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Background The incidence of second anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) is high in young, active populations. Failure to successfully meet return-to-sport (RTS) criteria may identify adult athletes at risk of future injury; however, these studies have yet to assess skeletally mature adolescent athletes. Objective To determine if failure to meet RTS criteria would identify adolescent and young adult athletes at risk for future ACL injury after ACLR and RTS. The tested hypothesis was that the risk of a second ACL injury after RTS would be lower in participants who met all RTS criteria compared with those who failed to meet all criteria before RTS. Design Prospective case-cohort (prognosis) study. Setting Laboratory. Patients or Other Participants A total of 159 individuals (age = 17.2 ± 2.6 years, males = 47, females = 112). Main Outcome Measure(s) Participants completed an RTS assessment (quadriceps strength, functional hop tests) and the International Knee Documentation Committee patient survey (0 to 100 scale) after ACLR and were then tracked for occurrence of a second ACL tear. Athletes were classified into groups that passed all 6 RTS tests at a criterion level of 90% (or 90 of 100) limb symmetry and were compared with those who failed to meet all criteria. Crude odds ratios and 95% CIs were calculated to determine if passing all 6 RTS measures resulted in a reduced risk of second ACL injury in the first 24 months after RTS. Results Thirty-five (22%) of the participants sustained a second ACL injury. At the time of RTS, 26% achieved ≥90 on all tests, and the remaining athletes scored less than 90 on at least 1 of the 6 assessments. The second ACL injury incidence did not differ between those who passed all RTS criteria (28.6%) and those who failed at least 1 criterion (19.7%, P = .23). Subgroup analysis by graft type also indicated no differences between groups (P > .05). Conclusions Current RTS criteria at a 90% threshold did not identify active skeletally mature adolescent and young adult athletes at high risk for second ACL injury.

Context Performance symmetry between limbs (limb symmetry index [LSI] ≥ 90%) on a battery of single-leg hop tests is recommended to inform return-to-sport (RTS) decisions after anterior cruciate ligament (ACL) reconstruction (ACLR). Achieving current hop test symmetry values has not been associated with future clinical outcomes. The identification of age-relevant and activity-relevant target values to benchmark the hop test performance of young athletes post-ACLR may provide greater specificity and clinical relevance for interpretation of hop test data. Objective To identify single-leg hop test-target values for individual-limb performance and symmetry between limbs for athletes without a history of ACL injury and evaluate the proportion of young athletes post-ACLR who met the newly derived target values at the time of RTS clearance. The secondary objective was to test the hypothesis that better function and strength would be associated with achieving the newly derived hop test target values. Design Cross-sectional study. Setting Pediatric medical center and academic medical center. Patients or Other Participants A total of 159 young athletes (age = 16.9 ± 2.2 years) at the time of RTS clearance after primary, unilateral ACLR and 47 uninjured control athletes (age = 17.0 ± 2.3 years). Main Outcome Measure(s) All participants completed a single-leg hop test battery (single hop, triple hop, and crossover hop for distance [cm], and 6-m timed hop [seconds]). Raw distance values were normalized by body height, and LSI (%) was calculated for each hop test. Target values were defined as the lower bound of the 95% CI for each hop test, using control group data. Participants with ACLR also completed the Knee injury and Osteoarthritis Outcome Score subscales and a quadriceps femoris strength (newton meters/kilogram) assessment. Logistic regression determined predictors of achieving hop test target values in the ACLR group among injury, function, and strength data (P < .05). Results In the ACLR group, 79% to 84% of participants met the 90% LSI threshold on each hop test. They achieved the target values for surgical-limb performance in the following proportions (% participants): single hop = 29%, triple hop = 24%, crossover hop = 30%, 6-m timed hop = 18%, all hops= 12%. Also, they met the target values for LSI in the following proportions: single hop = 43%, triple hop = 48%, crossover hop = 50%, 6-m timed hop = 69%, all hops = 25%. The only predictor of achieving all hop test targets for surgical-limb performance was greater surgical-limb quadriceps femoris strength (odds ratio = 4.10, P = .007). We noted a trend toward quadriceps femoris strength LSI ≥ 90% (odds ratio = 2.44, P = .058) as a predictor for meeting all hop test symmetry targets. Conclusions At the time of RTS post-ACLR, only a small proportion of young athletes achieved the age-relevant and activity-relevant single-leg hop test targets for surgical-limb performance or symmetry between limbs, even though a majority met the traditionally recommended 90% LSI threshold on hop tests.

Background: Joint hypermobility (JH) is a common clinical finding amongst hereditary connective tissue disorders that is observed in pediatric rheumatological settings, and often associated with chronic pain. JH may also contribute to deficits in physical functioning and physical activity, but previous findings have been inconsistent. It is possible that physical activity impairment in JH may be due to chronic aberrant movement patterns subsequent to increased joint laxity. Method: As part of a larger randomized pilot trial of juvenile onset fibromyalgia (JFM), asecondary analysis was conducted to explore whether adolescents with JFM and JH differed from non-JH peers in terms of pain, daily functioning, and movement biomechanics during a moderately vigorous functional task. Results: Thirteen adolescents (36.1%) from the larger sample of adolescents with JFM (N=36) met criteria for JH. Those with JH exhibited poorer overall functioning but there were no differences in pain. Those with JH exhibited decreased hip flexion and frontal plane hip moment (e.g., resistance to dynamic valgus) during the landing phase (early stance) and greater hip and knee transverse plane moments during the propulsion phase (late stance) of the drop vertical jump task (DVJ). No other differences in lower extremity biomechanics were observed between study groups. Conclusions: There were small but notable differences in biomechanics between patients with JFM who also had JH versus those without JH during a landing and jumping task (e.g., DVJ). These differences may indicate decreased joint stiffness during landing, associated with increased joint laxity and decreased joint stability, which may put them at greater risk for injury. Further study is warranted to examine whether these biomechanical differences in patients with JFM and JH affect their response to typical physical therapy or exercise recommendations.

PURPOSE National registry data have established Knee injury and Osteoarthritis Outcome Score (KOOS) functional recovery target values for adults after anterior cruciate ligament (ACL) reconstruction. However, the specificity of these target values for young athletes after ACL reconstruction is unclear. The purpose of this analysis was to (1) derive age- and activity-relevant KOOS functional recovery target values from uninjured young athlete data and (2) determine clinical measures at the time of RTS clearance associated with meeting the newly-derived functional recovery target values in young athletes following ACLR. METHODS Two hundred and twenty-two young athletes (56 uninjured controls, 17.2 ± 2.4 years, 73% female; 166 after ACL reconstruction, 16.9 ± 2.2 years, 68% female) were included in this cross-sectional analysis from a larger cohort study. Uninjured control participants completed the KOOS, and functional recovery target values were defined as the lower bound of the 95% confidence interval for KOOS subscales. ACL reconstruction participants completed testing within 4 weeks of return-to-sport clearance, including the KOOS, single-leg hop tests, and isometric quadriceps strength. In ACL reconstruction participants, logistic regression was used to determine predictors of meeting all KOOS functional recovery target values (primary outcome) among demographic/injury, hop, and strength data (α ≤ 0.05). RESULTS KOOS functional recovery target values for each subscale from uninjured athlete data were: Pain ≥ 94, Symptoms ≥ 92, Activities of Daily Living ≥ 97, Sport ≥ 92, and Quality-of-Life ≥ 92. At the time of return-to-sport clearance, ACL reconstruction participants met the KOOS functional recovery targets in the following proportions: Pain, 63%; Symptoms, 42%; Activities of Daily Living, 80%; Sport, 45%; Quality-of-Life, 24%; overall functional recovery (met all subscale targets), 17%. In ACL reconstruction participants, significant predictors of overall functional recovery (primary outcome) were: younger age, hamstring graft, pediatric ACL reconstruction, quadriceps strength limb-symmetry index > 90%, single-hop limb-symmetry index > 90%, and crossover-hop limb-symmetry index > 90%. CONCLUSIONS KOOS functional recovery target values derived from uninjured young athletes were higher than those previously reported. Small proportions of young athletes following recent RTS clearance after ACLR met these newly-derived functional recovery target values, and factors associated with meeting functional recovery target values included younger age, hamstring autograft and pediatric ACLR, and having > 90% LSI for quadriceps strength and single-leg hop tests. LEVEL OF EVIDENCE I.

Background: Joint hypermobility (JH) is a common clinical finding amongst hereditary connective tissue disorders that is observed in pediatric rheumatological settings, and often associated with chronic pain. JH may also contribute to deficits in physical functioning and physical activity, but previous findings have been inconsistent. It is possible that physical activity impairment in JH may be due to chronic aberrant movement patterns subsequent to increased joint laxity. Within a larger study of juvenile onset fibromyalgia (JFM), a secondary analysis was conducted to explore whether adolescents with JFM and JH differed from non-JH peers in terms of pain, daily functioning, and movement biomechanics during a moderately vigorous functional task. Findings: Thirteen adolescents (36.1%) from the larger sample of adolescents with JFM (N=36) met criteria for JH. Those with JH exhibited poorer overall functioning but there were no differences in pain. Those with JH exhibited decreased hip flexion and frontal plane hip moment (e.g., resistance to dynamic valgus) during the landing phase (early stance) and greater hip and knee transverse plane moments during the propulsion phase (late stance) of the drop vertical jump task (DVJ). No other differences in lower extremity biomechanics were observed between study groups. Conclusions: There were small but notable differences in biomechanics between patients with JFM who also had JH versus those without JH during a landing and jumping task (e.g., DVJ). These differences may indicate decreased joint stiffness during landing, associated with increased joint laxity and decreased joint stability, which may put them at greater risk for injury. Further study is warranted to examine whether these biomechanical differences in patients with JFM and JH affect their response to typical physical therapy or exercise recommendations.

This technical report describes the design and implementation of a novel biofeedback system to reduce biomechanical risk factors associated with anterior cruciate ligament (ACL) injuries. The system provided objective real-time biofeedback driven by biomechanical variables associated with increased ACL injury risk without the need of a present expert. Eleven adolescent female athletes (age = 16.7 ± 1.34 yrs; height = 1.70 ± 0.05 m; weight = 62.20 ± 5.63 kg) from the same varsity high school volleyball team were enrolled in the experiment. Participants first completed 10 bodyweight squats in the absence of the biofeedback (pretest), 40 bodyweight squats while interacting with the biofeedback, and a final 10 bodyweight squats in the absence of the biofeedback (posttest). Participants also completed three pretest drop vertical jumps and three posttest drop vertical jumps. Results revealed significant improvements in squat performance, as quantified by a novel heat map analysis, from the pretest to the posttest. Additionally, participants displayed improvements in landing mechanics during the drop vertical jump. This study demonstrates that participants were able to interact effectively with the real-time biofeedback and that biomechanical improvements observed during squatting translated to a separate task.

Context: Existing anterior cruciate ligament (ACL) injury prevention programs have failed to reverse the high rate of ACL injuries in adolescent female athletes. Objective: This investigation attempts to overcome factors that limit efficacy with existing injury prevention programs through the use of a novel, objective, and real-time interactive visual feedback system designed to reduce the biomechanical risk factors associated with ACL injuries. Design: Cross-over study. Setting: Medical center laboratory. Participants: A total of 20 females (age = 19.7 [1.34] y; height = 1.74 [0.09] m; weight = 72.16 [12.45] kg) participated in this study. Methods: Participants performed sets of 10 bodyweight squats in each of 8 training blocks (ie, 4 real-time and 4 control blocks) and 3 testing blocks for a total of 110 squats. Feedback conditions were blocked and counterbalanced with half of participants randomly assigned to receive the real-time feedback block first and half receiving the control (sham) feedback first. Results: Heat map analysis revealed that during interaction with the real-time feedback, squat performance measured in terms of key biomechanical parameters was improved compared with performance when participants squatted with the sham stimulus. Conclusions: This study demonstrates that the interactive feedback system guided participants to significantly improve movement biomechanics during performance of a body weight squat, which is a fundamental exercise for a longer term ACL injury risk reduction intervention. A longer training and testing period is necessary to investigate the efficacy of this feedback approach to effect long-term adaptations in the biomechanical risk profile of athletes.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the consistency of a novel MR safe lower extremity motor control neuroimaging paradigm to elicit reliable sensorimotor region brain activity. METHOD: Participants completed multiple sets of unilateral leg presses combining ankle, knee, and hip extension and flexion movements against resistance at a pace of 1.2 Hz while lying supine in a 3T MRI scanner. Regions of Interest (ROI) consisted of regions primarily involved in lower extremity motor control (right and left primary motor cortex, primary somatosensory cortex, pre-motor cortex, secondary somatosensory cortex, basal ganglia, and the cerebellum). RESULTS: The group analysis based on mixed effects paired samples t-test revealed no differences for brain activity between sessions (p>0.05). Intraclass correlation coefficients in the sensorimotor regions were good to excellent for average percent signal change (0.621 to 0.918) and Z-score (0.697 to 0.883), with the exception of the left secondary somatosensory cortex percent signal change (0.165). CONCLUSIONS: These results indicate that a loaded lower extremity force production and attenuation task that simulates the range of motion of squatting, stepping, and landing from a jump is reliable for longitudinal neuroimaging applications and support the use of this paradigm in further studies examining therapeutic interventions and changes in dynamic lower extremity motor function.

Special Weapons and Tactics (SWAT) personnel who conduct breacher exercises are at risk for blast-related head trauma. We aimed to investigate the potential impact of low-level blast exposure during breacher training on the neural functioning of working memory and auditory network connectivity. We also aimed to evaluate the effects of a jugular vein compression collar, designed to internally mitigate slosh energy absorption, preserving neural functioning and connectivity, following blast exposure. A total of 23 SWAT personnel were recruited and randomly assigned to a non-collar (n = 11) and collar group (n = 12). All participants completed a 1-day breacher training with multiple blast exposure. Prior to and following training, 18 participants (non-collar, n = 8; collar, n = 10) completed functional magnetic resonance imaging (fMRI) of working memory using N-Back task; 20 participants (non-collar, n = 10; collar, n = 12) completed resting-state fMRI. Key findings from the working memory analysis include significantly increased fMRI brain activation in the right insular, right superior temporal pole, right inferior frontal gyrus, and pars orbitalis post-training for the non-collar group (p 0.05, threshold-free cluster enhancement corrected), but no changes were noted for the collar group. The elevation in fMRI activation in the non-collar group was found to correlate significantly (n = 7, r = 0.943, p = 0.001) with average peak impulse amplitude experienced during the training. In the resting-state fMRI analysis, significant pre- to post-training increase in connectivity between the auditory network and two discrete regions (left middle frontal gyrus and left superior lateral occipital/angular gyri) was found in the non-collar group, while no change was observed in the collar group. These data provided initial evidence of the impact of low-level blast on working memory and auditory network connectivity as well as the protective effect of collar on brain function following blast exposure, and is congruent with previous collar findings in sport-related traumatic brain injury.

Background Lower extremity landing asymmetries are common and associated with strength deficits after anterior cruciate ligament reconstruction. However, less is known regarding trunk control during landing. This study's hypotheses were that frontal plane trunk excursion during single-leg landing would be greater in young athletes after anterior cruciate ligament reconstruction compared to controls and would be associated with strength deficits. Methods Participants included 130 young athletes recently cleared for return-to-sport following anterior cruciate ligament reconstruction and 56 uninjured young athletes. Frontal plane trunk excursion was quantified using three-dimensional motion analysis during a single-leg landing task. Quadriceps and hip abduction strength were measured using an isokinetic dynamometer. Frontal plane trunk excursion was compared between the anterior cruciate ligament reconstruction and control groups and among quadriceps strength subgroups using independent t-tests and one-way analysis of variance. Linear regression examined the association between frontal plane trunk excursion and strength measures in the anterior cruciate ligament reconstruction group. Findings The anterior cruciate ligament reconstruction group demonstrated greater frontal plane trunk excursion compared to controls. The low-quadriceps group demonstrated greater frontal plane trunk excursion compared to both the high-quadriceps and control groups. Additionally, the high-quadriceps group demonstrated greater frontal plane trunk excursion compared to controls. In the anterior cruciate ligament reconstruction group, lower quadriceps and hip abduction strength were weakly associated with greater frontal plane trunk excursion. Interpretation Young athletes at time of return-to-sport after anterior cruciate ligament reconstruction demonstrated increased frontal plane trunk excursion during single-leg landing. Additionally, increased frontal plane trunk excursion was weakly associated with strength deficits.

Background: The traditional index of return to sport (RTS) readiness following anterior cruciate ligament reconstruction (ACLR) is the achievement of physical competence criteria. Emerging research indicates that psychological response and self-perceptions of physical competence may be critical for successful RTS among young athletes. Hypothesis/Purpose: The purpose of this study was to test the hypothesis that young athletes with higher actual and perceived physical competence will demonstrate a more positive psychological response at time of RTS after ACLR. Methods: Thirty-eight athletes (median age=16.9 years [IQR: 16.1, 18.8]) following primary ACLR completed testing within 8 weeks of medical clearance to RTS. All participants completed isokinetic knee extension strength (180°/s) and single-limb crossover hop for distance, in addition to the Knee injury and Osteoarthritis Outcome Score (KOOS), Self-Perception Profile Athletic Competence, and ACL Return to Sport after Injury (ACL-RSI) questionnaires. Criteria for the achievement of actual (APC) and perceived physical competence (PPC) were operationally defined based on established age- and activity-relevant cutoff scores (Table 1). Psychological response was assessed with ACL-RSI overall score, in addition to each ACL-RSI subscale score (Emotions, Confidence, Risk Appraisal). Multiple linear regression analyses were used to determine differences in ACL-RSI scores based on achievement of APC and PPC, while adjusting for age and sex. Results: Of the 38 participants, 9 (23.7%) were able to meet all criteria for High APC, while 29 (76.3%) participants were categorized as Low APC. Twenty-one (55.3%) of the 38 participants were categorized as Very Good PPC, and 17 (44.7%) were categorized as Somewhat Good PPC. The regression model for overall ACL-RSI score was significant ( F (4,33) = 5.224, p=0.002, adj. R2 = 0.313), with age explaining 26.4% of the total variance (p=0.001). In evaluating the ACL-RSI subscales, the regression model for the ACL-RSI Emotions score was significant ( F(4,33) = 7.760, p2 = 0.422), with age, sex, and PPC explaining 33.9% (p2 = 0.207) was significant, with age and PPC explaining 10.5% (p=0.034) and 12.9% (p=0.02) of the total variance, respectively (Table 2). Conclusion: In partial accordance with our hypothesis, higher PPC, but not APC, was significantly associated with a more positive psychological response among young athletes after ACLR. Interventions to improve self-perceptions of competence may optimize psychological readiness to RTS. [Table: see text][Table: see text]

National registry data have established Knee injury and Osteoarthritis Outcome Score (KOOS) functional recovery target values for adults after anterior cruciate ligament (ACL) reconstruction. However, the specificity of these target values for young athletes after ACL reconstruction is unclear. The purpose of this analysis was to (1) derive age- and activity-relevant KOOS functional recovery target values from uninjured young athlete data and (2) determine clinical measures at the time of RTS clearance associated with meeting the newly-derived functional recovery target values in young athletes following ACLR.Two hundred and twenty-two young athletes (56 uninjured controls, 17.2 ± 2.4 years, 73% female; 166 after ACL reconstruction, 16.9 ± 2.2 years, 68% female) were included in this cross-sectional analysis from a larger cohort study. Uninjured control participants completed the KOOS, and functional recovery target values were defined as the lower bound of the 95% confidence interval for KOOS subscales. ACL reconstruction participants completed testing within 4 weeks of return-to-sport clearance, including the KOOS, single-leg hop tests, and isometric quadriceps strength. In ACL reconstruction participants, logistic regression was used to determine predictors of meeting all KOOS functional recovery target values (primary outcome) among demographic/injury, hop, and strength data (α ≤ 0.05).KOOS functional recovery target values for each subscale from uninjured athlete data were: Pain ≥ 94, Symptoms ≥ 92, Activities of Daily Living ≥ 97, Sport ≥ 92, and Quality-of-Life ≥ 92. At the time of return-to-sport clearance, ACL reconstruction participants met the KOOS functional recovery targets in the following proportions: Pain, 63%; Symptoms, 42%; Activities of Daily Living, 80%; Sport, 45%; Quality-of-Life, 24%; overall functional recovery (met all subscale targets), 17%. In ACL reconstruction participants, significant predictors of overall functional recovery (primary outcome) were: younger age, hamstring graft, pediatric ACL reconstruction, quadriceps strength limb-symmetry index 90%, single-hop limb-symmetry index 90%, and crossover-hop limb-symmetry index 90%.KOOS functional recovery target values derived from uninjured young athletes were higher than those previously reported. Small proportions of young athletes following recent RTS clearance after ACLR met these newly-derived functional recovery target values, and factors associated with meeting functional recovery target values included younger age, hamstring autograft and pediatric ACLR, and having 90% LSI for quadriceps strength and single-leg hop tests.I.

This study tested the hypotheses that participants with high knee-related confidence at the time of return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction (ACLR) would have a greater likelihood of meeting RTS criteria and would have a higher likelihood of second ACL injury. Participants completed RTS testing when cleared to RTS. Success was defined as an IKDC score more than or equal to 90 and all limb symmetry index (LSI) scores more than or equal to 90%. Confidence groups were created based on response to the KOOS Quality of Life subscale. Incidence of second ACL injury was tracked for 24 months after RTS. Associations among confidence, success in meeting RTS criteria, and second ACL injury were evaluated. At RTS, 37.7% were classified with high knee-related confidence, 26.4% met RTS criteria and 22.0% sustained a second ACL injury post-RTS. A higher proportion of confident participants met all RTS criteria (p = 0.001). Confident participants were over two times more likely to suffer a second ACL injury (odds ratio [OR] = 2.40; 95% confidence interval [CI]:1.21-5.20) (p = 0.02) and participants who were both confident and met all RTS criteria were 10 times more likely to suffer a second ACL injury (OR = 9.6; 95% CI:1.1, 84.2) (p = 0.02) than those who passed all RTS criteria but lacked knee-related confidence. Clinical significance: Confident, young athletes at the time of RTS after ACLR are more likely to meet all RTS criteria and more likely to sustain a second ACL injury after RTS. Future work must consider how the inclusion of additional factors into RTS criteria may better identify those at high risk for poor outcome after ACLR.

To evaluate the association between 2-D frontal plane movement and second anterior cruciate ligament (ACL) injury risk in young athletes at return to sport (RTS) after ACL reconstruction.Prospective cohort.Forty-nine participants who had ACL reconstruction (mean ± SD age, 16.5 ± 3.0 years) performed a single-leg drop landing from a 31-cm box at the time of their RTS. Frontal plane trunk, pelvis, and knee angles were measured using 2-D video analysis at the point of maximum depth during landing. Summated frontal plane angles were calculated by adding trunk, pelvis, and knee angles. Participants were grouped based on whether or not they sustained an ACL graft rupture over the 24 months after RTS.Seven participants (14%) sustained an ipsilateral graft rupture within 24 months after RTS. Participants who suffered a second ACL injury had a significant reduction in the summated frontal plane angle of the trunk, pelvis, and knee (Athletes who suffered an ACL graft rupture within 24 months of RTS had a more rigid posture when landing compared to their uninjured peers. The results of this pilot study should be replicated in a larger sample to determine whether this method has merit as a screening tool to identify athletes at high risk for second ACL injury.

BACKGROUND: Quadriceps strength asymmetry at the time of return-to-sport (RTS) after anterior cruciate ligament reconstruction (ACLR) contributes to altered landing mechanics. However, the impact of RTS quadriceps strength on longitudinal alterations in landing mechanics, a risk factor for poor knee joint health over time, is not understood. The purpose of this study was to test the hypothesis that young athletes with quadriceps strength asymmetry at the time of RTS clearance after ACLR would demonstrate asymmetric landing mechanics 2 years later compared to those without quadriceps strength asymmetry. METHODS: We followed 57 young athletes (age at RTS=17.6±3.0 years; 77% females) with primary, unilateral ACLR for 2 years following RTS clearance. At RTS, we measured isometric quadriceps strength bilaterally and calculated limb-symmetry indices [LSI=(involved/uninvolved)x100%]. Using RTS quadriceps LSI, we divided participants into High-Quadriceps (HQ; LSI≥90%) and Low-Quadriceps (LQ; LSI0.093). CONCLUSION: Young athletes after ACLR with quadriceps strength asymmetry at the time of RTS favored the uninvolved limb during DVJ landing 2 years later. These landing asymmetries may relate to long-term knee joint health after ACLR.

Objective Juvenile-onset fibromyalgia (JFM) is a chronic debilitating pain condition that negatively impacts physical, social and academic functioning. Cognitive-behavioral therapy (CBT) is beneficial in reducing functional disability among adolescents with JFM but has only a modest impact on pain reduction and does not improve physical exercise participation. This randomized controlled trial (RCT) aims to test whether a novel intervention that combines CBT with specialized neuromuscular exercise training (the Fibromyalgia Integrative Training program for Teens “FIT Teens”) is superior to CBT alone or a graded aerobic exercise (GAE) program. Design/Methods This 3-arm multi-site RCT will examine the efficacy of the FIT Teens intervention in reducing functional disability (primary outcome) and pain intensity (secondary outcome), relative to CBT or GAE. All interventions are 8-weeks (16 sessions) in duration and are delivered in small groups of 4–6 adolescents with JFM. A total of 420 participants are anticipated to be enrolled across seven sites with approximately equal allocation to each treatment arm. Functional disability and average pain intensity in the past week will be assessed at baseline, post-treatment and at 3-, 6-, 9- and 12-month follow-up. The 3-month follow-up is the primary endpoint to evaluate treatment efficacy; longitudinal assessments will determine maintenance of treatment gains. Changes in coping, fear of movement, biomechanical changes and physical fitness will also be evaluated. Conclusions This multi-site RCT is designed to evaluate whether the combined FIT Teens intervention will have significantly greater effects on disability and pain reduction than CBT or GAE alone for youth with JFM. Clinical trials.gov registration: NCT 03268421.

Background: Incidence of second anterior cruciate ligament (ACL) injury among the population of young athletes is reported to be as high as 30%. Time between ACL reconstruction (ACLR) and return to sport (RTS) has been considered as a factor in second injury risk. Hypothesis/Purpose: The purpose of this study was to investigate the effect of time between ACLR and RTS on incidence of 2nd ACL injury. The tested hypothesis was that incidence of 2nd ACL injury among young athletes would not be influenced by time to RTS or patient-reported function following primary ACLR. Methods: 188 participants (mean age=16.8±3.0 years; 124 females) underwent ACLR, completed rehabilitation, and were medically cleared to RTS. Subjects were enrolled in the study within 4 weeks of their medical clearance to RTS. At this time, each subject completed the International Knee Documentation Committee (IKDC) Survey, the Knee injury and Osteoarthritis Outcome Score (KOOS) and was grouped into an early RTS group (Results: No significant differences in age (p=0.40), height (p=0.65) or weight (p=0.92) existed among the groups. At time of RTS, no differences between the early RTS, average RTS and late RTS groups were seen in patient-reported function on the IKDC (84.9±10.8, 90.5±9.5, 88.7±10.9; p= 0.08) and all KOOS subscales (p=0.05-0.41). With respect to 2nd ACL injury, there were no group differences (p=0.716) in the proportion of patients within each group who suffered a 2nd ACL injury within 24 months of RTS date (26.3% (5/19) of patients in the early RTS group, 18.9% (20/106) in the average RTS group and 22.2% (14/63) in the late RTS group). Conclusion: In accordance with our hypothesis, length of time between ACLR and RTS had no influence on incidence of second ACL injury among a population of young athletes after ACLR. Furthermore, patient-reported function at time of RTS was similar among groups, regardless of time between ACLR and RTS.

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.

Exposure to explosive blasts places one at risk for traumatic brain injury, especially for special weapons and tactics (SWAT) and military personnel, who may be repeatedly exposed to blasts. In the current study, the effectiveness of a jugular vein compression collar to prevent alterations in resting-state electrocortical activity following a single-SWAT breacher training session was investigated. SWAT team personnel were randomly assigned to wear a compression collar during breacher training and resting state electroencephalography (EEG) was measured within 2 days prior to and two after breacher training. It was hypothesized that significant changes in brain dynamics-indicative of possible underlying neurodegenerative processes-would follow blast exposure for those who did not wear the collar, with ameliorated changes for the collar-wearing group. Using recurrence quantification analysis (RQA) it was found that participants who did not wear the collar displayed longer periods of laminar electrocortical behavior (as indexed by RQA's vertical max line measure) after breacher training. It is proposed that the blast wave exposure for the no-collar group may have reduced the number of pathways, via axonal disruption-for electrical transmission-resulting in the EEG signals becoming trapped in laminar states for longer periods of time. Longer laminar states have been associated with other electrocortical pathologies, such as seizure, and may be important for understanding head trauma and recovery.

Context: An estimated 40 million school-aged children (age range = 5−18 years) participate annually in sports in the United States, generating approximately 4 million sport-related injuries and requiring 2.6 million emergency department visits at a cost of nearly $2 billion.Objective: To determine the effects of a school-based neuromuscular training (NMT) program on sport-related injury incidence across 3 sports at the high school and middle school levels, focusing particularly on knee and ankle injuries.Design: Randomized controlled clinical trial.Setting: A total of 5 middle schools and 4 high schools in a single-county public school district.Patients or Other Participants: A total of 474 girls (222 middle school, 252 high school; age = 14.0 ± 1.7 years, height = 161.0 ± 8.1 cm, mass = 55.4 ± 12.2 kg) were cluster randomized to an NMT (CORE; n = 259 athletes) or sham (SHAM; n = 215 athletes) intervention group by team within each sport (basketball, soccer, and volleyball).Intervention(s): The CORE intervention consisted of exercises focused on the trunk and lower extremity, whereas the SHAM protocol consisted of resisted running using elastic bands. Each intervention was implemented at the start of the season and continued until the last competition. An athletic trainer evaluated athletes weekly for sport-related injuries. The coach recorded each athlete-exposure (AE), which was defined as 1 athlete participating in 1 coach-directed session (game or practice).Main Outcome Measure(s): Injury rates were calculated overall, by sport, and by competition level. We also calculated rates of specific knee and ankle injuries. A mixed-model approach was used to account for multiple injuries per athlete.Results: Overall, the CORE group reported 107 injuries (rate = 5.34 injuries/1000 AEs), and the SHAM group reported 134 injuries (rate = 8.54 injuries/1000 AEs; F1,578 = 18.65, P < .001). Basketball (rate = 4.99 injuries/1000 AEs) and volleyball (rate = 5.74 injuries/1000 AEs) athletes in the CORE group demonstrated lower injury incidences than basketball (rate = 7.72 injuries/1000 AEs) and volleyball (rate = 11.63 injuries/1000 AEs; F1,275 = 9.46, P = .002 and F1,149 = 11.36, P = .001, respectively) athletes in the SHAM group. The CORE intervention appeared to have a greater protective effect on knee injuries at the middle school level (knee-injury incidence rate = 4.16 injuries/1000 AEs) than the SHAM intervention (knee-injury incidence rate = 7.04 injuries/1000 AEs; F1,261 = 5.36, P = .02). We did not observe differences between groups for ankle injuries (F1,578 = 1.02, P = .31).Conclusions: Participation in an NMT intervention program resulted in a reduced injury incidence relative to participation in a SHAM intervention. This protective benefit of NMT was demonstrated at both the high school and middle school levels.

Background: Anterior cruciate ligament (ACL) injury is secondary to a multifactorial etiology encompassing anatomical, biological, mechanical, and neurological factors. The nature of the injury being primarily due to non-contact mechanics further implicates neural control as a key injury-risk factor, though it has received considerably less study. Purpose: To determine the contribution of neural activity to injury-risk mechanics in ecological sport-specific VR landing scenarios. Methods: Ten female high-school soccer players (15.5±0.85 years; 165.0±6.09 cm; 59.1±11.84 kg) completed a neuroimaging session to capture neural activity during a bilateral leg press and a 3D biomechanics session performing a header within a VR soccer scenario. The bilateral leg press involved four 30 s blocks of repeated bilateral leg presses paced to a metronome beat of 1.2 Hz with 30 s rest between blocks. The VR soccer scenario simulated a corner-kick, requiring the participant to jump and head a virtual soccer ball into a virtual goal (Figure 1A-E). Initial contact and peak knee flexion and abduction angles were extracted during the landing from the header as injury-risk variables of interest and were correlated with neural activity. Results: Evidenced in Table 1 and Figure 1 (bottom row), increased initial contact abduction, increased peak abduction, and decreased peak flexion were associated with increased sensory, visual-spatial, and cerebellar activity (r2= 0.42-0.57, p corrected < .05, z max > 3.1, table & figure 1). Decreased initial contact flexion was associated with increased frontal cortex activity (r2= 0.68, p corrected < .05, z max > 3.1). Conclusion: Reduced neural efficiency (increased activation) of key regions that integrate proprioceptive, visual-spatial, and neurocognitive activity for motor control may influence injury-risk mechanics in sport. The regions found to increase in activity in relation to higher injury-risk mechanics are typically activated to assist with spatial navigation, environmental interaction, and precise motor control. The requirement for athletes to increase their activity for more basic knee motor control may result in fewer neural resources available to maintain knee joint alignment, allocate environmental attention, and handle increased motor coordination demands. These data indicate that strategies to enhance efficiency of visual-spatial and cognitive-motor control during high demand sporting activities is warranted to improve ACL injury-risk reduction. [Figure: see text][Table: see text]

The cumulative effects of repetitive subclinical head impacts during sports may result in chronic white matter (WM) changes and possibly, neurodegenerative sequelae. In this pilot study, we investigated the longitudinal WM changes over the course of two consecutive high-school football seasons and explored the long-term effects of a jugular vein compression collar on these WM alterations. Diffusion tensor imaging data were prospectively collected both pre- and postseason in the two consecutive seasons. Participants were assigned into either collar or noncollar groups. Tract-based spatial statistics (TBSS) approach and region of interest-based approach were used to quantify changes in WM diffusion properties. Despite comparable exposure to repetitive head impacts, significant reductions in mean, axial, and/or radial diffusivity were identified in Season 1 in multiple WM regions in the noncollar group but not in the collar group. After an 8- to 9-month long off-season, these changes observed in the noncollar group partially and significantly reversed but also remained significantly different from the baseline. In Season 2, trend level WM alterations in the noncollar group were found but located in spatially different regions than Season 1. Last, the WM integrity in the collar group remained unchanged throughout the four time points. In conclusion, we quantitatively assessed the WM structural changes and partial reversal over the course of two consecutive high-school football seasons. In addition, the mitigated WM alterations in athletes in the collar group might indicate potential effect of the collar in ameliorating the changes against repetitive head impacts. Hum Brain Mapp 39:491-508, 2018. © 2017 Wiley Periodicals, Inc.

Objective Cognitive–behavioral therapy (CBT) is effective in reducing disability among youth with juvenile fibromyalgia (FM); however, engagement in moderate to vigorous physical activity remains poor, even after CBT. The purpose of this study was to evaluate the feasibility and preliminary outcomes of an innovative program combining CBT with specialized neuromuscular exercise: the Fibromyalgia Integrative Training for Teens (FIT Teens) program. Methods Adolescents with juvenile FM (n = 22, all female, ages 12–18 years) from 2 urban children's hospitals participated in the 8-week FIT Teens intervention. Participants completed measures of pain intensity, functional disability, depressive symptoms, pain catastrophizing, fear of movement, and readiness to change at baseline and after the intervention. Results The feasibility of the intervention across 2 sites was documented, including high retention rates (80%). Participants showed significant decreases in functional disability (P

Introduction Current strategies focused on mitigating concussion in sport have demonstrated limited effectiveness. There is a paucity of research on the optimization of intracranial brain dynamics to mitigate concussion; in the present study, we investigate a novel device that provides mild jugular vein compression and may provide adjunctive protection to protect the brain internally from concussive and sub-concussive impacts. The purpose of this study was to assess the tolerance and acceptance of this device in a population of normal, healthy adults undergoing exertion similar to that is experienced while participating in sports-related competition, while monitoring changes in their biomechanical, strength, power, and postural stability capabilities. Material and Methods A total 18 participants (8 females, 10 males) were tested and included in the final analysis. Laboratory data collection consisted of two separate testing sessions for all participants. During the first testing session, participants were tested while wearing either the mild jugular vein compression neck device or a sham arm device (Sham) that was worn on the upper arm and did not alter venous return; participants exchanged devices for the second session. Participants underwent a battery of physical and neurological tests that included three-dimensional (3-D) biomechanical analysis, dynamic postural control testing using a stabilometer, isokinetic strength testing using a dynamometer, and a maximum vertical jump test. Results Evaluation of vital biomechanics, postural control and dynamic stabilization, isokinetic strength, and power in this population showed no statistically significant effect of wearing a mild jugular vein compression neck device compared with a Sham armband. Conclusions The data evaluated in the current project indicate that the device is safe during high intensity and dynamic postural stabilization exercise and does not alter normal physical or neuromuscular capabilities during physical activity.

Context Early sport specialization, or the participation in 1 sport year-round to the exclusion of all others, is a growing concern in youth athletics because of its possible association with musculoskeletal injury. The underlying injury risk may be the result of coordination differences that sport-specialized athletes have been speculated to exhibit relative to multisport athletes; however, little evidence exists to support or refute this notion. Objective To examine relative hip- and knee-joint angular-motion variability among adolescent sport-specialized and multisport female adolescent athletes to determine how sport specialization may affect coordination. Design Cohort study. Setting Research laboratory. Patients or Other Participants A total of 366 sport-specialized and 366 multisport adolescent female basketball, soccer, and volleyball players. Intervention(s) Drop–vertical-jump (DVJ) assessment. Main Outcome Measure(s) Average coupling-angle variability (CAV) for hip flexion and knee flexion, knee flexion and ankle flexion, hip flexion and knee abduction, knee flexion and knee abduction, knee flexion and knee internal rotation, and knee abduction and knee internal rotation. Results The sport-specialized group exhibited increased coupling variability in dominant-limb hip flexion and knee flexion (P = .015), knee flexion and knee abduction (P = .014), and knee flexion and knee internal rotation (P = .048) while landing during the DVJ, although they had small effect sizes (η2 = 0.010, 0.010, and 0.007, respectively). No differences were present between groups for any of the other CAV measures of the dominant limb, and no differences were found for any CAV measures of the nondominant limb (all P values > .05). Conclusions Sport specialization was associated with increased variability of critical hip- and knee-joint couplings responsible for effective landing during the DVJ. Altered coordination strategies that involve the hip and knee joints may underlie unstable landings, inefficient force-absorption strategies, or greater contact forces that can place the lower extremities at risk for injury (or a combination of these).

Background: While between-limb landing asymmetries after anterior cruciate ligament reconstruction (ACLR) are linked with poor function and risk of additional injury, it is not currently understood how landing symmetry changes over time after ACLR. Purpose/Hypothesis: The purpose was to investigate how double-legged drop vertical jump (DVJ) landing and single-legged drop-landing symmetry changed from the time of return-to-sport (RTS) clearance to 2 years later in a prospective cohort of young athletes after ACLR. It was hypothesized that double-legged DVJ landing and single-legged drop-landing symmetry would improve from the time of RTS to 2 years later. Study Design: Descriptive laboratory study. Methods: The authors followed 64 young athletes with primary, unilateral ACLR for 2 years after RTS clearance. At the time of RTS and 2 years later, between-limb symmetry values for biomechanical variables of interest (VOIs) were calculated with 3-dimensional motion analysis during double-legged DVJ and single-legged drop-landing tasks. VOIs included knee flexion excursion, peak internal knee extension moment, peak vertical ground-reaction force, and peak trunk flexion (for single-legged task only). Symmetry values and proportions of participants meeting 90% symmetry cutoffs were compared between time points. Results: For double-legged DVJ landing, symmetry values for all VOIs and the proportions meeting 90% cutoffs for peak internal knee extension moment and peak vertical ground-reaction force were higher at 2 years after RTS as compared with RTS. For single-legged drop-landing, symmetry values were higher for knee flexion excursion and lower for peak trunk flexion at 2 years after RTS as compared with RTS, but the proportions meeting 90% cutoffs for all VOIs did not differ between time points. Conclusion: Double-legged DVJ landing symmetry improved across VOIs over the 2 years after RTS following ACLR, while single-legged drop-landing did not improve as consistently. The implications of longitudinal landing asymmetry after ACLR should be further studied.

Objectives: The ability of current return to sport (RTS) criteria to identify young, active patients after ACL reconstruction (ACLR) independently, at high risk for future ipsilateral or contralateral ACL injury is limited. The purpose of this study was to determine if meeting current, standard RTS criteria collectively, or in part, would identify young athletes at risk for an ipsilateral or contralateral ACL injury after primary ACLR and RTS. The tested hypothesis was the likelihood of an ipsilateral or contralateral 2nd ACL injury in the first 2 years after RTS would be the same in groups that successfully met or failed to meet all RTS criteria prior to RTS. The second hypothesis was that quadriceps femoris strength at the time of RTS would identify which limb was at greatest risk for future ACL injury. Methods: One hundred eighty-one patients (116 female) with a mean age of 16.7±2.9 years old underwent ACLR and were released to return to pivoting/cutting sports. These patients were enrolled in a prospective, observational cohort study, completed a RTS assessment and were tracked for occurrence of an ipsilateral graft tear or contralateral ACL injury after ACLR for 24 months. The RTS assessment included 6 tests: isometric quadriceps strength, 4 functional hop tests and the International Knee Documentation Committee (IKDC) patient reported outcome survey. Limb symmetry index (LSI) was calculated for strength and hop test assessments [(inv/uninv)*100]. Subjects were classified into groups that successfully passed all 6 RTS tests at a level of 90 compared to those that failed to meet all 6 criteria. Chi Square tests and Fisher Exact Tests were used to determine if successfully passing all 6 RTS measures resulted in a reduced risk of 2nd ACL injury in the first 24 months after RTS as well as to assess if ability to successfully pass individual RTS criteria resulted in reduced risk of 2nd ACL injury. Results: Thirty-nine (21.5%) patients suffered a 2nd ACL injury with 18 ipsilateral graft failures and 21 contralateral ACL tears in the first 24 months after RTS following ACLR. At the time of RTS, 57 patients (31.5%) achieved LSI values of 90% or greater on all testing as well as an IDKC value of 90 or greater. At this level, there was no difference in ipsilateral graft failures between patients who passed all RTS criteria (15.8%) and those who failed at least 1 criterion (7.3%; p=0.08). There was also no difference in contralateral ACL injuries between patients who passed all RTS criteria (7.0%) and those who failed at least 1 criterion (13.7%; p=0.22). When individual RTS criterion were evaluated, patients who failed to achieve 90% quadriceps strength LSI were 84% less likely to suffer an ipsilateral graft failure (OR=0.16; 95%CI: 0.04, 0.74;p=0.009), but 3 times more likely to suffer a contralateral ACL injury (OR=2.5; 95%CI:1.0, 6.5;p=0.05). Conclusion: Current criteria to evaluate readiness to return young athletes to pivoting and cutting sports, may not identify young, active patients independently at high risk for a future ipsilateral graft tear or contralateral ACL injury. Inability to achieve 90% LSI on an isometric quadriceps strength assessment resulted in a reduced risk of ipsilateral graft failure, but an increased risk in contralateral ACL injury after ACLR and RTS. Further investigation is needed on the relationship between quad strength and side of future ACL injury and whether other factors may help contribute to a predictive model of future ACL injury specific to limb.

This technical report describes the design and implementation of a novel biofeedback system to reduce biomechanical risk factors associated with anterior cruciate ligament (ACL) injuries. The system provided objective real-time biofeedback driven by biomechanical variables associated with increased ACL injury risk without the need of a present expert. Eleven adolescent female athletes (age = 16.7 ± 1.34 yrs; height = 1.70 ± 0.05 m; weight = 62.20 ± 5.63 kg) from the same varsity high school volleyball team were enrolled in the experiment. Participants first completed 10 bodyweight squats in the absence of the biofeedback (pretest), 40 bodyweight squats while interacting with the biofeedback, and a final 10 bodyweight squats in the absence of the biofeedback (posttest). Participants also completed three pretest drop vertical jumps and three posttest drop vertical jumps. Results revealed significant improvements in squat performance, as quantified by a novel heat map analysis, from the pretest to the posttest. Additionally, participants displayed improvements in landing mechanics during the drop vertical jump. This study demonstrates that participants were able to interact effectively with the real-time biofeedback and that biomechanical improvements observed during squatting translated to a separate task.

Following anterior cruciate ligament reconstruction (ACLR), young athletes demonstrate deficits in knee function and strength whose association with successful return to preinjury sports participation is not well understood.To examine differences in knee function and strength at the time of return-to-sport clearance between young athletes who successfully resumed preinjury sports participation, those who did not resume preinjury sports participation, and those who sustained a second anterior cruciate ligament (ACL) injury by 1 year following return-to-sport clearance.This prospective cohort study collected data in 124 young athletes (mean ± SD age, 17.1 ± 2.4 years) at the time of return-to-sport clearance post ACLR. Measures included the Knee injury and Osteoarthritis Outcome Score (KOOS), single-leg hop tests, isokinetic quadriceps and hamstring strength, and limb symmetry during hop tests and strength tests. Participants were allocated to 3 groups: resumed preinjury sports participation (Tegner score), did not resume preinjury sports participation, or sustained a second ACL injury. Group differences were compared using Kruskal-Wallis tests and Mann-Whitney U post hoc tests.Seventy (56%) participants successfully resumed preinjury sports participation and 26 (21%) sustained a second ACL injury by 1 year post return-to-sport clearance. Participants who successfully resumed preinjury sports participation demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .007 and P = .004, respectively) and the crossover hop (P = .033 and P = .037, respectively), and in the involved limb on the single hop (P = .043), compared to those who did not (n = 28). Participants who sustained a second ACL injury demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .034 and P = .027, respectively) compared to those who did not resume preinjury sports participation. There were no group differences between those who successfully resumed preinjury levels of sports participation and those who sustained a second ACL injury.Following ACLR, the small proportion of young athletes who successfully resumed preinjury levels of sports participation 1 year after return to sport demonstrated greater absolute functional performance at the time of return-to-sport clearance. No differences were identified between those who successfully resumed preinjury sports participation and those who sustained a second ACL injury. Measures of limb symmetry did not differ among any of the groups.Prognosis, level 2b. J Orthop Sports Phys Ther 2019;49(3):145-153. doi:10.2519/jospt.2019.8624.

Wide variation in outcomes after anterior cruciate ligament reconstruction (ACLR) exists among adolescents and young adults. However, little evidence is available regarding key rehabilitation factors that may be driving these differences.To explore patient and parent perceptions of key rehabilitation drivers related to outcomes after ACLR.In this qualitative study, which used an interpretive phenomenological methodology, semi-structured interviews were conducted with patients who had returned to sport after ACLR and with their parents. The interviews asked about respondents' experience with physical therapy and how it related to their outcomes after ACLR. The interviews were recorded, transcribed, and coded. Themes were then identified using open and axial coding processes.There were 3 primary themes that patients and parents perceived as key factors influencing their rehabilitation outcomes after ACLR: (1) patient attributes (ie, motivation, confidence, accountability, access to resources, and social support), (2) physical therapist-patient relationship qualities (physical therapist as guide, motivator, booster of confidence, fosterer of perseverance, and coordinator of care), and (3) elements of the system (ie, availability and utilization of therapy visits, clinic environment, and coordination among care providers).Patient and parent perspectives of key drivers that influence ACLR rehabilitation outcomes include patient, therapist, and system factors. Developing specific strategies to target these factors may enhance patient and parent perceptions of the experience. The awareness gained from these results provides a foundation for future studies examining how these factors affect outcomes and how to improve rehabilitation after ACLR.Therapy, level 3.

Objective This study’s purpose was to utilize a prospective dataset to examine differences in functional brain connectivity in male high school athletes who suffered an anterior cruciate ligament (ACL) injury relative to their non-injured peers. Methods Sixty-two male high school football players were evaluated using functional magnetic resonance imaging prior to their competitive season to evaluate resting-state functional brain connectivity. Three athletes later experienced an ACL injury and were matched to 12 teammates who did not go on to sustain an ACL injury (controls) based on school, age, height, weight, and year in school. Twenty-five knee-motor regions of interest (ROIs) were created to identify differences in connectivity between the two groups. Between-subject F and t tests were used to identify significant ROI differences using a false discovery rate correction for multiple comparisons. Results There was significantly less connectivity between the left secondary somatosensory cortex and the left supplementary motor area (p = 0.025), right pre-motor cortex (p = 0.026), right supplementary motor area (p = 0.026), left primary somatosensory cortex (superior division; p = 0.026), left primary somatosensory cortex (inferior division; p = 0.026), and left primary motor cortex (p = 0.048) for the ACL-injured compared to the control subjects. No other ROI-to-ROI comparisons were significantly different between the groups (all p > 0.05). Conclusion Our preliminary data indicate a potential sensorimotor disruption for male football players who go on to experience an ACL injury. Future studies with larger sample sizes and complementary measures of neuromuscular control are needed to support these findings.

Background Historical approaches to protect the brain from outside the skull (eg, helmets and mouthpieces) have been ineffective in reducing internal injury to the brain that arises from energy absorption during sports-related collisions. We aimed to evaluate the effects of a neck collar, which applies gentle bilateral jugular vein compression, resulting in cerebral venous engorgement to reduce head impact energy absorption during collision. Specifically, we investigated the effect of collar wearing during head impact exposure on brain microstructure integrity following a competitive high school American football season. Methods A prospective longitudinal controlled trial was employed to evaluate the effects of collar wearing (n=32) relative to controls (CTRL; n=30) during one competitive football season (age: 17.04±0.67 years). Impact exposure was collected using helmet sensors and white matter (WM) integrity was quantified based on diffusion tensor imaging (DTI) serving as the primary outcome. Results With similar overall g-forces and total head impact exposure experienced in the two study groups during the season (p>0.05), significant preseason to postseason changes in mean diffusivity, axial diffusivity and radial diffusivity in the WM integrity were noted in the CTRL group (corrected p0.05). The CTRL group demonstrated significantly larger preseason to postseason DTI change in multiple WM regions compared with the collar group (corrected p

Adolescents with juvenile fibromyalgia (JFM) are typically sedentary despite recommendations for physical exercise, a key component of pain management. Interventions such as cognitive-behavior therapy (CBT) are beneficial but do not improve exercise participation. The objective of this study was to obtain preliminary information about the feasibility, safety, and acceptability of a new intervention--Fibromyalgia Integrative Training for Teens (FIT Teens), which combines CBT with specialized neuromuscular exercise training modified from evidence-based injury prevention protocols.Participants were 17 adolescent females (aged 12 to 18 y) with JFM. Of these, 11 completed the 8-week (16 sessions) FIT Teens program in a small-group format with 3 to 4 patients per group. Patients provided detailed qualitative feedback via individual semistructured interviews after treatment. Interview content was coded using thematic analysis. Interventionist feedback about treatment implementation was also obtained.The intervention was found to be feasible, well tolerated, and safe for JFM patients. Barriers to enrollment (50% of those approached) included difficulties with transportation or time conflicts. Treatment completers enjoyed the group format and reported increased self-efficacy, strength, and motivation to exercise. Participants also reported decreased pain and increased energy levels. Feedback from participants and interventionists was incorporated into a final treatment manual to be used in a future trial.Results of this study provided initial support for the new FIT Teens program. An integrative strategy of combining pain coping skills via CBT enhanced with tailored exercise specifically designed to improve confidence in movement and improving activity participation holds promise in the management of JFM.

PURPOSE: The purpose of this study was to investigate how patient-reported knee function changed over a 2-year period in young athletes after anterior cruciate ligament reconstruction (ACLR) and return-to-sport (RTS), and to determine the impact of clinical measures, after controlling for demographic and surgical covariates. METHODS: At the time of RTS after primary, unilateral ACLR, the following data were collected in 67 young athletes: Quadriceps (QF), hamstring (HS), and hip abduction (HA) strength; knee range-of-motion, effusion, and anterior laxity; and patient-reported function using the Knee injury and Osteoarthritis Outcome Score (KOOS). At 2 years post-RTS, patient-reported function was reevaluated using the KOOS. Absolute KOOS scores and proportions of participants meeting functional recovery cutoffs were compared between time-points. Multivariable linear regression was used to determine clinical measures at RTS associated with 2-year post-RTS KOOS scores. RESULTS: KOOS scores for all subscales were higher at 2 years post-RTS (all p

This study examined knee joint angle and knee muscle contraction intensity effects on perceived exertion during isometric contractions. Fourteen healthy young adults participated in five experimental exercise sessions in which knee angles varied randomly (10°, 30°, 50°, 70°, and 90°), each separated by one week. During each session, subjects performed five isometric maximal voluntary contractions (MVCs) of knee extension, followed by nine, randomly ordered submaximal contractions (10%–90% MVC, 10% increments). The participants repeated the identical procedure for the knee flexor muscles. Immediately following each submaximal contraction, participants rated their perceived exertion using a modified Borg category-ratio scale. We found that the participants’ overall ratings of perceived exertion were significantly ( p

PurposeTo (1) quantify white matter (WM) alterations in female high school athletes during a soccer season and characterise the potential for normalisation during the off-season rest period, (2) determine the association between WM alterations and exposure to repetitive subconcussive head impacts, and (3) evaluate the efficacy of a jugular vein compression collar to prevent WM alterations associated with head impact exposure.MethodsDiffusion tensor imaging (DTI) data were prospectively collected from high school female soccer participants (14–18 years) at up to three time points over 9 months. Head impacts were monitored using accelerometers during all practices and games. Participants were assigned to a collar (n=24) or non-collar group (n=22). The Tract-Based Spatial Statistics approach was used in the analysis of within-group longitudinal change and between-group comparisons.ResultsDTI analyses revealed significant pre-season to post-season WM changes in the non-collar group in mean diffusivity (2.83%±2.46%), axial diffusivity (2.58%±2.34%) and radial diffusivity (3.52%±2.60%), but there was no significant change in the collar group despite similar head impact exposure. Significant correlation was found between head impact exposure and pre-season to post-season DTI changes in the non-collar group. WM changes in the non-collar group partially resolved at 3 months off-season follow-up.DiscussionMicrostructural changes in WM occurred during a season of female high school soccer among athletes who did not wear the collar device. In comparison, there were no changes in players who wore the collar, suggesting a potential prophylactic effect of the collar device in preventing changes associated with repetitive head impacts. In those without collar use, the microstructural changes showed a reversal towards normal over time in the off-season follow-up period.

Context: A limiting factor for reducing anterior cruciate ligament injury risk is ensuring that the movement adaptions made during the prevention program transfer to sport-specific activity. Virtual reality provides a mechanism to assess transferability, and neuroimaging provides a means to assay the neural processes allowing for such skill transfer. Objective: To determine the neural mechanisms for injury risk–reducing biomechanics transfer to sport after anterior cruciate ligament injury prevention training. Design: Cohort study. Setting: Research laboratory. Participants: Four healthy high school soccer athletes. Interventions: Participants completed augmented neuromuscular training utilizing real-time visual feedback. An unloaded knee extension task and a loaded leg press task were completed with neuroimaging before and after training. A virtual reality soccer-specific landing task was also competed following training to assess transfer of movement mechanics. Main Outcome Measures: Landing mechanics during the virtual reality soccer task and blood oxygen level–dependent signal change during neuroimaging. Results: Increased motor planning, sensory and visual region activity during unloaded knee extension and decreased motor cortex activity during loaded leg press were highly correlated with improvements in landing mechanics (decreased hip adduction and knee rotation). Conclusion: Changes in brain activity may underlie adaptation and transfer of injury risk–reducing movement mechanics to sport activity. Clinicians may be able to target these specific brain processes with adjunctive therapy to facilitate intervention improvements transferring to sport.

Objectives We aimed to present a unique prospective neurological dataset for participants who experienced an ACL injury. Design Prospective longitudinal case-control. Methods High school female soccer athletes were evaluated using functional magnetic resonance imaging to capture resting-state brain connectivity prior to their competitive season. Two of these athletes later experienced an ACL injury (ACLI). We matched these ACLI participants with eight teammates who did not go on to sustain an ACL injury (uninjured controls, Con) based on age, grade, sex, height, and weight to examine differences in preseason connectivity. Knee-motor regions of interest (ROIs) were created based on previously published data from which five specific areas were selected as seeds for analysis. Independent-samples t-tests with a false discovery rate correction for multiple comparisons determined differences in connectivity between the ACLI and Con. Results There was significantly greater connectivity between the left primary sensory cortex (a brain region responsible for proprioception) and the right posterior lobe of the cerebellum (a brain region responsible for balance and coordination) for the Con relative to ACLI, t (8) = 4.53, p = 0.03 (false discovery rate corrected). Conclusions These preliminary data indicate that those who do not later sustain an ACL injury exhibit a stronger functional connection between a cortical sensory-motor region and a cerebellar region responsible for balance and coordination. These findings may help to guide development of brain-driven biofeedback training that optimizes and promotes adaptive neuroplasticity to reduce motor coordination errors and injury risk.

Objectives: The incidence of 2nd anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) and return to sport (RTS) ranges from 25%-33% in young, active populations; with the greatest risk in the first 12 months after RTS. Recent data indicate that failure to successfully meet traditional RTS criteria, inclusive of strength, functional hop testing and patient reported outcome scores, may identify athletes at increased risk of future injury after ACLR. However, these studies have focused on adult populations and it is unknown if similar RTS criteria apply to young, adolescent, pivoting/cutting athletes. The purpose of this study was to determine if meeting all current, standard RTS criteria would identify young athletes at risk for future ACL injury after primary ACLR and RTS. The tested hypothesis was the likelihood of 2nd ACL injury in the first 2 years after RTS would be lower in patients who met all RTS criteria prior to initiation of pivoting and cutting activity compared to patients who failed to meet all RTS criteria prior to RTS. Methods: One hundred fifty-nine subjects (112 female, 47 male) with a mean age of 17.2±2.6 years old (range: 13-25 y.o.) underwent ACLR and were released to return to pivoting/cutting sport. These patients were enrolled in a prospective, observational cohort study, completed a RTS assessment and were then tracked for occurrence of 2nd ACL after ACLR for 24 months. The RTS assessment included 6 tests: isometric quadriceps strength, 4 functional hop tests and the International Knee Documentation Committee (IKDC) patient reported outcome survey. Limb symmetry index (LSI) was calculated for strength and hop test assessments [(involved/uninvolved)*100]. The IKDC was reported on a 0-100 scale with 100 representing a perfect score. Subjects were classified into groups that successfully passed all 6 RTS tests at a level of 90 and again at 95 compared to those that failed to meet all 6 criteria. Chi Square tests were used to determine if successfully passing all 6 RTS measures at various levels of symmetry resulted in a reduced risk of 2nd ACL injury in the first 24 months after RTS. Results: Thirty-five (22.0%) patients suffered a 2nd ACL injury, with 26 occurring in the first 12 months after RTS. At the time of RTS, 42 patients (26%) achieved LSI values of 90 or greater on all testing as well as an IKDC value of 90 or greater. The remaining 117 subjects (74%) scored below 90 on at least 1 of the 6 assessments. At this level, there was no difference in 2nd ACL injury prevalence between patients who passed all RTS criteria (12/42; 28.6%) and those who failed at least 1 criteria (23/117; 19.7%) (p=0.23). When the passing criteria was elevated to 95 on all RTS testing, only 15 subjects (9%) successfully passed all 6 tests. There was no significant difference in 2nd ACL injury prevalence between patients who passed all RTS criteria (5/15; 33%) and those who failed at least 1 test (30/144; 20.8%) (p=0.32). Sub-group analysis which evaluated the group by graft type, also indicated no significant differences between groups (p>0.05). Conclusion: Current criteria to evaluate readiness to return young athletes to pivoting and cutting sports, using quadriceps strength symmetry, functional hop performance symmetry and patient reported outcomes, may not identify young, active patients at high risk for 2nd ACL injury. Future work must identify more appropriate criteria to assess readiness to RTS in the young, athletic population and incorporate these findings into practice.

Recent neuroimaging studies have suggested that repetitive subconcussive head impacts, even after only one sport season, may lead to pre- to post-season structural and functional alterations in male high school football athletes. However, data on female athletes are limited. In the current investigation, we aimed to (1) assess the longitudinal pre- to post-season changes in functional MRI (fMRI) of working memory and working memory performance, (2) quantify the association between the pre- to post-season change in fMRI of working memory and the exposure to head impact and working memory performance, and (3) assess whether wearing a neck collar designed to reduce intracranial slosh via mild compression of the jugular veins can ameliorate the changes in fMRI brain activation observed in the female high school athletes who did not wear collars after a full soccer season. A total of 48 female high school soccer athletes (age range: 14.00-17.97 years) were included in the study. These athletes were assigned to the non-collar group (n = 21) or to the collar group (n = 27). All athletes undewent MRI at both pre-season and post-season. In each session, a fMRI verbal N-Back task was used to engage working memory. A significant pre- to post-season increase in fMRI blood oxygen level dependent (BOLD) signal was demonstrated when performing the N-back working memory task in the non-collar group but not in the collar group, despite the comparable exposure to head impacts during the season between the two groups. The collar group demonstrated significantly smaller pre- to post-season change in fMRI BOLD signal than the non-collar group, suggesting a potential protective effect from the collar device. Significant correlations were also found between the pre- to post-season increase in fMRI brain activation and the decrease in task accuracy in the non-collar group, indicating an association between the compensatory mechanism in underlying neurophysiology and the alteration in the behavioral outcomes.

Cognitive-behavioral therapy (CBT) improves coping and daily functioning in adolescents with juvenile fibromyalgia (JFM), but is less effective in reducing pain. This pilot trial evaluated the efficacy of a novel intervention (Fibromyalgia Integrative Training for Teens; FIT Teens) which integrates CBT with specialized neuromuscular exercise training to enhance the effect of treatment on reducing pain and disability. Forty adolescents with JFM (12–18 years) were randomized to CBT-only or FIT Teens. Treatment was conducted in group-based sessions over 8 weeks with assessments at baseline, post-treatment, and 3-month follow-up (primary end point). Primary outcomes were pain intensity and functional disability. Secondary outcomes were depressive symptoms, fear of movement, and pain catastrophizing. Thirty-six participants (mean age=15.33 years; 90% female) completed the program. Intent to treat analysis was conducted to evaluate differences between the FIT Teens and CBT groups from baseline to 3-month follow-up, controlling for baseline group differences. Participants in the FIT Teens group showed significantly greater decreases in pain than the CBT group. FIT Teens participants also showed significant improvements in disability, but did not differ from CBT-only at the 3-month end point. Results provide preliminary evidence that the FIT Teens intervention provides added benefits beyond CBT in the treatment of JFM, particularly in pain reduction. Perspective Results from this pilot randomized controlled trial of a new combined CBT and specialized neuromuscular exercise intervention (FIT Teens), compared with CBT alone suggested that FIT Teens offers stronger treatment benefits than CBT alone at initial treatment follow-up, especially with respect to the outcome of pain reduction.

The purpose was to test the following hypotheses: (1) magnetic resonance imaging (MRI) markers of early knee cartilage degeneration would be present in the involved limb of young athletes after anterior cruciate ligament reconstruction (ACLR) and (2) poor knee function would be associated with MRI markers of cartilage degeneration. Twenty-five young athletes after primary, unilateral ACLR (mean age, 16.7 years) were followed to 5-year post-return-to-sport (RTS) clearance, as a part of a larger, prospective cohort study in young athletes post-ACLR. At 2-year post-RTS, patient-reported knee function was evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS). At 5-year post-RTS, qualitative MRI sequences (3 T) and quantitative T1rho and T2 maps segmented into six regions at the femur and tibia were performed for the involved and uninvolved knee cartilages. Relaxation times were compared between knees using Holm-corrected paired t tests. Linear regression was used to examine the association between KOOS scores at 2 years and relaxation times at 5 years. Elevated T1rho and T2 relaxation times were observed in the involved knee at the anterior medial femoral condyle compared to the uninvolved knee (p = 0.006, p = 0.024, respectively). Lower KOOS-Pain, KOOS-Symptoms, KOOS-ADL, and KOOS-Sport scores at 2-year post-RTS were associated with higher T1rho or T2 relaxation times in various regions of the involved knee at 5-year post-RTS (all p

Background:Outcomes after anterior cruciate ligament reconstruction (ACLR) are highly variable. Previous studies have failed to report the relationship between fear, objective measures of function, and reinjury rates. The purpose of this study was to determine whether fear was related to functional performance measures and risk of second ACL injury after ACLR and return to sport (RTS).Hypothesis:Fear will be associated with performance on functional testing and second ACL injury rate.Study Design:Prospective cohort study.Level of Evidence:Level 2.Methods:A total of 40 patients cleared to RTS after ACLR completed the Tampa Scale of Kinesiophobia (TSK-11), hop testing, and quadriceps strength testing, bilaterally. Patients were tracked for 12 months after RTS to identify the incidence of second ACL injury. Chi-square analyses determined whether patients with high fear (TSK-11, ≥17) were more likely to have lower levels of activity, greater asymmetry on functional testing, and higher reinjury rates.Results:Patients with greater fear on the TSK-11 (≥17) at RTS were 4 times (odds ratio [OR], 3.73; 95% CI, 0.98-14.23) more likely to report lower levels of activity, 7 times (OR, 7.1; 95% CI, 1.5-33.0) more likely to have a hop limb symmetry lower than 95%, and 6 times (OR, 6.0; 95% CI, 1.3-27.8) more likely to have quadriceps strength symmetry lower than 90%. Patients who went on to suffer an ipsilateral second ACL injury had a greater TSK-11 score at the time of RTS (mean, 19.8 ± 4.0) than those who did not suffer a second ACL injury (mean, 16.4 ± 3.6) ( P = 0.03). Patients with a TSK-11 score of 19 or greater at the time of RTS were 13 times (relative risk, 13.0; 95% CI, 2.1-81.0) more likely to suffer a second ACL tear within 24 months after RTS.Conclusion:Patients with greater self-reported fear were less active, presented with lower single-leg hop performance and isometric quadriceps strength, and had an increased risk of suffering a second ACL injury in the 24 months after RTS.Clinical Relevance:Self-reported fear of movement/reinjury after ACLR at the time of RTS may be an important measure to incorporate into discharge criteria prior to release to return to pivoting and cutting sports after ACLR.

Background: An objective assessment of quadriceps strength after anterior cruciate ligament reconstruction (ACLR) is an important clinical measure to determine readiness to return to sport (RTS). Not all clinicians are equipped with the means to objectively quantify quadriceps strength limb symmetry indices (Q-LSIs) via lower extremity isokinetic dynamometers, as recommended by previous studies. Purpose/Hypothesis: The purpose of this study was to determine whether the International Knee Documentation Committee 2000 Subjective Knee Form (IKDC) score at time of RTS was a predictor of quadriceps strength in a young, athletic population after ACLR. Two hypotheses were tested: (1) Individuals with higher self-reports of function would demonstrate better quadriceps strength of the involved limb than individuals with lower self-reports of function at the time of RTS, and (2) individuals with higher self-reports of function would have normal quadriceps strength limb symmetry. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: At time of RTS, 139 subjects who had undergone ACLR completed the IKDC. In addition, an isometric quadriceps strength test (Biodex dynamometer) was performed on both lower extremities. Peak torques were calculated, as was the Q-LSI, determined by the formula ( involved limb peak torque/ uninvolved limb peak torque) × 100%. Participants were dichotomized based on IKDC scores: high IKDC (IKDC ≥90) and low IKDC (IKDC Results: At time of RTS, a significant correlation between IKDC scores and (1) peak isometric torque ( r = 0.282, P < .001) and (2) Q-LSI ( r = 0.357, P < .001) was observed. Individuals with IKDC scores ≥90 were 3 times (OR = 3.4; 95% CI, 1.71-6.93) more likely to demonstrate higher Q-LSI (≥90%). An IKDC score ≥94.8 predicted Q-LSI ≥90% with high sensitivity (0.813) and moderate specificity (0.493). Conclusion: Participants with higher IKDC scores demonstrated an increased likelihood of presenting with greater involved limb quadriceps strength and better Q-LSI. Based on the results of this study, a patient-reported outcome measure, such as the IKDC, may be able to serve as a valuable screening tool for the identification of quadriceps strength deficits in this population; however, it should not be considered an accurate surrogate for isokinetic dynamometry. Furthermore, a score of ≥94.8 on the IKDC is likely to indicate that a patient’s quadriceps strength is at an acceptable RTS level.

Juvenile Fibromyalgia (JFM) is a chronic pain condition characterized by widespread musculoskeletal pain and several associated symptoms that contribute to significant functional disability (1, 2) that persists over time (3). Regular participation in moderate to vigorous physical activity and muscle strengthening exercises at least two times a week is recommended for pain management in patients with JFM, but adherence to these recommendations is poor (4, 5). In fact, a majority of pediatric and adult patients with fibromyalgia have been found to engage in extended periods of inactivity (6, 7), and based on objective activity monitoring, adolescents with JFM were found to remain very sedentary even after completing cognitive-behavioral treatment that significantly reduced their self-reported functional disability (8). Prolonged engagement in sedentary behavior can contribute to physical deconditioning and loss of confidence in patients’ ability to engage in physical activity (9). In particular, fear of movement is a prevalent concern for adults with fibromyalgia and is associated with poorer physical performance, muscle weakness, and increased pain sensitivity (10, 11). As such, pain-related fear may reinforce patients’ activity avoidance, exacerbate pain, and contribute to functional deficits, which can further contribute to physical deconditioning (11, 12). Due to their reduced participation in physical activities, adolescents with JFM may be susceptible to functional deficits that affect the fundamental movements necessary to re-engage in physical activity. For example, adults with fibromyalgia and youth with rheumatic conditions are weaker in lower extremity strength compared to healthy controls (13–16). Such biodynamic deviations can alter their joint mechanics, exacerbate chronic pain, and consequently increase their risk of falls as demonstrated in adults with fibromyalgia (9, 17–19) and adolescents with other rheumatic or chronic pain conditions (20–22). The increased risk for functional deficits and pain flares with physical activity for patients with JFM can interfere with their ability to safely engage in exercise, and contribute to a downward progression of disability, pain-related fear, and activity avoidance into adulthood. There is a need to better understand the types of biomechanical and biodynamic deviations prevalent in adolescents with JFM so that tailored exercise-based treatments can be designed to meet their specific needs. The use of three-dimensional (3-D) biomechanical analyses to assess a range of functional abilities, from walking gait to more dynamic maneuvers like jumping, can provide valuable insight regarding the nature of functional deficits associated with musculoskeletal pain conditions such as JFM. Biomechanical assessments of gait are increasingly used to identify functional deficits in patients with a variety of health conditions (23, 24). In fact, quantitative data from gait analyses has guided the development of targeted interventions resulting in improved postoperative gait in children requiring orthopedic surgery (25). On tasks requiring higher levels of skill and coordination, the drop vertical jump test (DVJ) commonly has been used to identify poor neuromuscular control (26) and predict risk of lower extremity injury (27, 28). Biomechanical and biodynamic assessments provide an ideal methodology to better understand functional deficits associated with high levels of physical impairment in JFM. The primary aim of this study was to objectively assess a spectrum of functional abilities progressing in difficulty from walking gait and strength to functional performance. We hypothesized that adolescents with JFM would demonstrate altered gait and deficiencies in lower extremity strength and performance compared to healthy controls. Patients with JFM also were expected to demonstrate higher levels of self-reported functional disability, pain intensity, depressive symptoms, and pain-related fear of movement than healthy controls.