Y-balance normative data for female collegiate volleyball players

Development of a 3D active movement extent discrimination apparatus for testing proprioception at the ankle joint with inversion movements made in plantarflexion

Proprioception plays an important role in joint stability, and ankle sprains usually happen involving plantarflexion, internal rotation, and inversion. However, ankle 3D movement proprioception has never been measured in weight-bearing. Accordingly, the active 3-dimensional movement extent discrimination apparatus (AMEDA-3D) was developed and its reliability and validity were investigated. A total of 58 subjects volunteered for this trial, with 12 subjects with chronic ankle instability (CAI) and 12 healthy controls in the test-retest reliability study. There were 17 subjects with CAI and 17 healthy controls in the validity study. An intraclass correlation coefficient (ICC) and Minimum Detectable Change at the 90% confidence interval (MDC90) were computed. AMEDA-3D scores were analysed by independent samples t-tests, and Youden's index was used to calculate the optimal AMEDA-3D cut-off for discriminating individuals with CAI. Pearson's correlation analysis was used to explore the relationship between AMEDA-3D scores and Y Balance Test (YBT), Time In Balance Test (TIB), and Cumberland Ankle Instability Tool (CAIT) scores. The main results were as follows: (1) The ICC(3,1) value of AMEDA-3D scores was 0.817 (95% CI = 0.452-0.945) in CAI subjects. (2) The AMEDA-3D proprioceptive area under the curve score used to discriminate CAI subjects from healthy controls was 0.778, with a sensitivity of 94% and a specificity of 82%. (3) AMEDA-3D proprioceptive scores were moderately correlated with CAIT scores (r = 0.58 and p < 0.001), YBT (r = 0.47 and p = 0.005), and TIB (r = 0.68 and p < 0.001). Our findings suggest that the AMEDA-3D tool shows good reliability and validity for clinical assessment of proprioceptive deficits associated with CAI. Improved ankle 3D motor proprioception may positively impact subjects' balance control, self-rated symptoms, and function.

Symmetric unipedal balance in quiet stance and dynamic tasks in older individuals

Previous evidence of increased difference of muscular strength between the dominant and non-dominant legs in older adults suggests the possibility of dissimilar balance control between the legs (between-leg asymmetry) associated with aging. In the current investigation, we evaluated between-leg asymmetries in older adults when performing quiet and dynamic balance tasks. Fifty-two physically active and healthy older adults within the age range of 60 to 80 years were recruited. Participants performed balance tasks in unipedal stance, including quiet standing and cyclic sway (rhythmic oscillation) of the non-supporting leg in the anteroposterior or mediolateral directions, producing foot displacements with amplitudes of 20 cm paced in 1 Hz through a metronome. Body balance was evaluated through trunk accelerometry, by using the sensors embedded into a smartphone fixed at the height of the 10th-12th thoracic spines. Analysis revealed lack of significant differences in balance control between the legs either when comparing the right versus left or the preferred versus non-preferred legs, regardless of whether they were performing quiet stance or dynamic tasks. Further examination of the data showed high between-leg correlation coefficients (rs range: 0.71-0.84) across all tasks. Then, our results indicated symmetric and associated between-leg balance control in the examined older adults.

Reliability and validity of the ankle inversion discrimination apparatus during walking in individuals with chronic ankle instability

Purpose: 1) to explore the test-retest reliability of a new device for measuring ankle inversion proprioception during walking, i.e., the Ankle Inversion Discrimination Apparatus-Walking (AIDAW) in individuals with or without Chronic Ankle instability (CAI); 2) to assess its discriminant validity in differentiating individuals with or without CAI; 3) to investigate its convergent validity by examining its association with Cumberland Ankle Instability Tool (CAIT) and the Y Balance Test (YBT). Methods: For test-retest reliability, 15 participants with CAI and 15 non-CAI healthy controls were recruited. Participants completed the AIDAW test twice with a 7-day interval. The area under the receiver operating curve (AUC) was obtained as the AIDAW score. The intraclass correlation coefficient (ICC) and MDC₉₀ were calculated. For the validity study, another 20 individuals with CAI and 20 non-CAI healthy controls were involved. The AIDAW scores were analyzed by an independent samples t-test, and the optimal cutoff value of AIDAW scores to best distinguish individuals with CAI was calculated by Youden's index. Spearman or Pearson correlation analysis was used to analyze the correlation between AIDAW proprioceptive scores and the CAIT and final YBT scores. Results: For test-retest reliability, the ICC values for the CAI, non-CAI, and the whole group were 0.755, 0.757, and 0.761 respectively. The MDC₉₀ of the CAI and non-CAI group was 0.04 and 0.05. Regarding discriminant validity, the AIDAW proprioceptive discrimination scores in the CAI group were significantly lower than those in the non-CAI group (p = 0.003); and the cutoff score for distinguishing CAI from the non-CAI participants was 0.759. For convergent validity, the AIDAW scores were significantly correlated with the functional balance YBT final scores (p = 0.001) and the CAIT scores (p = 0.009). Conclusion: The AIDAW is a reliable and valid device for evaluating ankle inversion proprioception during walking in individuals with and without CAI. AIDAW can be used as a clinical assessment tool to discriminate CAI from non-CAI individuals and to monitor effects of rehabilitation. The AIDAW proprioceptive discrimination scores were significantly and positively correlated with YBT and CAIT scores.

Impact of time-of-day and chronotype on neuromuscular performance in semi-professional female volleyball players

This study aimed to determine if time-of-day could influence physical volleyball performance in females and to explore the relationship between chronotype and volleyball-specific performance. Fifteen young female athletes participated in a randomized counterbalanced trial, performing a neuromuscular test battery in the morning (9:00 h) and the evening (19:00 h) that consisted of volleyball standing spike, straight leg raise, dynamic balance, vertical jump, modified agility T-test and isometric handgrip tests. Chronotype was determined by the morningness-eveningness questionnaire. Compared to the morning, an increased performance was found in the standing spike (4.5%, p = .002, ES = 0.59), straight leg raise test (dominant-limb) (6.5%, p = .012, ES = 0.40), dynamic balance (non-dominant-limb) (5.0%, p = .010, ES = 0.57) and modified T-test (2.1%, p = .049, ES = 0.45) performance in the evening; while no statistical differences were reported in vertical jump tests or isometric handgrip strength. Moreover, no associations were found between chronotype and neuromuscular performance (r = -0.368-0.435, p = .052-0.439). Time-of-day affected spike ball velocity, flexibility in the dominant-limb, dynamic balance in the non-dominant-limb and agility tests. However, no association was reported among these improvements and the chronotype. Therefore, although the chronotype may not play critical role in volleyball-specific performance, evening training/matches schedules could benefit performance in semi-professional female volleyball players.

Systematic Review and Meta-Analysis of the Y-Balance Test Lower Quarter: Reliability, Discriminant Validity, and Predictive Validity

BACKGROUND

Deficits in dynamic neuromuscular control have been associated with post-injury sequelae and increased injury risk. The Y-Balance Test Lower Quarter (YBT-LQ) has emerged as a tool to identify these deficits.

PURPOSE

To review the reliability of the YBT-LQ, determine if performance on the YBT-LQ varies among populations (i.e., sex, sport/activity, and competition level), and to determine the injury risk identification validity of the YBT-LQ based on asymmetry, individual reach direction performance, or composite score.

STUDY DESIGN

Systematic Review.

METHODS

A comprehensive search was performed of 10 online databases from inception to October 30, 2019. Only studies that tested dynamic single leg balance using the YBT-LQ were included. Studies were excluded if the Y-Balance Test kit was not utilized during testing or if there was a major deviation from the Y-Balance test procedure. For methodological quality assessment, the modified Downs and Black scale and the Newcastle-Ottawa Scale were used.

RESULTS

Fifty-seven studies (four in multiple categories) were included with nine studies assessing reliability, 36 assessing population differences, and 16 assessing injury prediction were included. Intra-rater reliability ranged from 0.85-0.91. Sex differences were observed in the posteromedial direction (males: 109.6 [95%CI 107.4-111.8]; females: 102.3 [95%CI 97.2-107.4; p = 0.01]) and posterolateral direction (males: 107.0 [95%CI 105.0-109.1]; females: 102.0 [95%CI 97.8-106.2]). However, no difference was observed between sexes in the anterior reach direction (males: 71.9 [95%CI 69.5-74.5]; females: 70.8 [95%CI 65.7-75.9]; p=0.708). Differences in composite score were noted between soccer (97.6; 95%CI 95.9-99.3) and basketball (92.8; 95%CI 90.4-95.3; p <0.01), and baseball (97.4; 95%CI 94.6-100.2) and basketball (92.8; 95%CI 90.4-95.3; p=0.02). Given the heterogeneity of injury prediction studies, a meta-analysis of these data was not possible. Three of the 13 studies reported a relationship between anterior reach asymmetry reach and injury risk, three of 10 studies for posteromedial and posterolateral reach asymmetry, and one of 13 studies reported relationship with composite reach asymmetry.

CONCLUSIONS

There was moderate to high quality evidence demonstrating that the YBT-LQ is a reliable dynamic neuromuscular control test. Significant differences in sex and sport were observed. If general cut points (i.e., not population specific) are used, the YBT-LQ may not be predictive of injury. Clinical population specific requirements (e.g., age, sex, sport/activity) should be considered when interpreting YBT-LQ performance, particularly when used to identify risk factors for injury.

LEVEL OF EVIDENCE

1b.

Safety and Effectiveness of a Perturbation-based Neuromuscular Training Program on Dynamic Balance in Adolescent Females: A Randomized Controlled Trial

BACKGROUND

Adolescent females are at much greater risk for ACL injury than their male counterparts when participating in the same sports. Preventative and pre-operative rehabilitation neuromuscular (NM) exercise programs are often recommended to improve knee function and reduce injury rates. The effectiveness of perturbation-based NM training program has been established in an adult population but has yet to be investigated in the at-risk adolescent female population.

PURPOSE

To determine the effectiveness of a perturbation-based NM exercise program in a group of physically active adolescent females.

STUDY DESIGN

Prospective randomized trial.

METHODS

Twenty-four healthy and an exploratory group of 10 ACL-injured females (ages 12-18) were equally randomized into a perturbation-based NM training or control group and evaluated before and after a five-week intervention period. The primary outcome of dynamic balance was measured using the Y-Balance test (YBT); secondary outcome measures included lower limb strength, proprioception, and flexibility.

RESULTS

The perturbation-based NM training intervention was safely completed by all participants but had no significant effect on YBT scoring, lower limb strength, proprioception or flexibility in either the healthy or ACL-injured groups.

CONCLUSIONS

Perturbation-based NM training is safe, but may offer little preventative benefit for healthy or pre-operative rehabilitation benefit for ACL-injured adolescent females. Future research should examine whether the effectiveness of perturbation-based NM training is influenced by the length of the training intervention, training intensity, or when it is combined with other forms of prophylactic or pre-surgical rehabilitation frequently used with at-risk adolescent females who regularly participate in sport.

LEVEL OF EVIDENCE

Level 3.

Preseason functional tests discriminate injury risk in female collegiate volleyball players

OBJECTIVE

Preseason functional tests have been previously associated with noncontact time-loss lower extremity injuries in a variety of athletic populations. This study aimed to determine the effectiveness of one or more functional tests to discriminate injury risk in a cohort of female collegiate volleyball players in the United States.

DESIGN

Prospective cohort study.

SETTING

National Collegiate Athletic Association Division II & III, National Association of Intercollegiate Athletics female volleyball players; PARTICIPANTS: 130 female volleyball players (mean age: 19.31 ± 1.1 years).

MAIN OUTCOME MEASURE

Lower extremity functional test, single limb hop for distance, standing long jump, previous injury history, lower quarter Y-balance test, and limb symmetry index were measured prior to the season beginning. Noncontact time-loss lower quarter injuries were tracked during the season.

RESULTS

Athletes with suboptimal scores on the single limb hop test (<70% of height) and standing long jump (<80% of height), combined with a previous history of injury, were three times more likely to sustain an injury during the season (OR = 3.0; 95% CI: 1.09 to 8.30). Individual functional tests did not discriminate injury risk.

CONCLUSIONS

A battery of preseason functional tests and injury history discriminates injury risk in female collegiate volleyball players.

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.

The role of the dominant leg while assessing balance performance. A systematic review and meta-analysis

BACKGROUND

Good balance is a pre-requisite for various activities of daily life and sports. Physiotherapists thus regularly assess and train patient's balance capacities. In order to interpret the test results of unilateral balance tests, a comparison with normative data is common. In patients who had an injury or a surgery, the performance of the injured leg is often compared with performance of the non-injured leg. Nevertheless, it remains unclear if unilateral balance performance differs between the dominant and non- dominant legs. If so, this should take into consideration when interpreting test results.

RESEARCH QUESTION

This meta-analysis summarized the current evidence to determine if the balance performance of healthy adults was influenced by the leg's dominance.

METHODS

Articles were searched in PubMed, CINAHL, Cochrane and Embase. Data from studies meeting the pre-defined inclusion criteria were extracted in a standardized form. A meta-analysis was conducted using a random effect model.

RESULTS

Forty-six studies were included. Their data were allocated in 7 categories of balance tests. Significant differences between the dominant and the non-dominant legs were not found in any of the categories (surface stable, eyes open: -0.04, 95 % CI -0.12 to 0.05, surface stable eyes closed: -0.06, 95 % CI -0.22 to 0.11, surface unstable, eyes open: -0.15, 95 % CI -0.38 to 0.07, surface unstable, eyes closed: -0.06, 95 % CI -0.27 to 0.15, BESS (Balance Error Scoring System): 0.03, 95 % CI -1.09 to 1.14, SEBT (Star Excursion Balance Test)/YBT (Y Balance Test): 0.06, 95 % CI -0.04 to 0.16, jump: 0.04, 95 % CI -0.28 to 0.36).

SIGNIFICANCE

Results indicate that balance performance is not influenced by the leg's dominance. This means that performances of both legs can be used as reference. Evidence is strong for the one leg stance. However, future studies are needed to confirm our results for stabilization tasks after a jump landing.

Relationship between the strength of the hip and knee stabilizer muscles and the Y balance test performance in adolescent volleyball athletes

BACKGROUND

Due to the large number of jumping and landing movements, volleyball exerts a high demand on lower limbs, causing a high incidence of injuries. On average, 52% of volleyball injuries occur in lower limbs. Y Balance-test (YBT) is widely used to predict lower limb injury in athletes who jump, so it is important to identify whether the hip and knee stabilizer muscle strength is related to the performance of this test, since muscle strength is important for injury prevention, given the possibility of modifying these factors. The aim of this cross-sectional study was to correlate the strength of the knee and hip stabilizing muscles with YBT in adolescent volleyball athletes.

METHODS

A study including 25 young volleyball players (aged 15.3 [0.85] years), was evaluated. The isometric strength of knee extensor muscles, abductors, extensors and lateral hip rotators were assessed by using the manual isometric dynamometer (Lafaytte Instrument Company®, Lafayette, IN, USA). YBT was performed three times on each posterolateral (PL), anterior (ANT) and posteromedial (PM) direction to evaluate the dominant leg. The average of 3 repetitions of isometric strength tests of tested muscles and YBT was analyzed. Pearson's Correlation test was used for the correlation of the variables, considering as strong correlation values (0.5≤r<1), with P≤0.05.

RESULTS

A moderate correlation was observed between the knee extensor strength and the ANT direction, and a moderate correlation between the hip extensor strength and the PL direction in YBT.

CONCLUSIONS

The strength of knee and hip extensors may be one of the factors that influence the performance of YBT in adolescent volleyball players.

Effect of an injury prevention program on the lower limb stability in young volleyball players

BACKGROUND

Volleyball players have a high risk of injury in the lower limbs as a consequence of the specific characteristics of the sport, such as repetitive jumps and falls. The objective of the present study was to evaluate the effects of a multidisciplinary injury prevention program on lower limb stability in young volleyball players.

METHODS

The experimental design was a non-randomized controlled trial. All the measurements were performed in a standardized room in a sports center. Twenty-six young male volleyball players (mean age: 15.39±1.16 years), divided into experimental (N.=15) and control groups (N.=11) participated in this study. The experimental group performed an 8-week prevention program including lower limb strength and plyometric training, and joint and core stability. The Y-Balance and force platform landing tests were carried out as the pre- and post-tests.

RESULTS

The main outcome measures were the injuries history, distance and difference reached in anterior, post-lateral and post-medial axis of the Y-Balance test, and the force produced on the z, x, and y axis after landing. Differences were found between groups and measurements in all the variables of the Y-Balance test, except in the frontal axis for the dominant leg and for the differences between legs (P=0.039-0.001); and in the ground reaction forces (z axis) (P=0.040), the x axis (P=0.014) and the dynamic postural stability index (P=0.025) of the lateral jump with the non-dominant leg.

CONCLUSIONS

An 8-week prevention program seems to improve the lower limb stability in young volleyball players.

Lower Quarter Y Balance Test performance: Reference values for healthy youth aged 10 to 17 years

BACKGROUND

The Lower Quarter Y Balance Test (YBT-LQ) has been widely used to register dynamic balance performance in children and adolescents. However, studies evaluating age- and sex-specific normative data to assess and classify YBT-LQ performance for these age-cohorts are missing.

OBJECTIVE

Thus, we investigated YBT-LQ performance in healthy youth to provide age- and sex-specific reference values.

METHODS

Six-hundred and sixty-nine individuals (286 female, 383 male) aged 10-17 years performed the YBT-LQ with their left and right leg. Normalized maximal reach distances (% leg length) for all three directions (i.e., anterior, posterolateral, posteromedial) and the composite score were calculated. Further, age- and sex-specific percentile values (i.e., 10th to 90th percentile) were computed and plotted.

RESULTS

In boys, the oldest age group (16-17 years) performed better than the younger ones (14-15, 12-13, and 10-11 years). In girls, the youngest age group (10-11 years) often achieved better values compared to the 12-13-year olds. Further, 16-17-year old boys compared to the same aged girls showed better YBT-LQ performance in all but one measure (except left leg reach in posterolateral direction). For both sexes, curvilinear shaped curves were detected for percentile values across the reach directions.

CONCLUSIONS

The generated age- and sex-specific reference values for the YBT-LQ can be used by practitioners to evaluate dynamic balance performance in healthy youth aged 10-17 years.

Differences in lower quarter Y-balance test with player position and ankle injuries in professional baseball players

PURPOSE

Although there has been research about the correlation between ankle injury and Y-balance test (YBT) conducted in other sports, there has been a lack of research on the correlation between ankle injury among baseball players and YBT scores or on differences in scores according to baseball positions. This study focused on professional baseball players as its subjects with the aims of analyzing the correlation between YBT and ankle injury and assessing differences in YBT between baseball positions.

METHODS

Age, height, weight, body mass index, and spine malleolar distance of 42 professional baseball players were measured. YBT measurements were performed using each foot in three distinct directions. YBT normalized reach distances, composite score, and reach asymmetry were analyzed.

RESULTS

The mean right posteromedial normalized reach distances for the player positions were significantly different between the pitchers (107.7%) and infielders (113.7%) ( p = 0.028). For the composite score, the difference between the pitchers (92.3%) and infielders (95.0%) was statistically significant ( p = 0.048). The anterior reach asymmetry was larger in the injured group than in the noninjured group ( p = 0.041).

CONCLUSION

This study shows that YBT can be used as a way of evaluating the injury of baseball players. It also shows the reference value of YBT according to position in professional baseball players. This study could be useful for the treatment of ankle injury of baseball players. Level of evidence: Level 3.

Trampoline Versus Resistance Training in Young Adults: Effects on Knee Muscles Strength and Balance

Purpose: Trampoline parks are becoming popular in many countries, providing recreational facilities for children and adults. This study investigated the effects of trampoline training on knee muscles strength and balance in young adults. Methods: Twenty-six participants (14 males, 12 females) were randomized into trampoline training (TT) and resistance training (RT) groups to undergo a 6-week supervised intervention program (2 × 30 min per week). TT group performed basic trampoline exercises while the RT group performed resistance training targeting lower extremities muscles. Peak knee extension and flexion torque, postural sway characteristics, and Y balance test (YBT) performance were evaluated before and after the intervention. A mixed model analysis of variance (group × time) was applied. Results: After training there were significant improvements in knee extension torque (mean difference_post-pre [95% CI], TT: 0.27 [0.00, 0.54] N∙m/kg, RT: 0.31 [0.09,0.54] N∙m/kg, p = .001), knee flexion torque (TT: 0.25 [0.17,0.33] N∙m/kg, RT: 0.21 [0.08,0.34] N∙m/kg, p < .001), and dynamic balance (YBT composite scores, mean difference_post-pre [95% CI], TT: 4.9 [-0.3, 10.2]%, RT: 5.2 [2.4,8.0]%, p = .001). No difference between groups was found. Conclusion: Trampoline training can be as effective as resistance training for improving knee muscles strength and dynamic balance in young men and women.

COMPARISON of LOWER QUARTER Y-BALANCE TEST SCORES for FEMALE COLLEGIATE VOLLEYBALL PLAYERS BASED on COMPETITION LEVEL, POSITION, and STARTER STATUS

BACKGROUND

The Lower Quarter Y-Balance Test (YBT-LQ) is used by sports medicine professionals to measure an athlete's dynamic balance. The YBT-LQ is used by clinicians to track recovery during clinical rehabilitation, assess an athlete's readiness to return to sport after injury, and to identify athletes potentially at-risk for a time-loss injury. Normative data for the YBT-LQ are lacking for female collegiate volleyball (VB) players. The purpose of this study was to examine preseason YBT-LQ scores and their relationships to level of competition, starter status, player position, and prior lower quadrant (i.e., low back and lower extremities) injury history.

METHODS

One-hundred thirty-four female collegiate VB players (mean age = 19.3 ± 1.1 years) representing athletes from three levels of competition (D II = 32, D III = 77, NAIA = 25) participated in this study. Athletes reported their prior injury history and performed the YBT-LQ testing protocol.

RESULTS

NAIA and D III athletes demonstrated significantly greater reach measures on the YBT-LQ than D II athletes in several directions. Starters demonstrated significantly greater reach measures in five out of eight reach directions. Liberos/defensive specialists/setters demonstrated significantly greater posterolateral and composite reach measures bilaterally. There was no difference in reach measures based on prior history of lower quadrant (low back and lower extremities) injury.

CONCLUSION

This study provides normative data for YBT-LQ in female collegiate volleyball players. The data presented in this report may be used by coaches and rehabilitation professionals when evaluating dynamic balance in healthy volleyball players and by clinicians to compare an injured athlete's recovery to norms.

LEVEL OF EVIDENCE

3b.

Effect of a specialized injury prevention program on static balance, dynamic balance and kicking accuracy of young soccer players

AIM

To study the effect of balance intervention program using the “FIFA 11+” program on static and dynamic balance and kicking accuracy of young soccer players.

METHODS

Twenty young soccer players were allocated to experimental (n = 10) or control (n = 10) groups. The experimental group performed the “FIFA 11+” program three times a week for six weeks. The control group performed their normal warm-up routine. The primary outcomes were measured pre and post intervention, and assessed kicking accuracy, static balance and dynamic balance.

RESULTS

No differences were found in kicking accuracy following intervention, for both groups, however, static balance improved significantly among the experimental group with significant interaction with the control group, and with high effect size. In addition, the dynamic balance of the left leg of the experimental group, with medium effect size for interaction between groups.

CONCLUSION

The large effect size of balance improvement that was observed following six weeks of intervention sessions, implies that soccer trainers and coaches should consider the inclusion of “FIFA 11+” as components of programs aimed at improving balance ability/control in young soccer players, as improvement in balance abilities may prevent injuries.