Evaluation of Head Impact Exposure Between One Season of Youth Versus High School Football

In Volume 4, Issue 1 of the JSMAHS you will find Professional research abstracts, as well as Under Graduate student research abstracts, case reports, and critically appraised topics. Thank you for viewing this 4th Annual OATA Special Edition

Lower Extremity Biomechanics Are Altered Across Maturation in Sport-Specialized Female Adolescent Athletes

Sport specialization is a growing trend in youth athletes and may contribute to increased injury risk. The neuromuscular deficits that often manifest during maturation in young, female athletes may be exacerbated in athletes who specialize in a single sport. The purpose of this study was to investigate if sport specialization is associated with increased lower extremity biomechanical deficits pre- to post-puberty in adolescent female athletes. Seventy-nine sport-specialized female adolescent (Mean ± SD age = 13.4 ± 1.8 years) basketball, soccer, and volleyball athletes were identified and matched with seventy-nine multi-sport (soccer, basketball, and volleyball) female athletes from a database of 1,116 female adolescent basketball, soccer, and volleyball athletes who were enrolled in one of two large prospective, longitudinal studies. The athletes were assessed over two visits (Mean ± SD time = 724.5 ± 388.7 days) in which they were classified as pre-pubertal and post-pubertal, respectively. Separate 2 × 2 analyses of covariance were used to compare sport-specialized and multi-sport groups and dominant/non-dominant limbs with respect to pubertal changes in peak knee sagittal, frontal, and transverse plane joint angular measures and moments of force recorded while performing a drop vertical jump task. The sport-specialized group were found to exhibit significantly larger post-pubertal increases in peak knee abduction angle (p = 0.005) and knee abduction moment (p = 0.006), as well as a smaller increase in peak knee extensor moment (p = 0.032) during landing when compared to the multi-sport group. These biomechanical changes are indicative of potentially compromised neuromuscular control that may increase injury risk pre- to post-puberty in sport-specialized female athletes. Consideration of maturation status may be an important factor in assessing the injury risk profiles of adolescent athletes who specialize in sport

Reliability of 3-Dimensional Measures of Single-Leg Cross Drop Landing Across 3 Different Institutions: Implications for Multicenter Biomechanical and Epidemiological Research on ACL Injury Prevention

Background: Anterior cruciate ligament (ACL) injuries are physically and financially devastating but affect a relatively small percentage of the population. Prospective identification of risk factors for ACL injury necessitates a large sample size; therefore, study of this injury would benefit from a multicenter approach. Purpose: To determine the reliability of kinematic and kinetic measures of a single-leg cross drop task across 3 institutions. Study Design: Controlled laboratory study. Methods: Twenty-five female high school volleyball players participated in this study. Three-dimensional motion data of each participant performing the single-leg cross drop were collected at 3 institutions over a period of 4 weeks. Coefficients of multiple correlation were calculated to assess the reliability of kinematic and kinetic measures during the landing phase of the movement. Results: Between-centers reliability for kinematic waveforms in the frontal and sagittal planes was good, but moderate in the transverse plane. Between-centers reliability for kinetic waveforms was good in the sagittal, frontal, and transverse planes. Conclusion: Based on these findings, the single-leg cross drop task has moderate to good reliability of kinematic and kinetic measures across institutions after implementation of a standardized testing protocol. Clinical Relevance: Multicenter collaborations can increase study numbers and generalize results, which is beneficial for studies of relatively rare phenomena, such as ACL injury. An important step is to determine the reliability of risk assessments across institutions before a multicenter collaboration can be initiated

Real‐time biofeedback integrated into neuromuscular training reduces high‐risk knee biomechanics and increases functional brain connectivity: A preliminary longitudinal investigation

Prospective evidence indicates that functional biomechanics and brain connectivity may predispose an athlete to an anterior cruciate ligament injury, revealing novel neural linkages for targeted neuromuscular training interventions. The purpose of this study was to determine the efficacy of a real‐time biofeedback system for altering knee biomechanics and brain functional connectivity. Seventeen healthy, young, physically active female athletes completed 6 weeks of augmented neuromuscular training (aNMT) utilizing real‐time, interactive visual biofeedback and 13 served as untrained controls. A drop vertical jump and resting state functional magnetic resonance imaging were separately completed at pre‐ and posttest time points to assess sensorimotor adaptation. The aNMT group had a significant reduction in peak knee abduction moment (pKAM) compared to controls (p = .03, d = 0.71). The aNMT group also exhibited a significant increase in functional connectivity between the right supplementary motor area and the left thalamus (p = .0473 after false discovery rate correction). Greater percent change in pKAM was also related to increased connectivity between the right cerebellum and right thalamus for the aNMT group (p = .0292 after false discovery rate correction, r2 = .62). No significant changes were observed for the controls (ps > .05). Our data provide preliminary evidence of potential neural mechanisms for aNMT‐induced motor adaptations that reduce injury risk. Future research is warranted to understand the role of neuromuscular training alone and how each component of aNMT influences biomechanics and functional connectivity.Emergent evidence indicates that the risk of anterior cruciate ligament (ACL) injury is, in part, due to central nervous system alterations that could be targeted using neural mechanistic sensorimotor‐based treatments. Young female athletes completed 6 weeks of neuromuscular training while interacting with a real‐time, visual biofeedback stimulus. Our training was designed to reduce the risk of by (a) promoting injury‐resistant movement and (b) strengthening brain functional connectivity. Our data not only indicated that athletes’ biomechanics and brain connectivity were improved following training, but the observed biomechanical improvements were related to distinct, strengthened connectivity within regions important for sensorimotor control. This study supports the use of real‐time biofeedback systems to reduce the risk of ACL injury by leveraging neuroplasticity.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154933/1/psyp13545_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154933/2/psyp13545.pd

The Effects of External Jugular Compression Applied during Head Impact Exposure on Longitudinal Changes in Brain Neuroanatomical and Neurophysiological Biomarkers: A Preliminary Investigation

Objectives: Utilize a prospective in vivo clinical trial to evaluate the potential for mild neck compression applied during head impact exposure to reduce anatomical and physiological biomarkers of brain injury. Methods: This project utilized a prospective randomized controlled trial to evaluate effects of mild jugular vein (neck) compression (collar) relative to controls (no collar) during a competitive hockey season (males; 16.3 ± 1.2 years). The collar was designed to mildly compress the jugular vein bilaterally with the goal to increase intracranial blood volume to reduce risk of brain slosh injury during head impact exposure. Helmet sensors were used to collect daily impact data in excess of 20 g (games and practices) and the primary outcome measures, which included changes in white matter (WM) microstructure, were assessed by diffusion tensor imaging (DTI). Specifically, four DTI measures: fractional anisotropy, mean diffusivity (MD), axial diffusivity, and radial diffusivity (RD) were used in the study. These metrics were analyzed using the tract-based Spatial Statistics (TBSS) approach – a voxel-based analysis. In addition, electroencephalography-derived event-related potentials were used to assess changes in brain network activation (BNA) between study groups. Results: For athletes not wearing the collar, DTI measures corresponding to a disruption of WM microstructure, including MD and RD, increased significantly from pre-season to mid-season (p 0.05). In addition to these anatomical findings, electrophysiological network analysis of the degree of congruence in the network electrophysiological activation pattern demonstrated concomitant changes in brain network dynamics in the non-collar group only (p < 0.05). Similar to the DTI findings, the increased change in BNA score in the non-collar relative to the collar group was statistically significant (p < 0.01). Changes in DTI outcomes were also directly correlated with altered brain network dynamics (r = 0.76; p < 0.05) as measured by BNA. Conclusion: Group differences in the longitudinal changes in both neuroanatomical and electrophysiological measures, as well as the correlation between the measures, provide initial evidence indicating that mild jugular vein compression may have reduced alterations in the WM response to head impacts during a competitive hockey season. The data indicate sport-related alterations in WM microstructure were ameliorated by application of jugular compression during head impact exposure. These results may lead to a novel line of research inquiry to evaluate the effects of protecting the brain from sports-related head impacts via optimized intracranial fluid dynamics

Hip strength is greater in athletes who subsequently develop patellofemoral pain

Background: Hip and knee strength abnormalities have been implicated in patellofemoral pain (PFP) in multiple studies. However, the relationship is unclear, as many of these studies have been retrospective. Purpose: To compare prospective hip and knee isokinetic strength in young female athletes who subsequently went on to develop PFP relative to their uninjured, healthy peers. Study Design: Descriptive epidemiology study. Methods: Adolescent female athletes (N = 329) were tested for isokinetic strength of the knee (flexion and extension) and hip (abduction) and screened for the prevalence of PFP before their basketball seasons. After exclusion based on current PFP symptoms, 255 participants were prospectively enrolled in the study. A 1-way analysis of variance was used to determine between-group differences in incident PFP and the referent (no incident PFP) participants. Results: The cumulative incidence rate for the development of PFP was 0.97 per 1000 athlete-exposures. Female athletes who developed PFP demonstrated increased normalized hip abduction strength (normalized torque, 0.013 0.003) relative to the referent control group (normalized torque, 0.011 0.003) (P .05). Conclusion: The findings in this study indicate that young female athletes with greater hip abduction strength may be at an increased risk for the development of PFP. Previous studies that have looked at biomechanics indicated that those with PFP have greater hip adduction dynamic mechanics. Clinical Relevance: Combining the study data with previous literature, we theorize that greater hip abduction strength may be a resultant symptom of increased eccentric loading of the hip abductors associated with increased dynamic valgus biomechanics, demonstrated to underlie increased PFP incidence. Further research is needed to verify the proposed mechanistic link to the incidence of PFP

Reliability and Validity of the Anterior Knee Pain Scale: Applications for Use as an Epidemiologic Screener

<div><p>A screening instrument’s ability to provide clinicians with consistent and reproducible information is crucial to intervention. Despite widespread acceptance and clinical use of the Kujala Anterior Knee Pain Scale (AKPS) in orthopedics and sports medicine, few studies have reported on its reliability and no such studies have concentrated on child or adolescent samples exclusively, segments of the population for which this instrument is often used. The purpose of the current study was to describe and report on the reliability and validity of the AKPS for use with high school female athletes participating in interscholastic athletics. The study was a secondary analysis of prospective epidemiologic data using established scale validation methods. The records of 414 female athletes 11.0 to 18.1 years of age (Mean 13.9 yrs, SD = 1.7 yrs) were used for analysis. Four different approaches to scoring and scale reduction of the AKPS were evaluated, including the original, ordinal 13-item form, a modified, ordinal 6-item form, a modified, dichotomous 13-item form, and a modified, dichotomous 6-item form. Three different types of reliability (internal consistency, equivalence across forms, standard error of measurement) and one type of validity (criterion-related) were estimated for the AKPS in the current sample. The four scoring formats of the AKPS scale were found to have high internal consistency (α_coef = 0.83 to 0.91), equivalence across the short and long forms (<i>r</i> = 0.98), acceptable standard errors of measurement (0.82 to 3.00), and moderate to high criterion related validity—as determined by physican’s diagnosis: 0.92 (13-item form), 0.90 (6-item form). The Kujala AKPS is a valid and reliable measure of anterior knee pain and appropriate for use as an epidemiologic screening tool with adolescent female athletes.</p></div