Jacob E. Resch

Context : Following ACL reconstruction (ACLR) arthrogenic muscle inhibition limits quadriceps function. Arthrogenic muscle inhibition is characterized via a decreased central activation ratio and a higher active motor threshold. Although previous research has identified reductions in the torque–velocity relationship post-ACLR, our aim was to determine if this relationship is associated with measures of arthrogenic muscle inhibition following ACLR. Design : Cross-sectional. Methods : Nine participants (5 females and 4 males; 175.8 [7.8] cm, 79.4 [14.2] kg, 20.6 [28.8] mo postsurgery) following ACLR and 24 control participants (20 females and 4 males; 167.6 [8.1] cm, 66.9 [13.3] kg) completed isokinetic knee extension at 60, 90, 180, and 270°/s. A superimposed burst was delivered during maximal volitional isometric contraction using a square-wave stimulator to obtain central activation ratio. Transcranial magnetic stimulation was applied to obtain active motor threshold in ACLR involved limbs and control limbs. Correlations between 2-point torque–velocity relationships, central activation ratio, and active motor thresholds were analyzed separately by group with a false discovery rate correction applied. Results : The ACLR central activation ratio was not correlated with the torque–velocity relationship, but the control central activation ratio positively correlated with multiple 2-point torque–velocity relationships ( q < 0.05). The active motor threshold was higher in the ACLR participants (ACLR: 34.8 [7.8], control: 27.5 [9.4]). In the ACLR, the limbs active motor threshold was not correlated with torque–velocity relationships, but the control limb active motor threshold was correlated with T:V _60-0 ( r = .52, P < .001, q = 0.02); T:V _90-0 ( r = .47, P < .002, q = 0.024); T:V _180-0 ( r = .34, P = .04, q = 0.048); T:V _270-0 ( r = .37, P = .03, q = 0.045); and T:V _180-60 ( r = .41, P = .013, q = 0.037). Conclusion : Two-point torque–velocity relationships incorporating isometric contractions were associated with both voluntary activation and corticospinal excitability in healthy participants but not in ACLR limbs.

Context : The landing error scoring system (LESS) was developed to screen healthy individuals for anterior cruciate ligament (ACL) injury risk factors using a jump landing task. The purpose of this study was to evaluate unique landing error components of a modified LESS scoring criteria to determine its clinical utility in patients following ACL reconstruction (ACLR). Design : An observational cross-sectional study design was implemented to determine if each individual error component of the modified LESS provided unique information in an ACLR patient population. Methods : Post-ACLR patients (N = 194 [47.9% female]) completed the LESS 7.91 (1.80) months after surgery. To complete the LESS, patients stood on a 30-cm plyometric box and jumped down to a ground target, at 50% of their height in front of the box, then completed a maximal vertical jump. The LESS was repeated 3 times. Two video cameras positioned 3 m from the landing area at a height of 1 m above the floor (frontal and sagittal) recorded all trials. Video analysis of landing kinematics was performed to determine scores for each error item using the modified LESS. Itemized error scores for each patient were evaluated using an exploratory factor analysis, and factors were retained if eigenvalues were greater than 1. Results : Our exploratory factor analysis yielded 2 factor groupings. The first factor (λ = 1.61) was comprised of 4 biplanar error items (ie, errors that occur in both the frontal and sagittal plane) that evaluated body segment positioning (eg, hip and knee flexion during landing). The second factor (λ = 1.02) was comprised of 2 errors occurring in the frontal plane that evaluated knee valgus and the overall impression of their landing strategy. Conclusions : Reducing the modified LESS errors to 6-items could improve the efficiency and clinical utilization of the LESS in ACLR patients. An abbreviated version of the modified LESS may guide clinicians’ decision making in gauging patients’ readiness to return to play after ACLR.

Context: Athletes with a history of concussion (CON) have been demonstrated to have heightened levels of anxiety and depression that may continue well beyond the resolution of concussion symptoms. The global events of 2020 resulted in elevated levels of anxiety and depression in the general population, which may have unequally presented in collegiate athletes with (CON) than those without a history of concussion (NoCON). Using a deception design, our survey-based study compared levels of anxiety and depression in CON and NoCON collegiate athletes in response to the pandemic and social injustices. We hypothesized that the CON group would have significantly elevated anxiety and depression as compared to the NoCON group in response to events of 2020. Design and Methods: Collegiate athletes (N = 106) during the academic 2020–2021 academic year were divided into CON and NoCON groups based on their preinjury (baseline) concussion assessment. Participants completed the Social Readjustment Rating Scale (SSRS), Center for Epidemiologic Studies Depression Scale (CES-D), and Generalized Anxiety Disorder Scale-7 (GAD-7) via an electronic survey pertaining to the events of 2020. The term “concussion” was not used in any study materials which was the basis for our deception-based design. An analysis of covariance was used to compare group CES-D and GAD-7 outcome scores while controlling for the SSRS outcome score. Results: Our survey response rate was 14.2% (48/337 [77.1% female]) and 10.1% (58/580 [67.2% female]), for the NoCON and CON groups, respectively. The NoCON group had significantly (F₁ = 5.82, P = .018, ) higher anxiety (8.3 [5.89]) as compared to the CON group (5.5 [2.85]). The NoCON group also had significantly (F₁ = 13.7, P < .001, ) higher levels of depression (21.0 [12.52]) as compared to the CON group (16.07 [9.10]). Discussion: Our deception-based study revealed NoCON participants had elevated and clinically relevant mood states as compared to CON participants in response to the events of 2020.

Context: Racial identity may associate with clinical outcomes following sport-related concussion (SRC). This study compared clinical outcome scores before and after recovery from a SRC between Black or White college athletes. Design: Prospective cohort. Methods: Participants were self-reported White (n = 61, 18.5 [1.1] y of age) and Black (n = 24, 18.3 [1.1] y of age) NCAA Division 1 college athletes. The revised Head Injury Scale (HIS-r), the Immediate Postconcussion and Cognitive Test (ImPACT) battery, and the Sensory Organization Test (SOT) at baseline (T1), upon symptom resolution (T2) following a diagnosed SRC, and upon establishing a new baseline assessment (T3). Race was collected from paper and electronic medical records. The revised Head Injury Scale total symptom severity, ImPACT’s Verbal Memory, Visual Memory, Visual Motor Speed (VMS), and Reaction Time, and the SOT Equilibrium Score, were compared between groups at each time point. Multivariate analyses of variance (2 [group] × 3 [time]) were used to compare revised Head Injury Scale, ImPACT, and SOT outcome scores. Post hoc analyses consisted of independent and paired sample t tests. Results: A significant main effect for time (λ = 0.66, F_2,82 = 21.55, P < .001, ) was observed for the SOT. White athletes significantly improved on the Equilibrium Score between all time points (all P < .006). Similarly, Black athletes significantly improved on the Equilibrium Score between T1–T2 and T1–T3 (all P < .001). A significant main effect of time was observed for ImPACT’s Verbal Memory, Visual Memory, and VMS outcome scores (all P < .001). VMS improved for White athletes between T1–T2 (P = .02) and T3 (P = .006). Black athletes had improved VMS scores between T1–T3 (P = .015) and T2–T3 (P = .005). A between-group difference was observed for VMS at T2 (P = .004). Conclusions: There was 1 small and not clinically significant difference between groups for the VMS score at T2. Overall, groups performed consistently or improved upon their baseline balance, cognition, and symptom outcome scores at clinically relevant time points following a SRC.

Context: Race has been shown to influence computerized neurocognitive test scores, motor function test scores, and reported symptomology following sport-related concussion (SRC). However, the effect race may have on recovery time following SRC remains unknown. The objective of this study was to determine the influence of race on days until symptom free from SRC in NCAA Division 1 collegiate athletes. Design: Prospective cohort study. Methods: Participants were Black (n = 53 [28% female]) and White (n = 150 [43.3% female]) who were on average 19.0 (1.21) and 20.2 (1.3) years of age, respectively. Data were collected from the 2015–2016 to 2020–2021 collegiate sport seasons. Participants were evaluated before and after an SRC at empirically derived time points. The primary outcome measure was time until symptom free (days). Additional outcomes included baseline and postinjury Immediate Postconcussion Assessment and Cognitive Test and Sensory Organization Test (SOT) scores. A Mann–Whitney U test compared days to symptom free between groups. Immediate Postconcussion Assessment and Cognitive Test and SOT outcome scores were analyzed using a 2 (group) × 2 (time) analysis of variance. Results: White participants had a longer median recovery time (9 d) to symptom free compared with Black participants (6 d [P = .04]). Statistically significant differences were observed between Black 87.3 (9.84) and White 90.4 (8.30) groups for Immediate Postconcussion Assessment and Cognitive Test’s verbal memory composite score (P = .03). Postinjury, White participants scored significantly higher 44.5 (5.63) on visual motor speed compared with Black participants (42.4 (5.90) [P = .02]). Within-group SOT differences between baseline and postinjury testing were observed in both groups (all P < .001). Conclusions: Black collegiate athletes achieved symptom resolution sooner than White athletes. We did not explore underlying sociocultural factors such as socioeconomic status or previous concussion education, which may have influenced our results. Future studies should explore factors that may contextualize these findings.

Context: Anterior cruciate ligament reconstruction (ACLR) patients commonly adopt poor movement patterns that potentially place them at an increased risk for reinjury if untreated. Limb loading characteristics during functional tasks can highlight movement compensations. Objective: To examine loading symmetry during a bilateral bodyweight squatting task between sexes, compare loading metrics between limbs and sexes, and describe the relationship between loading metrics and patient-reported outcomes (PROs) after ACLR. Design: Cross-sectional study. Setting: Laboratory. Patients or Other Participants: One hundred forty-two patients (71 male, 71 female, age = 24.4 ± 11.10 years) with a primary, unilateral, uncomplicated ACLR completed a squatting assessment and PRO measures at approximately 5.2 months post-ACLR. Main Outcome Measure(s): Normalized limb loading peak force (N/kg) and unilateral cumulative load (%) were collected bilaterally during the squatting task. Limb symmetry index (%) was calculated for normalized peak force. First, we compared limb loading symmetry (%) between sexes using an independent-samples t test. Second, we assessed differences in limb loading metrics between limbs and sexes via an analysis of covariance. Third, we used Spearman ρ correlations to determine the relationship between limb loading metrics and PROs. Results: The majority of individuals (91 of 142, 64.1%) offloaded their ACLR limb (ACLR = 6.6 ± 1.56 N/kg, contralateral = 7.3 ± 1.61 N/kg, P < .001). Females significantly offloaded their ACLR limb (ACLR = 6.3 ± 1.38 N/kg, contralateral = 7.2 ± 1.62 N/kg, P < .001) whereas males did not significantly offload their ACLR limb (ACLR = 6.98 ± 1.65 N/kg, contralateral = 7.4 ± 1.60 N/kg, P = .07). Weak relationships were observed (Ρ value range: −.23 to .19) across limb loading metrics and PROs. Conclusions: Individuals approximately 5 months after ACLR, on average, offloaded their ACLR limb compared with the contralateral limb. Patients’ tendency to offload their weight during a squat was influenced by sex. Relationships between limb loading metrics and PROs indicate patients who load their limbs disproportionately have a lower perception of their capability to complete activities of daily living and lower subjective knee function.

Background: Several factors such as acute symptom severity, premorbid anxiety, and depression have been associated with concussion recovery. Elevated kinesiophobia has been associated with recovery from musculoskeletal conditions, as well as increased reaction time and vestibular–ocular motor dysfunction following concussion. However, kinesiophobia has yet to be evaluated as a modifier of concussion recovery time. Objectives: This study was designed to evaluate the role of acute kinesiophobia levels on days until clinical recovery in collegiate athletes with concussion. We hypothesized that collegiate athletes with elevated Tampa Scale of Kinesiophobia (TSK) scores would take a greater number of days to achieve clinical recovery compared with athletes with lower values. Methods: Division I collegiate athletes diagnosed with a concussion (N = 113, 19.9 ± 1.5 years, 42% female) participated in this descriptive laboratory study. Participants were assigned to high [≥ 37 (H-TSK, n = 54)] or low [< 37 (L-TSK, n = 59)] TSK groups on the basis of the first TSK values recorded within 72 h of their concussion. Participants were also administered the Revised Head Injury Scale (HIS-r) to assess symptom severity within 72 h of injury. The Immediate Postconcussion and Cognitive Test (ImPACT) battery was administered at baseline and used to gather demographic variables such as biological sex, age, history of anxiety/depression, and concussion history, and as part of the athletes’ symptom-free assessment. Days until clinical recovery between H-TSK and L-TSK groups were compared using a Mann–Whitney U test. Spearman’s rank correlation coefficients were calculated to determine the relationship between TSK and days until clinical recovery in addition to other modifiers of recovery. Multiple linear regression was used to evaluate days until clinical recovery as a function of the TSK total score, controlling for the HIS-r and ImPACT variables. Results: Days until clinical recovery was significantly longer in the H-TSK group (median difference = 2.5 days, p < 0.001) compared with the L-TSK group. A significant, moderate positive correlation between the TSK score and days to clinical recovery (ρ = 0.45, p < 0.001) was observed, which was also the strongest correlation among all variables. Our regression model demonstrated that for every point increase on the TSK, days until clinical recovery increased by 0.23 while controlling for total symptom severity, age, concussion history, psychiatric history, and biological sex (β = 0.23, p = 0.018). All other variables entered into the regression were not statistically significant. Conclusions: Our data suggest that athletes with TSK scores above 37 within 72 h of a concussion had a greater number of days until clinical recovery when compared with athletes with TSK values below 37. The TSK score had the highest correlation with days until clinical recovery when compared with other known modifiers of recovery, including total symptom severity. The TSK score was also the strongest predictor of days until clinical recovery. Collectively, these findings suggest that the TSK score should be considered by healthcare professionals to help inform effective management strategies for collegiate athletes with concussion.

Context: There is strong evidence that racial and ethnic disparities exist in multiple arenas of health and wellness. The causes of racial and ethnic differences in health care are multidimensional; one factor that may affect injury/illness communication, interactions, and outcomes is patient-provider racial and ethnic concordance. At present, it is unclear what role patient-provider racial and ethnic concordance and discordance plays in facilitating concussion care for collegiate athletes. Objective: To investigate the presence of athlete–athletic trainer (AT) racial and ethnic concordance and discordance among diagnosed concussion cases and examine if racial and ethnic concordance and discordance influences time (in days) until diagnosis, symptom resolution, or return-to-sport clinical milestones in collegiate athletes. Design: Retrospective cohort study. Setting: Collegiate athletics. Patients or Other Participants: A total of 694 concussion cases (38.6% [n = 268] sustained by women, 61.4% [n = 426] sustained by men) that occurred within the 2015–2016 through 2019–2020 sport seasons at 9 institutions. Main Outcome Measure(s): The number of days from the date of injury to diagnosis, symptom resolution, and return to sport and from the date of diagnosis to symptom resolution and return to sport. Results: Overall, 68.4% (n = 475) of concussion cases had patient-provider racial and ethnic concordance, and 31.6% (n = 219) were discordant. All concordant pairs included a White athlete and White AT. Time to diagnosis differed between the concordant and discordant groups (median [interquartile range] = 1 [0–2] versus 0 [0–1], respectively) only in the model adjusted for sex, sport type, and availability of an AT (odds ratio [95% CI] = 1.46 [1.07–1.85]). There were no other group differences. Conclusions: One-third of concussion cases had athlete-AT racial and ethnic discordance. Although this group was diagnosed with a concussion 1 day sooner than the concordant group, no differences were observed for any concussion recovery milestones. These findings suggest that patient-provider racial and ethnic concordance may play a minor role in concussion recognition or reporting but not necessarily in the management and recovery thereafter.

Background: Emerging research has suggested sleep to be a modifier of the trajectory of concussion recovery in adolescent and adult populations. Despite the growing recognition of the relationship between sleep and concussion, the mechanisms and physiological processes governing this association have yet to be established. Main Body: Following a concussion, a pathophysiologic cascade of events occurs, characterized by numerous factors including microglia activation, ionic imbalance, and release of excitatory neurotransmitters. Importantly, each of these factors plays a role in the regulation of the sleep-wake cycle. Therefore, dysregulation of sleep following injury may be a function of the diffuse disruption of cerebral functioning in the wake of both axonal damage and secondary physiological events. As the onset of sleep-related symptoms is highly variable following a concussion, clinicians should be aware of when and how these symptoms present. Post-injury changes in sleep have been reported in the acute, sub-acute, and chronic phases of recovery and can prolong symptom resolution, affect neurocognitive performance, and influence mood state. Though these changes support sleep as a modifier of recovery, limited guidance exists for clinicians or their patients in the management of sleep after concussion. This may be attributed to the fact that research has correlated sleep with concussion recovery but has failed to explain why the correlation exists. Sleep is a complex, multifactorial process and the changes seen in sleep that are seen following concussion are the result of interactions amongst numerous processes that regulate the sleep-wake cycle. Short Conclusion: The assessment and management of sleep by identifying and considering the biological, sociological, and psychological interactions of this multifactorial process will allow for clinicians to address the dynamic nature of changes in sleep following concussion.

Context: Biological sex and history of motion sickness are known modifiers associated with a false-positive baseline Vestibular/Ocular Motor Screening (VOMS). However, other factors may be associated with a false-positive VOMS in collegiate athletes. Objective: To identify contributing factors to false-positive VOMS assessments using population-specific criteria. We also critically appraised previously reported interpretation criteria. Design: Descriptive laboratory study. Setting: Single-site collegiate athletic training clinic. Patients or Other Participants: National Collegiate Athletic Association Division I athletes (n = 462 [41% female]) aged 18.8 ± 1.4 years. Main Outcome Measure(s): Participants completed the Athlete Sleep Behavior Questionnaire, the 7-Item Generalized Anxiety Index, the Immediate Postconcussion Assessment and Cognitive Testing battery, the Patient Health Questionnaire-9, the Revised Head Injury Scale, the Sensory Organization Test, and the VOMS as part of a multidimensional baseline concussion assessment. Participants were classified into 2 groups based on whether they had a total symptom score of greater than or equal to 8 after VOMS administration, excluding the baseline checklist. We used χ2 and independent t tests to compare group demographics. A binary logistic regression with adjusted odds ratios (ORs) was used to evaluate the influence of sex, corrected vision, attention-deficit/hyperactivity disorder, Immediate Postconcussion Assessment and Cognitive Testing composite scores, concussion history, history of treatment for headache and/or migraine, Generalized Anxiety Index scores, Patient Health Questionnaire-9 scores, Athlete Sleep Behavior Questionnaire scores, and Sensory Organization Test equilibrium scores and somatosensory, visual, and vestibular sensory ratios on false-positive rates. Results: Approximately 9.1% (42 of 462 [30 females]) met criteria for a false-positive VOMS. A significantly greater proportion of females had false positives (χ21 = 18.37, P < .001). Female sex (OR = 2.79; 95% CI = 1.17, 6.65; P = .02) and history of treatment for headache (OR = 4.99; 95% CI = 1.21, 20.59; P = .026) were the only significant predictors of false-positive VOMS. Depending on cutoff interpretation, false-positive rates using our data ranged from 9.1% to 22.5%. Conclusions: Our results support the most recent interpretation guidelines for the VOMS in collegiate athletes due to a low false-positive rate and ease of interpretation. Biological sex and history of headaches should be considered when administering the VOMS in the absence of a baseline.