Female National Collegiate Athletic Association Division-I Athlete Injury Prediction by Vertical Countermovement Jump Force-Time Metrics.

ABSTRACT: Merrigan, JJ, Stone, JD, Kraemer, WJ, Vatne, EA, Onate, J, and Hagen, JA. Female National Collegiate Athletic Association Division-I athlete injury prediction by vertical countermovement jump force-time metrics. J Strength Cond Res 38(4): 783-786, 2024-Vertical countermovement jump (CMJ) assessments on force plates have been purported to screen for musculoskeletal injury risk (MSKI) but with little scientific support. Thus, this study aimed to identify associations and noncontact lower-body injury predictability with CMJ force-time metrics in female athletes. The study entailed a retrospective analysis of routine injury and performance monitoring from 155 female National Collegiate Athletics Association Division I athletes. Noncontact lower-body injuries included in analysis were confirmed by medical staff, occurred during competition or training, resulted in time loss from training, and occurred within 3 months following CMJ testing (2 maximal effort, no arm swing, jumps on dual force plates). A total of 44 injuries occurred within 3 months following CMJ baseline testing and resulted in an average of 24.5 missed days from training. Those who sustained an injury were more likely to sustain another injury (15 of 44 injuries [33.1%]; odds ratio = 3.05 [95% CI = 1.31-6.99]). For every 1-unit increase from the mean in eccentric mean power and minimum eccentric force, there was a decrease in odds of sustaining a MSKI. Despite high overall model accuracy (85.6%), the receiving operating characteristic area under the curve (65.9%) was unacceptable and the true positive rate (recall) was 0.0%. Thus, no injuries in the testing data set were correctly classified by the logistic regression model with CMJ force-time metrics as predictors. Baseline CMJ assessment may not be useful for noncontact lower-body musculoskeletal injury screening or predictability in National Collegiate Athletics Association female athletes.

Suggestions and Considerations for Application of Movement Screens to Clinical Practice.

Pre-participation and return to activity functional assessments are commonly used in clinical practice to assess movement quality and identify athletes' limitations. While there are slight differences between each specific test battery, general guidelines suggest that the tests be completed without a warm-up. This has been suggested because dynamic stretching may improve range of motion and athletic performance. However, athletes typically warm up prior to participating in sport. Therefore, researchers should investigate the acute effects of dynamic stretching on functional tests and movement screens and evaluate other factors that may influence performance on these test batteries. Scientific evidence for standardized implementation of various movement screens is lacking, and future research should aim to identify gaps in the literature to allow clinicians to properly implement evidence-based practice functional assessments. The purpose of this commentary is to discuss various considerations for implementing movement screens and assessment tools into clinical practice. LEVEL OF EVIDENCE: 5.

Organization of sensorimotor activity in anterior cruciate ligament reconstructed individuals: an fMRI conjunction analysis.

Introduction: Anterior cruciate ligament reconstruction (ACLR) is characterized by persistent involved limb functional deficits that persist for years despite rehabilitation. Previous research provides evidence of both peripheral and central nervous system adaptations following ACLR. However, no study has compared functional organization of the brain for involved limb motor control relative to the uninvolved limb and healthy controls. The purpose of this study was to examine sensorimotor cortex and cerebellar functional activity overlap and non-overlap during a knee motor control task between groups (ACLR and control), and to determine cortical organization of involved and uninvolved limb movement between groups. Methods: Eighteen participants with left knee ACLR and 18 control participants performed a knee flexion/extension motor control task during functional magnetic resonance imaging (fMRI). A conjunction analysis was conducted to determine the degree of overlap in brain activity for involved and uninvolved limb knee motor control between groups. Results: The ACLR group had a statistically higher mean percent signal change in the sensorimotor cortex for the involved > uninvolved contrast compared to the control group. Brain activity between groups statistically overlapped in sensorimotor regions of the cortex and cerebellum for both group contrasts: involved > uninvolved and uninvolved > involved. Relative to the control group, the ACLR group uniquely activated superior parietal regions (precuneus, lateral occipital cortex) for involved limb motor control. Additionally, for involved limb motor control, the ACLR group displayed a medial and superior shift in peak voxel location in frontal regions; for parietal regions, the ACLR group had a more posterior and superior peak voxel location relative to the control group. Conclusion: ACLR may result in unique activation of the sensorimotor cortex via a cortically driven sensory integration strategy to maintain involved limb motor control. The ACLR group's unique brain activity was independent of strength, self-reported knee function, and time from surgery.

Characterizing Head Acceleration Events in Law Enforcement Cadets During Subject Control Technique Training.

Law enforcement cadets (LECs) complete weeks of subject control technique training. Similar sport-related combat training has been shown to expose participants to head acceleration events (HAEs) that have potential to result in short- and long-term impairments. The purpose of this study was to describe the number and magnitude of HAEs in LECs throughout their training. 37 LECs (7 females; age = 30.6 ± 8.8 years; BMI = 30.0 ± 6.0) were recruited from a law enforcement organization. Participants wore instrumented mouthguards, which recorded all HAEs exceeding a resultant 5 g threshold for training sessions with the potential for HAEs. Participants completed three defensive tactics (DT) training sessions, a DT skill assessment (DTA), and three boxing sessions. Outcome measures included the number of HAEs, peak linear acceleration (PLA), and peak rotational velocity (PRV). There were 2758 true-positive HAEs recorded across the duration of the study. Boxing sessions accounted for 63.7% of all true-positive HAEs, while DT accounted for 31.4% and DTA accounted for 4.9%. Boxing sessions resulted in a higher number of HAEs per session (F2,28 = 48.588, p < 0.001, ηp2 = 0.776), and higher median PLA (F2,28 = 8.609, p = 0.001, ηp2 = 0.381) and median PRV (F2,28 = 11.297, p < 0.001, ηp2 = 0.447) than DT and DTA. The LECs experience a high number of HAEs, particularly during boxing sessions. Although this training is necessary for job duties, HAE monitoring may lead to modifications in training structure to improve participant safety and enhance recovery.

Estimating marksmanship performance during walking while maintaining weapon aim.

Marksmanship performance while moving is a critical skill among tactical athletes due to the high demands of their occupational duties. Qualifications for dynamic marksmanship performance are not standardized across tactical athlete groups, which may limit comprehensive assessment of tactical athlete performance for situational awareness and adaptability to an unpredictable environment. Although static marksmanship performance provides foundational information on skills and level of ability, research is lacking on factors that influence dynamic marksmanship performance to best prepare tactical athletes for duties. The purpose of this study was to identify whether static marksmanship performance, speed of movement, load carriage, and biomechanical factors while 'shooting on the move' influenced dynamic marksmanship performance. Twenty-four male tactical athletes (22 active-duty Army Soldiers, two civilian SWAT operators; age: 23.83 ± 5.47 years; height: 1.80 ± 0.08 m; weight: 81.04 ± 7.87 kg) participated; final analyses did not include data from the two civilian operators to maintain sample homogeneity. Tactical athletes completed static and dynamic ('shoot on the move') marksmanship tasks under three load conditions: (1) no load (NL), (2) half kit (HK) of 11.34 kg, and (3) full kit (KIT) of 22.68 kg. Dynamic marksmanship was completed under three speed conditions: (1) self-selected slow speed, (2) standard speed, and (3) self-selected fast speed. Hip, knee, and ankle kinematics were collected via wireless inertial measurement units. Spatiotemporal parameters were collected via optical detection system. Marksmanship performance (accuracy) was collected via open-air acoustic target scoring and mean radial error (MRE) was calculated for both static and dynamic marksmanship tasks. Linear mixed-effects models were fit with dynamic MRE as the outcome variable with fixed effects of static MRE, load condition, speed condition, kinematics, and spatiotemporal parameters, adjusting for body mass. Alpha level was set a priori at p ≤ 0.10. The final statistical model included fixed effects of static MRE, load condition, speed condition, and time spent in double limb support. Static MRE (p < 0.01) and time spent in double limb support (p = 0.01) were significant factors. For each 1 cm increase in static MRE there was a 0.66 cm increase in dynamic MRE. For every 1% increase in time spent in double limb support while 'shooting on the move' there was a 0.13 cm increase in dynamic MRE. Findings from this study highlight that tactical athletes who have larger static stance MRE and spend a longer time in double limb support during a gait cycle exhibit an increase in MRE during 'shoot on the move' trials. Overall, dynamic shooting accuracy is not affected by lower extremity joint angles, load carriage, or speed of movement. Although strong relationships are known between gait speed, load, and lower extremity kinematics, the differences in tactical gait compared to normal gait and multi-task paradigm that likely favors marksmanship accuracy seem to present novel movement characteristics unique to occupational gait. Further investigation is warranted to identify other potential factors that may improve or worsen dynamic marksmanship performance.

Brain activity associated with quadriceps strength deficits after anterior cruciate ligament reconstruction.

Prolonged treatment resistant quadriceps weakness after anterior cruciate ligament reconstruction (ACL-R) contributes to re-injury risk, poor patient outcomes, and earlier development of osteoarthritis. The origin of post-injury weakness is in part neurological in nature, but it is unknown whether regional brain activity is related to clinical metrics of quadriceps weakness. Thus, the purpose of this investigation was to better understand the neural contributions to quadriceps weakness after injury by evaluating the relationship between brain activity for a quadriceps-dominated knee task (repeated cycles of unilateral knee flexion/extension from 45° to 0°), , and strength asymmetry in individuals returned to activity after ACL-R. Forty-four participants were recruited (22 with unilateral ACL reconstruction; 22 controls) and peak isokinetic knee extensor torque was assessed at 60°/s to calculate quadriceps limb symmetry index (Q-LSI, ratio of involved/uninvolved limb). Correlations were used to determine the relationship of mean % signal change within key sensorimotor brain regions and Q-LSI. Brain activity was also evaluated group wise based on clinical recommendations for strength (Q-LSI < 90%, n = 12; Q-LSI ≥ 90%, n = 10; controls, all n = 22 Q-LSI ≥ 90%). Lower Q-LSI was related to increased activity in the contralateral premotor cortex and lingual gyrus (p < .05). Those who did not meet clinical recommendations for strength demonstrated greater lingual gyrus activity compared to those who met clinical recommendations Q-LSI ≥ 90 and healthy controls (p < 0.05). Asymmetrically weak ACL-R patients displayed greater cortical activity than patients with no underlying asymmetry and healthy controls.

Effect of Video Feedback Model Type in Youth Athletes Performing an American Football Tackle.

CONTEXT: Video feedback is an expeditious method to improve athlete safety when performing activities with an inherent risk of injury. OBJECTIVE: Determine the effect of video feedback in the instruction of tackling form. Providing appropriate and validated feedback during tackling training in North American football may be a mechanism for athletes to learn safe tackling performance. DESIGN: Controlled Laboratory Study. SETTING: Youth American Football. INTERVENTIONS: This study utilizes video feedback using self as model, expert as model, combined self and expert model, and verbal feedback to promote safe tackling performance in a lab environment. PATIENTS OR OTHER PARTICIPANTS: Thirty-two youth football athletes participated in a 1-day training. Of those, fourteen participants completed two additional days of training and a 48-hour retention and transfer test. MAIN OUTCOME MEASURES: For 1-day training, main effects for time were seen in: shoulder extension (p=0.04), cervical extension (p=0.01), pelvis height (p=0.00), and step length (p=0.00) with significantly better performance in combined feedback for pelvis height and step length. For the 3-day training group, main effects of time were identified in pelvis height (p<0.01) and step length (p<0.01) with combined feedback showing significantly better performance over other groups in shoulder extension and pelvis height. RESULTS: Combined feedback video resulted in better performance compared to its component parts and verbal feedback alone. In the combined group, participants were able to see both their performance and the expert model allowing the participants to visually see the difference between required and current performance. CONCLUSION: These outcomes indicate combined feedback may be superior to other forms of feedback in improving movement performance. This effect can be generalized across disciplines that provide instruction and feedback in movement.

Comparing dynamic visual acuity between athletes who are deaf or hard-of-hearing and athletes who are hearing.

This study examined the difference in the dynamic visual acuity test (DVAT) between collegiate athletes who are deaf or hard-of-hearing (D/HoH) (n = 38) and university club-level athletes who are hearing (n = 38). Dynamic visual acuity was assessed using the Bertec Vision Advantage (Bertec® Corporation, Columbus, Ohio, USA). No statistically significant differences between athletes who are D/HoH and who are hearing were found in DVAT for leftward (χ2 = 0.71, p = 0.40) or rightward (χ2 = 0.04, p = 0.84) head yaw rotation around an earth vertical axis. Dynamic visual acuity was similar for athletes regardless of hearing status. Baseline DVAT data may be of use for post-injury management of athletes who are D/HoH.

A Preliminary Investigation into the Neural Correlates of Knee Loading during a Change of Direction Task in Individuals after Anterior Cruciate Ligament Reconstruction.

Background: Central nervous system (CNS) function after ACLR, quantified by the blood oxygen level dependent (BOLD) response, is altered in regions of sensory function during knee movement after ACLR. However, it is unknown how this altered neural response may manifest in knee loading and response to sensory perturbations during sport specific movements. Purpose: To investigate the relationship among CNS function and lower extremity kinetics, under multiple visual conditions, during 180° change of direction task in individuals with a history of ACLR. Methods: Eight participants, 39.3 ± 37.1 months after primary, left ACLR performed repetitive active knee flexion and extension of their involved knee during fMRI scanning. Participants separately performed 3D motion capture analysis of a 180° change of direction task under full vision (FV) and stroboscopic vision (SV) conditions. A neural correlate analysis was performed to associate BOLD signal to knee loading of the left lower extremity. Results: Involved limb peak internal knee extension moment (pKEM) was significantly lower in the SV condition (1.89 ± 0.37 N*m/Kg) compared to the FV condition (2.0 ± 0.34 N*m/Kg) (p = .018). Involved limb pKEM during the SV condition was positively correlated with BOLD signal in the contralateral precuneus and superior parietal lobe (Voxels: 53; p = .017; z-stat max: 6.47; MNI peak: 6, -50, 66). Conclusion: There is a positive association between involved limb pKEM in the SV condition and BOLD response in areas of visual-sensory integration. Activation of contralateral precuneus and superior parietal lobe brain regions may be a strategy to maintain joint loading when vision is perturbed. Level of Evidence: Level 3.

Use of accelerometers and inertial measurement units to quantify movement of tactical athletes: A systematic review.

The dynamic work environments of tactical athletes are difficult to replicate in a laboratory. Accelerometers and inertial measurement units provide a way to characterize movement in the field. This systematic review identified how accelerometers and inertial measurement units are currently being used to quantify movement patterns of tactical athletes. Seven research and military databases were searched, producing 26,228 potential articles with 78 articles included in this review. The articles studied military personnel (73.1%), firefighters (19.2%), paramedics (3.8%), and law enforcement officers (3.8%). Accelerometers were the most used type of sensor, and physical activity was the primarily reported outcome variable. Seventy of the studies had fair or poor quality. Research on firefighters, emergency medical services, and law enforcement officers was limited. Future research should strive to make quantified movement data more accessible and user-friendly for non-research personnel, thereby prompting increased use in tactical athlete groups, especially first responder agencies.

The relationship between drop vertical jump action-observation brain activity and kinesiophobia after anterior cruciate ligament reconstruction: A cross-sectional fMRI study.

BACKGROUND: Injury and reconstruction of anterior cruciate ligament (ACL) result in central nervous system alteration to control the muscles around the knee joint. Most individuals with ACL reconstruction (ACLR) experience kinesiophobia which can prevent them from returning to activity and is associated with negative outcomes after ACLR. However, it is unknown if kinesiophobia alters brain activity after ACL injury. OBJECTIVES: To compare brain activity between an ACLR group and matched uninjured controls during an action-observation drop vertical jump (AO-DVJ) paradigm and to explore the association between kinesiophobia and brain activity in the ACLR group. METHODS: This cross-sectional study enrolled 26 individuals, 13 with ACLR (5 males and 8 females, 20.62 ± 1.93 years, 1.71 ± 0.1 m, 68.42 ± 14.75 kg) and 13 matched uninjured controls (5 males and 8 females, 22.92 ± 3.17 years, 1.74 ± 0.10 m, 70.48 ± 15.38 kg). Individuals were matched on sex and activity level. Participants completed the Tampa Scale of Kinesiophobia-11 (TSK-11) to evaluate the level of movement-related fear. To assay the brain activity associated with a functional movement, the current study employed an action-observation/motor imagery paradigm during functional magnetic resonance imaging (fMRI). RESULTS: The ACLR group had lower brain activity in the right ventrolateral prefrontal cortex relative to the uninjured control group. Brain activity of the left cerebellum Crus I and Crus II, the right cerebellum lobule IX, amygdala, middle temporal gyrus, and temporal pole were positively correlated with TSK-11 scores in the ACLR group. CONCLUSION: Brain activity for the AO-DVJ paradigm was different between the ACLR group and uninjured controls. Secondly, in participants with ACLR, there was a positive relationship between TSK-11 scores and activity in brain areas engaged in fear and cognitive processes during the AO-DVJ paradigm.

Neural Correlates of Self-Reported Knee Function in Individuals After Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Anterior cruciate ligament (ACL) rupture is a common knee injury among athletes and physically active adults. Despite surgical reconstruction and extensive rehabilitation, reinjuries are common and disability levels are high, even years after therapy and return to activity. Prolonged knee dysfunction may result in part from unresolved neuromuscular deficits of the surrounding joint musculature in response to injury. Indeed, "upstream" neurological adaptations occurring after injury may explain these persistent functional deficits. Despite evidence for injury consequences extending beyond the joint to the nervous system, the link between neurophysiological impairments and patient-reported measures of knee function remains unclear. HYPOTHESIS: Patterns of brain activation for knee control are related to measures of patient-reported knee function in individuals after ACL reconstruction (ACL-R). STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: In this multicenter, cross-sectional study, participants with unilateral ACL-R (n = 25; 10 men, 15 women) underwent task-based functional magnetic resonance imaging testing. Participants performed repeated cycles of open-chain knee flexion/extension. Neural activation patterns during the movement task were quantified using blood oxygen level-dependent (BOLD) signals. Regions of interest were generated using the Juelich Histological Brain Atlas. Pearson product-moment correlations were used to determine the relationship between mean BOLD signal within each brain region and self-reported knee function level, as measured by the International Knee Documentation Committee index. Partial correlations were also calculated after controlling for time from surgery and sex. RESULTS: Patient-reported knee function was positively and moderately correlated with the ipsilateral secondary somatosensory cortex (r = 0.57, P = 0.005) and the ipsilateral supplementary motor area (r = 0.51, P = 0.01). CONCLUSION: Increased ipsilateral secondary sensorimotor cortical activity is related to higher perceived knee function. CLINICAL RELEVANCE: Central nervous system mechanisms for knee control are related to subjective levels of knee function after ACL-R. Increased neural activity may reflect central neuroplastic strategies to preserve knee functionality after traumatic injury.

Hearing Status and Static Postural Control of Collegiate Athletes.

CONTEXT: Because of the close proximity of the cochlea, vestibular apparatus, and shared neurovascular structures, the static postural control of athletes who are deaf or hard of hearing (D/HoH) may be different from that of athletes who are hearing. Limited research is available to quantify differences between these athletes. OBJECTIVE: To determine the effect of hearing status and stance condition on the static postural control of athletes. DESIGN: Cross-sectional study. SETTING: Athletic training facilities. PATIENTS OR OTHER PARTICIPANTS: Fifty-five collegiate varsity athletes who were D/HoH (age = 20.62 ± 1.80 years, height = 1.73 ± 0.08 m, mass = 80.34 ± 18.92 kg) and 100 university club athletes who were hearing (age = 20.11 ± 1.59 years, height = 1.76 ± 0.09 m, mass = 77.66 ± 14.37 kg). MAIN OUTCOME MEASURE(S): Participants completed the Modified Clinical Test of Sensory Interaction and Balance on a triaxial force plate. Anteroposterior and mediolateral (ML) center-of-pressure (CoP) velocity, anteroposterior and ML CoP amplitude root mean square, and 95% ellipse sway area were calculated. RESULTS: Athletes who were D/HoH had a larger CoP velocity, larger ML root mean square, and larger sway area than those who were hearing (P values < .01). A significant main effect of stance condition was observed for all postural control variables (P values < .01). CONCLUSIONS: During the Modified Clinical Test of Sensory Interaction and Balance, athletes who were D/HoH demonstrated a larger sway area compared with athletes who were hearing. Therefore, individualized baseline assessments of static postural control may be warranted for athletes who are D/HoH as opposed to comparisons with existing normative data.

Normative Performance Profiles of College Aged Esport Athletes in a Pilot Study.

Aims: This study aimed to holistically assess the physical and cognitive attributes of esport athletes. Methods and Results: Forty-six adults between 18 and 32 years old with experience playing videogames were enrolled in this study. Participants completed assessments in five areas: demographics, self-report questionnaires, cognitive performance, physical performance, and gaming performance. Participants self-reported Overwatch ranking and physical activity participation (Pediatric Physical Activity Measure), and grip strength was measured with a handheld dynamometer. Seven domains of physical, mental, and social health and well-being were measured with the Patient Reported Outcomes Measurement Information System (PROMIS-29). The List Sorting Working Memory Test and Picture Sequence Memory Test from the National Institutes of Health (NIH) Toolbox Cognition Batteries were used to measure cognitive performance. Finally, esports performance was measured using a series of tasks through Alienware Academy and AIM Booster to record accuracy, reaction time, and targets hit. Participants were separated into high and low ranking groups for comparisons. This sample of esport athletes was similar to the general population for grip strength, each of the PROMIS-29 metrics, the List Sorting Working Memory Test, and the Picture Sequence Memory Test. Reaction time was the variable with the only significant difference between ranking groups. Conclusion: This study represents a primary investigation of esport athletes using a holistic approach. By incorporating physical and cognitive components, the most important factors to esport athletes' health and performance can be better understood and applied.

Arousal/Stress Effects of "Overwatch" eSports Game Competition in Collegiate Gamers.

ABSTRACT: Kraemer, WJ, Caldwell, LK, Post, EM, Beeler, MK, Emerson, A, Volek, JS, Maresh, CM, Fogt, JS, Fogt, N, Häkkinen, K, Newton, RU, Lopez, P, Sanchez, BN, and Onate, JA. Arousal/stress effects of "Overwatch" eSports game competition in collegiate gamers. J Strength Cond Res 36(10): 2671-2675, 2022-To date, no physical response data are available for one of the most popular eSport games, Overwatch . The purpose of this investigation was to describe the stress signaling associated with competitive Overwatch play and to understand how acute hormonal responses may affect performance. Thirty-two male college-aged gamers (age: 21.3 ± 2.7 years; estimated time played per week: 18 ± 15 hours) completed the study. Subjects were randomly assigned to a 6-player team to compete in a tournament-style match. Salivary measures of cortisol and testosterone were collected immediately before (PRE) and after (POST) the first-round game, with the heart rate recorded continuously during the match. The mean characteristics were calculated for each variable and comparisons made by the skill level. Significance was defined as p ≤ 0.05. There were no differences in measures of salivary cortisol. A differential response pattern was observed by the skill level for testosterone. The low skill group displayed a significant increase in testosterone with game play (mean ± SD , testosterone PRE: 418.3 ± 89.5 pmol·L -1 , POST: 527.6 ± 132.4 pmol·L -1 , p < 0.001), whereas no change was observed in the high skill group. There were no differences in heart rate characteristics between skill groups. Overall, the average heart rate was 107.2 ± 17.8 bpm with an average max heart rate of 133.3 ± 19.1 bpm. This study provides unique physiological evidence that a sedentary Overwatch match modulates endocrine and cardiovascular responses, with the skill level emerging as a potential modulator.

The effects of knee osteoarthritis on neural activity during a motor task: A scoping systematic review.

OBJECTIVE: To examine the evidence of neural activation with functional magnetic resonance imaging (fMRI), corticospinal excitability, and other central nervous system measurement differences during motor tasks between those with and without knee osteoarthritis (KOA). METHODS: A scoping review strategy was systematically performed. We searched PubMed, CINAHL, Embase, PsychInfo, SportDiscus, SCOPUS and Web of Science from database inception to April 2021. Any study investigating central nervous system measures during a motor task for individuals with KOA with or without a healthy control group for comparison was included. Two reviewers independently screened all studies in accordance with the Preferred Reported Items for Systematic Reviews and Meta-analyses extension for scoping reviews. RESULTS: Thirteen studies met the inclusion criteria. KOA had reduced activation of the premotor cortex during a gait imagery task when examining the brain using fMRI. This hypoactivation was not significant when the task was combined with ankle movement. Individuals with KOA had decreased motor cortex activation during a force matching motor task. KOA was associated with gamma loop dysfunction of the quadriceps and increased responsiveness of the triceps surae muscles. Also, there was an increased soleus Hoffmann reflex during heel strike of gait cycle. The flexor withdrawal reflex was heighted for individuals with KOA with a lower threshold of the reflex occurring with increased joint compression, but this reflex was modulated with joint mobilizations. CONCLUSION: Individuals with KOA have motor deficits associated with decreased neural activation, central nervous system sensitization, decreased quadriceps muscle spindle responsiveness, and increased triceps surae muscle activity.

Clinical Utility and Validity of Exercise Vital Sign in Children.

ABSTRACT: We reviewed charts of 14,446 sports medicine patients, children aged 5 to 18 years, over a 3-year period to determine the discriminant validity of Exercise Vital Sign (EVS) questions. A logistic regression analyzed factors related to any moderate to vigorous physical activity (MVPA). A linear regression analyzed factors related to amount of MVPA for those who participated in any weekly MVPA. Overall, 48% of children reported meeting physical activity guidelines for 420 min·wk-1. Overall, children reported 400.36 ± 280.04 min·wk-1 of MVPA. Those with depression had significantly less MVPA than those without (95% confidence interval [CI], -96.65 to -26.31). Girls had significantly less MVPA than boys (95% CI, -59.15 to -40.31). Overweight and obese children reported less MVPA compared with normal weight children (95% CIs, -42.65 to -17.29 and -91.61 to -65.50, respectively). EVS demonstrates strong discriminant validity to detect differences between groups as a function of sex, body mass index, and depression.

Visual cognition associated with knee proprioception, time to stability, and sensory integration neural activity after ACL reconstruction.

Visual cognitive ability has previously been associated with anterior cruciate ligament injury and injury risk biomechanics in healthy athletes. Neuroimaging reports have identified increased neural activity in regions corresponding to visual-spatial processing, sensory integration, and visual cognition in individuals after anterior cruciate ligament reconstruction (ACLR), indicating potential neural compensatory strategies for motor control. However, it remains unclear whether there is a relationship between visual cognition, neural activity, and metrics of neuromuscular ability after ACLR. The purpose of this study was to (1) evaluate the relationship between visual cognitive function and measurements of neuromuscular control (proprioception and time to stability [TTS]), isokinetic strength, and subjective function, and (2) examine the neural correlates of visual cognition between ACLR (n = 16; time since surgery 41.4 ± 33.0 months) and demographically similar controls (n = 15). Visual cognition was assessed by the ImPACT visual motor and visual memory subscales. Outcome variables of proprioception to target knee angle 20°, landing TTS, strength, and subjective function were compared between groups, and visual cognition was correlated within groups to determine the relationship between visual cognition and outcome variables controlled for time from surgery (ACLR group). The control group had better IKDC scores and strength. Visual memory and visual motor ability were negatively associated with proprioception error (r = -0.63) and TTS (r = -0.61), respectively, in the ACLR group but not controls. Visual cognition was associated with increased neural activity in the precuneus and posterior cingulate cortex in the ACLR group but not control participants. These data suggest the neural strategy in which ACLR participants maintain proprioception and stability varies, and may depend on visual cognition and sensory integration neural activity.

Perceived Management of Acute Sports Injuries and Medical Conditions by Athletic Trainers and Physical Therapists.

BACKGROUND: While Athletic Trainers' (ATs) education emphasizes sport event coverage, Physical Therapists' (PTs) education may prepare them for event coverage responsibilities. The objectives of this study were to compare the perceived preparedness and decision-making related to acute injury/medical condition management among ATs and PTs and evaluate the relationship between perceived preparedness and decision-making. HYPOTHESIS: ATs would report greater perceived preparedness and appropriate decision-making related to acute injury/medical conditions compared to PTs. STUDY DESIGN: Cross-sectional, Online survey. METHODS: An electronic survey was disseminated to licensed ATs (n=2,790) and PTs (n=10,207). Survey questions focused on perceived preparedness for management of acute injuries/medical conditions. Respondents also completed questions that assessed clinical decision-making related to acute injury case scenarios. Kruskal-Wallis H-Tests and Spearman's Rho Correlations were used for the analysis. Significance was set to p<0.003 after adjustment for family-wise error. RESULTS: Six-hundred and fifty-five respondents (292 ATs, 317 PTs, 46 dual credentialed PT/ATs) completed the entire survey. ATs had the highest level of perceived preparedness of all the groups (p<0.0003). Greater than 75% of PTs responded either "appropriately" or "overly cautious" to 10 of the 17 case scenarios, as opposed to 11 of the 17 case scenarios by ATs. Greater than 75% of the PTs who were board specialty certified in sports responded either "appropriately" or "overly cautious" to 13 case scenarios. CONCLUSION: More ATs than PTs perceived themselves to be prepared to manage acute injuries/ medical conditions. Further, results indicate that PTs may be an effective and safe provider of event coverage. Conditions/injuries with low perceived preparedness or poor performance may offer both ATs and PTs an opportunity to identify areas for future training and education to optimize care for athletes with acute injuries or medical conditions. LEVEL OF EVIDENCE: Level 3b.

Prevalence and Incidence of Injury during Olympic-style Shooting Events: A Systematic Review.

BACKGROUND: Shooting sports are included in collegiate and Olympic events. However, there is minimal evidence examining injury prevalence and incidence for these athletes. HYPOTHESIS/PURPOSE: The purpose of this study was to systematically review the literature to examine the available evidence regarding the incidence, prevalence, and types of injuries that affect athletes in Olympic-style shooting events. STUDY DESIGN: Systematic review. METHODS: The electronic databases PubMed, Cochrane Library, Cinahl, MEDLINE, and SPORTDiscus were searched utilizing terms related to shooting and injuries. Studies were included if they reported prevalence or incidence of injury in collegiate or Olympic shooting events, and were excluded if inclusion criteria were not met, full text was unavailable, or not in English. Two reviewers independently screened articles in two phases: 1) screening of titles/abstracts 2) full text review. A third reviewer resolved conflicts. RESULTS: Nineteen studies were ultimately included. The sports identified were biathlon, rifle, pistol, and shotgun. Shooting events in both winter and summer Olympics had low percentages of injuries compared to other sports. Winter shooting events had a higher percentage of injuries (6.9%) compared to summer (2.3%). In summer, females demonstrated a higher percentage of injuries (6.9%) compared to males (1.7%). In winter, males had a higher percentage of injuries (8.6%) versus females (5.1%). CONCLUSION: Injury incidence and prevalence was low for athletes in shooting sports in the Olympics. Injury rate was higher in the winter Olympic shooting events likely from increased physiological demand. With injury surveillance focusing on acute injuries rather than chronic, the number of injuries may be underestimated. Females had higher injury rates than males in the summer Olympics while the opposite was observed in the winter Olympics, likely from sex differences and differences in physiological demand for each event. LEVEL OF EVIDENCE: Level 3.