Star Excursion Balance Test Anterior Asymmetry Is Associated With Injury Status in Division I Collegiate Athletes

Current Rehabilitation Principles Following Meniscus Repairs

PURPOSE OF REVIEW

The purpose of this review is to synthesize current science on meniscus anatomy and biomechanics and repair techniques to create an empirical foundation for postoperative rehabilitation precautions and guidelines, including timelines, clinical and performance-based criteria for return to activity, to maximize both meniscal healing potential and patient recovery.

RECENT FINDINGS

Recent literature has focused on meniscus repair rather than debridement, and rehabilitation protocols should be designed to optimize healing. Complex, unstable tears, like root and radial tears, disrupt hoop stress and warrant a more conservative protocol including 6 weeks of non-weightbearing; however, more stable tears, like ramp and vertical tears, can often weight bear immediately after surgery. All protocols should emphasize early protected joint motion. Return to activity guidelines remain ill-defined but this review explores evidence-based recommendations for timelines, strength and performance testing. Patients typically should wait ≥ 4 months for a return to activity and the presence of joint line tenderness or effusion could be a sign of delayed/failed healing. It is essential for therapists to know the size, type, and location of a meniscus repair to optimize patient outcomes. Guidelines for weight bearing, range of motion, strength training, and return to activity should vary per tear type and repair technique and recovery should be both time- and criteria-based. Return to activity should align with healing time, objective clinical and performance testing, and clinical and imaging exam findings. Future research should aim to optimize repair techniques and rehabilitation protocols, specifically further study on the timing to initiate weightbearing, early motion, and return to activity.

Risk Assessment of FMS and YBT on Sports Injuries in Collegiate Athletes

This prospective cohort study investigated the predictive validity of the Functional Movement Screen (FMS) and Y Balance Test (YBT) for sports injuries in 458 collegiate athletes across various sports. Preseason screening using FMS and YBT was conducted, followed by injury data collection over the competitive season. Logistic regression analysis examined the relationship between screening scores and subsequent injury risk. Results indicated that lower composite FMS scores (≤14) were associated with increased injury risk (OR=2.32; 95% CI: 1.54-3.48; p<0.001), as were YBT anterior reach asymmetries > 4 cm (OR=2.16; 95% CI: 1.43-3.26; p<0.001). The combination of both risk factors demonstrated the strongest association (OR=3.57; 95% CI: 2.18-5.83; p<0.001) when compared to individuals with FMS scores >14 and YBT asymmetry < 4 cm.The combination of low FMS scores and YBT asymmetries demonstrated the strongest predictive value. These findings underscore the value of the FMS and YBT as screening tools to identify collegiate athletes who may be at elevated risk for sports injuries, potentially guiding the implementation of targeted injury prevention strategies.

Anterior Cruciate Ligament Reconstruction Return to Sport Testing Passing Rates for Healthy People: A Systematic Review

BACKGROUND

Return to sport (RTS) is a common goal after anterior cruciate ligament (ACL) reconstruction (ACLR) but carries a relatively high risk of reinjury with up to 20% to 25% of athletes experiencing graft rupture or contralateral ACL tear. While there is increased emphasis on establishing safe RTS criteria for athletes to return to previous activity levels, studies show that even healthy individuals have difficulty passing RTS testing.

PURPOSE

To synthesize data concerning whether healthy individuals can pass ACLR RTS rehabilitation tests.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Following the established PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors conducted a systematic literature search in May 2023. Three databases were used in the search (PubMed, EMBASE, and SPORTDiscus) to retrieve all studies that conducted ACLR RTS rehabilitation tests on healthy individuals. Tests included were isometric strength, isokinetic strength, hop, and balance tests. The search was performed in duplicate, and a quality assessment of all studies was included.

RESULTS

A total of 1724 studies were retrieved, of which 32 were included, involving 1552 controls with no history of ACL injury. From the studies analyzed, 5.3% to 42.2% of healthy participants failed 6 different hop tests, 15.2% failed the Star Excursion Balance Test, 37% failed the isometric knee flexion test, 50% failed the isometric knee extension test, and 23.7% to 28.9% failed the drop vertical jump test. An asymmetry index ≥10% was found in 6 of the 18 isokinetic tests and 2 of the 14 isometric tests. Hop testing was the most common test in the included studies (56.3%), followed by balance testing (31.3%), isometric strength testing (31.3%), isokinetic strength testing (25%), and drop vertical jump (6.3%).

CONCLUSION

Many healthy individuals fail ACLR RTS tests, with some having an inherent variation from side to side that is >10%. The passing threshold for RTS testing should be a value that is practical yet helps reduce reinjury rates.

Clinical Measures Associated with Subsequent Injury after Adolescent Concussion: A Prospective Cohort Study

PURPOSE

This study aimed to examine associations between clinical measures (self-reported and clinician administered) and subsequent injury rates in the year after concussion return to play (RTP) among adolescent athletes.

METHODS

We performed a prospective, longitudinal study of adolescents ages 13-18 yr. Each participant was initially assessed within 21 d of concussion and again within 5 d of receiving RTP clearance from their physician. Participants completed self-report measures: the Pittsburgh Sleep Quality Index and Tampa Scale of Kinesiophobia, and clinician-administered measures: single- and dual-task tandem gait and reaction time (RT; simple and clinical) assessments. They then completed monthly surveys for a year after RTP, which assessed exposure to injury (sport participation) and subsequent injuries (musculoskeletal or concussions) sustained. We used Poisson regression models to calculate injury rate ratios with the number of subsequent injuries sustained as the outcome, adjusted for RTP clearance time and competitive exposures for each measure.

RESULTS

Forty-one participants were included (age = 15.5 ± 1.3 yr, 56% female, 9.6 ± 4.6 d postconcussion; 38.0 ± 31.5 d to RTP). A higher injury rate per athletic exposure was observed for simple RT ≥ 505 ms versus <505 ms (injury rate ratio = 2.96, 95% confidence interval = 1.41-6.60, P = 0.005). Injury rates did not significantly differ by Pittsburgh Sleep Quality Index or Tampa Scale of Kinesiophobia scores, single/dual-task tandem gait time, or clinical RT.

CONCLUSIONS

Simple RT may be one risk factor that is associated with higher rates of subsequent injury after adolescent concussion. A simple RT measure incorporated into a comprehensive concussion RTP assessment may identify some individuals at higher risk of subsequent injury in the year after concussion, although further research is needed to better understand this relationship.

Effects of early sports specialization on landing and balance ability in female college basketball players

OBJECTIVES

Early specialization in a single sport from childhood is associated with an increased risk for acute and overuse injuries. Conversely, experience in multiple sports may be associated with improved neuromuscular control and performance. Currently, early sports specialization remains poorly researched in Japan. Therefore, this study aimed to clarify the relationship between early sports specialization and landing and balance ability in Japan.

METHODS

Thirty-eight female college basketball players were included and divided into the early specialization and nonspecialization groups. Landing and balance ability was measured using the one-leg jump-landing test, and the Star Excursion Balance Test (SEBT) differences between the two groups were examined using unpaired t-test.

RESULTS

Results showed no significant differences in SEBT between the two groups. In the one-leg jump-landing test, the vertical maximum ground reaction force and loading rate of the nondominant foot were significantly higher in the early specialization group than in the nonspecialization group.

CONCLUSION

Thus, in female college basketball players, early specialization may affect ground reaction forces and loading rate and may be a factor in developing acute and overuse injuries.

Relationship Between Postural Stability and Proprioception, Pain, Quadriceps Strength, and Muscle Tightness in Athletes With Patellar Tendinopathy

BACKGROUND

Athletes with patellar tendinopathy (PT) have postural stability deficits; however, the underlying mechanisms and factors responsible remain unknown. The effect on postural stability in PT of decreased quadriceps strength, altered proprioception, lower-limb muscle tightness, and knee pain, which explain postural stability deficiency in other populations, is uninvestigated.

HYPOTHESIS

Proprioceptive acuity, muscle tightness, quadriceps strength, and pain predict postural stability in athletes with PT.

STUDY DESIGN

Cross-sectional comparative study.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 43 athletes with PT and 43 healthy athletes were enrolled. Static and dynamic postural stability, proprioceptive acuity, muscle tightness, quadriceps strength, and pain were evaluated using a force platform, Y-balance test (YBT), a weight discrimination protocol, a goniometer, an isometric dynamometer, and a valid questionnaire, respectively.

RESULTS

Athletes with PT had significantly worse static and dynamic postural stability in the affected limb (AL) compared with the nonaffected limb (NAL) (P < 0.01) and the control group (P < 0.01). Athletes suffering from PT revealed lower quadriceps strength (P < 0.01), proprioceptive acuity (P = 0.02), and higher muscle tightness in the AL compared with the NAL and controls. Quadriceps weakness of the AL and pain in athletes with PT explained the variance of dynamic postural stability impairment.

CONCLUSION

Athletes with PT have postural stability deficiency compared with healthy peers. Our results demonstrate that quadriceps muscle weakness and pain are the factors that explain postural stability impairment.

CLINICAL RELEVANCE

These results can assist clinicians in the design of therapeutic balance rehabilitation programs by acting not only on pain relief but also on quadriceps strengthening through resistance training to avoid subsequent injuries in athletes with PT.

Comparing reach distance between the Y-Balance Test-Lower Quarter and Star Excursion Balance Test: Are practitioners using the correct protocol?

OBJECTIVES

To compare reach distances between the YBT-LQ and SEBT using the correct protocols as outlined by the developers. This will provide an accurate insight on the actual magnitude differences in reach distance between the movement screen tests and will safeguard practitioners on the subsequent use of these outcomes to inform clinical decision making.

DESIGN

Observational.

SETTING

Laboratory.

PARTICIPANTS

Participants included sixteen healthy female subjects from the university and amateur sports teams.

MAIN OUTCOME

Reach distances in the anterior direction (ANT), posterior medial (PM) and posterior lateral (PL) between participants on the YBT-LQ and SEBT.

RESULTS

The principal findings highlighted that a statistically significantly greater reach distance on the left and right side for the YBT-LQ compared to the SEBT in the ANT, PM, and PL directions (p < 0.0005).

CONCLUSION

The results of this study suggest that the YBT-LQ and SEBT are not comparable tests due to the differences in reach distance and methodological differences. Therefore, previous, and future research using the YBT-LQ and SEBT cannot be used interchangeably. Not following developed guidelines questions the applicability of the findings of reach distance scores to infer on performance and assessment of injury risk.

Changes in Dynamic Balance Ability Among Firefighter Recruits: A Longitudinal Cohort Study

ABSTRACT

Cornell, DJ, Gnacinski, SL, and Ebersole, KT. Changes in dynamic balance ability among firefighter recruits: A longitudinal cohort study. J Strength Cond Res 38(4): 734-741, 2024-It has been suggested that enhanced balance ability may mitigate the high musculoskeletal injury (MSKI) rate among firefighters, but the longitudinal changes in dynamic balance ability within this tactical athlete population have yet to be characterized. The purpose of this study was to examine the changes in dynamic balance ability of a cohort population of firefighter recruits completing a training academy and their probationary period as active-duty firefighters. Twenty-seven male firefighter recruits completed the modified Star Excursion Balance Test (mSEBT) at the beginning (W1) and at the end of their training academy (W14) and after completing their probationary period as active-duty firefighters (W38). After controlling for age and changes in body fat (BF) over time, significant changes in mSEBTANT ( p < 0.001), mSEBTPL ( p = 0.015), mSEBTPM ( p < 0.001), and mSEBTCOMP ( p = 0.003) were observed across time. Although mSEBTPL performance significantly increased ( p = 0.033) in from W1 to W14, significant decreases in all mSEBT reach directions were observed from W14 to W38 ( p < 0.05), with mSEBTANT ( p < 0.001) and mSEBTCOMP ( p = 0.002) also significantly decreasing from W1 to W38. However, the frequency of right vs. left asymmetries (>4 cm) did not significantly change over time in any mSEBT reach direction ( p > 0.05). Irrespective of age or changes in BF, minimal changes in the dynamic balance ability of firefighter recruits were observed during their training academy, but significant decreases in balance ability were noted by the end of their probationary period.

Risk Factors for Running-Related Injury in High School and Collegiate Cross-country Runners: A Systematic Review

OBJECTIVE: To summarize and describe risk factors for running-related injuries (RRIs) among high school and collegiate cross-country runners. DESIGN: Descriptive systematic review. LITERATURE SEARCH: Four databases (Scopus, SPORTDiscus, CINAHL, Cochrane) were searched from inception to August 2023. STUDY SELECTION CRITERIA: Studies assessing RRI risk factors in high school or collegiate runners using a prospective design with at least 1 season of follow-up were included. DATA SYNTHESIS: Results across each study for a given risk factor were summarized and described. The NOS and GRADE frameworks were used to evaluate quality of each study and certainty of evidence for each risk factor. RESULTS: Twenty-four studies were included. Overall, study quality and certainty of evidence were low to moderate. Females or runners with prior RRI or increased RED-S (relative energy deficiency in sport) risk factors were most at risk for RRI, as were runners with a quadriceps angle of >20° and lower step rates. Runners with weaker thigh muscle groups had increased risk of anterior knee pain. Certainty of evidence regarding training, sleep, and specialization was low, but suggests that changes in training volume, poorer sleep, and increased specialization may increase RRI risk. CONCLUSION: The strongest predictors of RRI in high school and collegiate cross-country runners were sex and RRI history, which are nonmodifiable. There was moderate certainty that increased RED-S risk factors increased RRI risk, particularly bone stress injuries. There was limited evidence that changes in training and sleep quality influenced RRI risk, but these are modifiable factors that should be studied further in this population. J Orthop Sports Phys Ther 2024;54(2):1-13. Epub 16 November 2023. doi:10.2519/jospt.2023.11550.

Effects of External Abdominal Pressure Support on Dynamic Balance: A Randomized Crossover Study

Abdominal pressure is vital in protecting the lumbar spine and controlling postural balance. Dynamic balance is associated with movement stability, adaptation to load, and reduced injury risk. Although trunk stability has been examined using belts and braces, the effects of external abdominal pressure support (APS) on balance control remain unknown. In this study, we aimed to determine the effects of external APS on dynamic balance. Overall, 31 young adults participated in this randomized crossover study. External APS was provided using a device that could be pressurized and decompressed by inflating a cuff belt wrapped around the trunk. The modified Star Excursion Balance Test was performed under external APS and non-APS conditions. The maximum anterior, posterolateral, and posteromedial values normalized to the spinal malleolar distance and their respective composite values were compared between the two conditions with and without APS. Posterolateral, posteromedial, and composite values were significantly higher in the APS condition than in the non-APS condition (p < 0.001). The external APS was effective in immediately improving dynamic balance. Furthermore, APS was effective in dynamic balance control as it improved stability during anterior trunk tilt, which displaces the center of gravity forward.

Anterior component of Y-Balance test is correlated to ankle dorsiflexion range of motion in futsal players: A cross-sectional study

BACKGROUND AND PURPOSE

Restricted dorsiflexion range of motion (DFROM) could impact dynamic balance in sports. This study aimed to investigate the relationship between dorsiflexion range of motion and the Y-Balance Test (YBT) in elite futsal players.

METHODS

Sixty-one asymptomatic male futsal players (mean age 26.57 (5.64) years, a mean body mass index of 25.40 (2.69) kg/m2 ) were included. DFROM was measured by the weight-bearing lunge test (WBLT). DFROM data were obtained using smartphone-based motion capture. The Pearson correlation coefficient verified the correlation between the variables.

RESULTS

Dominant and nondominant leg ankle DFROM was significantly correlated with the anterior component of YBT (r = 0.27 and 0.51, respectively). The posteromedial component and the composite score of the YBT were also significantly correlated with nondominant leg ankle DFROM (r = 0.31 and 0.34, respectively)]. The other measures were not statistically significant. DFROM explained between 7% and 24% of the variation of the distances reached in the YBT.

CONCLUSION

Dorsiflexion range of motion measured by weight bearing lunge test is positively correlated with dynamic balance in futsal players.

Deficits in Dynamic Balance and Hop Performance Following ACL Reconstruction Are Not Dependent on Meniscal Injury History

Background

Athletes often exhibit persistent deficits in dynamic balance and hop performance in their involved limb following ACL reconstruction. However, it is unclear how meniscal injury history affects inter-limb asymmetry.

Purpose

The purpose of this study was to compare inter-limb asymmetry in dynamic balance and hop performance in athletes with and without a history of concomitant meniscal injury.

Study Design

Cross-sectional study.

Methods

Dynamic balance and hop test data were analyzed for 34 adolescent athletes who had undergone ACL reconstruction; 19 athletes had sustained an isolated ACL tear, while 15 had sustained an ACL tear along with a meniscus injury. Athletes who had sustained a meniscus injury were sub-divided into those who underwent a meniscal repair (n = 9) versus a partial meniscectomy (n = 6). Dynamic balance was assessed using the Y-Balance Test, while hop performance was assessed using the single and triple hop tests. Data were recorded at the time of return-to-sport testing (5-11 months post-surgery). For each variable, mixed-model analysis of variance, with a between-subjects factor of group (isolated ACL tear, meniscal repair, partial meniscectomy) and a within-subjects factor of limb (involved, uninvolved), was conducted.

Results

The groups exhibited similar degrees of inter-limb asymmetry in dynamic balance and hop test performance, as there was not a group-by-limb interaction effect for the Y-Balance Test distances (p ≥ 0.43) or hop test distances (p ≥ 0.96). However, there was a main effect of limb for the anterior and posteromedial Y-Balance Test distances and the single and triple hop test distances (p ≤ 0.004). For each variable, performance was worse for the involved limb, compared to the uninvolved limb.

Conclusion

It appears that deficits in dynamic balance and hop performance among adolescent athletes who have undergone ACL reconstruction are not dependent on meniscal injury/surgery history.

Level of Evidence

3.

Establishing Normative Dynamic Postural Control Values in Elite Female Handball Players

Background

Lower extremity injuries among young female handball players are very common. The modified Star Excursion Balance Test (mSEBT) is a valid clinical tool to assess dynamic postural control and identify athletes with higher risk of injury. However, its interpretation is difficult since performance on this test is highly sport dependent. No normative values on the mSEBT exist in handball.

Purpose

The aim of this investigation was to establish normative ranges of mSEBT performance in young, healthy female handball players to help practitioners when interpreting risk estimates.

Study design

Cross-Sectional Study.

Methods

Athletes from 14 elite teams were recruited during a national tournament and performed 3 trials in the anterior (ANT), posteromedial (PM), posterolateral (PL) directions of the mSEBT. Means, standard deviations and 95% confidence intervals (95%CI) of normalized reached distances were calculated for each direction and the composite score (COMP). Level of asymmetry between dominant and non-dominant limbs were calculated for each direction using Bland Altman analyses. Group differences were weighed against the established mSEBT minimum detectable differences (MDD) to compare scores between limbs and across different player positions.

Results

One-hundred and eighty-eight females (16.8±0.9 years) were tested. Mean reach distances were 65.2±5% (64.7-65.7), 110.0±6.2% (109.3-110.6), 107.1±6.2% (106.5-107.8) and 94.1±4.9% (93.6-94.6) for the ANT, PM, PL directions and COMP score respectively. Bias and limits of agreement for limb asymmetry were -0.23% (-5.85%, 5.38%) for ANT, -0.83% (-8.80%, 7.14%) for PM, 0.33% (-8.51%, 9.17%) for PL and -0.27% (-4.88%, 4.33%) for COMP score. No meaningful differences were observed between limbs or across player positions since the values did not exceed the MDD and all 95%CIs overlapped.

Conclusion

This study provides normative performance values for dynamic postural control as measured by the mSEBT among young, healthy, elite female handball players. Considering the high incidence of injury in this population, these values can be used for injury risk reduction and return to sport decisions. Further prospective studies are needed to established specific cut-off scores in this population.

Level of evidence

2c.

Investigation of Joint Position Sense and Balance in Individuals With Chronic Idiopathic Neck Pain: A Cross-Sectional Study

OBJECTIVE

The aim of this study was to determine the relationship between joint position sense and static and dynamic balance in female patients with chronic neck pain compared with healthy controls.

METHODS

The study sample comprised 25 female patients with chronic neck pain and 25 healthy (asymptomatic) female controls. Pain severity with the visual analog scale, joint position sense with the laser pointer method, static balance with the Single-Leg Balance Test, and dynamic balance with the Y Balance Test were assessed.

RESULTS

The deviation in cervical joint position sense was greater in extension (P < .001), right rotation (P < .001), and left lateral rotation (P < .05) in the patients with chronic neck pain compared with the healthy controls. The results of the patients with chronic neck pain were worse than the healthy controls in the Single-Leg Balance Test with both eyes open (P < .05) and eyes closed (P < .05). The patients with chronic neck pain had worse dynamic balance only in the anterior direction reach of the left leg (P < .05).

CONCLUSION

Cervical joint position sense and static balance were worse in female patients with chronic idiopathic neck pain when compared with asymptomatic controls. Dynamic balance in all other directions except for the anterior direction was not negatively affected in individuals with chronic idiopathic neck pain.

Quantifying balance deficit in people with ankle fracture six months after surgical intervention through the Y-Balance test

BACKGROUND

Ankle fractures are among the most common traumatic fractures and have a great socio-economic impact. Consequences of an ankle fracture requiring surgical treatment (e.g. pain, reduced ankle range of motion (ROM), muscle weakness, etc.) lead to balance deterioration, which has a profound impact on activities of daily living. However, to the best of the authors' knowledge, no reliable clinical tests are available to monitor balance in patients after ankle surgery.

OBJECTIVES

To quantify single-leg dynamic balance in patients with bimalleolar ankle fracture through the Y-Balance test (YBT). The second objective was to analyze the impact of ankle dorsiflexion ROM and hip strength on balance to optimize balance rehabilitation programs.

DESIGN

Cross-sectional study.

METHODS

22 participants, who had undergone surgery after bimalleolar ankle fractures, were assessed for ankle ROM, hip strength, and dynamic balance six-months after the surgical intervention. The within-session reliability of YBT was calculated through the intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). Student's t-tests were used to assess leg differences. A multiple regression analysis was performed to evaluate the role of ankle dorsiflexion ROM and hip abductor and adductor strength in predicting balance performance.

RESULTS

YBT showed high-to-excellent within-session relative reliability (Healthy leg: 0.85 ≤ ICC≤0.96; Operated leg: 0.84 ≤ ICC≤0.96). SEM values were below 3.3 %. The operated leg showed significant lower YBT scores for anterior reach direction (-9.0 %; g=-0.70) and composite score (-4.5 %; g=-0.34). Multiple regression analysis showed that both, ankle dorsiflexion and hip abductor and adductor strength explained 66 % of the variance in the YBT anterior direction of the operated leg.

CONCLUSIONS

The YBT is a reliable tool that allows the quantification of single-leg dynamic balance impairments from 6-months after surgery in patients with bimalleolar ankle fracture. Between-leg YBT differences in the anterior direction can be used as reference scores (3.3 %) for balance restoration. Balance rehabilitation programs should focus on improving ankle functionality and reducing hip muscle weakness with specific hip strength exercises and balance exercises with similar demands to the reaching tasks of the YBT to promote a faster recovery.

Which Functional Tests and Self-Reported Questionnaires Can Help Clinicians Make Valid Return to Sport Decisions in Patients With Chronic Ankle Instability? A Narrative Review and Expert Opinion

Lateral ankle sprain is the most common injury in sports, with up to 40% of patients developing chronic ankle instability (CAI). One possible cause underlying this high rate of recurrence or feeling of giving way may be a premature return to sport (RTS). Indeed, except for time-based parameters, there are no specific criteria to guide clinicians in their RTS decisions in patients with CAI. A recent international consensus highlighted the relevance and importance of including patient-reported ankle function questionnaires combined with functional tests targeting ankle impairments in this population. Thus, the aim of this narrative review and expert opinion was to identify the most relevant functional performance tests and self-reported questionnaires to help clinicians in their RTS decision-making process following recurrent ankle sprains or surgical ankle stabilization. The PubMed (MEDLINE), PEDro, Cochrane Library and ScienceDirect databases were searched to identify published articles. Results showed that the single leg stance test on firm surfaces, the modified version of the star excursion balance test, the side hop test and the figure-of-8 test appeared to be the most relevant functional performance tests to target ankle impairments in patients with CAI. A combination of the Foot and Ankle Ability Measure (FAAM) and the Ankle Ligament Reconstruction-Return to Sport after Injury (ALR-RSI) questionnaires were the most relevant self-reported questionnaires to assess patient function in the context of CAI. Although these functional tests and questionnaires provide a solid foundation for clinicians to validate their RTS decisions in patient with CAI, objective scientific criteria with cut-off scores are still lacking. In addition to the proposed test cluster, an analysis of the context, in particular characteristics related to sports (e.g., fatigue, cognitive constraints), to obtain more information about the patient's risk of recurrent injury could be of added value when making a RTS decision in patients with CAI. In order to evaluate the strength of evertors under ecological conditions, it would also be interesting to assess the ability to control weight-bearing ankle inversion in a unipodal stance. Further studies are needed to assess the relevance of this proposed test cluster in RTS decision-making following lateral ankle sprain injury and CAI.

Interday Reliability of a Testing Battery to Assess Lateral Symmetry and Performance in Well-Trained Volleyball Players

ABSTRACT

Iglesias-Caamaño, M, Álvarez-Yates, T, Carballo-López, J, Cuba-Dorado, A, and García-García, O. Interday reliability of a testing battery to assess lateral symmetry and performance in well-trained volleyball players. J Strength Cond Res 36(4): 895-901, 2022-This study aimed to determine the relative and absolute interday reliability of a testing battery for lateral asymmetry detection and performance in well-trained volleyball players and to determine whether retaining for analysis the best or the average value of 3 attempts would modulate the interday reliability and the magnitude of asymmetry. Thirteen Superleague-2 male volleyball players performed on 3 different days a 5-test battery composed of 4 tests for assessing muscle asymmetries: active knee extension, Y-balance test (YBT), modified 20-yard shuttle run (M-20Y), and single-leg countermovement jump; and one for volleyball sports performance: attack jump (AJ). The intraclass correlation index and coefficient of variation (CV) together with the standard error of measurement (SEM, %SEM) and the minimum detectable change (MDC, %MDC) were taken to calculate relative and absolute reliability. Two-way repeated-measures analysis of variance was used to establish the differences between the best value and the average value in each session. The low %MDC (<10%) suggests that all the tests that make up the testing battery would have good sensitivity to detect possible asymmetries. All tests have shown an excellent interday absolute reliability (CV <4.5%; %SEM < 5%), both when retaining the best value and the average value of the 3 attempts. In addition, AJ and YBT (on both legs) obtained a good-excellent relative reliability, whereas the M-20Y test seems to show a lower relative reliability. Retaining the best value or the average value to determine the magnitude and direction of asymmetry seems to be equally reliable with no differences between both values.

Load-Induced Changes of Inter-Limb Asymmetries in Dynamic Postural Control in Healthy Subjects

Inter-limb asymmetries are associated with a higher potential risk for non-contact injuries. Differences in function or performance between the limbs might lead to imbalances and promote instability, increasing the potential risk for injuries. Consequently, an investigation of inter-limb asymmetries should be included in injury risk assessment. Furthermore, since non-contact injuries mainly occur under loaded conditions, an investigation of load-induced changes of inter-limb asymmetries can provide additional information on the athlete's potential injury risk. Therefore, the current study aimed to investigate the influence of physical load on inter-limb asymmetries in dynamic postural control, which is essential in situations with a high risk for non-contact injuries such as landing, cutting, or stopping. In total, dynamic postural control of 128 active and healthy subjects (64 males and 64 females, age: 23.64 ± 2.44, height: 176.54 ± 8.96 cm, weight: 68.85 ± 10.98 kg) was examined. Dynamic postural control was tested with the Y-Balance Test (YBT) before and after a loading protocol on a bicycle ergometer or a treadmill. The results showed no significant increase of the inter-limb asymmetries in anterior direction [F (1, 126) = 4.44, p = 0.04, η2 p = 0.03]. Moreover, there is high variation between the subjects regarding the magnitude and the direction of the asymmetries and the changes due to load. Therefore, a more individual analysis considering the magnitude and the direction of the asymmetries is required. Thereby, considering different modifying factors, e.g., sex, injury history, and baseline level of asymmetries, can be helpful. Moreover, an analysis of the changes during load might provide further insights, reveal possible differences, and help detect the reasons and mechanisms underlying inter-limb asymmetries and asymmetrical loading.

Can Compression Garments Reduce Inter-Limb Balance Asymmetries?

Sensory cues provided by compression garments (CG) can improve movement accuracy and potentially reduce inter-limb balance asymmetries and the associated risk of injury. The aim of this study was to analyze the effects of CG wearing on inter-limb balance asymmetries. The hypothesis was that CG would reduce inter-limb balance asymmetries, especially in subjects with high level of asymmetries. Twenty-five sportsmen were recruited. They had to stand as motionless as possible in a one-leg stance in two postural tasks (stable and unstable), while wearing CG or not. Asymmetry indexes were calculated from center of foot pressure parameters. The effects of CG wearing were analyzed according to participants’ baseline level of asymmetry (i.e., without wearing CG) with correlation analyses. A qualitative analysis was also performed after a dichotomization procedure to check for a specific influence of CG on the dominant and non-dominant leg. Inter-limb balance asymmetries were reduced with CG in participants with high levels of asymmetries at baseline. However, asymmetries were increased with CG in participants with low levels of asymmetries at baseline. The dominant leg was more affected by this negative effect. CG wearing could reduce inter-limb balance asymmetries and the related injury risk in subjects with high levels of inter-limb balance asymmetries at baseline. Nevertheless, CG should not be used in individuals with low baseline balance asymmetries since it can increase asymmetries in these subjects, likely by confusing and overloading the sensorimotor processing on the dominant leg.

The Star Excursion Balance Test: An Update Review and Practical Guidelines

The Star Excursion Balance Test (SEBT) is a reliable, responsive, and clinically relevant functional assessment of lower limbs’ dynamic postural control. However, great disparity exists regarding its methodology and the reported outcomes. Large and specific databases from various population (sport, age, and gender) are needed to help clinicians when interpreting SEBT performances in daily practice. Several contributors to SEBT performances in each direction were recently highlighted. The purpose of this clinical commentary is to (a) provide an updated review of the design, implementation, and interpretation of the SEBT and (b) propose guidelines to standardize SEBT procedures for better comparisons across studies.

Scoring Performance on the Y-Balance Test Using a Deep Learning Approach

The Y Balance Test (YBT) is a dynamic balance assessment typically used in sports medicine. This work proposes a deep learning approach to automatically score this YBT by estimating the normalized reach distance (NRD) using a wearable sensor to register inertial signals during the movement. This paper evaluates several signal processing techniques to extract relevant information to feed the deep neural network. This evaluation was performed using a state-of-the-art human activity recognition system based on recurrent neural networks (RNNs). This deep neural network includes long short-term memory (LSTM) layers to learn features from time series by modeling temporal patterns and an additional fully connected layer to estimate the NRD (normalized by the leg length). All analyses were carried out using a dataset with YBT assessments from 407 subjects, including young and middle-aged volunteers and athletes from different sports. This dataset allowed developing a global and robust solution for scoring the YBT in a wide range of applications. The experimentation setup considered a 10-fold subject-wise cross-validation using training, validation, and testing subsets. The mean absolute percentage error (MAPE) obtained was 7.88 ± 0.20%. Moreover, this work proposes specific regression systems to estimate the NRD for each direction separately, obtaining an average MAPE of 7.33 ± 0.26%. This deep learning approach was compared to a previous work using dynamic time warping and k-NN algorithms, obtaining a relative MAPE reduction of 10%.

Risk Factors for Non-Contact Lower-Limb Injury: A Retrospective Survey in Pediatric-Age Athletes

Background: Risk factors for non-contact lower-limb injury in pediatric-age athletes and the effects of lateral dominance in sport (laterally vs. non-laterally dominant sports) on injury have not been investigated. Purpose: To identify risk factors for non-contact lower-limb injury in pediatric-age athletes. Methods: Parents and/or legal guardians of 2269 athletes aged between 6–17 years were recruited. Each participant completed an online questionnaire that contained 10 questions about the athlete’s training and non-contact lower-limb injury in the preceding 12 months. Results: The multivariate logistic regression model determined that lateral dominance in sport (adjusted OR (laterally vs. non-laterally dominant sports), 1.38; 95% CI, 1.10–1.75; p = 0.006), leg preference (adjusted OR (right vs. left-leg preference), 0.71; 95% CI, 0.53–0.95; p = 0.023), increased age (adjusted OR, 1.21; 95% CI, 1.16–1.26; p = 0.000), training intensity (adjusted OR, 1.77; 95% CI, 1.43–2.19; p = 0.000), and training frequency (adjusted OR, 1.36; 95% CI, 1.25–1.48; p = 0.000) were significantly associated with non-contact lower-limb injury in pediatric-age athletes. Length of training (p = 0.396) and sex (p = 0.310) were not associated with a non-contact lower-limb injury. Conclusions: Specializing in laterally dominant sports, left-leg preference, increase in age, training intensity, and training frequency indicated an increased risk of non-contact lower-limb injury in pediatric-age athletes. Future research should take into account exposure time and previous injury.

Relationships between balance and physical fitness variables in firefighter recruits

BACKGROUND

Research has suggested that balance ability contributes to musculoskeletal injury (MSKI) rates in firefighters. Though the Y-Balance Test (YBT) can predict injury, it is unclear what physical measures inform YBT performance in firefighters. Thus, there is a lack of knowledge regarding best practice for improving balance in firefighters.

OBJECTIVE

To evaluate the relationship between the YBT and fitness measures, including body composition, aerobic capacity, functional total-body power, upper and lower-body strength, and movement efficiency, among firefighters.

METHODS

Dynamic balance (YBT), body mass index (BMI), body-fat percentage (BF%), fat free mass (FFM), aerobic capacity (VO2max), stair climb (SC), upper (1RMbench) and lower-body (1RMsquat) strength, and Fusionetics™ Movement Efficiency Screen (ME) measures were collected among 35 firefighter recruits. Pearson correlation coefficients were used to examine relationships between YBT and the performance measures.

RESULTS

Dynamic balance ability in firefighter recruits is significantly (p < 0.05) related to BMI, lower-body strength, and movement quality, but not with aerobic capacity, stair climb performance, and upper body strength.

CONCLUSIONS

Greater YBT performance in firefighter recruits is associated with lower BMI, greater functional movement, and greater lower-body strength. Future research is warranted to incorporate these elements into balance training programs for firefighter recruits.

A Narrative Review of Limb Dominance: Task Specificity and the Importance of Fitness Testing

ABSTRACT

Virgile, A and Bishop, C. A narrative review of limb dominance: Task specificity and the importance of fitness testing. J Strength Cond Res 35(3): 846-858, 2021-Preferential limb function must be sustained through repetitious asymmetrical activities for continuous athletic development and, ultimately, optimal athletic performance. As such, the prevalence of limb dominance and between-limb differences is common in athletes. Severe between-limb differences have been associated with reductions in athletic performance and increased injury risk in athletes. However, in the current literature, the terms limb preference and limb dominance have been used interchangeably. Together, these terms include a limb that is subjectively preferred and one that is objectively dominant in 1 or more performance measures from a variety of athletic tasks. In this review, we (a) discuss reported correspondence between task-specific limb preference and limb dominance outcomes in athletes, (b) provide greater context and distinction between the terms limb preference and limb dominance, and (c) offer pragmatic strategies for practitioners to assess context-specific limb dominance. A limb that is subjectively preferred is not necessarily objectively dominant in 1 or more athletic qualities or sport-specific tasks. Further to this, a limb that is objectively superior in 1 task may not exhibit such superiority in a separate task. Thus, limb preference and limb dominance are both task-specific. As such, we propose that practitioners intentionally select tasks for limb dominance assessment which resemble the most relevant demands of sport. Because limb dominance profiles are inconsistent, we suggest that practitioners increase assessment frequency by integrating limb dominance testing into standard training activities. This will allow practitioners to better understand when changes reflect sport-specific adaptation vs. potential performance or injury ramifications.

Game Exposure, Player Characteristics, and Neuromuscular Performance Influence Injury Risk in Professional and Youth Field Hockey Players

BACKGROUND

Identifying factors that contribute to the occurrence of injury is an important step in designing training programs to minimize the risk of injury. However, despite high injury rates, variables contributing to injury in field hockey players remain relatively unexplored.

PURPOSE

To identify factors that may predict injury in professional and youth field hockey players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHOD

Professional and youth hockey players completed preseason neuromuscular performance testing and were monitored for injuries, training, and game exposure throughout the subsequent 12-month indoor and outdoor hockey season. Least absolute shrinkage and selection operator analysis was conducted to identify injury risk factors. Receiver operating characteristic curves were then calculated to determine the individual predictive accuracy of the identified variables.

RESULTS

A total of 83 players (mean ± SD age, 20.7 ± 4.9 years; 34.9% female) with complete performance, injury, and exposure data were included for data analysis. Almost half of players (44.6%) sustained a time-loss injury during the season, and 73% of these injuries occurred in the lower limb. Playing more games and having an older age, asymmetrical and poor dynamic postural control, and better explosive performance were identified as jointly influencing the risk of injury. When considered individually, number of games played throughout the season was the most accurate predictor of injury risk (area under the curve [AUC] = 0.74; P < .001), while asymmetrical and poor dynamic postural control (AUCs = 0.61-0.65; P = .01-.04) and better explosive athletic performance (AUCs = 0.65-0.67; P < .01) were identified as moderate individual predictors of sustaining a general or lower limb injury.

CONCLUSION

A number of modifiable factors were individually and jointly associated with an increased injury risk in field hockey players, providing initial evidence for the design of targeted and sport-specific training programs to mitigate the risk of injury.

Does lower-limb asymmetry increase injury risk in sport? A systematic review

OBJECTIVE

The aim of this review was to synthesize the current understanding relating to the risks of lower body functional asymmetry with injury in athletic populations.

METHODS

An iterative data mining and sampling approach was used to construct a search phrase from key words, which were used to identify studies within SPORTdiscus, Medline and Academic Search Complete databases. Additional references were sourced from the reference lists of these articles.

RESULTS

After screening, 31 papers were reviewed, from an initial search identifying 302 possible studies. A total of 6228 participants were involved in the studies, of which soccer players were the most observed sporting demographic (n = 2171). Of the 31 studies reviewed eight found no statistical association between lower limb asymmetry and injury risk, 10 studies provided partial statistically significant evidence and a further 10 provided statistically significant statistical links.

CONCLUSION

Overall moderate to lower quality evidence for functional asymmetry as a risk factor for injury in sport was observed. While the possibility of a relationship between lower limb functional asymmetry and injury risk cannot be ruled out, further higher quality investigations, adopting standardised methodologies, is required.

Accumulative Competitive Season Training Stress Affects Neuromuscular Function and Increases Injury Risk in Uninjured D1 Female Athletes

Previous research has shown that acute competition training stress negatively affects neuromuscular function which can perpetuate a predisposition to injury. This study's aim was to investigate the effect of accumulated competition training stress effect on neuromuscular function and incidence of increased injury risk in uninjured female D1 soccer players. Neuromuscular function was evaluated in fifteen female division I soccer athletes who played >85% of competitive season competitions who were tested for mobility/stability, leg length symmetry, and vertical power at three different points across the competitive season (pre, mid, and post time blocks). Leg length symmetry was measured from the anterior superior iliac spine to the lateral malleolus prior to Y-balance testing. The Y-balance testing measures unilateral anterior, posteromedial, and posterolateral reach achieved in single leg stance using metrics that include L/R normalized composite reach (NCOMP), L/R normalized antiorior reach (NANT), and L/R NCOMP/NANT segmental differences across time. Injury risk was evaluated using validated objective criteria that included: (NCOMP total reach <94% of limb length^*3), (NANT reach distance <84% leg length) along with NCOMP and NANT asymmetries >4.0. Maximal vertical power (MVP) was measured via vertical jump. Multiple repeated measures ANOVAs evaluated NCOMP, NANT, MVP, and leg length symmetry across time with LSD post hoc testing when relevant (X ± SD). A significant main effect was found [F_{(1, 14)} = 62.92, p < 0.001; η² =0.82] with training stress and neuromuscular function without affecting maximal vertical power. Eighty percent of subject's bilateral NCOMP scores fell below the YBT reach standard at midseason (ES = 0.95, p = 0.02) while all subjects NANT reach distance remained below the reach threshold (ES = 0.74, p = 0.003) indicating a 6.5× and 2.5× greater injury risk, respectively. Competition stress affected neuromuscular function without affecting maximal power, which negatively impacted stability and increased injury risk.

Analyzing the Magnitude of Interlimb Asymmetries in Young Female Soccer Players: A Preliminary Study

Although asymmetries in lower limbs have been linked with players' performance in male soccer players, literature that has been published addressing female soccer is scarce. Thus, the aim of this study was twofold: (i) describe the asymmetries of women soccer players during jumping, change-of-direction and range-of-motion tests; and (ii) test possible relationships between asymmetries and injury risk in female soccer players. Sixteen female players (15.5 ± 1.5 years) performed a battery of fitness tests (i.e., jump ability, change-of-direction ability and passive range-of-motion) and muscle mass analysis via dual-energy X-ray absorptiometry, through which the specific asymmetry index and the related injury risk were calculated. Significant (p < 0.05) lower asymmetries in the change-of-direction test were observed in comparison to those observed in jumping and range-of-motion tests; significant (p < 0.05) lower asymmetries in muscle mass were also reported compared to those found in the change-of-direction and countermovement jump tests. Additionally, increased injury risk for countermovement jump and hip flexion with extended knee range-of-motion (relating to asymmetry values) and for ankle flexion with flexed knee range-of-motion in both legs (relating to reference range-of-motion values), as well as increased individual injury risk values, were observed across all tests. These findings suggest the necessity to implement individual approaches for asymmetry and injury risk analyses.

Functional Movement Assessments Are Not Associated with Risk of Injury During Military Basic Training

INTRODUCTION

Musculoskeletal injuries (MSK-I) in the U.S. military accounted for more than four million medical encounters in 2017. The Military Entrance Processing Screen to Assess Risk of Training (MEPSTART) was created to identify MSK-I risk during the first 180 days of military service.

METHODS

Active duty applicants to the United States Army, Navy, Air Force, and Marine Corps between February 2013 and December 2014 who consented completed a behavioral and injury history questionnaire and the MEPSTART screen [Functional Movement Screen (FMS), Y-Balance Test (YBT), Landing Error Scoring System (LESS), and Overhead Squat assessment (OHS)] the day they shipped to basic training. Male (n = 1,433) and Female (n = 281) applicants were enrolled and MSK-I were tracked for 180 days. Binomial logistic regression and multivariate Cox proportional hazards modeling were used to assess relationships among MEPSTART screens and MSK-I independent of age, BMI, sex, Service, injury history, and smoking status. Analyses were finalized and performed in 2017.

RESULTS

The only functional screen related to injury was the LESS score. Compared to those with good LESS scores, applicants with poor LESS scores had lower odds of MSK-I (OR = 0.54, 95% CI = 0.30-0.97, p = 0.04), and a lower instantaneous risk of MSK-I during the first 180 d (HR = 0.58, 95%CI = 0.34-0.96, p = 0.04). However, secondary receiver operator characteristic (ROC) analyses revealed poor discriminative value (AUC = 0.49, 95%CI = 0.43-0.54).

CONCLUSIONS

Functional performance did not predict future injury risk during the first 180 days of service. Poor LESS scores were associated with lower injury risk, but ROC analyses revealed little predictive value and limited clinical usefulness. Comprehensive risk reduction strategies may be preferable for mitigating MSK-I in military training populations.

Identification of Ankle Injury Risk Factors in Professional Soccer Players Through a Preseason Functional Assessment

Background

Etiologically, the risk of an ankle injury depends on extrinsic and intrinsic factors, such as muscle strength asymmetry, decreased flexibility, and decreased proprioception, as well as patient age and history of injuries.

Purpose/Hypothesis

The purpose of this study was to identify risk factors present in the preseason assessment that may predispose professional soccer players to ankle injuries. We hypothesized that analysis of these parameters could relate the incidence of injuries to the deficits found during the preseason period, enabling the identification of risk factors to predict the occurrence of injuries.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 89 professional soccer athletes were evaluated in the preseason period; the evaluation included athlete history and anthropometric data collection, an isokinetic ankle evaluation, and functional tests: the Dorsiflexion Lunge Test and Y-Balance Test (YBT). The athletes were monitored during the competitive period, and the incidence of injuries was surveyed. The association of quantitative variables and injury outcomes was analyzed using the Student t test for independent samples, with P < .05. For the association of categorical variables and injury outcomes, the chi-square test was performed, with P < .05.

Results

A higher incidence of ankle injuries was associated with lower YBT scores in the dominant (P = .04) and nondominant (P = .01) limbs. A higher body mass index was also associated with a higher injury occurrence (P = .01).

Conclusion

Functional tests, such as the YBT, are indicated tools for assessing the physical capacities and possible risks of ankle sprains, as they can evaluate the ankle functional capacity in a complex way, identifying athletes more prone to ankle injuries. Athletes' body mass index should also be taken into account to prevent such injuries.

Kinematic and kinetic factors associated with leg reach asymmetry during the Star Excursion Balance Test in division I athletes

OBJECTIVES

To explore which balance and movement factors contribute most to reach distance asymmetry during the Star Excursion Balance Test (SEBT) in Division I athletes.

DESIGN

Cross-Sectional Study.

SETTING

Rehabilitation Biomechanics Laboratory, NCAA Division I Athletics Program.

PARTICIPANTS

36 Division I athletes (20 Male; 16 Female).

MAIN OUTCOME MEASURES

Center of Pressure, Kinematic and Kinetic variables were measured during performance of anterior, Posterior-Medial (PM), and Posterior-Lateral (PL) directions of the SEBT in order to determine which factors predict reach distance asymmetry.

RESULTS

COP variables approached significance in predicting asymmetry for the anterior direction (p <0.08), kinematic variables approached significance in predicting asymmetry in the PL direction (p < 0.06), and kinetic variables were significant in predicting asymmetry in the PM direction (p < 0.03).

CONCLUSIONS

Findings suggest that different strategies could be used to improve leg reach asymmetry based on specific direction of the asymmetry. Improving ability to control COP area seems to be important for the anterior direction, while control of limb movement seems to be most important for leg reach asymmetry in the PM and PL directions.

Ankle Sprains Risk Factors in a Sample of French Firefighters: A Preliminary Prospective Study

Context: Firefighters participating in mandatory physical exercise sessions are exposed to a high risk of ankle sprain injury. Although both physiological and psychological risk factors have been identified, few prospective studies considered the complex interaction of these factors in firefighters. Objective: To prospectively determine whether intrinsic physical risk factors and work-related environments predict ankle sprains occurring during on-duty physical exercise in firefighters during an 8-month follow-up period. Design: Prospective. Setting: Fire Department and Rescue Service. Participants: Thirty-nine firefighters were selected based on convenience sampling. Intervention: Participants performed physical tests and completed questionnaires. Main Outcome Measures: Lower Quarter Y-Balance Test, Weight-Bearing Lunge Test, anthropometric measures, postural stability, chronic ankle instability (Cumberland Ankle Instability Tool) scores, previous injuries, and perceived psychosocial work environment (Copenhagen Psychosocial Questionnaire [COPSOQ]). Results: During the follow-up, 9 firefighters sustained an injury. Lower Quarter Y-Balance Test and Weight-Bearing Lunge Test performances, Cumberland Ankle Instability Tool scores, history of previous ankle sprain, and specific dimensions of the COPSOQ significantly differed between injured and uninjured firefighters. Lower-limbs asymmetries of the Lower Quarter Y-Balance Test (ie, anterior, posteromedial, and posterolateral directions) and the Weight-Bearing Lunge Test were predictors of ankle sprains. Conclusions: These findings originally provide evidence that intrinsic factors mainly contribute to ankle sprains, although psychosocial work environment assessment could also characterize firefighters at risk.

Athletes with a concussion history in the last two years have impairments in dynamic balance performance

The purpose of this study was to determine if National Collegiate Athletics Association Division 1 American Football and Ice Hockey athletes with a history of concussion have impaired dynamic balance control when compared to healthy control athletes. This cross-sectional observational study recruited 146 athletes; 90 control athletes and 56 athletes with a history of concussion. Athletes were tested during a pre-season evaluation using the inertial-sensor instrumented Y Balance Test. Independent variables were normalized reach distance, gyroscope magnitude sample entropy, and jerk magnitude root mean square. Kruskal-Wallis H test and Dunn-Bonferroni analysis demonstrated that individuals with a concussion history within the last 2 years have statistically significantly lower jerk magnitude root mean square in the posteromedial (Z = 23.22, P = .015) and posterolateral (Z = 24.64, P = .010) reach directions, when compared to the control group. There was no significant difference between those who sustained a concussion longer than two years ago and the control group for the posteromedial (Z = -1.25; P = .889) and posterolateral (Z = 6.44; P = .469) directions. These findings show that athletes with a concussion history within the last two years possess dynamic balance deficits, when compared to healthy control athletes. Conversely, athletes whose injury occurred greater than 2 years ago possessed comparable performance to the healthy controls. This suggests that sensorimotor control deficits may persist beyond clinical recovery, for up to 2 years. Therefore, clinicians should integrate balance training interventions into the return-to-play process to accelerate sensorimotor recovery and mitigate the risk of future injury.

Comparison of Functional Movement Screen, Star Excursion Balance Test, and Physical Fitness in Junior Athletes with Different Sports Injury Risk

Objectives

The aim of this study was to assess the relationships between functional movement screen (FMS), star excursion balance test (SEBT), agility T test, and vertical jump test scores and sports injury risk in junior athletes. We compared these assessments and the differences between groups with high and low risks of sports injury. Subjects and Methods. Eleven volleyball, 12 basketball, and 9 handball athletes were recruited. All participants followed the routine training in school sports teams. Weekly training schedules followed a similar pattern. The 32 junior athletes (age = 16.06 ± 0.21 years; height = 167.28 ± 6.32 cm; and body mass = 68.45 ± 9.67 kg) were assessed using the FMS, SEBT, agility T test, and vertical jump test in random order. The correlations of composite and individual item scores of these assessments were analyzed, and the differences between groups with high and low risks of sports injury were compared.

Results

All participants completed the study protocol. No significant differences were observed between FMS, SEBT, agility T test, and vertical jump test scores in groups with high and low risks of sports injuries. Fair and moderate-to-good correlations were observed for anterior reach maximum of SEBT and deep squat (r = 0.47, P = 0.02) as well as inline lunge (r = 0.53, P = 0.01) of FMS. The hurdle step of FMS also exhibited moderate-to-good (r = 0.52, P = 0.01) and fair (r = 0.42, P = 0.04) correlations with posterior medial and posterior lateral reach maximum of SEBT, respectively. A fair correlation was observed between posterior lateral reach maximum of SEBT and rotary stability of FMS (r = −0.23, P = 0.03). Fair and moderate-to-good correlations were identified for agility T test and maximum anterior reach in the SEBT (r = −0.42, P = 0.04) and trunk stability push-up in the FMS, respectively (r = −0.57 and P = 0.006).

Conclusions

Junior athletes with a high risk of sports injury did not exhibit differences in terms of FMS, SEBT, and physical fitness test scores. Deep squat, hurdle step, inline lunge, and rotary stability scores in the FMS were correlated with the item scores in the SEBT, which may be due to the use of similar movement patterns. Scores for anterior reach maximum in the SEBT and trunk stability push-up in the FMS were correlated with agility T test scores, suggesting a similar task requirement of trunk stability and dynamic weight shifting ability.

Preseason Dynamic Balance Performance in Healthy Elite Male Soccer Players

Lower limb musculoskeletal injuries in sports are linked with balance abnormalities and altered postural control. Dynamic balance screening should be performed in order to identify athletes at risk. The purpose of the study was to evaluate the preseason dynamic balance performance and side-to-side asymmetry of healthy elite male soccer players, using modified Star Excursion Balance Test (mSEBT). Seventy-three elite soccer players (23.8 ± 5.4 years) were evaluated using the mSEBT. Normalized reach distances, side-to-side asymmetries, and composite scores were determined. The composite scores were 93.33% ± 8.99% for dominant leg and 93.36% ± 9.23% for nondominant leg. No significant differences were found between dominant and nondominant limb in any direction. The mSEBT is an easy-to-use tool to measure the dynamic balance performance in elite athletes. It can be applied successfully during preseason physical examinations. Future studies are needed to establish predictive cutoff points in order to increase mSEBT use in screening soccer players for dynamic balance abnormalities and identify those at risk for noncontact lower limb injuries.

Reliability, Validity and Utility of Inertial Sensor Systems for Postural Control Assessment in Sport Science and Medicine Applications: A Systematic Review

BACKGROUND

Recent advances in mobile sensing and computing technology have provided a means to objectively and unobtrusively quantify postural control. This has resulted in the rapid development and evaluation of a series of wearable inertial sensor-based assessments. However, the validity, reliability and clinical utility of such systems is not fully understood.

OBJECTIVES

This systematic review aims to synthesise and evaluate studies that have investigated the ability of wearable inertial sensor systems to validly and reliably quantify postural control performance in sports science and medicine applications.

METHODS

A systematic search strategy utilising the PRISMA guidelines was employed to identify eligible articles through ScienceDirect, Embase and PubMed databases. In total, 47 articles met the inclusion criteria and were evaluated and qualitatively synthesised under two main headings: measurement validity and measurement reliability. Furthermore, studies that investigated the utility of these systems in clinical populations were summarised and discussed.

RESULTS

After duplicate removal, 4374 articles were identified with the search strategy, with 47 papers included in the final review. In total, 28 studies investigated validity in healthy populations, and 15 studies investigated validity in clinical populations; 13 investigated the measurement reliability of these sensor-based systems.

CONCLUSIONS

The application of wearable inertial sensors for sports science and medicine postural control applications is an evolving field. To date, research has primarily focused on evaluating the validity and reliability of a heterogeneous set of assessment protocols, in a laboratory environment. While researchers have begun to investigate their utility in clinical use cases such as concussion and musculoskeletal injury, most studies have leveraged small sample sizes, are of low quality and use a variety of descriptive variables, assessment protocols and sensor-mounting locations. Future research should evaluate the clinical utility of these systems in large high-quality prospective cohort studies to establish the role they may play in injury risk identification, diagnosis and management. This systematic review was registered with the International Prospective Register of Systematic Reviews on 10 August 2018 (PROSPERO registration: CRD42018106363): https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=106363 .

Identification of Risk Factors Prospectively Associated With Musculoskeletal Injury in a Warrior Athlete Population

BACKGROUND

Musculoskeletal injuries are a primary source of disability. Understanding how risk factors predict injury is necessary to individualize and enhance injury reduction programs.

HYPOTHESIS

Because of the multifactorial nature of musculoskeletal injuries, multiple risk factors will provide a useful method of categorizing warrior athletes based on injury risk.

STUDY DESIGN

Prospective observational cohort study.

LEVEL OF EVIDENCE

Level 2.

METHODS

Baseline data were collected on 922 US Army soldiers/warrior athletes (mean age, 24.7 ± 5.2 years; mean body mass index, 26.8 ± 3.4 kg/m²) using surveys and physical measures. Injury occurrence and health care utilization were collected for 1 year. Variables were compared in healthy versus injured participants using independent t tests or chi-square analysis. Significantly different factors between each group were entered into a logistic regression equation. Receiver operating characteristic curve and accuracy statistics were calculated for regression variables.

RESULTS

Of the 922 warrior athletes, 38.8% suffered a time-loss injury (TLI). Overall, 35 variables had a significant relationship with TLIs. The logistic regression equation, consisting of 11 variables of interest, was significant (adjusted R² = 0.21; odds ratio, 5.7 [95% CI, 4.1-7.9]; relative risk, 2.5 [95% CI, 2.1-2.9]; area under the curve, 0.73). Individuals with 2 variables had a sensitivity of 0.89, those with 7 or more variables had a specificity of 0.94.

CONCLUSION

The sum of individual risk factors (prior injury, prior work restrictions, lower perceived recovery from injury, asymmetrical ankle dorsiflexion, decreased or asymmetrical performance on the Lower and Upper Quarter Y-Balance test, pain with movement, slower 2-mile run times, age, and sex) produced a highly sensitive and specific multivariate model for TLI in military servicemembers.

CLINICAL RELEVANCE

A better understanding of characteristics associated with future injury risk can provide a foundation for prevention programs designed to reduce medical costs and time lost.

Baseline Assessments of Strength and Balance Performance and Bilateral Asymmetries in Collegiate Athletes

Dai, B, Layer, J, Vertz, C, Hinshaw, T, Cook, R, Li, Y, and Sha, Z. Baseline assessments of strength and balance performance and bilateral asymmetries in collegiate athletes. J Strength Cond Res 33(11): 3015-3029, 2019-Injuries to upper and lower extremities comprise more than 70% of the total injuries in collegiate athletes. Establishing normative data of upper and lower extremity strength and balance may help guide postinjury rehabilitation and return-to-play decisions. The purposes of the current study were to develop the normative data of performance and bilateral asymmetries during 4 upper and lower extremity strength and balance tests in collegiate athletes and to quantify the correlations between strength and balance performance and bilateral asymmetries. A total of 304 male and 195 female Division I athletes from 14 sports performed a maximum push-up test to assess upper extremity strength, a countermovement jump test to assess lower extremity strength, an upper extremity reaching test to assess upper extremity balance, and a lower extremity reaching test to assess lower extremity balance. Bilateral ground reaction forces were collected for the push-up and jump tests. Reaching distances were measured for the 2 balance tests. Bilateral asymmetries were generally less than 10%. Significant sports effects were observed for all 5 performance variables (p < 0.001) but not for asymmetry variables (p ≥ 0.36). Weak correlations were found between strength and balance performance and asymmetries (r < 0.3). Normative data are sex and sports specific in collegiate athletes. Increased asymmetries could be more individualized rather than sex and sports specific. When return-to-play decisions are made, athletes following injuries need to demonstrate less than 10% of asymmetries to be consistent with the normative data. Strength and balance should be evaluated and improved with specific focuses.

Investigating the Prevalence and Predictors of Injury Occurrence in Competitive Hip Hop Dancers: Prospective Analysis

Hip hop is a popular form of competitive and recreational sport worldwide, but studies rarely investigate injury prevalence and factors associated with injury occurrence in this sport. This study aimed to prospectively examine injury occurrence in hip hop dancers in a three-month period and to evaluate potential predictors of injury occurrence in hip hop dancers. The participants were 129 competitive hip hop dancers (114 females, 17.95 ± 4.15 years of age). Study predictors were obtained at study baseline and included sociodemographic factors, sport-related factors, previous injury status, anthropometric and body build indices (body height, mass, body mass index, and body composition variables), and dynamic balance performance (obtained by the Star Excursion Balance Test—SEBT). The outcome was injury occurrence, which was prospectively observed once a week by the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC). During the course of the study, 101 injuries occurred, equating to an annual injury incidence of 312%. On average, each dancer suffered 0.78 injuries (95% Confidence Interval (95% CI): 0.61–0.97) across a study period of three months (0.76 (95% CI: 0.60–0.95) and 0.93 (95% CI: 0.75–1.13), in females and males, respectively; Mann Whitney Z-value: 0.68, p = 0.52). Seventeen percent of dancers suffered multiple injuries, and 49% of all injuries were time-loss injuries. The knee was the most frequently injured body location (42% of all reported injuries), followed by the back region (32%) and the ankle (15%). Previous injury was a strong predictor of injury occurrence (Odds Ratio: 3.76, 95% CI: 1.87–4.59). Lower injury risk was evidenced among those participants who achieved better scores on several SEBT variables, irrespective of gender and previous injury status; with no significant influence of anthropometric and body build variables on injury occurrence. This study highlighted a high injury rate in hip hop dancers. Dancers and coaches should be informed about the certain protective effects of dynamic balance on the prevention of musculoskeletal injury in hip hop in order to assure safe and effective practices. The usage of SEBT as a convenient and cheap testing procedure is encouraged in other dance disciplines.

Do asymmetry scores influence speed and power performance in elite female soccer players?

This study examined the relationships between vertical jump asymmetries and speed and power performance in elite female soccer athletes. Sixteen professional female soccer players (age: 23.0 ± 3.8 years; body mass: 60.2 ± 7.3 kg; height: 165.1 ± 5.5 cm) from the same professional club participated in this study. Athletes performed unilateral and bilateral squat jumps (SJ) and countermovement jumps (CMJ) on a portable force plate; 30-m sprinting test; Zigzag change-of-direction (COD) test; and muscle power testing using the jump squat (JS) exercise. Asymmetry scores were obtained from the results of the unilateral SJ and CMJ by the percentage difference between the dominant and non-dominant legs. The Pearson product-moment coefficient of correlation was used to analyse the correlations between the bilateral and unilateral vertical jump variables and the physical tests. The bilateral vertical jump performance (in both SJ and CMJ) was closely related to sprinting and JS power performances (r values ranging from 0.50 to 0.73; P< 0.05). In contrast, no significant associations were found between jump asymmetries and performance measures. Our data suggest that asymmetry scores derived from unilateral vertical jumps are not capable of influencing the speed-power performance of professional female soccer players.

Relative and absolute within-session reliability of the modified Star Excursion Balance Test in healthy elite athletes

Background

The Star Excursion Balance Test (SEBT) is commonly used to assess dynamic postural balance both in clinical practice and research. The aim of our study was to assess the within-session relative and absolute reliability of participants’ performance of the modified SEBT (mSEBT) using a single practice trial in healthy elite athletes who were familiar with the test.

Methods

An intra-session repeated-measures design was used to investigate the relative and absolute reliability of participants’ (healthy athletes partaking in sports at a high-risk of ankle sprain injury) performance of the mSEBT. A total of 122 healthy elite athletes from soccer (n = 73), basketball (n = 15), and volleyball (n = 34) performed one practice trial and three test trials within one session, in three directions (anterior, postero-medial, and postero-lateral), for both legs. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and smallest detectable change at a 95% confidence were calculated.

Results

We found a good to excellent relative within-session intra-rater reliability between the three trials on specified directions, with an ICC (3,1) from 0.90 to 0.95. SEM and SDC₉₅ for normalized and composite scores, for both legs ranged from 0.91 to 2.86, and 2.54 to 7.94, respectively.

Conclusions

In conclusion, we report good to excellent within-session reliability for the mSEBT. Our results confirm that the test can be reliably used with only one practice trial in healthy elite athletes familiar with the test.

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.

Preseason Y Balance Test Scores are not Associated with Noncontact Time-Loss Lower Quadrant Injury in Male Collegiate Basketball Players

The Y-Balance Test-Lower Quarter has shown promise as a screening tool for identifying athletes at risk of injury. Subsequent studies, utilizing heterogeneous populations or different operational definitions of injury, have presented equivocal findings. Therefore, studies evaluating the efficacy of the Y-Balance Test to discriminate injury risk in a homogeneous population is warranted. One-hundred sixty-nine male (mean age 19.9 ± 1.5 y) collegiate basketball players were recruited during 2 consecutive seasons (2016–2017/2017–2018). Athletes completed the Y-Balance testing protocol at the start of each preseason. Athletic trainers tracked noncontact time-loss lower quadrant injuries over the course of the season. Receiver operator characteristic curves failed to identify cutoff scores; therefore, previously reported cutoff scores were utilized when calculating relative risk. There was no association between preseason Y-Balance Test scores and noncontact time-loss lower back or lower extremity injury in a population of male collegiate basketball players. This study adds to a growing body of evidence that demonstrates no relationship between preseason Y-Balance Test scores and subsequent injury.

Dynamic balance performance varies by position but not by age group in elite Rugby Union players - a normative study

This cohort study aimed to provide normative Y Balance Test scores for an elite Rugby Union population, while investigating the effect player age groups (senior/under-20), playing positions (forwards/backs) and anthropometrics (height and body mass) had on performance.  Two-hundred and sixty-one elite male under-20 (n = 50) and senior (n = 211) players completed baseline Y Balance Test during the 2015/2016 season. One-way ANCOVA and post-hoc t-tests were used to investigate the effect playing position, player group, height and weight had on performance. The cohort was then stratified into groups (age group and/or playing position), and normative percentiles were presented. There was a statistically significant difference (p < 0.05) in Y Balance Test performance between playing positions, when controlling for age group. This difference did not remain when controlling for player body mass. Post-hoc analysis demonstrated that backs had a longer normalised reach distance, with medium-large and small-medium effect sizes for the under-20 and senior cohorts respectively. The one-way ANCOVA analysis suggests that this difference is likely due to the larger differences in player body mass between forward and back playing positions. The normative values presented in this paper may be used by clinicians and researchers to aid injury prevention and rehabilitation strategies.