Factor Structure for the Sport Concussion Assessment Tool Symptom Scale in Adolescents After Concussion.

OBJECTIVE: To examine the factor structure of the Sport Concussion Assessment Tool-5 (SCAT5) symptom scale in adolescents on their initial presentation to a concussion clinic within the typical recovery period after concussion (ie, <30 days). We hypothesize that the SCAT5 symptoms represent various clinically meaningful groups. A secondary purpose was to examine the effects of sex on the factor structure of the SCAT5 symptom scale. STUDY DESIGN: Retrospective cross-sectional analysis. SETTING: Tertiary, institutional. PATIENTS: Nine hundred eighty-one adolescents (45% women) aged between 13 and 18 years. INDEPENDENT VARIABLES: Adolescents completed the SCAT5 symptom scale. MAIN OUTCOME MEASURES: The factor structure of SCAT5 examined using a principal axis factor analysis. RESULTS: A 5-factor structure model explained 61% of the variance in symptoms. These 5 factors are identified as Energy (17%), Mental Health (13%), Migrainous (13%), Cognitive (9%), and Vestibulo-Ocular (9%). A similar 5-factor model emerged for each sex, and the proportion of variance in symptoms explained by the 5-factor model was comparable between the sexes. CONCLUSIONS: The findings of this report indicate that the SCAT5 symptoms aggregated into 5 delineated factors, and these factors were largely consistent across the sexes. The delineation of symptoms into 5 factors provides preliminary validation for the presence of different concussion phenotypes. Confirmatory factor analysis is warranted to examine the applicability and clinical utility of the use of the 5-factor structure in a clinical setting.

Does Exercise Increase Vestibular and Ocular Motor Symptom Detection After Sport-Related Concussion?

BACKGROUND AND PURPOSE: Postconcussive vestibular and ocular motor symptoms are common and contribute to longer recovery. The Vestibular/Ocular Motor Screening (VOMS) is used to detect such symptoms, but a VOMS performed at rest may miss symptoms that are only provoked by exertion. Supervised exercise challenges (SECs) have been shown to detect concussion-related symptoms provoked by physical exertion. The purpose of this study was to determine whether athletes undergoing an SEC will exhibit greater symptom provocation with the VOMS compared to a VOMS performed at rest prior to an SEC. METHODS: Thirty-six athletes (58.3% male) between ages 10 and 18 years and within 30 days of concussion were included. All participants completed VOMS assessments at rest and immediately after an SEC. VOMS total symptom score increases were calculated for both pre- and post-SEC assessments compared using Wilcoxon ranked sum tests. The frequencies of positive assessments for each VOMS item were compared using McNemar's test. RESULTS: There were significant increases in post-SEC symptom provocation scores compared with pre-SEC scores for all VOMS items. The post-SEC VOMS identified 29 participants (80.6%) as positive in at least 1 VOMS item compared with 21 participants (58.3%) identified as positive pre-SEC (P = 0.008). For all VOMS items, the post-SEC VOMS identified participants who were previously negative on a pre-SEC VOMS but became positive after the SEC. DISCUSSION AND CONCLUSIONS: An SEC performed prior to a VOMS assessment may increase the detection of vestibular and ocular motor symptoms that may be missed if the VOMS was performed only at rest.Video Abstract available for more insight from the authors (see the Video Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A342).

Do male and female adolescents report symptoms differently after concussion?

We investigated sex-based differences in the presence and severity of aggregated symptom indicators as well as individual concussion symptoms.Materials and Methods: A cross-sectional examination of sex differences in symptoms reported by adolescents upon initial concussion evaluation at a concussion clinic. Nine hundred and eighty-six adolescents completed the Sport Concussion Assessment Tool (SCAT5) symptom checklist. Chi-square and Mann-Whitney U tests were used for differences in the presence and severity of symptoms, respectively. Sex differences in global indices of symptom distress were compared.Results: Females endorsed more symptoms (Female: Median (M)=15, Interquartile range (IQR):9-18 vs. Male: M=11, IQR: 6-15, p<0.001) and a greater total symptom score (Female: M=37, IQR:16-45 vs. Male: M=20, IQR:8-39). After False Discovery Rate (FDR) adjustment, females endorsed the presence of 21 of 22 individual symptoms more frequently than males (p≤ 0.039), with greater symptom severity for 20 of 22 individual symptoms (p≤0.036). Moderate ESs were observed for sex-based differences in the total symptom score and the global severity index. Small ESs was observed for differences in most individual symptoms.Conclusions: The greater frequency and severity of concussion symptoms reported by female adolescents highlights the importance of considering sex as a modifier for the management of concussion.

Use of Supervised Exercise During Recovery Following Sports-Related Concussion.

OBJECTIVE: To assess the safety of supervised exercise (SE) in acute sport-related concussion (SRC) and its influence on recovery. DESIGN: Retrospective cohort study. SETTING: University SRC clinic at a tertiary care center. PATIENTS: One hundred ninety-four consecutive new patient charts were reviewed. Patients were included if they were seen within 30 days of sustaining a SRC, and their medical records included all required data elements. One hundred twenty-six patients were included in the analysis. INTERVENTIONS: Symptomatic patients who initiated SE within 16 days of SRC (n = 24) were compared with those who did not undergo SE or initiated SE after postinjury day 16 (n = 84). Age, sex, history of previous concussions, injury severity, relevant comorbidities, and other treatments received were included in the analysis. MAIN OUTCOME MEASURES: The association between early SE and clearance for return to sport was determined using a hazard ratio (HR). The number of days from SRC until clearance for return to sport and the number of days symptomatic from concussion were also compared between early SE and nonearly SE cohorts. RESULTS: No serious adverse events occurred in the early SE group. Early SE was associated with earlier return to sport (HR = 2.35, P = 0.030). The early SE group had fewer days from SRC until clearance for return to sport (mean 26.5 ± 11.2 days vs 35.1 ± 26.5 days, P = 0.020). There was a trend toward fewer symptomatic days in the early SE group (P = 0.054). CONCLUSION: Early SE performed in the symptomatic stage of SRC was safe and associated with earlier return to sport.

Measurement Properties of the Dizziness Handicap Inventory-Children and Adolescents for Children and Adolescents Postconcussion.

PURPOSE: The purpose of this study was to examine and report the construct validity, internal consistency, and item structure of the Dizziness Handicap Inventory-Children and Adolescents (DHI-CA) in postconcussion children and adolescents. METHODS: A retrospective chart review was conducted for 132 participants. Data were extracted on the DHI-CA, Sports Concussion Assessment Tool-III symptom inventory, and Vestibulo-ocular Motor Screening. The DHI-CA was examined for validity, internal consistency, and factor structure. RESULTS: The DHI-CA had fair convergent validity (rs = 0.30-0.40), but discriminant validity findings were inconclusive. The functional subscale demonstrated least consistent loadings and 4 items had cross-loading. Reliability analysis indicated possible item redundancy given that the overall Cronbach α was higher than the subscales. CONCLUSION: Despite demonstrating convergent validity, structural inconsistencies and possible item redundancy warrant further exploration and restructuring of the DHI-CA. Caution is recommended while making clinical decisions based on the DHI-CA results alone. VIDEO ABSTRACT: For more insights from the authors, see Supplemental Digital Content 1, available at: http://links.lww.com/PPT/A303.

Changes in Vestibular/Ocular-Motor Screen Scores in Adolescents Treated With Vestibular Therapy After Concussion.

PURPOSE: To examine interrelationships among Vestibular/Ocular-Motor Screen (VOMS) items and to characterize the recovery of VOMS performance in a sample of adolescents treated with vestibular physical therapy (VPT) after concussion. METHODS: Seventy-seven patients with concussion and 77 participants without concussion completed the study. Adolescents with concussion received an individualized VPT intervention consisting of targeted exercises for gaze stability, postural stability, ocular-motor control, habituation, and aerobic activities. The exercises were performed during a weekly clinic visit and via a home exercise program. RESULTS: Except for near-point convergence distance, all VOMS items were significantly interrelated. Over the course of VPT, significant improvements in VOMS performance were observed, and discharge scores were similar to scores observed in adolescents without concussion. CONCLUSIONS: The VOMS measured moderately related functions and captured changes over the course of VPT. Clinicians should consider the contextual risk of "false positive" in their interpretation of VOMS.

Measurement Error in the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT): Systematic Review.

OBJECTIVE: To review the literature on the reliability of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). DESIGN: Systematic review of the relevant literature in PubMed, CINAHL, and PSYCHINFO. Studies were evaluated using the STROBE instrument and custom developed items. RESULTS: Search yielded 5 943 articles. Ten studies met the inclusion criteria and were reviewed. With the exception of processing speed, all composite scores consistently exhibited poor to moderate reliability (ie, intraclass correlation coefficient <0.80). When considering 2 time points, participants who were misclassified as experiencing a "reliable change" in any score ranged between 5% and 26% for verbal memory, 2.2% and 19.6% for visual memory, 4% and 24% for processing speed, and 4% and 23.2% for reaction time. CONCLUSIONS: The Pearson r correlation coefficient and average measures intraclass correlation coefficient may be inappropriately utilized to examine the reliability of ImPACT scores. Given the poor to moderate reliability of most ImPACT scores, clinicians should be cautious when ImPACT is used as a criterion for medical clearance to return to play after concussion. Because of its widespread use in concussion-related clinical research, researchers must exercise due diligence when utilizing ImPACT to evaluate outcomes after concussion or to validate other outcome measures.

Reference values for the balance error scoring system in adolescents.

OBJECTIVES: Adolescents with mild traumatic brain injury (i.e. concussion) may experience postural stability impairments. The Balance Error Scoring System (BESS) is widely used in assessment of postural stability after concussion. Despite its common use in adolescents, the BESS lacks reference values in adolescents, limiting its clinical utility. The objective of this study is to report the reference values for the BESS in adolescents and to examine the effect of gender on the BESS scores. METHODS: One hundred and ninety-one high school adolescents between the ages of 14-18 (M = 16.1, SD = 1.1) years of age completed the BESS. The effects of gender, age, body mass and height on the performance of BESS were examined. Additionally, the reported reference values for the BESS were stratified by gender. RESULTS: Female participants demonstrated better performance on five of the six BESS conditions as well as the total error score (p < 0.001). No relationships were observed between age and body mass to the BESS scores. CONCLUSIONS: The effects of gender on the BESS performance support the gender-specific reference values reported in this study. These reference values provide benchmarks for clinicians when interpreting the BESS in the absence of individual baseline scores.

Relationship Between Cognitive Assessment and Balance Measures in Adolescents Referred for Vestibular Physical Therapy After Concussion.

OBJECTIVE: To examine the relationship between cognitive and balance performance in adolescents with concussion. DESIGN: Retrospective case series. SETTING: Tertiary. PATIENTS: Sixty patients. INTERVENTIONS: Correlation analyses were performed to describe the relationship between symptoms, cognitive measure, and balance measure at the time of initiation of vestibular physical therapy. MAIN OUTCOME MEASURES: Cognitive performance was assessed using the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT). The dizziness and balance function measures included dizziness severity rating, Activities-specific Balance Confidence scale (ABC), Dizziness Handicap Inventory (DHI), Functional Gait Assessment, gait speed, Timed "UP and GO," Five Times Sit to Stand, and Sensory Organization Test (SOT). To account for multiple comparisons, the False Discovery Rate method was used. RESULTS: Performance measures of balance were significantly correlated with cognitive measures. Greater total symptom scores were related to greater impairment in the ABC and DHI (r = 0.35-0.39, P ≤ 0.008) and worse performance in condition 2 of the SOT (r = -0.48, P = 0.004). Among the ImPACT composite scores, lower memory scores were correlated with impaired balance performance measures (r = 0.37-0.59, P ≤ 0.012). Lower visual memory was also correlated with worse ABC scores. CONCLUSIONS: The significant relationships reported between the cognitive performance scores and balance measures may reflect that similar levels of functioning exist across domains in individuals with protracted recovery who receive vestibular physical therapy. CLINICAL RELEVANCE: The weak-to-moderate relationships warrant the continuous use of multiple domains of assessment. A better understanding to the relationships between the domains of functioning after concussion may improve the overall management approach for adolescents with concussion.

Reliability and Construct Validity of Limits of Stability Test in Adolescents Using a Portable Forceplate System.

OBJECTIVE: To examine the reliability, convergent, and discriminant validity of the limits of stability (LOS) test to assess dynamic postural stability in adolescents using a portable forceplate system. DESIGN: Cross-sectional reliability observational study. SETTING: School setting. PARTICIPANTS: Adolescents (N=36) completed all measures during the first session. To examine the reliability of the LOS test, a subset of 15 participants repeated the LOS test after 1 week. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Outcome measurements included the LOS test, Balance Error Scoring System, Instrumented Balance Error Scoring System, and Modified Clinical Test for Sensory Interaction on Balance. RESULTS: A significant relation was observed among LOS composite scores (r=.36-.87, P<.05). However, no relation was observed between LOS and static balance outcome measurements. The reliability of the LOS composite scores ranged from moderate to good (intraclass correlation coefficient model 2,1=.73-.96). CONCLUSIONS: The results suggest that the LOS composite scores provide unique information about dynamic postural stability, and the LOS test completed at 100% of the theoretical limit appeared to be a reliable test of dynamic postural stability in adolescents. Clinicians should use dynamic balance measurement as part of their balance assessment and should not use static balance testing (eg, Balance Error Scoring System) to make inferences about dynamic balance, especially when balance assessment is used to determine rehabilitation outcomes, or when making return to play decisions after injury.

Performance of high school adolescents on functional gait and balance measures.

PURPOSE: To describe the performance of high school adolescents during common functional gait and balance measures used in vestibular physical therapy. METHODS: A cross-sectional study of 91 participants determined their performance on the Activities-specific Balance Confidence (ABC) scale, Dynamic Gait Index, Functional Gait Assessment, Timed "Up and Go" (TUG), Five Times Sit to Stand (FTSTS) test, tests of gait speed (GS), and the Balance Error Scoring System. In a subset of this sample, GS, TUG, and the FTSTS were repeated twice to examine test-retest reliability. RESULTS: The measures of GS, TUG, and FTSTS were normally distributed. The Activities-specific Balance Confidence, Dynamic Gait Index, and Functional Gait Assessment exhibited a ceiling effect. The timed measures exhibited moderate to good reliability. CONCLUSIONS: These performance scores may provide end points for discharge from vestibular physical therapy. However, clinicians should be aware of the ceiling effect exhibited by some measures.

Headache Characteristics of Pediatric Sport-Related Concussion.

BACKGROUND: Headache is among the most common symptoms following concussion, yet headache after concussion (HAC) remains poorly characterized. This study describes headache characteristics over the first four weeks following pediatric sport-related concussion. METHODS: This is a retrospective case series of 87 athletes (mean: 14.9 years; range: 8.4-18.8 years; 38% female) treated in a specialty sports concussion clinic within 28 days of injury. Primary outcomes of headache consistency, frequency, duration, and associated migrainous symptoms were assessed at immediate (0 to 48 h) and weekly time points over the first 28 days post-injury. Generalized mixed linear models compared headache characteristics across time points. Secondary analyses compared each outcome by as-needed analgesic use. RESULTS: During the immediate post-injury period, headache was more often constant (p = 0.002) and associated with migrainous symptoms (p < 0.001). By the third week post-injury, episodic headache was more prevalent (p < 0.001). Most patients (54%) transitioned from constant, migrainous headache to episodic, non-migrainous headache. This finding was uninfluenced by as-needed analgesic medication use. CONCLUSIONS: These findings document the trajectory of HAC. Future studies should assess relationships between initial headache characteristics and recovery.

Understanding Abnormal Examination Findings During Concussion Recovery: A Retrospective Chart Review.

Background and Objective: Physical examination findings in athletes with sport-related concussion (SRC) are not well described in the literature. The objective of this study was to describe physical examination findings during the first month following concussion in athletes, with a focus on the effect of sex, age, and time since injury. Methods: This was a retrospective electronic medical record (EMR) review of physical examination findings in 500 patients aged 6-24 who were initially seen within 15 days of SRC at a multidisciplinary outpatient academic concussion clinic between 2017 and 2019. A standardized concussion examination built in the EMR recorded mental status, cranial nerve, vestibulo-ocular motor screen, and balance findings for all patients. The primary outcome was the frequency of abnormal examination findings during the first 30 days postinjury, which was further analyzed by sex, age, and time since injury using mixed logistic regression models. Results: The most common abnormal examination findings overall were eyes-closed single-leg stance, vestibular-ocular reflex, visual motion sensitivity, the neck examination, and eyes-closed tandem stance. Abnormal findings were more frequent in female athletes for vestibular ocular reflex and visual motion sensitivity. The frequency of abnormal findings increased with age for vestibulo-ocular reflex, visual motion sensitivity, the neck examination, convergence testing, and eyes-open single-leg stance, whereas abnormalities decreased in frequency with age for eyes-open tandem stance and tandem gait. The frequency of abnormal findings generally decreased with time over the first 4 weeks following injury. Discussion: A comprehensive physical examination is pivotal for evaluation of athletes with concussion. These findings highlight high-yield components of the concussion examination and support use of these examination components as injury markers. Future work should investigate associations between physical examination findings and postconcussion symptoms and recovery outcomes. Classification of Evidence: This retrospective cohort study provides Class IV evidence that neurologic examination with specifically designed clinical tests are helpful for diagnosis of traumatic brain injury in young athletes at age 6-24.

Content comparison of neck pain outcome measures using the international classification of functioning, disability and health.

The purpose of this study was to compare the content covered by existing neck pain measures based on the linkage to the International Classification of Functioning, Disability and Health (ICF) framework to examine the extent to which the existing measures represent ICF categories and to identify content gaps in existing measures that would inform further research. Ten commonly used measures were identified, and their content was linked to ICF categories using established coding systems. Two clinical experts reviewed every measure independently and identified the central meaningful concepts from individual items of each measure. A total of 177 concepts were identified from 193 items across 10 measures. Body functions were the most represented category across measures (23-64%). The representation of activities ranged from 14 to 61% whereas the representation of participation ranged from 6 to 31% across measures. The ProFitMap-Neck was the only measure that addressed the environmental factors. The ProFit-Map neck captured a majority of concepts from body structures and function and the neck outcome score captured maximum concepts from the activities and participation categories. A combination of ProFit-Map neck and Neck Outcome Score can be used with caution to obtain a more comprehensive assessment of the impact of neck pain on function, activities and participation.

Validation of the Gait Disorientation Test in children with concussion.

Background: Mild traumatic brain injury (mTBI) or concussion is a complex injury that is difficult to diagnose and assess. There are negative impacts on cognition, balance, and mobility after a concussion. The Gait Disorientation Test (GDT) is an objective measure that assesses a person's balance ability by comparing the walking time with eyes open and the walking time with eyes closed in a standardized walking task. The purpose of this study was to assess the validity and the diagnostic properties of the GDT in children with concussions. Methods: Thirty-six children with concussions, and 91 controls aged between 9 and 18 years old participated in the study. Participants completed demographics, the GDT, the Functional Gait Assessment (FGA), the Pediatric Vestibular Symptom Questionnaire (PVSQ), and the Pediatric Visually Induced Dizziness Questionnaire (PVID). Results: Children with concussions showed higher (worse) GDT scores (M = 2.18 ± 1.93 s) than healthy controls (M = 1.13 ± 0.95 s), which was statistically significant (P = 0.014). Conclusion: The GDT was able to distinguish between children with concussions and healthy controls. Given the simplicity of the GDT, it can be used to assist in discriminating between children with and without concussion.

Symptom Provocation During Aerobic and Dynamic Supervised Exercise Challenges in Adolescents With Sport-Related Concussion.

CONTEXT: Supervised exercise challenges (SECs) have been shown to be safe and beneficial in the early symptomatic period after concussion. Thus far, most in-clinic SECs studied have included a form of basic aerobic exercise only. An SEC that also includes dynamic forms of exercise mimics all steps of a standard return-to-play progression and may enhance the detection of concussion symptoms to guide in-clinic management decisions. OBJECTIVE: To determine whether an SEC that includes a dynamic SEC (DSEC) uncovered symptoms that would not have been identified by an SEC involving an aerobic SEC (ASEC) alone in adolescent patients with sport-related concussion. DESIGN: Retrospective case series. SETTING: Multidisciplinary sport concussion clinic at a tertiary care center. PATIENTS OR OTHER PARTICIPANTS: A total of 65 adolescent athletes (mean age = 14.9 ± 2.0 years, 72.3% males) who underwent an in-clinic SEC within 30 days of concussion. MAIN OUTCOME MEASURE(S): Presence of pre-exercise symptoms and symptom provocation during the SEC were recorded, with exercise-provoked symptoms categorized as occurring during ASEC or DSEC. RESULTS: Of the total patient sample, 69.2% (n = 45/65) experienced symptom provocation at some point during the SEC. Symptoms were provoked in 20 patients during the ASEC, whereas 25 completed the ASEC without symptom provocation before becoming symptomatic during the subsequent DSEC and 20 completed the SEC without any symptom provocation. Of the 65 patients in the total sample, 46 were asymptomatic immediately before the SEC. Of these previously asymptomatic patients, 23.9% (n = 11/46) experienced symptom provocation during the ASEC, and an additional 37.0% (n = 17/46) remained asymptomatic during the ASEC but then developed symptoms during the DSEC. CONCLUSIONS: The ASEC alone may not detect symptom provocation in a significant proportion of concussion patients who otherwise would develop symptoms during a DSEC.

Vestibular rehabilitation for dizziness and balance disorders after concussion.

BACKGROUND AND PURPOSE: Management of dizziness and balance dysfunction is a major challenge after concussion. The purpose of this study was to examine the effect of vestibular rehabilitation in reducing dizziness and to improve gait and balance function in people after concussion. METHODS: A retrospective chart review of 114 patients (67 children aged 18 years and younger [mean, 16 years; range, 8-18 years]; 47 adults older than 18 years [mean, 41 years; range, 19-73 years]) referred for vestibular rehabilitation after concussion was performed. At the time of initial evaluation and discharge, recordings were made of outcome measures of self-report (eg, dizziness severity, Activities-specific Balance Confidence Scale, and Dizziness Handicap Inventory) and gait and balance performance (eg, Dynamic Gait Index, gait speed, and the Sensory Organization Test). A mixed-factor repeated-measures analysis of variance was used to test whether there was an effect of vestibular rehabilitation therapy and age on the outcome measures. RESULTS: The median length of time between concussion and initial evaluation was 61 days. Of the 114 patients who were referred, 84 returned for at least 1 visit. In these patients, improvements were observed in all self-report, gait, and balance performance measures at the time of discharge (P < .05). Children improved by a greater amount in dizziness severity (P = .005) and conditions 1 (eyes open, fixed support) and 2 (eyes closed, fixed support) of the Sensory Organization Test (P < .025). DISCUSSION: Vestibular rehabilitation may reduce dizziness and improve gait and balance function after concussion. For most measures, the improvement did not depend on age, indicating that vestibular rehabilitation may equally benefit both children and adults. CONCLUSIONS: Vestibular rehabilitation should be considered in the management of individuals post concussion who have dizziness and gait and balance dysfunction that do not resolve with rest.

Physical Therapy Evaluation and Treatment After Concussion/Mild Traumatic Brain Injury.

Over the last decade, numerous concussion evidence-based clinical practice guidelines (CPGs), consensus statements, and clinical guidance documents have been published. These documents have typically focused on the diagnosis of concussion and medical management of individuals post concussion, but provide little specific guidance for physical therapy management of concussion and its associated impairments. Further, many of these guidance documents have targeted specific populations in specific care contexts. The primary purpose of this CPG is to provide a set of evidence-based recommendations for physical therapist management of the wide spectrum of patients who have experienced a concussive event. J Orthop Sports Phys Ther 2020;50(4):CPG1-CPG73. doi:10.2519/jospt.2020.0301.

Women and Men Use Different Strategies to Stabilize the Head in Response to Impulsive Loads: Implications for Concussion Injury Risk.

BACKGROUND: Cervical musculoskeletal and neuromuscular attributes, which may vary between men and women, influence an individual's capacity to stabilize the head. OBJECTIVES: To examine sex differences in cervical musculoskeletal and neuromuscular attributes and their impact on head stability. The secondary objective was to examine the effects of anticipation and preload on head kinematics. METHODS: Thirty-four (20 men, 14 women) recreationally active adult athletes completed a perturbation protocol with anticipation and preloading conditions in this descriptive cross-sectional study. We assessed the neuromuscular response of the sternocleidomastoid to perturbation and head kinematics. We measured neck girth, sternocleidomastoid physiological cross-sectional area, and isometric strength. RESULTS: Women had smaller neck girth, smaller sternocleidomastoid physiological cross-sectional area, and lower isometric strength than men. Women had greater baseline electromyography (EMG) amplitude and greater peak EMG response than men. There were no sex differences in sternocleidomastoid onset latency or head kinematics. Women had a greater increase in baseline EMG amplitude after preloading and anticipated conditions. Preloading attenuated sex differences in muscle onset latency. Across the sexes, there was a significant main effect of anticipation on head kinematics. CONCLUSION: Men and women used different strategies to stabilize the head, and responded differently to the preloading and anticipation conditions. J Orthop Sports Phys Ther 2019;49(11):779-786. Epub 15 May 2019. doi:10.2519/jospt.2019.8760.