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To determine factors associated with localized anterior arthrofibrosis (cyclops lesion), such as graft size, warranting early reoperation for lysis of adhesions after anterior cruciate ligament reconstruction (ACLR) with all-soft tissue quadriceps tendon (ASTQT) autograft.All primary ASTQT autograft ACLRs within a single surgeon's prospectively collected registry with minimum 6-month follow-up were included. Patients who underwent multiligament knee reconstruction or cartilage restoration procedures were excluded. Localized anterior arthrofibrosis was defined as the requirement for a second procedure to achieve debridement and lysis of adhesions owing to the inability to regain terminal extension within 6 months of ACLR. The sex-specific incidence of arthrofibrosis was evaluated relative to age, weight, femoral and tibial tunnel sizes, meniscal repair, and meniscectomy by a binary logistic regression.This study included 721 patients (46% female patients). There were 52 cases of localized anterior arthrofibrosis (7.2%). Female patients had a greater incidence of arthrofibrosis than male patients. Male patients with a femoral tunnel diameter of 9.25 mm or greater had an increased incidence of arthrofibrosis compared with those with a diameter of less than 9.25 mm, whereas a similar cutoff was not found to be statistically significant for female patients. Concomitant meniscal repair was associated with an increased risk of arthrofibrosis.Female sex and concomitant meniscal repair were associated with an increased localized anterior arthrofibrosis incidence. Furthermore, ASTQT with a femoral tunnel diameter of 9.25 mm or greater in male patients was associated with an increased incidence of arthrofibrosis. LEVEL OF EVIDENCE: Level III, retrospective, comparative prognostic trial.

Background: Young athletes who specialize early in a single sport may subsequently be at increased risk of injury. While heightened injury risk has been theorized to be related to volume or length of exposure to a single sport, the development of unhealthy, homogenous movement patterns, and rigid neuromuscular control strategies may also be indicted. Unfortunately, traditional laboratory assessments have limited capability to expose such deficits due to the simplistic and constrained nature of laboratory measurement techniques and analyses. Methods: To overcome limitations of prior studies, the authors proposed a soccer-specific virtual reality header assessment to characterize the generalized movement regularity of 44 young female athletes relative to their degree of sport specialization (high vs low). Participants also completed a traditional drop vertical jump assessment. Results: During the virtual reality header assessment, significant differences in center of gravity sample entropy (a measure of movement regularity) were present between specialized (center of gravity sample entropy: mean = 0.08, SD = 0.02) and nonspecialized center of gravity sample entropy: mean = 0.10, SD = 0.03) groups. Specifically, specialized athletes exhibited more regular movement patterns during the soccer header than the nonspecialized athletes. However, no significant between-group differences were observed when comparing participants’ center of gravity time series data from the drop vertical jump assessment. Conclusions: This pattern of altered movement strategy indicates that realistic, sport-specific virtual reality assessments may be uniquely beneficial in exposing overly rigid movement patterns of individuals who engage in repeated sport specialized practice.

Examine longitudinal changes in trunk, hip, and knee kinematics in maturing boys during an unanticipated cutting task.Prospective cohort study.Biomechanical laboratory.Forty-two high-school male basketball, volleyball, and soccer athletes.Trunk, hip, and knee range-of-motion (RoM), peak angles, and angles at initial contact during an unanticipated 45 degrees sidestep cutting task were estimated using laboratory-based three-dimensional optoelectronic motion capture. Maturation was classified using a modified Pubertal Maturational Observational Scale (PMOS) into prepubertal, midpubertal, or postpubertal stages.Trunk total RoM in frontal, sagittal, and transverse planes; peak trunk flexion, right lateral flexion and right rotation angles; hip total RoM in frontal, sagittal, and transverse planes; hip flexion angle at initial contact; peak hip flexion and adduction angles; knee total RoM in frontal, sagittal, and transverse planes; knee flexion angle at initial contact; peak knee flexion and abduction angles.As boys matured, there was a decrease in hip sagittal-plane RoM (49.02 degrees to 43.45 degrees, Benjamini-Hochberg adjusted P = 0.027), hip flexion at initial contact (29.33 degrees to 23.08 degrees, P = 0.018), and peak hip flexion (38.66 degrees to 32.71 degrees, P = 0.046), and an increase in trunk contralateral rotation (17.47 degrees to 25.05 degrees, P = 0.027).Maturing male athletes adopted a more erect cutting strategy that is associated with greater knee joint loading. Knee kinematic changes that increase knee joint loading were not observed in this cohort.

Context: An Optimizing Performance through Intrinsic Motivation and Attention for Learning theory-based motor learning intervention delivering autonomy support and enhanced expectancies (EE) shows promise for reducing cognitive-motor dual-task costs, or the relative difference in primary task performance when completed with and without a secondary cognitive task, that facilitate adaptive injury-resistant movement response. The current pilot study sought to determine the effectiveness of an autonomy support versus an EE-enhanced virtual reality motor learning intervention to reduce dual-task costs during single-leg balance. Design: Within-subjects 3 × 3 trial. Methods: Twenty-one male and 24 female participants, between the ages of 18 and 30 years, with no history of concussion, vertigo, lower-extremity surgery, or lower-extremity injuries the previous 6 months, were recruited for training sessions on consecutive days. Training consisted of 5 × 8 single-leg squats on each leg, during which all participants mimicked an avatar through virtual reality goggles. The autonomy support group chose an avatar color, and the EE group received positive kinematic biofeedback. Baseline, immediate, and delayed retention testing consisted of single-leg balancing under single- and dual-task conditions. Mixed-model analysis of variances compared dual-task costs for center of pressure velocity and SD between groups on each limb. Results: On the right side, dual-task costs for anterior–posterior center of pressure mean and SD were reduced in the EE group (mean Δ = −51.40, Cohen d = 0.80 and SD Δ = −66.00%, Cohen d = 0.88) compared with the control group (mean Δ = −22.09, Cohen d = 0.33 and SD Δ = −36.10%, Cohen d = 0.68) from baseline to immediate retention. Conclusions: These findings indicate that EE strategies that can be easily implemented in a clinic or sport setting may be superior to task-irrelevant AS approaches for influencing injury-resistant movement adaptations.

The purpose of this study was to compare the effects of wearing older, lower-ranked football helmets (LRank) to wearing newer, higher-ranked football helmets (HRank) on pre- to post-season changes in cortical thickness in response to repetitive head impacts and assess whether changes in cortical thickness are associated with head impact exposure for either helmet type. 105 male high-school athletes (N

Participants in American football experience repetitive head impacts that induce negative changes in neurocognitive function over the course of a single season. This study aimed to quantify the transfer function connecting the force input to the measured output acceleration of the helmet system to provide a comparison of the impact attenuation of various modern American football helmets. Impact mitigation varied considerably between helmet models and with location for each helmet model. The current data indicate that helmet mass is a key variable driving force attenuation, however flexible helmet shells, helmet shell cutouts, and more compliant padding can improve energy absorption.

To identify the neural substrates of a clinician-based test and associated pain perception in young female athletes with patellofemoral pain.Cross-sectional.Females with patellofemoral pain (n = 14; 14.3 ± 3.2 years) completed a patella displacement test during brain functional magnetic resonance imaging. The neuroimaging protocol included 18 s of interspersed rest/test blocks during which an experimenter manually applied intermittent frontal plane stress to the patella during test blocks. Patients rated their pain unpleasantness and pain intensity immediately after testing using a visual analog scale.During the patella displacement test, increased activation was observed in previously identified sensorimotor and neural pain regions, including the primary and secondary somatosensory cortices, primary motor cortex, prefrontal cortex, cerebellum, and other cognitive-related brain regions (z's 4.4, p's 0.05). Furthermore, pain unpleasantness during the test was positively correlated with increased activation of the posterior cerebellum (z = 4.51, p = 0.02), which is involved in both motor and pain processing as well as cognitive and affective feedback.These preliminary findings suggest that the posterior cerebellum may represent a critical modulator in the cognitive appraisal of pain in patellofemoral pain through cortico-cerebellar loops, which may have downstream effects on motor function. However further exploration of task-based functional connectivity between the posterior cerebellum and cortical regions is necessary to support these novel findings and associated interpretations.

Context: Kinetic profiles of athletes performing the tuck jump assessment (TJA) are unknown and may provide insight into the risk of anterior cruciate ligament injury. Design: The purpose of this study was to (1) analyze vertical kinetics of the TJA and (2) determine the stabilization of the kinetics across successive jumping cycles. Methods: Twenty-five healthy female athletes (age = 22.0 [4.6] y; height = 1.69 [0.07] m; body mass = 69.3 [10.3] kg) completed one trial of repeated tuck jumps on a force plate for 10 seconds. Results: Vertical ground reaction force data were used to calculate the following variables across all jump cycles: time of jump cycle (0.65 [0.04] s), ground contact time (0.22 [0.03] s), flight time (0.43 [0.04] s), duty factor (0.34 [0.05]), jump height (0.23 [0.04] m), peak vertical force (5.52 [0.91] body weight [BW]), peak center of mass displacement (0.15 [0.02] m), vertical leg stiffness (27.09 [7.06] BW·m−1), vertical average loading rate (105.94 [28.43] BW·s−1), vertical instantaneous loading rate (140.90 [28.49] BW·s−1), and net impulse (0.43 [0.03] BW·s). A sequential averaging technique indicated a minimum of 11 jumps were required for stabilization of the kinetics. Conclusions: The TJA exposes athletes to high magnitudes of vertical force. Based on the high variability of performance during early repetitions and the potential to miscategorize high-risk landing in female athletes, practitioners should consider scoring the TJA after 11 successive cycles and using kinetic profiling to support landing assessments.

The identified domains of child physical literacy include knowledge/understanding, behavior, motivation/confidence, and physical competency. Understanding physical literacy is critical to moving forward intervention efforts surrounding physical inactivity.To investigate physical literacy domains by presenting responses to the Play, LifestyleActivity in Youth (PLAY) questionnaire and analyze the relationship between comparable questions in the child and parent sections.Cross-sectional questionnaire study.Suburban youth program, United States.Parent and child responses to the PLAY questionnaire.Questionnaire data were collected for 106 children 6-11 years old and 91 parents. Children (93.3%, 83/91) reported enjoyment in physical education, despite 70% participation in physical education 0-1 day/week. 66.6% (26/91) of children preferred active to passive play and played outside most days/week (5.0 median). Similarly, a high proportion of children (93.3%, 83/91) reported feeling that they physically performed similar to or higher than their peers and took ownership to improve motor competency versus taking a more passive approach. Most children (96.7%, 87/91) reported feeling happy when they were able to play sports/run around, enjoyed gym class (93.3%, 83/91), and reported feeling sad if they cannot play sports/run around during the day (75.6%, 68/91). Parents and children reported rules around screen time and bed time, and reinforced these rules often. Child and parent responses were associated for comparable questions about bedtime and screen-time/media rules, moderate-to-vigorous physical activity per day, sport camp preference, and play equipment use (Fisher's p = .051 screen time, p .001 other questions).PLAY questionnaire internal validity showed agreement between comparable parent and child responses and an association for select comparable questions.

Strategies to identify lower extremity musculoskeletal (LEMSK) injury risk have been informed by prospectively identified biomechanical and neuromuscular risk factors. Emergent evidence suggests that cognitive and oculomotor performance may also contribute to LEMSK injury. The purpose of this study was to determine whether prospective cognitive and oculomotor measures identify adolescent athletes who sustain an in-season LEMSK injury.Prospective longitudinal study.Controlled laboratory and athletic event settings.Four hundred eighty-eight adolescent male football and female soccer athletes aged 13 to 18 years.Preseason baseline cognitive and oculomotor performance: Attention Network Task (ANT), cued task switching, King-Devick test, and near point of convergence.Incidence of LEMSK sprains and strains during a single competitive season.Attention Network Task-orienting network reaction time (RT) was the only cognitive or oculomotor measure significantly associated with LEMSK injury [B = 1.015, 95% confidence interval (CI): 1.01-1.024, P0.01]. Every 10 milliseconds increase in orienting network RT was associated with a 15% increased risk for LEMSK injury. Athletes demonstrating an orienting network RT ≥ 32.8 milliseconds had a higher risk for LEMSK injury relative to athletes below the cut-point (relative risk, 2.62; 95% CI, 1.52-4.52; odds ratio, 3.00; 95% CI, 1.63-5.52).Deficits in visual-spatial components of attention were associated with 2.62 times greater risk for LEMSK injury in adolescent athletes. The present results add evidence to suggest that visual-spatial attentional processing contributes to LEMSK injury and may supplement previously established LEMSK injury risk assessments.

Context Neuromuscular training (NMT) facilitates the acquisition of new movement patterns that reduce the anterior cruciate ligament injury risk. However, the neural mechanisms underlying these changes are unknown. Objective To determine the relationship between brain activation and biomechanical changes after NMT with biofeedback. Design Cohort study. Setting Research laboratory. Patients or Other Participants Twenty female high school soccer athletes, with 10 in an augmented NMT group and 10 in a control (no training) group. Main Outcome Measure(s) Ten participants completed 6 weeks of NMT augmented with real-time biofeedback to reduce knee injury-risk movements, and 10 participants pursued no training. Augmented neuromuscular training (aNMT) was implemented with visual biofeedback that responded in real time to injury-risk biomechanical variables. A drop vertical jump with 3-dimensional motion capture was used to assess injury-risk neuromuscular changes before and after the 6-week intervention. Brain-activation changes were measured using functional magnetic resonance imaging during unilateral knee and multijoint motor tasks. Results After aNMT, sensory (precuneus), visual-spatial (lingual gyrus), and motor-planning (premotor) brain activity increased for knee-specific movement; sensorimotor cortex activity for multijoint movement decreased. The knee-abduction moment during landing also decreased (4.66 ± 5.45 newton meters; P = .02; Hedges g = 0.82) in the aNMT group but did not change in the control group (P > .05). The training-induced increased brain activity with isolated knee movement was associated with decreases in knee-abduction moment (r = 0.67; P = .036) and sensorimotor cortex activity for multijoint movement (r = 0.87; P = .001). No change in brain activity was observed in the control group (P > .05). Conclusions The relationship between neural changes observed across tasks and reduced knee abduction suggests that aNMT facilitated recruitment of sensory integration centers to support reduced injury-risk mechanics and improve sensorimotor neural efficiency for multijoint control. Further research is warranted to determine if this training-related multimodal neuroplasticity enhances neuromuscular control during more complex sport-specific activities.

Context Anterior cruciate ligament injury commonly occurs via noncontact motor coordination errors that result in excessive multiplanar loading during athletic movements. Preventing motor coordination errors requires neural sensorimotor integration activity to support knee-joint neuromuscular control, but the underlying neural mechanisms driving injury-risk motor control are not well understood. Objective To evaluate brain activity differences for knee sensorimotor control between athletes with high or low injury-risk mechanics. Design Case-control study. Setting Research laboratory. Patients or Other Participants Of 38 female high school soccer players screened, 10 were selected for analysis based on magnetic resonance imaging compliance, injury-risk classification via 3-dimensional biomechanics during a drop vertical jump, and matching criteria to complete neuroimaging during knee motor tasks. Main Outcome Measure(s) Peak knee-abduction moment during landing was used for group allocation into the high (≥21.74 newton meters [Nm], n = 9) or low (≤10.6 Nm, n = 11) injury-risk classification (n = 11 uncategorized, n = 7 who were not compliant with magnetic resonance imaging). Ten participants (5 high risk, 5 low risk) with adequate data were matched and compared across 2 neuroimaging paradigms: unilateral knee-joint control and unilateral multijoint leg press against resistance. Results Athletes with high injury-risk biomechanics had less neural activity in 1 sensory-motor cluster for isolated knee-joint control (precuneus, peak Z score = 4.14, P ≤ .01, 788 voxels) and greater brain activity for the multijoint leg press in 2 cognitive-motor clusters: the frontal cortex (peak Z score = 4.71, P < .01, 1602 voxels) and posterior cingulate gyrus (peak Z score = 4.43, P < .01, 725 voxels) relative to the low injury-risk group. Conclusions The high injury-risk group's lower relative engagement of neural sensory resources controlling the knee joint may elevate demand on cognitive motor resources to control loaded multijoint action. The neural activity profile in the high injury-risk group may manifest as a breakdown in neuromuscular coordination, resulting in elevated knee-abduction moments during landing.

To examine the isolated and combined effects of sex and perceptual-motor function on single-leg squatting mechanics in males and females. We employed a cross-sectional design in a research laboratory. Fifty-eight females (22.2 ± 3.5 yrs, 1.60 ± .07 m, 64.1 ± 13.0 kg) and 35 males (23.5 ± 5.0 yrs, 1.80 ± .06m, 84.7 ± 15.3 kg) free from time-loss injury in the six months prior, vertigo, and vestibular conditions participated in this study. Independent variables were sex, perceptual-motor metrics (reaction time, efficiency index, conflict discrepancy), and interaction effects. Dependent variables were peak frontal plane angles of knee projection, ipsilateral trunk flexion, and contralateral pelvic drop during single-leg squatting. After accounting for the sex-specific variance and perceptual-motor function effects on frontal plane squatting kinematics, female sex amplified the associations of: higher reaction time, lower efficiency index, and higher conflict discrepancy with greater right ipsilateral peak trunk lean (R2 = .13; p = .05); higher reaction time, lower efficiency index, and higher conflict discrepancy with decreased right contralateral pelvic drop (R2 = .22; p < .001); higher reaction time and lower conflict discrepancy with greater right frontal plane knee projection angle (R2 = .12; p = .03); and higher reaction time with greater left frontal plane knee projection angle (R2 = .22; p < .001). Female sex amplified the relationship between perceptual-motor function and two-dimensional frontal plane squatting kinematics. Future work should determine the extent to which perceptual-motor improvements translate to safer movement strategies.

Objective:Having attention-deficit/hyperactivity disorder (ADHD) is a risk factor for concussion that impacts concussion diagnosis and recovery. The relationship between ADHD and repetitive subconcussive head impacts on neurocognitive and behavioral outcomes is less well known. This study evaluated the role of ADHD as a moderator of the association between repetitive head impacts on neurocognitive test performance and behavioral concussion symptoms over the course of an athletic season.Method:Study participants included 284 male athletes aged 13–18 years who participated in high school football. Parents completed the Strengths and Weaknesses of ADHD Symptoms and Normal Behavior (SWAN) ratings about their teen athlete before the season began. Head impacts were measured using an accelerometer worn during all practices and games. Athletes and parents completed behavioral ratings of concussion symptoms and the Attention Network Task (ANT), Digital Trail Making Task (dTMT), and Cued Task Switching Task at pre- and post-season.Results:Mixed model analyses indicated that neither head impacts nor ADHD symptoms were associated with post-season athlete- or parent-reported concussion symptom ratings or neurocognitive task performance. Moreover, no relationships between head impact exposure and neurocognitive or behavioral outcomes emerged when severity of pre-season ADHD symptoms was included as a moderator.Conclusion:Athletes’ pre-season ADHD symptoms do not appear to influence behavioral or neurocognitive outcomes following a single season of competitive football competition. Results are interpreted in light of several study limitations (e.g., single season, assessment of constructs) that may have impacted this study’s pattern of largely null results.

Schlink, BR, Nordin, AD, Diekfuss, JA, and Myer, GD. Quantification of global myoelectric spatial activations to delineate normal hamstring function at progressive running speeds: A technical report. J Strength Cond Res 36(3): 867-870, 2022-Hamstring function is critical to maintain sport performance, and strain injuries to the biceps femoris muscle commonly force an athlete to withdraw from their sport while the muscle heals. Current mechanistic understanding of underlying injury and return-to-play (RTP) guidelines has limited prognostic value because of limitations in technology and nonfunctional assessment strategies to guide clinical care. Integrated structural and functional determinants and dynamic assessment methods are needed to guide advanced rehabilitation strategies for safe and rapid return to sport. A potential solution for assessment of hamstring function is high-density electromyography (EMG), which can noninvasively measure spatial muscle activity in dynamic environments. In this study, we demonstrated the utility of high-density EMG by measuring spatial myoelectric activity from the biceps femoris from a group of recreational athletes running at a range of speeds. The level of significance set for this study was p0.05. During the late swing phase of running, we observed increased EMG amplitudes in the central and distal portions of the muscle. There were no changes in this pattern of EMG activation across speed, suggesting that running speed does not affect the general neuromuscular recruitment in the biceps femoris. Applying these methods to athletes with hamstring strains may lead to a more complete understanding of muscle function during rehabilitation and adjunctively support current methods to enhance RTP decision-making.

The purpose was to evaluate selected physical tests in children and to compare the outcomes by sex. A cross-sectional study design was used to evaluate children 6–11 years who completed five physical tests: hand grip, vertical jump, sit and reach, Y-balance, and obstacle course (time and score). The outcome measures including test results were descriptively examined and compared by sex. The study participants consisted of 133 children (62 males and 71 females, with a median age of 7.8 years). Girls showed superior sit and reach performance (p = 0.002) compared with boys. Boys demonstrated better Y-balance scores (p = 0.007) and faster obstacle time (p = 0.042) than girls. Sex comparison within three age groups (6&ndash

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.

We aimed to objectively compare the effects of wearing newer, higher-ranked football helmets (HRank) vs. wearing older, lower-ranked helmets (LRank) on pre- to post-season alterations to neuroimaging-derived metrics of athletes' white matter. Fifty-four high-school athletes wore an HRank helmet, and 62 athletes wore an LRank helmet during their competitive football season and completed pre- and post-season diffusion tensor imaging (DTI). Longitudinal within- and between-group DTI metrics [fractional anisotropy (FA) and mean/axial/radial diffusivity (MD, AD, RD)] were analyzed using tract-based spatial statistics. The LRank helmet group exhibited significant pre- to post-season reductions in MD, AD, and RD, the HRank helmet group displayed significant pre- to post-season increases in FA, and both groups showed significant pre- to post-season increases in AD (p's < .05 [corrected]). Between-group analyses revealed the pre- to post-season increase in AD was significantly less for athletes wearing HRank compared to LRank (p < .05 [corrected]). These data provide in vivo evidence that wearing an HRank helmet may be efficacious for preserving white matter from head impact exposure during high school football. Future prospective longitudinal investigations with complimentary imaging and behavioral outcomes are warranted to corroborate these initial in vivo findings.

El objetivo principal del presente estudio fue analizar el rendimiento de la técnica del salto y aterrizaje en deportistas adolescentes mediante la versión modificada del Tuck Jump Assessment (TJA). Como objetivo secundario se compararon los resultados obtenidos, según sexo. Se puntuó cada variable de la herramienta mediante el análisis en video de la prueba de los 75 participantes incluidos en el estudio. Las variables contempladas fueron la puntuación global del TJA y cada criterio del instrumento: 1) Valgo de la extremidad inferior en el aterrizaje; 2) Muslos no paralelos (punto máximo de salto); 3) Muslos no alineados durante la fase de vuelo; 4) Mala alineación de los pies con los hombros; 5) Posición de los pies no paralela (de la punta al talón); 6) Contacto desigual de los pies (aterrizaje asimétrico); 7) Demasiado ruido en el aterrizaje; 8) Pausa entre saltos; 9) La técnica empeora antes de los 10 segundos; 10) No aterriza en el mismo punto (salto consistente). Los valores promedios de la puntuación global de la versión modificada del TJA fueron 8.85±2.31 en el total de la muestra (8.85±2.63 hombres vs. 8.86±2.14 mujeres). Los resultados de la comparación según sexo indicaron diferencias significativas en el criterio 1 (χ2=10.288; p< 0.01), en el criterio 2 (χ2=20.788; p< 0.01), en el criterio 4 (χ2=22.587; p< 0.01) y en el criterio 10 (χ2=8.883; p< 0.01). En consecuencia, el análisis del patrón de salto y aterrizaje permite identificar alteraciones neuromusculares y biomecánicas del patrón de salto-aterrizaje. The main objective of the present study was to analyze the performance of the jump and landing technique in adolescent team sports athletes through the modified version of the Tuck Jump Assessment, (TJA). As a secondary objective, the results obtained werecompared, according to sex. Each outcome measure of the tool was scored through video analysis of the test of the 75 participants included in the study. The main outcome measures were the total score of TJA and each of the ten items: Knee valgus at landing (1), thighs do not reach parallel (2), thighs not equal side-to-side (3), foot placement not shoulder width apart (4), foot placement not parallel (5), foot contact timing not equal (6), excessive landing contact noise (7), pause between jumps (8), technique declines prior to ten seconds (9), and does not land in same footprint (10). The variables contemplated were the global score of the TJA and the ten criteria of the instrument. The average values of the global score of the modified version of the TJA were 8.85±2.31 in the total sample (8.85±2.63 men vs. 8.86±2.14 women). The results of the gender comparison indicated significant differences in item 1(χ2=10.288; p< 0.01), item 2 (χ2=20.788; p

Bilateral sensorimotor coordination is required for everyday activities, such as walking and sitting down/standing up from a chair. Sensorimotor coordination functional neuroimaging (fMRI) paradigms (e.g., stepping, cycling) increase activity in the sensorimotor cortex, supplementary motor area, insula, and cerebellum. Although these paradigms are designed to assay coordination, performance measures are rarely collected simultaneously with fMRI. Therefore, we aimed to identify neural correlates of lower extremity coordination using a bilateral, in-phase, multi-joint coordination task with concurrent MRI-compatible 3D motion analysis. Seventeen female athletes (15.0 ± 1.4 years) completed a bilateral, multi-joint lower-extremity coordination task during brain fMRI. Interlimb coordination was quantified from kinematic data as the correlation between peak-to-peak knee flexion cycle time between legs. Standard preprocessing and whole-brain analyses for task-based fMRI were completed in FSL, controlling for total movement cycles and neuroanatomical differences, with interlimb coordination as a covariate of interest. A clusterwise multi-comparison correction was applied at z 3.1 and p .05. Less interlimb coordination during the task was associated with greater activation in the posterior cingulate and precuneus (z

Patellofemoral pain (PFP) is defined as retro- or peri-patellar knee pain without a clear structural abnormality. Unfortunately, many current treatment approaches fail to provide long-term pain relief, potentially due to an incomplete understanding of pain-disrupted sensorimotor dysfunction within the central nervous system. The purposes of this study were to evaluate brain functional connectivity in participants with and without PFP, and to determine the relationship between altered brain functional connectivity in association with patient-reported outcomes. Young female patients with PFP (n = 15; 14.3 ± 3.2 years) completed resting-state functional magnetic resonance imaging (rs-fMRI) and patient-reported outcome measures. Each patient with PFP was matched with two controls (n = 30, 15.5 ± 1.4 years) who also completed identical rs-fMRI testing. Six bilateral seeds important for pain and sensorimotor control were created, and seed-to-voxel analyses were conducted to compare functional connectivity between the two groups, as well as to determine the relationship between connectivity alterations and patient-reported outcomes. Relative to controls, patients with PFP exhibited altered functional connectivity between regions important for pain, psychological functioning, and sensorimotor control, and the connectivity alterations were related to perceived disability, dysfunction, and kinesiophobia. The present results support emergent evidence that PFP is not localized to structural knee dysfunction, but may actually be resultant to altered central neural processes. Clinical significance: These data provide potential neuro-therapeutic targets for novel therapies aimed to reorganize neural processes, improve neuromuscular function, and restore an active pain-free lifestyle in young females with PFP.

Current best practices to direct recovery after sports-related concussion (SRC) typically require asymptomatic presentation at both rest and during a graduated exercise progression, and cognitive performance resolution. However, this standard of care results in a significantly elevated risk for musculoskeletal (MSK) injury after return-to-sport (RTS). The elevated risk is likely secondary to, in part, residual neurophysiological and dual-task motor stability deficits that remain despite RTS. These deficits present as a loss of autonomous control of gait and posture and an increased need for cognition for motor stability. Thus, the incorporation of strategies that can enhance motor stability and restore autonomous control of gait and posture during SRC recovery and RTS progression may facilitate a reduction of the elevated risk of secondary MSK injury. We provide a theoretical framework for the application of motor learning principles to restore autonomous gait and postural stability after SRC via incorporation, or targeted manipulation, of external focus, enhanced expectations, autonomy support, practice schedule variability, and dual-task strategies during rehabilitation and RTS training.

The stretch-shortening cycle (SSC) assists in effective force attenuation upon landing and augments force generation at take-off during a drop vertical jump (DVJ). General performance outcomes such as jump height or peak measures have been used to assess SSC function in youth populations; however, these discrete metrics fail to provide insight into temporal jump-landing characteristics. This study assessed DVJ force-time profiles in 1013 middle and high-school female athletes (n = 279 prepubertal, n = 401 pubertal, and n = 333 postpubertal). Maturity status was determined using the Pubertal Maturation Observation Scale. Ground reaction force data were analyzed to extract a range of variables to characterize force-time profiles. SSC function was categorized as poor, moderate, or good dependent on the presence of an impact peak and spring-like behavior. No differences in jump height or ground contact time were observed between maturity groups (p 0.05). Significant differences in absolute peak landing and take-off force were evident between all maturational statuses (p 0.05). Relative to bodyweight normalized forces, only peak take-off force was significantly different between prepubertal and postpubertal groups (p 0.05; d = 0.22). Spring-like behavior showed small improvements from pubertal to postpubertal (p 0.05; d = 0.25). Most females displayed poor SSC function at prepubertal (79.6%), pubertal (77.3%), and postpubertal (65.5%) stages of maturity. Large increases in absolute forces occur throughout maturation in female athletes; however, only small maturational differences were found in relative force or spring-like behavior. Consequently, most girls display poor SSC function irrespective of maturity.

Background: Despite knee extensor and flexor strength reportedly being associated with injury risk, including rupture of the anterior cruciate ligament in girls, there is limited evidence for the longitudinal changes in lower extremity strength. Purpose: To investigate the sex-specific relationship with longitudinal changes of knee extensor and flexor strength associated with maturation. Study design: Cohort study; Level of evidence, 2. Methods: Adolescent boys and girls (N = 257; 208 adolsecent girls) participating in high school basketball, volleyball, and soccer were assessed longitudinally in at least 2 different pubertal stages. Pubertal status (prepubertal, pubertal, and postpubertal) was determined with the modified Pubertal Maturation Observation Scale questionnaire. After a warm-up of 5 submaximal repetitions, participants were tested for concentric peak isokinetic strength for knee extension and flexion at 300 deg/s over 10 repetitions and normalized to body weight. Linear mixed models were used to test for the effect of pubertal stage, sex, and their interaction. Results: Significant interactions were identified that indicated different maturational trajectories for knee muscle strength for adolescent boys and girls, particularly between prepubertal and pubertal stages, in which boys demonstrated greater mass normalized knee extensor increases than girls (right, +12% vs +5%; left, +13% vs +7%; P < .001). For knee flexors, boys demonstrated increased strength, while girls demonstrated decreased relative knee flexor strength (right, +4% vs −1%, P = .03; left, +3 vs −3%, P = .009). Conclusion: The findings of this study support a differential effect of sex and maturation on important knee strength outcomes that may have implications for knee injury reduction, particularly in adolescent girls as they mature.

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.

Radnor, JM, Oliver, JL, Waugh, CM, Myer, GD, and Lloyd, RS. Muscle Architecture and Maturation Influence Sprint and Jump Ability in Young Boys: A Multistudy Approach. J Strength Cond Res XX(X): 000-000, 2020-This series of experiments examined the influence of medial gastrocnemius (GM) and vastus lateralis (VL) muscle architecture (muscle thickness, pennation angle, and fascicle length) on sprint and jump performance in pre-, circa-, and post-peak height velocity (PHV) boys. In experiment 1, 1-way analysis of variance and Cohen's d effect sizes demonstrated that most muscle architecture measures were significantly greater in post-PHV compared with pre-PHV boys (d = 0.77-1.41; p < 0.05). For most sprint and jump variables, there were small to moderate differences between pre-PHV to circa-PHV and circa-PHV to post-PHV groups (d = 0.58-0.93; p < 0.05) and moderate to large differences between pre-PHV and post-PHV groups (d = 1.01-1.47; p < 0.05). Pearson's correlation analyses in experiment 2 determined that muscle architecture had small to moderate correlations with sprint and jump performance (r = 0.228-0.707, p < 0.05), with strongest associations within the post-PHV cohort. Chi-squared analyses in experiment 3 identified that, over 18 months, more POST-POST responders than expected made positive changes in GM and VL muscle thickness. Significantly more PRE-POST subjects than expected displayed changes in maximal sprint speed, while significantly more POST-POST individuals than expected showed positive changes in jump height. Muscle architecture seems to be larger in more mature boys compared with their less mature peers and likely underlies their greater performance in sprinting and jumping tasks. Boys experiencing, or having experienced, PHV make the largest increases in muscle architecture and sprinting and jumping performance when tracked over 18 months.