Concussion history is associated with poor sleep quality in adolescent athletes: a cross-sectional study.

STUDY OBJECTIVES: While previous research has primarily focused on the immediate effects of concussion within the first year post-injury, this study examines the persistent effects of concussion on subsequent sleep quality in adolescent soccer players. METHODS: This study utilized a cross-sectional design, recruiting a convenience sample of adolescent athletes from US Youth Soccer camps. Participants completed a self-reported questionnaire including the Pittsburgh Sleep Quality Index (PSQI) to assess their sleep quality. Athletes were also asked to report sport participation information, any past occurrence of concussion or knee injury, and any sport-related injury in the past 12 months. Independent Samples t-tests were performed to identify significant differences in PSQI scores between injured and non-injured participants. RESULTS: A total of 177 participants (103 male, 14.61±1.88 years) were included in the analysis. The concussion injury group exhibited later bedtimes (difference: 0.32±0.05 hours; p=0.047), fewer hours of sleep (difference: 0.56±0.11 hours, p=0.015), and more frequent sleep disturbances (p=0.012). Furthermore, these athletes reported lengthened sleep latency (difference: 2.55±3.36 minutes, p=0.016) and higher levels of daytime dysfunction (p=0.041) following their concussion injuries. Moreover, athletes in the concussion injury group displayed worse sleep quality scores (difference: 0.42±0.06, p<0.001) and higher total PSQI scores (difference: 1.91±0.41, p<0.001). No significant differences were found based on past knee injury or sport-related injury in the past 12 months. CONCLUSIONS: These findings suggest the need for targeted interventions aimed at improving sleep quality in adolescent athletes with a history of concussion.

Assessment of Sex-Specific Associations between Athletic Identity and Nutrition Habits in Competitive Youth Athletes.

Given the psychological aspects of sports nutrition, understanding one's athletic identity (AI) may improve targeted nutrition education. Therefore, the purpose of this study was to examine nutrition habits and AI among uninjured youth athletes. Athletic Identity Measurement Scale (AIMS) and custom Sports Nutrition Assessment for Consultation (SNAC) scores collected prospectively at local sporting events were retrospectively assessed via Mann-Whitney, Kruskal-Wallis, logistic regression, and ANCOVA tests (95% CI). Among 583 athletes (14.5 ± 2.1 years; 59.9% female), the total AIMS scores did not differ by sex (males 39.9 ± 7.2; females 39.3 ± 7.5; maximum 70). The Social Identity (p = 0.009) and Exclusivity (p = 0.001) subscores were higher in males, while the Negative Affectivity subscores were lower (p = 0.019). Females reported frequent associations between SNAC and AIMS, particularly Negative Affectivity, which was positively associated with stress fracture history (p = 0.001), meal-skipping (p = 0.026), and desiring nutrition knowledge (p = 0.017). Males receiving weight recommendations reported higher Negative Affectivity subscores (p = 0.003), and higher total AIMS scores were observed in males with fatigue history (p = 0.004) and a desire for nutrition knowledge (p = 0.012). Fatigue and stress fracture history predominated in high-AI males and females, respectively, suggesting that poor sports nutrition may present differently by sex. As suboptimal nutrition was frequently related to high Negative Affectivity subscores, these habits may increase following poor sports performance.

Lower-Quarter Y-Balance Test Differs by Age: Younger Athletes May Not Be Generalized to High School-Aged Counterparts.

Background: Given rising youth sport participation, 8 to 10-year-olds increasingly display comparable lower-extremity injury incidence to 11 to 17-year-olds and require effective return to sport criteria. One such criterion which quantifies dynamic stability is the Y-Balance Test (YBT), though it has not been validated in children under age 11. Hypothesis/Purpose: The purpose of this study was to examine the performance of 8 to 10-year-old patients on the YBT after lower-extremity injury and determine how these results compare to larger samples of age-grouped athletes within the validated 11 to 17-year-old range. It was hypothesized that 8 to 10-year-olds would display different normalized YBT distances compared to 11 to 17-year-olds. Study Design: Cross-sectional Study. Methods: Patients (N=1093) aged 8 to 17 who presented to a pediatric sports medicine practice with a lower-extremity injury and completed the YBT between December 2015-May 2021 were included. Anterior, posteromedial, and posterolateral YBT scores were collected at return-to-sport for affected and unaffected limbs. Scores were normalized to limb length, and composite scores were created. Between-limb differences were calculated in groups of ages 8-10, 11-12, 13-14, and 15-17. Groups were also evaluated for differences by sex. Results: A rise in performance was observed in unaffected limb anterior reach from ages 8 to 10 years to 11 to 12 years followed by a subsequent significant decrease at older ages (p<0.001). Affected limb anterior reach differed between the youngest group and two oldest groups (p=0.004). Anterior and composite difference were significantly different between the oldest three groups (p=0.014 anterior; p=0.024 composite). No differences were observed between sexes in 8 to 10-year-olds, though 11 to 12-year-old females reached further during all eight distances. In the older three groups, males generally displayed greater between-limb differences. Conclusion: YBT scores, specifically anterior reach, demonstrated inconsistency by age and sex across a large adolescent cohort. Existing return-to-sport standards should not be used with younger athletes, and individual validation is required. Level of Evidence: Level III.

Model variations for tracking the trunk during sports testing in a motion capture lab.

Introduction: As motion capture technology becomes more popular for athlete monitoring and return-to-play evaluation, it is imperative that trunk mechanics are modeled similarly across participants. The purpose of this study was to determine how adjusting marker placement at the sternum or removing potentially occluded markers for purposes of tracking the trunk segment influences trunk kinematics during gait and a drop vertical jump (DVJ). Methods: Sagittal plane trunk angles of 18 participants were computed for a Definition Model and three trunk model variations. Model variations were specifically chosen to avoid difficulties with placement of the sternum and/or thorax markers in female participants due to sports bra coverage and/or occlusion. Intraclass correlation coefficients were computed per trunk model variation to determine agreement with the Definition Model. Results: The Mid-Sternum model, in which the xiphoid process marker was adjusted to the midpoint of the xiphoid process and jugular notch, exhibited the least discrepancies and excellent agreement with the Definition Model across both tasks. Alternatively, the No-Thorax model, in which the thorax marker was removed, exhibited the greatest kinematic differences during the DVJ and moderate to excellent agreement across both tasks. Conclusion: The marker set chosen to track trunk motion during dynamic tasks must include locations that can be placed similarly on all participants. Based on these findings, the xiphoid process marker may be adjusted superiorly prior to the collection of dynamic trials. The recommended model for tracking the trunk segment includes marker placements on the jugular notch, mid-sternum, and 1st and 10th thoracic spinous processes.

Greater Post-Operative Nutrition Risks Identified in Pediatric and Adolescent Patients after Anterior Cruciate Ligament Reconstruction Regardless of Age and Sex.

Systematic detection of risky nutrition behaviors after sports surgery may better promote healing for return-to-sport. The purpose of this study was to assess nutritional behavior differences between patients following anterior cruciate ligament reconstruction (ACLR) and following other lower-extremity orthopedic surgeries. One pediatric sports medicine center was reviewed for a custom Sports Nutrition Assessment for Consultation, which investigates nutrition-related risk factors for youth athletes at their first post-operative visit. Patients reported "Yes" or "No" to eight questions, after which they were offered a nutrition consultation for any response indicating risk. A total of 243 post-ACLR and 242 non-ACLR patients were reviewed. The post-ACLR patients more often reported a change in appetite (p = 0.021), recent weight changes (p = 0.011), a desire to better understand nutrition (p = 0.004), and recommendations to change their body composition (p = 0.032). More post-ACLR patients were identified for a nutrition consultation (p = 0.002), though an equal percentage accepted the consultation between groups. Age and sex were not determined to be significant confounders after matched sub-analysis. The post-ACLR patients more often reported nutrition risks, specifically weight-related issues, regardless of age or sex. Sports surgeons should regularly inquire about nutrition-related concerns with patients and refer to sports dietitians for recovery nutrition support as needed, particularly after ACLR.

Trends in Nutrition-Related Risk Factors Identified Post-Operatively in Patients Treated for a Lower-Extremity Injury.

This study investigated trends within a custom Sports Nutrition Assessment for Consultation (SNAC) survey designed to identify nutrition-related risk factors among post-operative lower-extremity youth athletes. Athletes aged 8-18 years who completed the SNAC at a sports medicine institution after lower-extremity surgery were reviewed for associations between SNAC questions and age/sex differences. Of 477 patients (15.0 ± 2.0 years; 47.8% female), 319 (66.9%) answered 'yes' to at least one question and were identified for a consult, though 216 (64.3%) declined. The most frequent questions to prompt a consult were a desire to better understand nutrition for recovery (41.5%) and regularly skipping at least one meal a day (29.8%). Inter-question responses were often significantly related, especially regarding appetite changes, weight changes, and/or meal-skipping. While consult acceptance was not significantly different between sex/age, males were more likely to report a desire to better understand nutrition (p = 0.004) and a weight change (p = 0.019), and females were more likely to report struggling with dizziness/fatigue (p < 0.001). Additionally, older athletes reported an appetite change (p = 0.022), meal-skipping (p = 0.002), a desire to better understand nutrition (p < 0.001), a weight change (p < 0.001), and an effort/recommendation to change their body composition/weight (p = 0.005). These findings demonstrate a link between risky nutrition behaviors and physical detriments.

Unraveling sex-specific risks of knee osteoarthritis before menopause: Do sex differences start early in life?

OBJECTIVE: Sufficient evidence within the past two decades have shown that osteoarthritis (OA) has a sex-specific component. However, efforts to reveal the biological causes of this disparity have emerged more gradually. In this narrative review, we discuss anatomical differences within the knee, incidence of injuries in youth sports, and metabolic factors that present early in life (childhood and early adulthood) that can contribute to a higher risk of OA in females. DESIGN: We compiled clinical data from multiple tissues within the knee joint-since OA is a whole joint disorder-aiming to reveal relevant factors behind the sex differences from different perspectives. RESULTS: The data gathered in this review indicate that sex differences in articular cartilage, meniscus, and anterior cruciate ligament are detected as early as childhood and are not only explained by sex hormones. Aiming to unveil the biological causes of the uneven sex-specific risks for knee OA, we review the current knowledge of sex differences mostly in young, but also including old populations, from the perspective of (i) human anatomy in both healthy and pathological conditions, (ii) physical activity and response to injury, and (iii) metabolic signatures. CONCLUSIONS: We propose that to close the gap in health disparities, and specifically regarding OA, we should address sex-specific anatomic, biologic, and metabolic factors at early stages in life, as a way to prevent the higher severity and incidence of OA in women later in life.

Greater changes in self-reported activity level are associated with decreased quality of life in patients following an anterior cruciate ligament reconstruction.

OBJECTIVE: To determine the association between change in physical activity level, as defined as the change from pre-to post-operative Tegner Activity Scale, and quality of life (QOL) after anterior cruciate ligament reconstruction (ACLR), before patients are cleared for return to sport. PARTICIPANTS: 1198 participants (42.9% male; 18.7 ± 3.6 years; 7.1 ± 3.7 months post-ACLR). MAIN OUTCOME MEASURES: Surveys included Knee Injury and Osteoarthritis Outcome Score QOL (KOOS-QOL) subscale and Tegner Activity Scale. KOOS-QOL score ≥62.5 is considered as meeting a previously established patient acceptable symptom state. RESULTS: The acceptable KOOS-QOL group reported a significantly smaller decrease in activity level from pre-injury to time of data collection (median: 2.00, IQR: 2.00) than the unacceptable KOOS-QOL group (median: 3.00, IQR: 3.00). Across the full cohort, for every one-point larger decrease in Tegner score from pre-to post-ACLR, there is a 52% increase in the odds of having an unacceptable KOOS-QOL score. For adolescents, the odds increase to 60% while the odds for adults were lower at 39%. CONCLUSIONS: Following ACLR, greater decreases in physical activity level are associated with poorer QOL for both adolescents and adults at short-term follow-up, and this effect is larger amongst adolescents.

Identifying links between athletic identity and risk factors related to youth sport participation.

Introduction: The development of identity formation occurs during adolescence through experiences, ideals and principle. With greater accessibility to sports, recent trends have shown increased rates of sports specialization over the past decade in youth athletes. Athletic identity measures the strength an individual is tied to the athlete role and can be formed in conjunction to adolescent identity formation. More specialized youth athletes may have stronger ties to their athletic identity during their adolescent identity formation period. Methods: Youth basketball athletes were surveyed on specialization levels and athletic identity via the Athletic Identity Measurement Scale (AIMS), including three submeasures: social identity, exclusivity, and negative affectivity. Results: Participants showed stronger identification to social identity items and the weakest identification with exclusivity items. Athletes reporting more time spent playing their primary sport presented higher scores across all measures of athletic identity, and total athletic identity was stronger in athletes reporting specialization at an earlier age. Exclusivity and negative affectivity tended to increase with specialization level which may primarily be driven by specialized athletes choosing to quit non-primary sports. Discussion: Athletic identity may be worth noting as a psychological indicator of potential risk of injury. The long-term goal of this work is to provide the research and clinical community a greater understanding of a potential psychosocial risk factor as youth athletes continue specializing and spending more time training in a singular sport.

A 2D video-based assessment is associated with 3D biomechanical contributors to dynamic knee valgus in the coronal plane.

Introduction: Adolescent athletes involved in sports that involve cutting and landing maneuvers have an increased risk of anterior cruciate ligament (ACL) tears, highlighting the importance of identifying risky movement patterns such as dynamic knee valgus (DKV). Qualitative movement screenings have explored two-dimensional (2D) scoring criteria for DKV, however, there remains limited data on the validity of these screening tools. Determining a 2D scoring criterion for DKV that closely aligns with three-dimensional (3D) biomechanical measures will allow for the identification of poor knee position in adolescent athletes on a broad scale. The purpose of this study was to establish a 2D scoring criterion that corresponds to 3D biomechanical measures of DKV. Methods: A total of 41 adolescent female club volleyball athletes performed a three-task movement screen consisting of a single-leg squat (SLS), single-leg drop landing (SLDL), and double-leg vertical jump (DLVJ). A single rater scored 2D videos of each task using four criteria for poor knee position. A motion capture system was used to calculate 3D joint angles, including pelvic obliquity, hip adduction, knee abduction, ankle eversion, and foot progression angle. Receiver operating characteristic curves were created for each 2D scoring criterion to determine cut points for the presence of movement faults, and areas under the curve (AUC) were computed to describe the accuracy of each 2D criterion compared to 3D biomechanical data. Results: 3D measures indicated knee abduction angles between 2.4°-4.6° (SD 4.1°-4.3°) at the time point when the center of the knee joint was most medial during the three tasks. AUCs were between 0.62 and 0.93 across scoring items. The MEDIAL scoring item, defined as the knee joint positioned inside the medial border of the shoe, demonstrated the greatest association to components of DKV, with AUCs ranging from 0.67 to 0.93. Conclusion: The MEDIAL scoring criterion demonstrated the best performance in distinguishing components of DKV, specifically pelvic obliquity, hip adduction, ankle eversion, and foot progression. Along with the previously published scoring definitions for trunk-specific risk factors, the authors suggest that the MEDIAL criterion may be the most indicative of DKV, given an association with 3D biomechanical risk factors.

Relationship of Knee Abduction Moment to Trunk and Lower Extremity Segment Acceleration during Sport-Specific Movements.

The knee abduction moment (KAM) has been identified as a significant predictor of anterior cruciate ligament (ACL) injury risk; however, the cost and time demands associated with collecting three-dimensional (3D) kinetic data have prompted the need for alternative solutions. Wearable inertial measurement units (IMUs) have been explored as a potential solution for quantitative on-field assessment of injury risk. Most previous work has focused on angular velocity data, which are highly susceptible to bias and noise relative to acceleration data. The purpose of this pilot study was to assess the relationship between KAM and body segment acceleration during sport-specific movements. Three functional tasks were selected to analyze peak KAM using optical motion capture and force plates as well as peak triaxial segment accelerations using IMUs. Moderate correlations with peak KAM were observed for peak shank acceleration during single-leg hop; peak trunk, thigh, and shank accelerations during a deceleration task; and peak trunk, pelvis, and shank accelerations during a 45° cut. These findings provide preliminary support for the use of wearable IMUs to identify peak KAM during athletic tasks.

Are Recreational Sports a Relic of the Past OR a Solution for the Future?

ABSTRACT: Children's participation in sport is a critical component to their physical and social development and as such, efforts should be made to provide all children with the opportunity to play. In recent years, there has been an observed shift in the focus of youth sports from that of participation for the health benefits of physical activity and fun to that of winning and competing. As a result, there has been a rise in club sports offerings and a subsequent reduction in recreational sports opportunities. This change presents unique challenges to children's access to sport and may not adequately support their overall physical, social, and emotional development. This commentary will discuss the benefits and barriers to increasing recreational sport opportunities using the Social Ecological Model as a framework. It also will propose solutions that can be implemented at the intrapersonal, interpersonal, organizational, community, and public policy levels to revive recreational sports.

A comparison between manual and automated event detection for a drop vertical jump task using motion capture.

BACKGROUND: The use of movement screens as a clinical tool for injury risk assessment requires variables to be extracted across specific phases of interest. While manually selecting task events is the traditional method, automated event detection is an effective technique that maintains consistency across a cohort. This study aimed to examine variations in event identification, comparing manual detection and the application of an automated algorithm, with a specific focus on a drop vertical jump task. METHODS: Thirty participants cleared to return-to-play after anterior cruciate ligament reconstruction and thirty controls were tested. For the automated event detection, normalized vertical ground reaction force and the velocity of the sacrum marker were used to identify five events during the drop vertical jump: initial contact, end of loading, end of propulsion, second contact, and end of second loading. Two raters manually selected events and were compared to the event times of the automated algorithm. FINDINGS: Manual event detection exhibited excellent reliability Significant differences between manual and automated detection were observed, particularly at events indicating the lowest squat position (Event2 and Event5). Participants who had undergone anterior cruciate ligament reconstruction demonstrated larger differences than controls at Event5, correlating with significant squat depth disparities. INTERPRETATION: While manual event detection demonstrated reliability, automated algorithms revealed differences, specifically in events of the drop vertical jump involving the lowest squat position. The automated algorithm presents potential benefits in reducing processing time and enhancing accuracy for event identification, offering valuable insights for motion capture applications in clinical settings.

Pre-operative gait kinematics and kinetics do not change following surgery in adolescent patients with femoroacetabular impingement.

BACKGROUND: Femoroacetabular impingement (FAI) is a condition where the femoral head-neck junction collides with the acetabulum. Open or arthroscopic treatment of FAI aims to increase hip motion while reducing impingement during passive or dynamic movements. RESEARCH QUESTION: What are the biomechanical characteristics of the hip and pelvis in adolescents and young adults diagnosed with FAI syndrome 1) pre-operatively compared to controls and 2) pre- to post-operatively? METHODS: 43 patients with FAI and 43 controls were included in the study. All patients with FAI had cam deformities and underwent unilateral hip preservation surgery (either open or arthroscopic). Pre- and post-operative imaging, patient-reported outcomes, and gait analysis were performed. Joint angles and internal joint moments were evaluated with an emphasis on the pelvis and hip. A comparative analysis was conducted to evaluate the gait patterns before and after surgical treatment, as well as to compare pre-operative gait patterns to a control group. RESULTS: 43 patients with FAI (28 female, 16.5 ± 1.5 yrs) and 43 controls (28 female, 16.0 ± 1.5 yrs) were included. Pre-operative patients with FAI had decreased stride length and walking speed compared to controls, with no significant change following surgery. There were no differences in sagittal and coronal plane hip and pelvis kinematics comparing pre- to post-operative and pre-operative to controls. Pre-operatively, differences in internal hip rotation angle (pre: 3.3˚, post: 3.9˚, controls: 7.7˚) and hip extensor moment (pre: 0.121, post: 0.090, controls: 0.334 Nm/kg) were observed compared to controls with no significant changes observed following surgery. SIGNIFICANCE: Compensatory movement strategies in pelvic and hip motion are evident during gait in patients with FAI, particularly in the sagittal and transverse planes. These strategies remained consistent two years post-surgery. While surgery improved radiographic measures and patient-reported outcomes, gait did not elicit biomechanical changes following surgical treatment.

Lower-extremity kinematics and kinetics differ based on drop vertical jump variation: An assessment of methodology for a return-to-play protocol using motion analysis.

BACKGROUND: The drop vertical jump (DVJ) is commonly used in return-to-play evaluations to assess movement quality and risk during a dynamic task. However, across biomechanics literature, a multitude of DVJ variations have been used, influencing the generalizability and potential interpretation of the reported findings. RESEARCH QUESTION: The purpose of this study was to identify differences in lower extremity kinematics and kinetics between DVJ variations that differ based on horizontal jump distance, verbal instructions, and the use of a jump target. METHODS: A single-group repeated measures design was used in a laboratory setting. Twenty participants were tested, and three-dimensional angles and moments of the pelvis, hip, knee, and ankle were computed. Wilcoxon signed rank tests were performed to determine differences between DVJ variations. RESULTS: Reduced knee flexion at initial contact and greater knee extensor moments across the descent phase were observed with increased horizontal jump distance. Additionally, both verbal instructions and a jump target influenced movement strategies at the pelvis, hip, and knee. Ground reaction forces were found to be similar across conditions and jump height following the first landing increased with a target. SIGNIFICANCE: Although subtle, the biomechanical differences observed between task variations emphasize the importance of standardizing motion analysis protocols for research and clinical decision-making. Given the findings of the current study, the authors recommend using the Half Height variation in patients treated for a knee injury as it will likely be the most indicative of movement quality.

Comparison of Gait and Functional Outcomes Between Open and Arthroscopic Treatment of Adolescent and Young Adult Femoroacetabular Impingement.

BACKGROUND: Management of femoroacetabular impingement (FAI) through an arthroscopic or surgical hip dislocation (SHD) approach has been shown to have similar clinical success and patient-reported outcomes. However, there are limited data comparing functional outcomes. The purpose of this study was to compare gait and functional outcomes of adolescent/young adult patients with FAI treated by either an arthroscopic or open SHD approach. METHODS: We identified prospectively enrolled adolescent/young adult patients (≤20 years old) who underwent surgical treatment for FAI through an SHD or arthroscopic approach. Participants were evaluated in a movement science lab preoperatively and postoperatively (minimum 8 months postoperatively) with barefoot walking and a 30-second single-limb balance trial on the affected side. Participants also completed the Harris Hip Score at the same timepoints. Differences from preoperative to postoperative were determined using a paired-samples t test for each surgical technique, and differences between the SHD and arthroscopic groups were determined using an independent samples t test (α=0.05). RESULTS: Fifty-five participants (42F, 16.2±1.4 y) were tested and grouped by surgical intervention. The SHD and arthroscopy groups consisted of 28 and 27 participants, respectively, with no significant difference between the SHD and arthroscopic cohorts in age (16.4±1.2 vs. 15.9±1.5 y, respectively, P =0.218) or sex distribution (78.6% vs. 74.1% females, respectively, P =0.75). Each group demonstrated significant postoperative improvement in Harris Hip Score (SHD: 64.8±16.4 to 81.8±17.8; arthroscopy: 57.0±16.7 to 84.7±19.7; preoperatively to postoperatively, respectively, both P <0.001). During gait, increased maximum hip flexion was observed following surgical intervention for the SHD group (32.3±5.7 vs. 36.1±5.2, P =0.003). No other clinically significant changes were detected in the SHD or arthroscopic groups preoperatively to postoperatively in trunk, pelvis, or hip kinematics in the coronal plane. During the balance task, neither cohort demonstrated markers of clinically significant abductor dysfunction. However, post operatively, the arthroscopy group was able to balance longer than the SHD group (18.8±7.8 vs. 14.2±2.7 s, respectively, P =0.008), although no differences were detected in trunk or pelvis position in the coronal plane during balance. CONCLUSIONS: Both open SHD and arthroscopic treatment of FAI resulted in improved clinical outcomes with no clinically significant abductor dysfunction 1 year post operatively. However, further study is needed to determine whether more dynamic tasks can potentially elicit subtle differences between the groups. LEVELS OF EVIDENCE: Level II-prospective study.

Concurrent Validity of The Expanded Cutting Alignment Scoring Tool (E-CAST).

Background: The Expanded Cutting Alignment Scoring Tool (E-CAST) has been previously shown to be reliable when assessing lower extremity alignment during a 45-degree sidestep cut, however, the validity of this tool remains unknown. The purpose of this study was to assess the concurrent validity of the E-CAST by comparing visually identified movement errors from two-dimensional (2D) video with three-dimensional (3D) biomechanical variables collected using motion capture. Study Design: Cross Sectional. Methods: Sixty female athletes (age 14.1 ± 1.5 years) who regularly participated in cutting/pivoting sports performed a sidestep cut with 2D video and 3D motion capture simultaneously recording. One clinician scored the 2D videos for each limb using the E-CAST criteria. Joint angles and moments captured in 3D were computed for the trunk and knee. Receiver operating characteristic (ROC) curve analyses were performed to determine the accuracy of each E-CAST item and to provide cut-off points for risk factor identification. Results: ROC analyses identified a cut-off point for all biomechanical variables with sensitivity and specificity ranging from 70-85% and 55-89%, respectively. Across items, the area under the curve ranged from 0.67 to 0.91. Conclusion: The E-CAST performed with acceptable to outstanding area under the curve values for all variables except static knee valgus. Level of evidence: 3b.

Inertial Measurement Unit Sensor-to-Segment Calibration Comparison for Sport-Specific Motion Analysis.

Wearable inertial measurement units (IMUs) can be utilized as an alternative to optical motion capture as a method of measuring joint angles. These sensors require functional calibration prior to data collection, known as sensor-to-segment calibration. This study aims to evaluate previously described sensor-to-segment calibration methods to measure joint angle range of motion (ROM) during highly dynamic sports-related movements. Seven calibration methods were selected to compare lower extremity ROM measured using IMUs to an optical motion capture system. The accuracy of ROM measurements for each calibration method varied across joints and sport-specific tasks, with absolute mean differences between IMU measurement and motion capture measurement ranging from <0.1° to 24.1°. Fewer significant differences were observed at the pelvis than at the hip, knee, or ankle across all tasks. For each task, one or more calibration movements demonstrated non-significant differences in ROM for at least nine out of the twelve ROM variables. These results suggest that IMUs may be a viable alternative to optical motion capture for sport-specific lower-extremity ROM measurement, although the sensor-to-segment calibration methods used should be selected based on the specific tasks and variables of interest for a given application.

No Difference in Two-Dimensional Kinematic Assessment of a 45-Degree Sidestep Cut Compared to Qualitative Assessment.

Background and Purpose: The Expanded Cutting Alignment Scoring Tool (E-CAST) is a two-dimensional qualitative scoring system that has demonstrated moderate inter-rater and good intra-rater reliability for the assessment of trunk and lower extremity alignment during a 45-degree sidestep cut. The primary purpose of this study was to examine the reliability of the quantitative version of the E-CAST among physical therapists and to compare the reliability of the quantitative E-CAST to the original qualitative E-CAST. The hypothesis was that the quantitative version of the E-CAST would demonstrate greater inter-rater and intra-rater reliability compared to the qualitative E-CAST. Study Design: Observational cohort, repeated measures reliability study. Methods: Twenty-five healthy female athletes (age 13.8±1.4 years) performed three sidestep cuts with two-dimensional video capturing frontal and sagittal views. Two physical therapist raters independently scored a single trial using both views on two separate occasions. Based on the E-CAST criteria, select kinematic measurements were extracted using a motion analysis phone application. Intraclass correlation coefficients and 95% confident intervals were calculated for the total score, and kappa coefficients were calculated per kinematic variable. Correlations were converted to z-scores and compared to the six original criteria for significance (α<0.05). Results: Cumulative intra- and inter-rater reliability were both good (ICC=0.821, 95% CI 0.687-0.898 and ICC=0.752, 95% CI 0.565-0.859). Cumulative intra-rater kappa coefficients ranged from moderate to almost perfect, and cumulative inter-rater kappa coefficients ranged from slight to good. No significant differences were observed between the quantitative and qualitative criteria for either inter- or intra-rater reliability (Zobs(intra)= -0.38, p=0.352 and Zobs(inter)= -0.30, p=0.382). Conclusion: The quantitative E-CAST is a reliable tool to assess trunk and lower extremity alignment during a 45-degree sidestep cut. No significant differences were observed in reliability of the quantitative versus qualitative assessment. Level of evidence: 3b.

Highly Active Middle School Athletes Demonstrate Poor Motor Skill Proficiency.

BACKGROUND: Fundamental movement skills (FMS) are critical components to lifelong participation in sports and physical activity. With the rise in early sports specialization, mastery of motor skills may be limited in youth athletes. The purpose of this study was to assess FMS proficiency in highly active middle school athletes and determine whether proficiency differed between specialization levels and sex. HYPOTHESIS: (1) Most athletes would fail to achieve proficiency in all domains of the Test of Gross Motor Development (TGMD-2), (2) highly specialized athletes would demonstrate lower proficiency in all domains of the TGMD-2, and (3) male athletes would demonstrate higher proficiency than female athletes. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 4. METHODS: A total of 91 athletes were recruited (44 male, 12.6 ± 0.9 years). Activity level was quantified using the Hospital for Special Surgery (HSS) Pediatric Functional Activity Brief Scale (Pedi-FABS), specialization level was determined using the Jayanthi Specialization Scale, and the TGMD-2 was used to assess FMS proficiency. Descriptive statistics were used to describe gross motor, locomotor, and object control percentile rank. A 1-way analysis of variance (ANOVA) was used to assess differences in percentile rank between low, moderate, and high specialization groups and independent samples t tests were used to compare sexes (α < 0.05). RESULTS: Mean Pedi-FABS score was 23.6 ± 4.9. In total, 24.2%, 38.5%, and 37.4% of athletes classified as low, moderate, and highly specialized, respectively. Mean percentile ranks were 56.2%, 64.7%, and 62.6% for locomotor, object control, and gross motor domains, respectively. No athlete achieved a percentile rank >99% in any domain of the TGMD-2, and there was no significant difference between specialization groups or sex. CONCLUSION: Despite high activity levels, no athlete demonstrated proficiency in any domain of the TGMD-2, and there was no difference in proficiency between specialization levels or by sex. CLINICAL RELEVANCE: Sport participation, regardless of level, does not ensure adequate mastery of FMS.