balance training (BT) on measures of static and dynamic balance in healthy children and adolescents. Additionally, dose-response relations for BT modalities (e.g. training period, frequency, volume) were quantified through the analysis of controlled trials.

DATA SOURCES

A computerized systematic literature search was conducted in the electronic databases PubMed and Web of Science from January 1986 until June 2017 to identify articles related to BT in healthy trained and untrained children and adolescents.

STUDY ELIGIBILITY CRITERIA

A systematic approach was used to evaluate articles that examined the effects of BT on balance outcomes in youth. Controlled trials with pre- and post-measures were included if they examined healthy youth with a mean age of 6-19 years and assessed at least one measure of balance (i.e. static/dynamic steady-state balance, reactive balance, proactive balance) with behavioural (e.g. time during single-leg stance) or biomechanical (e.g. centre of pressure displacements during single-leg stance) test methods.

STUDY APPRAISAL AND SYNTHESIS METHODS

The included studies were coded for the following criteria: training modalities (i.e. training period, frequency, volume), balance outcomes (i.e. static and dynamic balance) as well as chronological age, sex (male vs. female), training status (trained vs. untrained), setting (school vs. club), and testing method (biomechanical vs. physical fitness test). Weighted mean standardized mean differences (SMD_wm) were calculated using a random-effects model to compute overall intervention effects relative to active and passive control groups. Between-study heterogeneity was assessed using I² and χ² statistics. A multivariate random effects meta-regression was computed to explain the influence of key training modalities (i.e. training period, training frequency, total number of training sessions, duration of training sessions, and total duration of training per week) on the effectiveness of BT on measures of balance performance. Further, subgroup univariate analyses were computed for each training modality. Additionally, dose-response relationships were characterized independently by interpreting the modality specific magnitude of effect sizes. Methodological quality of the included studies was rated with the help of the Physiotherapy Evidence Database (PEDro) Scale.

RESULTS

Overall, our literature search revealed 198 hits of which 17 studies were eligible for inclusion in this systematic review and meta-analysis. Irrespective of age, sex, training status, sport discipline and training method, moderate to large BT-related effects were found for measures of static (SMD_wm = 0.71) and dynamic (SMD_wm = 1.03) balance in youth. However, our subgroup analyses did not reveal any statistically significant effects of the moderator variables age, sex, training status, setting and testing method on overall balance (i.e. aggregation of static and dynamic balance). BT-related effects in adolescents were moderate to large for measures of static (SMD_wm = 0.61) and dynamic (SMD_wm = 0.86) balance. With regard to the dose-response relationships, findings from the multivariate random effects meta-regression revealed that none of the examined training modalities predicted the effects of BT on balance performance in adolescents (R² = 0.00). In addition, results from univariate analysis have to be interpreted with caution because training modalities were computed as single factors irrespective of potential between-modality interactions. For training period, 12 weeks of training achieved the largest effect (SMDwm = 1.40). For training frequency, the largest effect was found for two sessions per week (SMDwm = 1.29). For total number of training sessions, the largest effect was observed for 24-36 sessions (SMDwm = 1.58). For the modality duration of a single training session, 4-15 min reached the largest effect (SMDwm = 1.03). Finally, for the modality training per week, a total duration of 31-60 min per week (SMDwm = 1.33) provided the largest effects on overall balance in adolescents. Methodological quality of the studies was rated as moderate with a median PEDro score of 6.0.

LIMITATIONS

Dose-response relationships were calculated independently for training modalities (i.e. modality specific) and not interdependently. Training intensity was not considered for the calculation of dose-response relationships because the included studies did not report this training modality. Further, the number of included studies allowed the characterization of dose-response relationships in adolescents for overall balance only. In addition, our analyses revealed a considerable between-study heterogeneity (I² = 66-83%). The results of this meta-analysis have to be interpreted with caution due to their preliminary status.

CONCLUSIONS

BT is a highly effective means to improve balance performance with moderate to large effects on static and dynamic balance in healthy youth irrespective of age, sex, training status, setting and testing method. The examined training modalities did not have a moderating effect on balance performance in healthy adolescents. Thus, we conclude that an additional but so far unidentified training modality may have a major effect on balance performance that was not assessed in our analysis. Training intensity could be a promising candidate. However, future studies are needed to find appropriate methods to assess BT intensity.

Effects of Increasing Balance Task Difficulty on Postural Sway and Muscle Activity in Healthy Adolescents

Evidence-based prescriptions for balance training in youth have recently been established. However, there is currently no standardized means available to assess and quantify balance task difficulty (BTD). Therefore, the objectives of this study were to examine the effects of graded BTD on postural sway, lower limb muscle activity and coactivation in adolescents. Thirteen healthy high-school students aged 16 to 17 volunteered to participate in this cross-sectional study. Testing involved participants to stand on a commercially available balance board with an adjustable pivot that allowed six levels of increasing task difficulty. Postural sway [i.e., total center of pressure (CoP) displacements] and lower limb muscle activity were recorded simultaneously during each trial. Surface electromyography (EMG) was applied in muscles encompassing the ankle (m. tibialis anterior, medial gastrocnemius, peroneus longus) and knee joint (m. vastus medialis, biceps femoris). The coactivation index (CAI) was calculated for ankle and thigh muscles. Repeated measures analyses of variance revealed a significant main effect of BTD with increasing task difficulty for postural sway (p < 0.001; d = 6.36), muscle activity (p < 0.001; 2.19 < d < 4.88), and CAI (p < 0.001; 1.32 < d < 1.41). Multiple regression analyses showed that m. tibialis anterior activity best explained overall CoP displacements with 32.5% explained variance (p < 0.001). The observed increases in postural sway, lower limb muscle activity, and coactivation indicate increasing postural demands while standing on the balance board. Thus, the examined board can be implemented in balance training to progressively increase BTD in healthy adolescents.

Do Exercise Interventions Improve Balance for Children and Adolescents With Down Syndrome? A Systematic Review

BACKGROUND

Youths with Down syndrome are characterized by deficits in balance/postural stability. One way to palliate balance deficits among this population is through exercise interventions. However, to the authors' knowledge, the effects of exercise interventions designed to improve the balance of youths with Down syndrome have never been systematically reviewed.

PURPOSE

The purpose of this review was to summarize the findings from studies examining the effects of exercise interventions designed to improve balance in youths with Down syndrome.

DATA SOURCES

A systematic literature search was performed in 10 databases (Academic Search Complete, CINAHL Plus With Full-Text, Education Source, ERIC, Medline With Full-Text, PsycARTICLES, Psychology and Behavioral Sciences Collection, Scopus, SocINDEX, and SPORTDiscus With Full-Text) on June 12, 2017.

STUDY SELECTION

Randomized controlled trials and controlled trials examining the effects of exercise interventions designed to improve balance in youths with Down syndrome were included.

DATA EXTRACTION

Two authors selected the studies and extracted their characteristics and results. Three authors assessed the risk of bias in the studies using the Cochrane Collaboration tool.

DATA SYNTHESIS

Eleven studies, published between 2010 and 2017, met the inclusion criteria. The findings showed that exercise interventions were more effective than control conditions for improving the static balance of children with Down syndrome and the static-dynamic balance (ie, global balance score obtained with a scale measuring both static and dynamic balance) of children and adolescents with Down syndrome. Nevertheless, the findings on dynamic balance in children and static balance in adolescents were inconclusive.

LIMITATIONS

With a small number of studies and their high risk of bias, the present findings must be interpreted with caution.

CONCLUSIONS

The reviewed exercise interventions were successful in improving the static balance of children with Down syndrome and the static-dynamic balance of children and adolescents with Down syndrome.

Age and sex differences in human balance performance from 6-18 years of age: A systematic review and meta-analysis

Background

The process of growing leads to inter-individual differences in the timing of growth, maturational, and developmental processes during childhood and adolescence, also affecting balance performance in youth. However, differences in balance performance by age and sex in youth have not been systematically investigated yet.

Objective

The objective of the present study was to characterize and quantify age- and sex-related differences in balance performance in healthy youth.

Methods

A computerized systematic literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus. To be applicable for analysis, studies had to report at least one measure of static steady-state, dynamic steady-state, proactive or reactive balance in healthy children (6–12 years) and/or adolescents (13–18 years). Coding of the studies was done according to the following criteria: age, sex, and balance outcome. Study quality was assessed using the Appraisal tool for Cross-Sectional Studies. Weighted standardized mean differences were calculated and classified according to their magnitude.

Results

Twenty-one studies examined age-related differences in balance performance. A large effect for measures of static steady-state balance (SMD_ba = 1.20) and small effects for proxies of dynamic steady-state (SMD_ba = 0.26) and proactive balance (SMD_ba = 0.28) were found; all in favor of adolescents. Twenty-five studies investigated sex-related differences in balance performance. A small-sized effect was observed for static steady-state balance (SMD_bs = 0.33) in favor of girls and for dynamic steady-state (SMD_bs -0.02) and proactive balance (SMD_bs = -0.15) in favor of boys. Due to a lack of studies, no analysis for measures of reactive balance was performed.

Conclusions

Our systematic review and meta-analysis revealed better balance performances in adolescents compared to children, irrespective of the measure considered. Sex-related differences were inconsistent. These findings may have implications for example in terms of trainability of balance in youth that should be investigated in future studies.

Single- and Dual-Task Balance Training Are Equally Effective in Youth

Due to maturation of the postural control system and secular declines in motor performance, adolescents experience deficits in postural control during standing and walking while concurrently performing cognitive interference tasks. Thus, adequately designed balance training programs may help to counteract these deficits. While the general effectiveness of youth balance training is well-documented, there is hardly any information available on the specific effects of single-task (ST) versus dual-task (DT) balance training. Therefore, the objectives of this study were (i) to examine static/dynamic balance performance under ST and DT conditions in adolescents and (ii) to study the effects of ST versus DT balance training on static/dynamic balance under ST and DT conditions in adolescents. Twenty-eight healthy girls and boys aged 12-13 years were randomly assigned to either 8 weeks of ST or DT balance training. Before and after training, postural sway and spatio-temporal gait parameters were registered under ST (standing/walking only) and DT conditions (standing/walking while concurrently performing an arithmetic task). At baseline, significantly slower gait speed (p < 0.001, d = 5.1), shorter stride length (p < 0.001, d = 4.8), and longer stride time (p < 0.001, d = 3.8) were found for DT compared to ST walking but not standing. Training resulted in significant pre-post decreases in DT costs for gait velocity (p < 0.001, d = 3.1), stride length (-45%, p < 0.001, d = 2.4), and stride time (-44%, p < 0.01, d = 1.9). Training did not induce any significant changes (p > 0.05, d = 0-0.1) in DT costs for all parameters of secondary task performance during standing and walking. Training produced significant pre-post increases (p = 0.001; d = 1.47) in secondary task performance while sitting. The observed increase was significantly greater for the ST training group (p = 0.04; d = 0.81). For standing, no significant changes were found over time irrespective of the experimental group. We conclude that adolescents showed impaired DT compared to ST walking but not standing. ST and DT balance training resulted in significant and similar changes in DT costs during walking. Thus, there appears to be no preference for either ST or DT balance training in adolescents.

Age-dependent adaptations to anticipated and non-anticipated perturbations after balance training in children

Postural control undergoes rapid changes during child development. However, the influence of balance training (BT) on the compensation of perturbations has not yet been investigated in children. For this purpose, young (6.7 ± 0.6 years) and old children (12.0 ± 0.4 years) were exposed to externally induced anticipated (direction known) and non-anticipated (direction unknown) perturbations on a free swinging platform before and after either child-oriented BT (INT; young: n = 12, old: n = 18) or regular physical education (CON; young: n = 9, old: n = 9). At baseline, old children exhibited less platform sway after perturbations than young children (p = .004; η²_p = 0.17). However, no differences were found between anticipated and non-anticipated perturbations. After training, INT reduced the platform sway path while CON remained stable (-11.1% vs. +2.7%; p < .001; η²_p = 0.26). Furthermore, the young INT group adapted statistically similarly in anticipated and non-anticipated situations (-7.9% vs. -12.6%; p = .556; r = 0.33), whereas the old INT group tended to improve more in anticipated perturbations (-15.1% vs. -8.2%; p = .052; r = 0.51). Thus, the maturity of the postural system seems to influence the extent of training adaptations in anticipated perturbations. Furthermore, this study provides evidence that BT can improve postural responses to external perturbations in children and may represent a useful intervention to prevent falls.