The Effects of Gluteal Strength and Activation on the Relationship Between Femoral Alignment and Functional Valgus Collapse During a Single-Leg Landing.

CONTEXT: A bias toward femoral internal rotation is a potential precursor to functional valgus collapse. The gluteal muscles may play a critical role in mitigating these effects. OBJECTIVE: Determine the extent to which gluteal strength and activation mediate associations between femoral alignment measures and functional valgus collapse. DESIGN: Cross-sectional. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-five females (age = 20.1 [1.7] y; height = 165.2 [7.6] cm; weight = 68.6 [13.1] kg) and 45 males (age = 20.8 [2.0] y; height = 177.5 [8.7] cm; weight = 82.7 [16.5] kg), healthy for 6 months prior. INTERVENTION(S): Femoral alignment was measured prone. Hip-extension and abduction strength were obtained using a handheld dynamometer. Three-dimensional biomechanics and surface electromyography were obtained during single-leg forward landings. MAIN OUTCOME MEASURES: Forward stepwise multiple linear regressions determined the influence of femoral alignment on functional valgus collapse and the mediating effects of gluteus maximus and medius strength and activation. RESULTS: In females, less hip abduction strength predicted greater peak hip adduction angle (R2 change = .10; P = .02), and greater hip-extensor activation predicted greater peak knee internal rotation angle (R2 change = .14; P = .01). In males, lesser hip abduction strength predicted smaller peak knee abduction moment (R2 change = .11; P = .03), and the combination of lesser hip abduction peak torque and lesser gluteus medius activation predicted greater hip internal rotation angle (R2 change = .15; P = .04). No meaningful mediation effects were observed (υadj < .01). CONCLUSIONS: In females, after accounting for femoral alignment, less gluteal strength and higher muscle activation were marginally associated with valgus movement. In males, less gluteal strength was associated with a more varus posture. Gluteal strength did not mediate femoral alignment. Future research should determine the capability of females to use their strength efficiently.

Sex-Specific Dependence of Linear and Nonlinear Postural Control Metrics on Anthropometrics During Clinical Balance Tests in Healthy Young Adults.

CONTEXT: Previous work suggests that balance behavior is a sex-dependent, complex process that can be characterized by linear and nonlinear metrics. Although a certain degree of center of pressure variability may be expected based on sexual dimorphism, there is evidence to suggest that these effects are obscured by potential interactions between sex and anthropometric factors. To date, no study has accounted for such interactive effects using both linear and nonlinear measures. OBJECTIVE: This investigation sought to analyze interactive models featuring sex, height, and weight as predictors of linear and nonlinear aspects of postural control. DESIGN: Cross-sectional study. SETTING: Controlled laboratory. PARTICIPANTS: A total of 26 males (23.80 [3.44] y, 177.87 [6.44] cm, 81.70 [10.80] kg) and 28 females (21.14 [2.03] y, 169.57 [8.80] cm, 64.48 [8.86] kg) were sampled from a healthy university population. MAIN OUTCOME MEASURES: Linear (range [RNG], velocity [VEL], and SD) and nonlinear (detrended fluctuation analysis scaling exponent, multivariate multiscale sample entropy [MMSECI]) summary metrics of center of pressure time series. PROCEDURE: Participants stood on a force plate for 20 seconds in 3 conditions: double (D), single (S), and tandem (T) stance. Data for each stance condition were analyzed using regression models with interaction terms for sex × height and sex × weight. In D, weight had a positive, significant main effect on VELy, MMSECId, and MMSECIv. In men, height was observed to have a positive effect on SDy (S), RNGy (S), and RNGx (T) and a negative effect on MMSECIv (T). In women, weight was observed to have a positive effect on SDy and VELx (both T). CONCLUSIONS: Our findings suggest that men and women differ with respect to certain linear and nonlinear aspects of balance behavior, and that these differences may reflect sex-specific behavioral patterns in addition to effects related to sexual dimorphism.

Sport-specific biomechanical responses to an ACL injury prevention programme: A randomised controlled trial.

Anterior cruciate ligament (ACL) injury prevention programmes have not been as successful at reducing injury rates in women's basketball as in soccer. This randomised controlled trial (ClinicalTrials.gov #NCT02530333) compared biomechanical adaptations in basketball and soccer players during jump-landing activities after an ACL injury prevention programme. Eighty-seven athletes were cluster randomised into intervention (6-week programme) and control groups. Three-dimensional biomechanical analyses of drop vertical jump (DVJ), double- (SAG-DL) and single-leg (SAG-SL) sagittal, and double- (FRONT-DL) and single-leg (FRONT-SL) frontal plane jump landing tasks were tested before and after the intervention. Peak angles, excursions, and joint moments were analysed using two-way MANCOVAs of post-test scores while controlling for pre-test scores. During SAG-SL the basketball intervention group exhibited increased peak knee abduction angles (p = .004) and excursions (p = .003) compared to the basketball control group (p = .01) and soccer intervention group (p = .01). During FRONT-SL, the basketball intervention group exhibited greater knee flexion excursion after training than the control group (p = .01), but not the soccer intervention group (p = .11). Although women's soccer players exhibit greater improvements in knee abduction kinematics than basketball players, these athletes largely exhibit similar biomechanical adaptations to ACL injury prevention programmes.

A 6-week warm-up injury prevention programme results in minimal biomechanical changes during jump landings: a randomized controlled trial.

PURPOSE: To examine the extent to which an ACL injury prevention programme modifies lower extremity biomechanics during single- and double-leg landing tasks in both the sagittal and frontal plane. It was hypothesized that the training programme would elicit improvements in lower extremity biomechanics, but that these improvements would be greater during a double-leg sagittal plane landing task than tasks performed on a single leg or in the frontal plane. METHODS: Ninety-seven competitive multi-directional sport athletes that competed at the middle- or high-school level were cluster randomized into intervention (n = 48, age = 15.4 ± 1.0 years, height = 1.7 ± 0.07 m, mass = 59.9 ± 11.0 kg) and control (n = 49, age = 15.7 ± 1.6 years, height = 1.7 ± 0.06 m, mass = 60.4 ± 7.7 kg) groups. The intervention group participated in an established 6-week warm-up-based ACL injury prevention programme. Three-dimensional biomechanical analyses of a double- (SAG-DL) and single-leg (SAG-SL) sagittal, and double- (FRONT-DL) and single-leg (FRONT-SL) frontal plane jump landing tasks were tested before and after the intervention. Peak angles, excursions, and external joint moments were analysed for group differences using 2 (group) × 4 (task) repeated measures MANOVA models of delta scores (post-pre-test value) (α < 0.05). RESULTS: Relative to the control group, no significant biomechanical changes were identified in the intervention group for any of the tasks (n.s.). However, a group by task interaction was identified for knee abduction (λ = 0.80, p = 0.02), such that participants in the intervention group showed relative decreases in knee abduction moments during the SAG-DL compared to the SAG-SL (p = 0.005; d = 0.45, CI = 0.04-0.85) task. CONCLUSION: A 6-week warm-up-based ACL injury prevention programme resulted in no significant biomechanical changes during a variety of multi-directional jump landings. Clinically, future prevention programmes should provide a greater training stimulus (intensity, volume), more specificity to tasks associated with the mechanism of ACL injury (single-leg, non-sagittal plane jump landings), and longer programme duration (> 6 weeks) to elicit meaningful biomechanical changes. LEVEL OF EVIDENCE: I.

Changes in Posture Following a Single Session of Long-Duration Water Immersion.

Transitioning between different sensory environments is known to affect sensorimotor function and postural control. Water immersion presents a novel environmental stimulus common to many professional and recreational pursuits, but is not well-studied with regard to its sensorimotor effects upon transitioning back to land. The authors investigated the effects of long-duration water immersion on terrestrial postural control outcomes in veteran divers. Eleven healthy men completed a 6-hour thermoneutral pool dive (4.57 m) breathing diver air. Center of pressure was observed before and 15 minutes after the dive under 4 conditions: (1) eyes open/stable surface (Open-Stable); (2) eyes open/foam surface (Open-Foam); (3) eyes closed/stable surface (Closed-Stable); and (4) eyes closed/foam surface (Closed-Foam). Postdive decreases in postural sway were observed in all testing conditions except for Open-Stable. The specific pattern of center of pressure changes in the postdive window is consistent with (1) a stiffening/overregulation of the ankle strategy during Open-Foam, Closed-Stable, and Closed-Foam or (2) acute upweighting of vestibular input along with downweighting of somatosensory, proprioceptive, and visual inputs. Thus, our findings suggest that postimmersion decreases in postural sway may have been driven by changes in weighting of sensory inputs and associated changes in balance strategy following adaptation to the aquatic environment.

Biomechanical Differences of Multidirectional Jump Landings Among Female Basketball and Soccer Players.

Taylor, JB, Ford, KR, Schmitz, RJ, Ross, SE, Ackerman, TA, and Shultz, SJ. Biomechanical differences of multidirectional jump landings among female basketball and soccer players. J Strength Cond Res 31(11): 3034-3045, 2017-Anterior cruciate ligament (ACL) injury prevention programs are less successful in basketball than soccer and may be due to distinct movement strategies that these athletes develop from sport-specific training. The purpose of this study was to identify biomechanical differences between female basketball and soccer players during multidirectional jump landings. Lower extremity biomechanics of 89 female athletes who played competitive basketball (n = 40) or soccer (n = 49) at the middle- or high-school level were analyzed with 3-dimensional motion analysis during a drop vertical jump, double- (SAG-DL) and single-leg forward jump (SAG-SL), and double- (FRONT-DL) and single-leg (FRONT-SL) lateral jump. Basketball players landed with either less hip or knee, or both hip and knee excursion during all tasks (p ≤ 0.05) except for the SAGSL task, basketball players landed with greater peak hip flexion angles (p = 0.04). The FRONT-SL task elicited the most distinct sport-specific differences, including decreased hip adduction (p < 0.001) angles, increased hip internal rotation (p = 0.003), and increased relative knee external rotation (p = 0.001) excursions in basketball players. In addition, the FRONT-SL task elicited greater forces in knee abduction (p = 0.003) and lesser forces in hip adduction (p = 0.001) and knee external rotation (p < 0.001) in basketball players. Joint energetics were different during the FRONT-DL task, as basketball players exhibited less sagittal plane energy absorption at the hip (p < 0.001) and greater hip (p < 0.001) and knee (p = 0.001) joint stiffness. Sport-specific movement strategies were identified during all jump landing tasks, such that soccer players exhibited a more protective landing strategy than basketball players, justifying future efforts toward sport-specific ACL injury prevention programs.

Wobble Board Rehabilitation for Improving Balance in Ankles With Chronic Instability.

OBJECTIVE: To quantify improvements in clinical impairments using a wobble board rehabilitation protocol for chronic ankle instability (CAI). DESIGN: Prospective randomized controlled trial. SETTING: Laboratory. PATIENTS: Thirty-four participants with "giving way" and history of ankle sprains were randomly assigned to a rehabilitation group (REH) (170.22 ± 8.71 cm; 75.57 ± 13.55 kg; 22.94 ± 2.77 years) or control group (CON) (168.57 ± 9.81 cm; 77.19 ± 19.93 kg; 23.18 ± 3.64 years). INTERVENTIONS: Four weeks with no intervention for CON or wobble board rehabilitation for REH, consisting of 3 sessions per week of 5 repetitions. MAIN OUTCOME MEASURES: Dependent variables were preintervention and postintervention score on foot lift test (average number of errors), Time-in-Balance Test (TBT) (longest time), Star Excursion Balance Test (SEBT)-anteromedial, medial, and posteromedial (average reach distance normalized to leg length), side hop test (fastest time), and figure-of-eight hop test (fastest time). RESULTS: Main effects for time were significant for all measures (P < 0.05); but main effects for groups were not (P > 0.05) except for SEBT-anteromedial reach direction. Significant interactions were found for all dependent measures (P < 0.05) except for TBT (P > 0.05). Post hoc testing of significant interactions showed REH improved performance at posttest, whereas CON did not. CONCLUSIONS: These findings demonstrate that a single intervention using a wobble board improved static and dynamic balance deficits associated with CAI. CLINICAL RELEVANCE: This approach provides a potentially more economical, time efficient, and space efficient means of improving clinical outcome measures associated with CAI in patients who are physically active.

Recalibration and validation of the Cumberland Ankle Instability Tool cutoff score for individuals with chronic ankle instability.

OBJECTIVE: To independently recalibrate and revalidate the Cumberland Ankle Instability Tool (CAIT) cutoff score for discriminating individuals with and without chronic ankle instability (CAI). There are concerns the original cutoff score (≤27) may be suboptimal for use in the CAI population. DESIGN: Case control. SETTING: Research laboratory. PARTICIPANTS: Two independent datasets were used (total N=200). Dataset 1 included 61 individuals with a history of ≥1 ankle sprain and ≥2 episodes of giving way in the last year (CAI group) and 57 participants with no history of ankle sprain or instability in their lifetime (uninjured group). Dataset 2 included 27 uninjured participants, 29 participants with CAI, and 26 individuals with a history of a single ankle sprain and no subsequent instability (copers). INTERVENTIONS: All participants completed the CAIT during a single session. In dataset 1, a receiver operating characteristic (ROC) curve was calculated using the CAIT score and group membership as test variables. The ideal cutoff score was identified using the Youden index. The recalibrated cutoff score was validated in dataset 2 using the ROC analysis and clinimetric characteristics. MAIN OUTCOME MEASURES: CAIT cutoff score and clinimetrics. RESULTS: In dataset 1, the optimal cutoff score was ≤25, which is lower than previously reported. In dataset 2, the recalibrated cutoff score demonstrated a sensitivity of 96.6%, specificity of 86.8%, positive likelihood ratio of 7.318, and negative likelihood ratio of .039. There were 7 false positives and 1 false negative. CONCLUSIONS: The recalibrated CAIT score demonstrated very good clinimetric properties; all properties improved compared with the original cutoff score. Clinicians using the CAIT should use the recalibrated cutoff score to maximize test characteristics. Caution should be taken with copers, who had a high rate of false positives.

The dispositional flow scale-2 as a measure of autotelic personality: an examination of criterion-related validity.

The Dispositional Flow Scale-2 (DFS-2; Jackson & Eklund, 2002) may be one of the most promising measures for assessing Csikszentmihalyi's (1990) construct of "autotelic personality." Despite strong internal validity, external validity of the DFS-2 remains open. We used 2 methods to provide evidence for external validity: (1) multiple-time assessments of experience sampling (1,856 entries generated over 7 days) to derive aggregate indices of criterion validity; and (2) single-time assessments of flow and personality for additional criterion-related validity. For single-time assessments of flow, we used a modified version of the Flow Questionnaire (Csikszentmihalyi & Larson, 1984). To assess personality, we included a measure of the Five-factor traits using the Revised NEO Personality Inventory (Costa & McCrae, 1992). A path model of NEO domains, DFS-2 global scores, and experience sampling aggregates fit the data well.

Understanding the effects of a sudden directional shift in somatosensory feedback and increasing task complexity on postural adaptation in individuals with and without chronic ankle instability.

BACKGROUND: Individuals with chronic ankle instability (CAI) present somatosensory dysfunction following an initial ankle sprain. However, little is known about how individuals with CAI adapt to a sudden sensory perturbation of instability with increasing task and environmental constraints to maintain postural stability. METHODS: Forty-four individuals with and without unilateral CAI performed the Adaptation Test to a sudden somatosensory inversion and plantarflexion perturbations (environment) in double-, injured-, and uninjured- limbs. Mean sway energy scores were analyzed using 2 (group) × 2 (somatosensory perturbations) × 3 (task) repeated measures analysis of variance. RESULTS: There were significant interactions between the group, environment, and task (P=.025). The CAI group adapted faster than healthy controls to a sudden somatosensory inversion perturbation in the uninjured- (P=.002) and injured- (P<.001) limbs, as well as a sudden somatosensory plantarflexion perturbation in the double- (P=.033) and uninjured- (P=.035) limbs. The CAI and healthy groups presented slower postural adaptation to a sudden inversion perturbation than a sudden somatosensory plantarflexion perturbation in double-limb (P<.001). Whereas both groups demonstrated faster postural adaptation to a sudden somatosensory inversion perturbation compared to somatosensory plantarflexion perturbation while maintaining posture in the injured- (P<.001) and uninjured- (P<.001) limbs. The CAI and healthy groups adapted faster to a sudden somatosensory inversion perturbation in the injured- (P<.001) and uninjured- (P<.001) limbs than in double-limb, respectively. DISCUSSION: Postural adaptation in individuals with and without CAI depended on environmental (somatosensory perturbations) and task constraints. The CAI group displayed comparable and faster postural adaptation to a sudden somatosensory inversion and plantarflexion in double-, injured-, and uninjured- limbs, which may reflect a centrally mediated alteration in neuromuscular control in CAI.

Differences in pre-season balance among student athletes based on level of contact, age, and sex.

BACKGROUND: Assessing postural control is important for the assessment of motor function after concussion. Data used for postural control assessment typically do not take the sport played, age, or sex of the athlete into consideration. It is plausible these variables may be significant when making return-to-play decisions. RESEARCH QUESTION: This study used the BTrackS database to examine differences in postural control in athletes playing different types of sports and across sex and age. METHODS: BTrackS data from 9093 high school to college-aged athletes (aged 14-22 years) were examined employing a One-way ANOVA with a post-hoc test to compare CoP path length between sport types. A moderation analysis was used to test interaction effects of sex and age on a CoP/BMI ratio. RESULTS: Significant differences were observed between sport types, F(3,9089) = 42.4, p <.001, η2 = 0.014. Post hoc tests indicated that collision (M = 25.0, SD = 7.6) sport athletes exhibited significantly higher CoP measures compared to the contact (M = 23.4, SD = 7.4), limited contact (M = 22.9, SD = 6.9), and non-contact (M = 23.0, SD = 7.4) athletes. There was no difference between other sport types (p >.20). A significant mean sex difference (Mmale = 0.924, Mfemale = 0.898, p <.001) and a quadratic association with age, (ß = -0.042, p <.001) was observed. Further, magnitude of those age differences decreased with age (ß = 0.011, p <.001). An interaction of age and sex was significant for linear (ß = 0.020, p <.001) and quadratic terms (ß = -0.006, p <.001). SIGNIFICANCE: Athletes exhibited different postural control when the type of sport, age, and sex was taken into consideration. This data possess clinical significance as this suggests that normative postural control data for collision sport athletes should be derived from data based upon type of sport played, age, and sex of the athlete.

Regional anesthesia and ambulatory surgery.

PURPOSE OF REVIEW: Advances in surgery and anesthesia have allowed for more surgeries to be done on an outpatient basis. A recent important advance entails availability of suitable recovery criteria to capitalize on the benefits of regional anesthesia for ambulatory surgery. With ever-escalating healthcare costs and expectations for faster recovery, anesthesiologists are now challenged to design anesthesia plans focused on Phase I postanesthesia care unit bypass and early facility discharge. Satisfying the recently published WAKE Score criteria upon operating room exit is associated with hospital cost reductions. This review highlights regional anesthesia techniques with focus on outpatient orthopedics. We also discuss 'multimodalities' addressing postoperative nausea and vomiting prophylaxis, perioperative analgesia (including perineural analgesia), and sedation-hypnosis, which are all central to timely recovery using now-available suitable recovery criteria. RECENT FINDINGS: Ultrasound-guided regional anesthesia has increased the comfort level for many anesthesiologists performing blocks. Other advances include better monitoring of anesthetic depth for titration of sedatives, en route to avoiding emetogenic and hyperalgesic volatile anesthetics. SUMMARY: Routine regional anesthesia use, multimodal postoperative nausea and vomiting prophylaxis, multimodal sedation-hypnosis, and multimodal analgesia, along with avoiding volatile agents and short-duration opioids, can lead to both routine Phase 1 postanesthesia care unit bypass and expedited same-day discharge, when using suitable recovery criteria.

Modified proximal thigh kinematics captured with a novel smartphone app in individuals with a history of recurrent ankle sprains and altered dorsiflexion with walking.

BACKGROUND: We examined sagittal-plane thigh angular kinematics in individuals with and without recurrent ankle sprains using a clinical smartphone app called AccWalker. Sagittal-plane ankle kinematics were also compared to ascertain that altered ankle dorsiflexion, which is typically displayed with chronic ankle instability, is also present in individuals with recurrent ankle sprains. METHODS: Participants with (n = 22) and without (n = 22) recurrent ankle sprains were evaluated on average sagittal-plane ankle kinematics during walking and average sagittal-plane thigh angular kinematics during stepping-in-place with AccWalker. FINDINGS: Significant group-by-limb interactions were found for sagittal-plane ankle kinematics (F(1,42) = 63.786, P < .010) during walking and sagittal-plane average thigh angular range-of-motion (F(1,42) = 6.166, P = .017) with AccWalker. Individuals with recurrent ankle sprains displayed more ankle dorsiflexion in affected (P < .001) and unaffected (P = .001) limbs during walking than healthy controls and exhibited more ankle dorsiflexion in their affected-limb compared to their unaffected-limb (P < .001). The average sagittal-plane thigh angular range-of-motion was lower in the unaffected-limb for recurrent ankle sprains compared to their affected-limb (P = .038) and the assigned unaffected-limb of healthy controls (P = .035). INTERPRETATION: Increased dorsiflexion was present in both limbs of the recurrent ankle sprain group with walking. AccWalker does not assess ankle movement, but uniquely identified thigh motion impairments associated with recurrent ankle sprains in their unaffected-limb, potentially identifying central deficits associated with recurrent ankle sprains. This app has clinical implications for assessing potential pathological movement that can be corrected through rehabilitation.

Sensory Reweighting System Differences on Vestibular Feedback with Increased Task Constraints in Individuals with Chronic Ankle Instability Compared to Healthy Controls.

CONTEXT: Chronic ankle instability (CAI) is associated with a less flexibly adaptable sensorimotor system. Thus, individuals with CAI may present an inadequate sensory reweighting system inhibiting the ability to emphasize weight on reliable sensory feedback to control posture. However, how individuals with CAI reweight sensory feedback to maintain postural control in bilateral and unilateral stances has yet to be established. OBJECTIVES: The primary purpose was to examine group differences in how the sensory reweighting system changes to control posture in a simple double-limb stance and a more complex single-limb stance (uninjured-limb, injured-limb) under increased environmental constraints manipulating somatosensory and visual information for individuals with and without CAI. The secondary purpose was to examine the effect of environmental and task constraints on postural control. STUDY DESIGN: Case-control study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: 21 individuals with CAI (26.4±5.7years, 171.2±9.8cm, 76.6±15.17kg) and 21 healthy controls (25.8±5.7years, 169.5±9.5cm, 72.4±15.0kg) participated in the study. MAIN OUTCOME MEASURE(S): Equilibrium10 were examined while completing 6 environmental conditions of the Sensory Organization Test (SOT) during 3 tasks (double-limb and single-limb [uninjured, injured] stances). Sensory reweighting ratios for sensory systems (somatosensory, vision, vestibular) were computed from paired Equilibrium10. RESULTS: Significant 3-factor interactions were found between group, sensory systems, and tasks (P=0.006) and for groups, task, and environment (P=0.007). The CAI group failed to downweight vestibular feedback compared to healthy controls while maintaining posture in the injured-limb (P=0.030). The CAI group displayed better postural stability than healthy controls while standing with absent vision, fixed surroundings, and a moving platform in the injured-limb (P=0.032). CONCLUSIONS: The CAI group relied on vestibular feedback while maintaining better postural stability than healthy controls in the injured-limb. Group differences in postural control depended on both environmental (absent vision, moving platform) and task (injured-limb) constraints.

The Impact of Differential Knee Laxity on Brain Activation During Passive Knee Joint Loading.

Although higher anterior knee laxity is an established risk factor of ACL injury, underlying mechanisms are uncertain. While decreased proprioception and altered movement patterns in individuals with anterior knee laxity have been identified, the potential impact of higher laxity on brain activity is not well understood. Thus, the purpose of this study is to identify the impact of different magnitudes of knee laxity on brain function during anterior knee joint loading. Twenty-seven healthy and active female college students without any previous severe lower leg injuries volunteered for this study. Anterior knee laxity was measured using a knee arthrometer KT-2000 to assign participants to a higher laxity (N=15) or relatively lower laxity group (N=12). Functional magnetic resonance images were obtained during passive anterior knee joint loading in a task-based design using a 3T MRI scanner. Higher knee laxity individuals demonstrated diminished cortical activation in the left superior parietal lobe during passive anterior knee joint loading. Less brain activation in the regions associated with awareness of bodily movements in females with higher knee laxity may indicate a possible connection between brain activity and knee laxity. The results of this study may help researchers and clinicians develop effective rehabilitation programs for individuals with increased knee laxity. This article is protected by copyright. All rights reserved.

The Cornell COVID-19 Testing Laboratory: A Model to High-Capacity Testing Hubs for Infectious Disease Emergency Response and Preparedness.

The unprecedented COVID-19 pandemic posed major challenges to local, regional, and global economies and health systems, and fast clinical diagnostic workflows were urgently needed to contain the spread of SARS-CoV-2. Here, we describe the platform and workflow established at the Cornell COVID-19 Testing Laboratory (CCTL) for the high-throughput testing of clinical samples from the university and the surrounding community. This workflow enabled efficient and rapid detection and the successful control of SARS-CoV-2 infection on campus and its surrounding communities. Our cost-effective and fully automated workflow enabled the testing of over 8000 pooled samples per day and provided results for over 2 million samples. The automation of time- and effort-intensive sample processing steps such as accessioning and pooling increased laboratory efficiency. Customized software applications were developed to track and store samples, deconvolute positive pools, track and report results, and for workflow integration from sample receipt to result reporting. Additionally, quality control dashboards and turnaround-time tracking applications were built to monitor assay and laboratory performance. As infectious disease outbreaks pose a constant threat to both human and animal health, the highly effective workflow implemented at CCTL could be modeled to establish regional high-capacity testing hubs for infectious disease preparedness and emergency response.

Neuromotor changes in participants with a concussion history can be detected with a custom smartphone app.

Neuromotor dysfunction after a concussion is common, but balance tests used to assess neuromotor dysfunction are typically subjective. Current objective balance tests are either cost- or space-prohibitive, or utilize a static balance protocol, which may mask neuromotor dysfunction due to the simplicity of the task. To address this gap, our team developed an Android-based smartphone app (portable and cost-effective) that uses the sensors in the device (objective) to record movement profiles during a stepping-in-place task (dynamic movement). The purpose of this study was to examine the extent to which our custom smartphone app and protocol could discriminate neuromotor behavior between concussed and non-concussed participants. Data were collected at two university laboratories and two military sites. Participants included civilians and Service Members (N = 216) with and without a clinically diagnosed concussion. Kinematic and variability metrics were derived from a thigh angle time series while the participants completed a series of stepping-in-place tasks in three conditions: eyes open, eyes closed, and head shake. We observed that the standard deviation of the mean maximum angular velocity of the thigh was higher in the participants with a concussion history in the eyes closed and head shake conditions of the stepping-in-place task. Consistent with the optimal movement variability hypothesis, we showed that increased movement variability occurs in participants with a concussion history, for which our smartphone app and protocol were sensitive enough to capture.

Retrospective and Current Peer Victimization in College Students with Disabilities: Examining the Intersectionality of Sexual Orientation and Gender.

The present, exploratory study examined retrospective and current peer victimization in a multi-university sample of 58 college students with disabilities, 18 (31%) of whom identified as sexual minorities. Fifty-seven participants reported peer victimization during childhood, and approximately half reported experiencing peer victimization in the past 2 months. Students who identified as sexual minorities reported more retrospective victimization but current victimization did not differ between the two groups. Current and retrospective peer victimization were significantly correlated with present psychological distress. Professionals who work with students with disabilities should be aware of the high prevalence of peer victimization and its psychological correlates in this population.

Direction-Specific Signatures of Sport Participation in Center of Pressure Profiles of Division I Athletes.

BACKGROUND: Descriptive and comparative studies of human postural control generally report effects for component or resultant dimensions of a measured signal, which may obscure potentially important information related to off-cardinal directionality. Recent work has demonstrated highly specific balance behavior that is often not easily reconciled with conventional theories of postural control. PURPOSE: The purpose of this study was to quantify the effects of sport-specific training history on directional profiles of center of pressure (COP) displacement and velocity among collegiate athletes. STUDY DESIGN: Cross-Sectional Study. METHODS: One-hundred sixty-seven NCAA Division-I varsity athletes (80 female: 19.12±1.08 years, 169.79±7.03 cm, 65.69±10.43 kg; 87 male: 19.59±1.33 years, 181.25±9.06 cm, 76.40±12.73 kg) representing four sports (basketball, soccer, tennis, and cross county) participated in this study. Participants balanced barefoot with eyes closed on a force plate for 10-s. in double leg and single leg stance. Effects of sport on mean COP velocity and total displacement were assessed within eight non-overlapping directions (i.e. heading bins). RESULTS: Greater double leg COP displacement and velocity were observed within specific heading bins in cross country athletes when compared to soccer athletes. Greater double leg COP velocity was also observed in multiple heading bins in basketball athletes when compared to soccer athletes. Greater single leg (non-dominant limb) COP displacement was observed in the 135° heading bin in basketball athletes when compared to soccer athletes. CONCLUSIONS: The observed effects are likely attributable to sport-specific sensorimotor adaptations, including lower extremity strength/power, proprioceptive acuity, and efficiency of integrating vestibular information. Other potential mechanism-namely the involvement of cutaneous feedback and/or muscle synergies-deserve consideration. Directional profiling of spontaneous COP motion may improve understanding of sport-related balance behavior, enhancing its application in therapeutic and performance monitoring contexts. LEVEL OF EVIDENCE: 3b.

Relationship of Anterior Cruciate Ligament Volume and T2* Relaxation Time to Anterior Knee Laxity.

BACKGROUND: High anterior knee laxity (AKL) has been prospectively identified as a risk factor for anterior cruciate ligament (ACL) injuries. Given that ACL morphometry and structural composition have the potential to influence ligamentous strength, understanding how these factors are associated with greater AKL is warranted. HYPOTHESIS: Smaller ACL volumes combined with longer T2* relaxation times would collectively predict greater AKL. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: College-aged active male (n = 20) and female (n = 30) participants underwent magnetic resonance imaging (MRI) and AKL testing. T2-weighted MRI scans were used to assess ACL volumes, and T2* relaxation times were used to assess ACL structural composition. AKL was measured via a commercial knee arthrometer. Forward stepwise linear regression with sex and weight (first step; suppressor variables) as well as ACL volume and T2* relaxation time (second step; independent variables) was used to predict AKL (dependent variable). RESULTS: After initially adjusting for sex and weight (R 2 = 0.19; P = .006), smaller ACL volumes combined with longer T2* relaxation times collectively predicted greater AKL (R 2 = 0.52; P < .001; R 2 Δ = 0.32; P Δ < .001). A smaller ACL volume was the primary predictor of greater AKL (R 2 Δ = 0.28; P < .001), with a longer T2* relaxation time trending toward a significant contribution to greater AKL (R 2 Δ = 0.04; P = .062). After adjusting for ACL volume and T2* relaxation time, sex (partial r = 0.05; P = .735) and weight (partial r = 0.05; P = .725) were no longer significant predictors. CONCLUSION: AKL was largely predicted by ACL volume and to a lesser extent by T2* relaxation time (and not a person's sex and weight). These findings enhance our understanding of how AKL may be associated with a structurally weaker ACL. The current study presents initial evidence that AKL is a cost-effective and clinically accessible measure that shows us something about the structural composition of the ACL. As AKL has been consistently shown to be a risk factor for ACL injuries, work should be done to continue to investigate what AKL may tell a clinician about the structure and composition of the ACL.