Dynamic postural stability in young adolescent male and female athletes

Developmental patterns of athletic performance and physical fitness in youth baseball players: A longitudinal analysis

This study aimed to evaluate developmental patterns in athletic performance during youth and determine their association with changes in physical fitness. The testing included three athletic performance (i.e. ball speed in pitching, swing velocity in batting, 30-metre sprint time) and two physical fitness tests (i.e. medicine ball [MB] back throw and modified star excursion balance test [SEBT]). Data from 235 players (557 measurements) aged 6 to 14 were eligible for a longitudinal evaluation. The statistical analysis was based on the latent growth curve models of the athletic performance development process and the random-effect panel data multivariate regression analysis for ball speed, swing velocity, and 30-metre sprint time. The 30-metre sprint time showed a small curvature but an accelerated increase around 12‒13 years old. However, the ball speed, swing velocity, and modified SEBT demonstrated a slower or less accelerated change in the developmental pattern starting around 12‒13 years old. Multivariate longitudinal analysis revealed that developmental change in athletic performance was positively associated with age and MB back throw. Our findings highlight the developmental patterns of athletic performance associated with baseball exhibiting stagnation as well as acceleration, which may help develop effective age-appropriate strategies for improving performance in youth baseball players.

Associations between biological maturation, physical performance, postural control, and mathematical achievement in youth soccer players

This investigation explored relationships between biological maturation, physical and academic performance in young male soccer players. Thirty-eight players (age: 9.79 ± 1.21 years; body mass index (BMI): 20.4 ± 2.39 kg/m2; body fat: 16.8 ± 2.21%) participated. Measures of anthropometry used for body mass, body fat percentage (%BF), and BMI as well. Postural control, 15 m sprint, squat jumps and counter-movement jumps (SJ, CMJ), and T-half test for change-of-direction (CoD) were parameters of physical performance. The grade point average (GPA) of mathematics determined academic attainment. Moore's equations were used to estimate their maturity status (PHV). Biological maturation was highly correlated with most (not 15 m sprint) physical and academic performance parameters, especially CMJ (r = -0.812) and mathematics (r = -0.781). Academic performance showed the largest relations to the jumping performance (CMJ: r = 0.771; SJ: r = 0.723). In contrast, anthropometric and fatness parameters were not relevantly (r ≥ 0.5) correlated with any other parameters. The largest correlations were calculated for sitting height vs. SJ (r = -0.408), sitting height vs. postural control (r = -0.355), leg length vs. postural control (r = -0.339). As a result, it is essential to take biological maturation inconsideration while assessing the physical and academic achievement of young soccer players. In consequence, soccer coaches and physical education (PE) teachers should be cognizant of the impact of biological maturity on physical and academic performance to assist fair and equal opportunities for achievement in young players.

Differences in the manifestation of balance according to BMI levels for women students of the Faculty of Physical Education and Sports

Abstract Background: Static and dynamic balance are factors of major importance in the manifestation of human motor skills at a higher level. Purpose: The determination of vari-ations in the performance of balance tests for young women students at the Faculty of Physical Education and Sports (48 cases in the 1st year of bachelor's degree), divided and analyzed 3 BMI levels (underweight / 7 cases, normal weight / 34 cases and overweight / 7 cases) and comparing these results with other similar research. Material and method: The testing of the group was scheduled at the Research Center for Human Performance, be-longing to the Faculty of Physical Education and Sports in Galați, in the month of April of the 2018-2019 academic year. For the assessment of balance, 7 tests were used, of which 4 associated with dynamic postural stability (Walk and turn field sobriety test/errors, Func-tional reach test/cm, Fukuda test/degrees of rotation, Bass test/ points) and 3 measuring static stability (Flamingo test/falls, One leg standing with eyes closed/sec, Stork test/sec). Nonparametric tests (Mann-Whitney U) were applied to compare differences between batches. Results: The average values of underweight and normal-weight women are better than those of overweight women for the entire set of assessment tests. The underweight group has the best results for the Standing balance test, Functional reach test, Flamingo test, Walk and turn field sobriety test, Fukuda test, and the normal weight women for Stork test, respectively Bass test. We found a lack of significant thresholds when comparing the results between the 3 groups (P> 0.05) for Stork test, Standing balance test and Functional reach test, so the working hypothesis formulated is only partially confirmed. The only significant difference between underweight and normal weight (P <0.05) is found in the Flamingo test, with better values for underweight. Significant difference thresholds for Flamingo test and Fukuda test are recorded between the underweight and overweight groups (Z values have associated thresholds P<0.05). The most significant differences are found between the normal weight and overweight groups (P <0.05), respectively for the Bass test, Fukuda test and Walk and turn field sobriety test. Conclusion: Constant physical activity (as a feature of the analyzed group) reduces the chances of significant differences in all balance tests between BMI levels. Keywords: female students; university specialization; static and dynamic postural control; physical activity

The effects of footwear on dynamic stability and impact loading in jump landing

Research into the effect of footwear on dynamic stability and impact loading is still in its infancy. The aim of this study was to determine whether cushioned footwear influenced dynamic stability (dynamic postural stability index (DPSI) and time to stabilisation (TTS)) or impact loading (peak ground reaction force (pGRF) and loading rate (LR)) through a series of single-leg jump landings when compared to barefoot and minimalist shoes. Fourteen healthy, active participants (9 males, 5 females, Age: 21 ± 1 years; height: 174 ± 9.87 cm; weight: 75 ± 15.40 kg) were recruited to undergo a series of single-leg jump landings. Each participant randomly performed three jumps in each footwear condition. Repeated measures ANOVA was conducted to determine whether any differences occurred between condition. No statistically significant difference was observed for DPSI (p = 0.300, pη2 = 0.083) between footwear types. A statistically significant difference was determined between footwear condition for TTS (p = 0.001, pη2 = 0.52), and also for pGRF (p = 0.003, pη2 = 0.39), and LR (p ≤ 0.001, pη2 = 0.53). For TTS, pGRF, and LR, no differences were noted between minimalist and barefoot, but were worse in the cushioned shoe vs. both other conditions. Overall, this study determined that cushioned footwear can negatively influence both TTS and impact loading, but not DPSI.

An association between excessive valgus hindfoot alignment and postural stability during single-leg standing in adolescent athletes

BACKGROUND

Diminished balance is associated with the incidence of ankle and lower extremity injuries in adolescents. Although flexible flatfoot is a common foot condition in pediatric and adolescent populations, the association between balance control and foot morphology remain unclear in adolescent athletes.

METHODS

Rearfoot angle in the double-limb standing position, body mass index (BMI), and isometric muscle strength related to the knee joint were retrospectively reviewed in 101 adolescent athletes (75 boys and 26 girls) with a mean age of 14.0 years (range 12-17). Postural stability during single-leg standing on static and dynamic platforms was investigated using Balance System SD in 119 feet without functional ankle instability. The participants were divided according to their rearfoot angle into control (less than 7°) and valgus (greater than or equal to 7°) groups. The measured parameters were compared between the control and valgus groups using Welch's t-test, and P values < 0.05 were considered statistically significant. Multiple regression analysis was conducted to identify the factors that significantly influenced postural control.

RESULTS

The average rearfoot angle was 4.6° in all participants. An excessive valgus rearfoot angle was detected in 53 feet (26.2%). No significant difference was found between the groups in terms of BMI and isometric knee muscle strength. Although no statistical differences were observed in postural stability on the static platform between the control and valgus groups, the valgus group demonstrated poorer postural stability for single-leg standing on the dynamic platform. Multiple regression analysis revealed that BMI and rearfoot angle were significantly associated with a poor postural control on the dynamic platform.

CONCLUSIONS

Our findings suggest that excessive rearfoot valgus specifically contributes to the deterioration of postural stability in adolescent athletes, and that rearfoot alignment should be evaluated for the adolescent population to prevent sports-related lower extremity injury.

Effect of Skiing on Physical Performance, Pain, and Quality of Life Based on Gender

Context: Identifying gender-specific differentiation in each sport type is significant. In this way, sport- and gender-specific gains can be predicted. Therefore, this study aimed to examine the effects of skiing on physical performance, pain, quality of life, and gender-based differentiation. Design: Crossover trial. Methods: Sixty-eight volunteers, between 18 and 25 years of age, with no history of severe trauma in the spine and extremities, participated in our study. The skiers group consisted of licensed athletes (17 males and 17 females) who did active skiing for at least the past 2 years, the control group consisted of nonathletic and age-matched participants with no skiing experience (17 males and 17 females). Step test, vertical jump test, Flamingo balance test, hand-grip strength, and back-leg-chest strength measurements were performed to evaluate physical performance. Visual Analog Scale, McGill Pain Questionnaire, and Oswestry Low Back Pain Disability Questionnaire were used to evaluate pain experience. Quality of life was evaluated with Short Form-36 (SF-36). Results: Compared to the sedentary controls, VAS-activity and Oswestry Disability Index scores were lower; and aerobic performance, balance, hand-grip strength, back-leg-chest strength, and quality of life (SF-36-general health, SF-36-vitality, SF-36-mental health, and SF-total score) were higher in skiers. Skiing was found to be effective in eliminating gender-based differentiation of the variables of hand-grip strength, pain, and quality of life; however, back-leg-chest strength and anaerobic performance variables were found to be ineffective in eliminating gender differentiation. Conclusions: Skiing allows that the individual increases physical performance and quality of life. It can also minimize gender-based differentiation of certain variables, such as muscular force, pain, and quality of life.

Comparison of lower limb muscle activity during the dynamic balance test between baseball pitchers and healthy young adults

BACKGROUND: Dynamic balance is an essential factor for efficient pitching by baseball pitchers. OBJECTIVE: To compare distances reached and lower-extremity muscle activity during the star excursion balance test (SEBT) in baseball pitchers and healthy young adults. METHODS: Nineteen baseball pitchers (BPG) and 20 healthy adults (HAG) were recruited. Surface EMG was used to measure the activity of vastus medialis (VM), vastus lateralis (VL), tibialis anterior, and lateral gastrocnemius. RESULTS: The BPG exhibited greater dynamic balance than in the HAG (p< 0.05) in the posteromedial (PM) and posterolateral (PL) directions. For the PM and PL directions, significantly greater muscle activity of VM and VL was found in the BPG than in the HAG (p< 0.05). CONCLUSION: SEBT performance is characterized by high-level VM and VL muscle activities. Neuromuscular control of knee extensors, such as the VM and VL of pitchers, might affect the dynamic balance measured by the SEBT.

Lower Extremity Kinematics of the Y-Balance Test in Healthy and ACL Injured Adolescent Females

BACKGROUND

Adolescent females are at significant risk for sustaining an ACL injury. The Y-Balance Test (YBT) is frequently used to evaluate neuromuscular control and lower extremity function. However, few studies have quantified 2D lower extremity kinematics during performance of the YBT, and there is an absence of kinematic data specific to at-risk adolescent females.

PURPOSE

To examine lower extremity joint kinematics during execution of the YBT by healthy and ACL-injured adolescent females.

STUDY DESIGN

Prospective cohort.

METHODS

Twenty-five healthy and ten ACL-injured (mean time from injury 143 days) adolescent females were assessed using the YBT. Sagittal and frontal plane knee and ankle motion was video recorded during execution of the YBT anterior reach movement. Ankle dorsi-flexion, knee flexion, and knee valgus angles were quantified via kinematic analysis. ANOVAs with a post hoc Bonferroni correction were used to compare YBT scoring (%LL) and kinematic data between groups. Pearson product-moment correlations determined the relationship between kinematic data and YBT scoring.

RESULTS

Healthy and ACL-injured subjects demonstrated similar YBT scores and lower extremity kinematic data. Healthy subjects demonstrated a weak positive correlation between ankle dorsiflexion and YBT scoring, and a weak negative correlation between knee valgus and YBT scoring. These relationships did not exist for ACL-injured subjects. Kinematic data for both groups also demonstrated a large degree of variability, regardless of YBT score.

CONCLUSIONS

Adolescent females frequently utilize a variety of lower extremity movement strategies when performing a functional movement task, and scoring on the YBT offers limited insight regarding lower extremity joint kinematics and ACL-injury risk in a physically active adolescent female population.

LEVEL OF EVIDENCE

Level 3.

Influence of biological maturity on static and dynamic postural control among male youth soccer players

BACKGROUND

Peak height velocity has been reported to be associated with the phenomenon of adolescent awkwardness, a temporary disruption in motor skills, and an increase in injuries in some adolescents. To date, it is not entirely clear which motor abilities are deficient during the phase of rapid growth.

RESEARCH QUESTION

We hypothesized that static as well as dynamic postural control is influenced by biological maturation.

METHODS

The study was conducted in a prospective, cross-sectional design. Maturity offset, a somatic indicator for biological maturation was captured for n = 99 male soccer players (13.7 ± 0.5 years). Static and dynamic balance were assessed by the Balance Error Scoring System (BESS) and the Y-Balance Test (YBT), respectively. Influences of biological maturation on balance performances have been analyzed by linear mixed models.

RESULTS

Linear mixed model analyses revealed that biological maturation is significantly associated with the total BESS score (p = 0.022, b = 2.195) as well as the YBT anterior (right leg: p = 0.023, b = -0.022; left leg: p = 0.015, b = -0.024) and posteromedial reach directions (left leg: p = 0.02, b = -0.029). No significant associations were found for the other YBT distances.

SIGNIFICANCE

Based on our results, maturation seems to have a considerable influence on postural control. It might be that deficits in balance performance contribute to the phenomenon of adolescent awkwardness and therefore lead to an increased injury risk during the adolescent growth spurt. To possibly prevent injuries in youth soccer, biological maturation should be taken into consideration in youth sport coaching.

The influence of biological maturity on motor performance among habitually barefoot versus habitually shod adolescents

Biological maturation is associated with physiological changes which in turn affect motor performance. No study has assessed the association between growing up habitually shod versus habitually barefoot and motor performance in the context of maturation, so this approach is unique. The purpose of this study was to examine the influence of biological maturity on motor performance dependent on the participants' footwear habits. Sixty-five German habitually shod (mean age 13.28 ± 0.83 years) and fifty-five South African habitually barefoot (mean age 13.38 ± 0.87 years) participants were included. Dynamic postural control was determined via backward balancing, explosive strength by standing long jump and sprinting performance based on a 20-m sprinting test. All tests were performed barefoot and shod. Biological maturation was calculated by using the maturity offset value. Linear mixed models were used to analyse interactions between the maturity offset value, footwear habits and motor performance. Throughout maturation, there was a significant difference between habitually barefoot and habitually shod balance performance (P = 0.001). Maturation led to balance improvements in habitually barefoot adolescents, but not in habitually shod adolescents. No such differences could be observed for standing long jump and 20-m sprint performance. Maturity offset was a significant predictor for jumping and sprinting performances (P < 0.001), independent of being habitually barefoot or habitually shod. Better performances could be observed in more mature subjects. Biological maturation seems to be a relevant predictor for motor performance characteristics for the jumping and sprinting performance in adolescents.

Reproducibility of Static and Dynamic Postural Control Measurement in Adolescent Athletes with Back Pain

Static (one-legged stance) and dynamic (star excursion balance) postural control tests were performed by 14 adolescent athletes with and 17 without back pain to determine reproducibility. The total displacement, mediolateral and anterior-posterior displacements of the centre of pressure in mm for the static, and the normalized and composite reach distances for the dynamic tests were analysed. Intraclass correlation coefficients, 95% confidence intervals, and a Bland-Altman analysis were calculated for reproducibility. Intraclass correlation coefficients for subjects with (0.54 to 0.65), (0.61 to 0.69) and without (0.45 to 0.49), (0.52 to 0.60) back pain were obtained on the static test for right and left legs, respectively. Likewise, (0.79 to 0.88), (0.75 to 0.93) for subjects with and (0.61 to 0.82), (0.60 to 0.85) for those without back pain were obtained on the dynamic test for the right and left legs, respectively. Systematic bias was not observed between test and retest of subjects on both static and dynamic tests. The one-legged stance and star excursion balance tests have fair to excellent reliabilities on measures of postural control in adolescent athletes with and without back pain. They can be used as measures of postural control in adolescent athletes with and without back pain.

Postural Stability in Healthy Child and Youth Athletes: The Effect of Age, Sex, and Concussion-Related Factors on Performance

Background:

Postural stability plays a key role in sport performance, especially after concussion. Specific to healthy child and youth athletes, little is known about the influence development and sex may have on postural stability while considering other subjective clinical measures used in baseline/preinjury concussion assessment. This study aims to describe age- and sex-based trends in postural stability in uninjured child and youth athletes at baseline while accounting for concussion-related factors.

Hypotheses:

(1) Postural stability performance will improve with age, (2) females will display better postural stability compared to males, and (3) concussion-like symptoms will affect postural stability performance in healthy children and youth.

Study Design:

Cross-sectional study.

Level of Evidence:

Level 3.

Methods:

This study comprised 889 healthy/uninjured child and youth athletes (54% female, 46% male) between the ages of 9 and 18 years old. Participants completed preseason baseline testing, which included demographic information (age, sex, concussion history), self-report of concussion-like symptoms (Post-Concussion Symptom Inventory [PCSI]–Child and PCSI-Youth), and measures of postural stability (BioSway; Biodex Medical Systems). Two versions of the PCSI were used (PCSI-C, 9- to 12-year-olds; PCSI-Y, 13- to 18-year-olds). Postural stability was assessed via sway index under 4 sway conditions of increasing difficulty by removing visual and proprioceptive cues.

Results:

In children aged 9 to 12 years old, there were significant age- (P < 0.05) and sex-based effects (P < 0.05) on postural stability. Performance improved with age, and girls performed better than boys. For youth ages 13 to 18 years old, postural stability also improved with age (P < 0.05). In both child and youth subgroups, postural stability worsened with increasing concussion-like symptoms (P < 0.05).

Conclusion:

There are developmental and baseline symptom trends regarding postural stability performance.

Clinical Relevance:

These findings provide a preliminary foundation for postconcussion comparisons and highlight the need for a multimodal approach in assessing and understanding physical measures such as postural stability.

Sex Differences in Balance Among Alpine Ski Racers: Cross-Sectional Age Comparisons

Although balance is a key ability in the strength demands of alpine ski racing, affecting both performance and injury prevention, few studies have examined balance or related sex differences among still-maturing athletes. In this 10-year study, we investigated cross-sectional balance performances at different age periods of a representative sample of over 500 11–18-year-old elite skiers of both genders. Participants performed balance tests using the MFT S3-Check. Left–right and forward–backward movements were used to calculate sensory and symmetry balance scores, which were both incorporated into a stability score. Mann–Whitney U tests assessed gender-specific differences by age-group with a significance level set at p < .05. Results showed gender differences only on forward–backward measurements for 14–16-year-olds, with females showing better stability and sensory (but not symmetry) scores than males. Thus, gender interacted with age and maturation to influence balance ability in these participants. Additionally, these rare 10-year data support coaches in their training and talent development of maturing athletes by providing important sport-, age-, and gender-specific normative comparison data for individual trainees.

External load training does not alter balance performance in well-trained women

This study investigated the influence of external load training (ELT) on static and dynamic balance. Nineteen females stratified into two groups (ELT = 9, control = 10) completed three testing sessions over 6 weeks. The ELT group wore weighted vests (WV) of ~8% body mass for 32 h/week during daily living and three training sessions/week for 3 weeks. Following completion of ELT, a 3 week detraining (DET) phase was completed. Bilateral and unilateral static balance were assessed with eyes open and closed. Dynamic balance was assessed using the star excursion balance test (SEBT). Static and dynamic balance variables were analysed using a 2 (group) x 3 (time) between participants repeated measures ANOVA (p < 0.05). Results revealed significant reductions in average centre of pressure (COP) velocity in the control group on the non-dominant limb with eyes closed, and significantly greater reach distances in the ELT group on the SEBT for the posteromedial and medial directions on the dominant limb (p < 0.05). These findings suggest the ELT group did not significantly improve their balance in comparison to the control group. However, future research should further examine this unique, supplemental training method and the impact on balance performance.

Reference values for developing responsive functional outcome measures across the lifespan

Objective:

To generate a reference dataset of commonly performed functional outcome measures in 1,000 children and adults and investigate the influence of demographic, anthropometric, strength, and flexibility characteristics.

Methods:

Twelve functional outcome measures were collected from 1,000 healthy individuals aged 3–101 years: 6-minute walk test, 30-second chair stand test, timed stairs test, long jump, vertical jump, choice stepping reaction time, balance (Star Excursion Balance Test, tandem stance eyes open and closed, single-leg stance eyes closed), and dexterity (9-hole peg test, Functional Dexterity Test). Correlation and multiple regression analyses were performed to identify factors independently associated with each measure.

Results:

Age- and sex-stratified reference values for functional outcome measures were generated. Functional performance increased through childhood and adolescence, plateaued during adulthood, and declined in older adulthood. While balance did not differ between the sexes, male participants generally performed better at gross motor tasks while female participants performed better at dexterous tasks. Height was the most consistent correlate of functional performance in children, while lower limb muscle strength was a major determinant in adolescents and adults. In older adults, age, lower limb strength, and joint flexibility explained up to 63% of the variance in functional measures.

Conclusions:

These normative reference values provide a framework to accurately track functional decline associated with neuromuscular disorders and assist development and validation of responsive outcome measures for therapeutic trials.

Star Excursion Balance Test in Young Athletes with Back Pain

The Star Excursion Balance Test (SEBT) is effective in measuring dynamic postural control (DPC). This research aimed to determine whether DPC measured by the SEBT in young athletes (YA) with back pain (BP) is different from those without BP (NBP). 53 BP YA and 53 NBP YA matched for age, height, weight, training years, training sessions/week and training minutes/session were studied. Participants performed 4 practice trials after which 3 measurements in the anterior, posteromedial and posterolateral SEBT reach directions were recorded. Normalized reach distance was analyzed using the mean of all 3 measurements. There was no statistical significant difference (p > 0.05) between the reach distance of BP (87.2 ± 5.3, 82.4 ± 8.2, 78.7 ± 8.1) and NBP (87.8 ± 5.6, 82.4 ± 8.0, 80.0 ± 8.8) in the anterior, posteromedial and posterolateral directions respectively. DPC in YA with BP, as assessed by the SEBT, was not different from NBP YA.

A longitudinal investigation into the progression of dynamic postural stability performance in adolescents

Adolescent female athletes have a higher incidence of certain non-contact lower limb injuries compared to their male counterparts. Decreased postural stability is an established risk factor for lower limb injuries; however developmental-related sex differences in postural stability during adolescence have not been investigated. The objectives of this study were to longitudinally examine changes over time, and potential sex differences in dynamic postural stability performance in adolescents. One hundred and eighty four adolescent athletes participated (mean age=13±0.34 years). Participants were assessed, using the Star Excursion Balance Test (SEBT) at baseline (T1) and at 6 (T2), 12 (T3), 18 (T4) and 24 (T5) months. At each time-point, participants performed 3 trials of the anterior, posterior-medial and posterior-lateral directions of the SEBT on each limb. Reach distance for each direction was averaged across the 3 trials normalised to leg length. General linear mixed model analyses were carried out on each of the dependant variables (reach directions) with sex and time as the categorical independent variables. There was a significant sex×time interaction for the posterior-lateral reach distance scores. There were no significant sex×time interactions for any of the other reach directions. Males increased performance on the posterior-lateral reach direction from T1 to T5, while females only increased performance until T3. Young males and females demonstrate diverging postural stability profiles during adolescence.

Prediction of Lateral Ankle Sprains in Football Players Based on Clinical Tests and Body Mass Index

BACKGROUND

The lateral ankle sprain (LAS) is the most common injury suffered in sports, especially in football. While suggested in some studies, a predictive role of clinical tests for LAS has not been established.

PURPOSE

To determine which clinical tests, focused on potentially modifiable factors of movement patterns and body mass index (BMI), could best demonstrate risk of LAS among high school and collegiate football players.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A total of 539 high school and collegiate football players were evaluated during the preseason with the Star Excursion Balance Test (SEBT) and Functional Movement Screen as well as BMI. Results were compared between players who did and did not suffer an LAS during the season. Logistic regression analyses and calculated odds ratios were used to determine which measures predicted risk of LAS.

RESULTS

The LAS group performed worse on the SEBT-anterior reaching direction (SEBT-ANT) and had higher BMI as compared with the noninjured group (P < .001). The strongest prediction models corresponded with the SEBT-ANT.

CONCLUSION

Low performance on the SEBT-ANT predicted a risk of LAS in football players. BMI was also significantly higher in football players who sustained an LAS. Identifying clinical tools for successful LAS injury risk prediction will be a critical step toward the creation of effective prevention programs to reduce risk of sustaining an LAS during participation in football.