Thoracolumbar Fascia and Lumbar Muscle Stiffness in Athletes with A History of Hamstring Injury.

The purpose of this study was to examine the differences in thoracolumbar fascia (TLF) and lumbar muscle modulus in individuals with and without hamstring injury using shear wave elastography (SWE). Thirteen male soccer players without a previous hamstring injury and eleven players with a history of hamstring injury performed passive and active (submaximal) knee flexion efforts from 0°, 45° and 90° angle of knee flexion as well as an active prone trunk extension test. The elastic modulus of the TLF, the erector spinae (ES) and the multifidus (MF) was measured using ultrasound SWE simultaneously with the surface electromyography (EMG) signal of the ES and MF. The TLF SWE modulus was significantly (p < 0.05) higher in the injured group (range: 29.86 ± 8.58 to 66.57 ± 11.71 kPa) than in the uninjured group (range: 17.47 ± 9.37 to 47.03 ± 16.04 kPa). The ES and MF modulus ranged from 14.97 ± 4.10 to 66.57 ± 11.71 kPa in the injured group and it was significantly (p < .05) greater compared to the uninjured group (range: 11.65 ± 5.99 to 40.49 ± 12.35 kPa). TLF modulus was greater than ES and MF modulus (p < 0.05). Active modulus was greater during the prone trunk extension test compared to the knee flexion tests and it was greater in the knee flexion test at 0° than at 90° (p < 0.05). The muscle EMG was greater in the injured compared to the uninjured group in the passive tests only (p < 0.05). SWE modulus of the TLF and ES and MF was greater in soccer players with previous hamstring injury than uninjured players. Further research could establish whether exercises that target the paraspinal muscles and the lumbar fascia can assist in preventing individuals with a history of hamstring injury from sustaining a new injury.

Biomarkers of Neurobiologic Recovery in Adults With Sport-Related Concussion.

Importance: Sport-related concussion (SRC), a form of mild traumatic brain injury, is a prevalent occurrence in collision sports. There are no well-established approaches for tracking neurobiologic recovery after SRC. Objective: To examine the levels of serum glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) in Australian football athletes who experience SRC. Design, Setting, and Participants: A cohort study recruiting from April 10, 2021, to September 17, 2022, was conducted through the Victorian Amateur Football Association, Melbourne, Australia. Participants included adult Australian football players with or without SRC. Data analysis was performed from May 26, 2023, to March 27, 2024. Exposure: Sport-related concussion, defined as at least 1 observable sign and/or 2 or more symptoms. Main Outcomes and Measures: Primary outcomes were serum GFAP and NfL levels at 24 hours, and 1, 2, 4, 6, 8, 12, and 26 weeks. Secondary outcomes were symptoms, cognitive performance, and return to training times. Results: Eighty-one individuals with SRC (median age, 22.8 [IQR, 21.3-26.0] years; 89% male) and 56 control individuals (median age, 24.6 [IQR, 22.4-27.3] years; 96% male) completed a total of 945 of 1057 eligible testing sessions. Compared with control participants, those with SRC exhibited higher GFAP levels at 24 hours (mean difference [MD] in natural log, pg/mL, 0.66 [95% CI, 0.50-0.82]) and 4 weeks (MD, 0.17 [95% CI, 0.02-0.32]), and NfL from 1 to 12 weeks (1-week MD, 0.31 [95% CI, 0.12-0.51]; 2-week MD, 0.38 [95% CI, 0.19-0.58]; 4-week MD, 0.31 [95% CI, 0.12-0.51]; 6-week MD, 0.27 [95% CI, 0.07-0.47]; 8-week MD, 0.36 [95% CI, 0.15-0.56]; and 12-week MD, 0.25 [95% CI, 0.04-0.46]). Growth mixture modeling identified 2 GFAP subgroups: extreme prolonged (16%) and moderate transient (84%). For NfL, 3 subgroups were identified: extreme prolonged (7%), moderate prolonged (15%), and minimal or no change (78%). Individuals with SRC who reported loss of consciousness (LOC) (33% of SRC cases) had higher GFAP at 24 hours (MD, 1.01 [95% CI, 0.77-1.24]), 1 week (MD, 0.27 [95% CI, 0.06-0.49]), 2 weeks (MD, 0.21 [95% CI, 0.004-0.42]) and 4 weeks (MD, 0.34 [95% CI, 0.13-0.55]), and higher NfL from 1 week to 12 weeks (1-week MD, 0.73 [95% CI, 0.42-1.03]; 2-week MD, 0.91 [95% CI, 0.61-1.21]; 4-week MD, 0.90 [95% CI, 0.59-1.20]; 6-week MD, 0.81 [95% CI, 0.50-1.13]; 8-week MD, 0.73 [95% CI, 0.42-1.04]; and 12-week MD, 0.54 [95% CI, 0.22-0.85]) compared with SRC participants without LOC. Return to training times were longer in the GFAP extreme compared with moderate subgroup (incident rate ratio [IRR], 1.99 [95% CI, 1.69-2.34]; NfL extreme (IRR, 3.24 [95% CI, 2.63-3.97]) and moderate (IRR, 1.43 [95% CI, 1.18-1.72]) subgroups compared with the minimal subgroup, and for individuals with LOC compared with those without LOC (IRR, 1.65 [95% CI, 1.41-1.93]). Conclusions and Relevance: In this cohort study, a subset of SRC cases, particularly those with LOC, showed heightened and prolonged increases in GFAP and NfL levels, that persisted for at least 4 weeks. These findings suggest that serial biomarker measurement could identify such cases, guiding return to play decisions based on neurobiologic recovery. While further investigation is warranted, the association between prolonged biomarker elevations and LOC may support the use of more conservative return to play timelines for athletes with this clinical feature.

Do athletes with hamstring strain injury have shorter muscle fascicles in the injured limb?

INTRODUCTION: Previous studies have suggested that a reduced length of the biceps femoris long head (BFlh) fascicles may increase the risk of hamstring strain injury (HSI). However, it remains unclear whether the BFlh fascicles of the injured limb are shorter than those of the contralateral limb in athletes with an acute HSI. OBJECTIVE: To investigate the between-limb asymmetry of BFlh fascicle length in amateur athletes with an acute HSI. METHODS: Male amateur athletes were evaluated using ultrasound scans within five days following an HSI. The BFlh fascicle length was estimated using a validated equation. RESULTS: Eighteen injured athletes participated in this study. There was no significant difference (p = 0.27) in the length of BFlh fascicles between the injured limb (9.53 ± 2.55 cm; 95%CI 8.26 to 10.80 cm) and the uninjured limb (10.54 ± 2.87 cm; 95%CI 9.11 to 11.97 cm). Individual analysis revealed high heterogeneity, with between-limb asymmetries (percentage difference of the injured limb compared to the uninjured limb) ranging from -42% to 25%. Nine out of the 18 athletes had a fascicle length that was more than 10% shorter in the injured limb compared to the uninjured limb, five athletes had a difference of less than 10%, and four athletes had a fascicle length that was more than 10% longer in the injured limb compared to the uninjured limb. CONCLUSION: The architecture characteristics of injured and uninjured muscles is not consistent among athletes with HSI. Therefore, rehabilitation programs focused on fascicle lengthening should be evaluated on a case-by-case basis.

Effects of Photobiomodulation on Pain and Return to Play of Injured Athletes: A Systematic Review and Meta-analysis.

ABSTRACT: Morgan, RM, Wheeler, TD, Poolman, MA, Haugen, ENJ, LeMire, SD, and Fitzgerald, JS. Effects of photobiomodulation on pain and return to play of injured athletes: A systematic review and meta-analysis. J Strength Cond Res 38(6): e310-e319, 2024-The aims of this systematic review and meta-analysis were to evaluate the effect of photobiomodulation (PBM) on musculoskeletal pain in injured athletes and to determine if the effects of PBM allowed injured athletes to return to play faster. Electronic databases (MEDLINE Complete, CINAHL, and SPORTDiscus, PubMed, Web of Science, and Embase) were systematically searched (up to and including November 7, 2023) for peer-reviewed randomized controlled trials (RCTs) meeting criteria. Six RCTs, representing 205 competitive and recreational athletes with a mean age of 24 years, were included in the analysis. There were 6 intervention groups using standard physical therapy (n = 1), placebo PBM (n = 4), and aloe gel (n = 1) lasting between 10 minutes and 8 weeks in duration. The level of significance set for the study was p < 0.05. Overall, the use of PBM indicated a positive effect on pain reduction for PBM vs. control groups, standardized mean differences = 1.03, SE = 0.22, 95% confidence intervals = [0.43-1.63], p = 0.0089, but the 2 RCTs found evaluating the effect of PBM on time to return to play after injury in athletes do not support a benefit. Allied healthcare professionals may use PBM to reduce pain, thus allowing an athlete to return to their normal biomechanical movement faster; however, limited evidence suggests that PBM does not reduce time to return to play after an injury.

Diagnosis and management of thoracic outlet syndrome in athletes.

The physical demands of sports can place patients at elevated risk of use-related pathologies, including thoracic outlet syndrome (TOS). Overhead athletes in particular (eg, baseball and football players, swimmers, divers, and weightlifters) often subject their subclavian vessels and brachial plexuses to repetitive trauma, resulting in venous effort thrombosis, arterial occlusions, brachial plexopathy, and more. This patient population is at higher risk for Paget-Schroetter syndrome, or effort thrombosis, although neurogenic TOS (nTOS) is still the predominant form of the disease among all groups. First-rib resection is almost always recommended for vascular TOS in a young, active population, although a surgical benefit for patients with nTOS is less clear. Practitioners specializing in upper extremity disorders should take care to differentiate TOS from other repetitive use-related disorders, including shoulder orthopedic injuries and nerve entrapments at other areas of the neck and arm, as TOS is usually a diagnosis of exclusion. For nTOS, physical therapy is a cornerstone of diagnosis, along with response to injections. Most patients first undergo some period of nonoperative management with intense physical therapy and training before proceeding with rib resection. It is particularly essential for ensuring that athletes can return to their baselines of flexibility, strength, and stamina in the upper extremity. Botulinum toxin and lidocaine injections in the anterior scalene muscle might predict which patients will likely benefit from first-rib resection. Athletes are usually satisfied with their decisions to undergo first-rib resection, although the risk of rare but potentially career- or life-threatening complications, such as brachial plexus injury or subclavian vessel injury, must be considered. Frequently, they are able to return to the same or a higher level of play after full recovery.

3-Dimensional Biomechanics of Noncontact Anterior Cruciate Ligament Injuries in Male Professional Soccer Players.

BACKGROUND: The understanding of noncontact anterior cruciate ligament (ACL) injury causation in soccer has improved over the past decades. Bidimensional video analyses have significantly augmented our awareness, representing to date the only practical method to describe injury biomechanics. However, the extent of the problem continues to raise serious concerns. PURPOSE: To advance our understanding of the causal pathways leading to ACL injury with a large-scale reconstruction of 3-dimensional (3D) whole-body joint kinematics of injuries that occurred to male elite soccer players, as well as to compare the joint angle time course among situational patterns. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 33 consecutive noncontact and indirect contact ACL injuries that occurred in 6 national and 2 international professional leagues (seasons 2020-2021 to 2022-2023 until December 2022) were analyzed: (1) multiview noncoaxial television images were inspected; (2) multiple camera views were taken from 400 ms before the initial ground contact to 200 ms after the injury frame; (3) a size-matched pitch was modeled and used to calibrate cameras; (4) a 3D skeletal model was adjusted to fit the player's pose in each frame/view; and (5) poses were interpolated, and Euler joint angles were extracted. RESULTS: The authors reconstructed the 3D lower limb joint kinematic curves preceding and during ACL injuries in 33 cases; notably, a sudden external (up to 5°) and then internal knee rotation was observed after the initial contact and before the injury frame. The overall kinematics at injury were knee moderately flexed (45.9°± 21.7°), abducted (4.3°± 5.1°), and externally rotated (3.0°± 6.4°); trunk shallowly flexed (17.4°± 12.5°) and rotated and tilted toward the injured side; and hip flexed (32.0°± 18.7°), abducted (31.1°± 12.0°), and slightly internally rotated (6.6°± 12.2°). Variable behaviors were observed at the ankle level. CONCLUSION: Via reconstruction of the sequence of whole-body joint motion leading to injury, we confirmed the accepted gross biomechanics (dynamic valgus trend). This study significantly enriches the current knowledge on multiplanar kinematic features (transverse and coronal plane rotations). Furthermore, it was shown that ACL injuries in male professional soccer players manifest through distinct biomechanical footprints related to the concurrent game situation. CLINICAL RELEVANCE: Interventions aimed at reducing ACL injuries in soccer should consider that environmental features (ie, situational patterns) affect injury mechanics.

Does kinesio tape alter muscle strength in athletes? - Systematic review and meta-analysis.

BACKGROUND: Kinesio tape (KT) is still a matter of debate and the results of studies that evaluated its effects on muscle strength in athletes are still contradictory and inconclusive. OBJECTIVES: To analyze randomized clinical trials (RCT) to compare the effects of KT on muscle strength with the control/placebo group among athletes with and without musculoskeletal injury. METHOD: The search involved the databases: PubMed, Web of Science, LILACS, PEDro, The Cochrane Library, Medline, Scopus, SPORTDiscus and Embase, without filter and included RCTs evaluating the effects of KT on muscle strength in athletes with or without musculoskeletal injury, comparing it to a control/placebo intervention. The following were excluded: studies with duplicate information; who used instruments for indirect assessment of muscle strength; involving a different population of athletes. Meta-analysis calculations were performed using post-intervention muscle strength data in the Review Manager (RevMan) program. RESULTS: 10 articles were eligible, among which 5 studies were included in the meta-analysis. In the primary analysis, no relevant clinical effect was found (immediate post-intervention <24h: Z = 1.97 CI95% = 0.35[0.00-0.70]; p = 0.05 I2 = 0% and late post-intervention ≥24h: Z = 1.47 CI95% = 0.59[-0.20-1.38]; p = 0.14 I2 = 69%) when comparing the KT group with the control/placebo groups for muscle strength of lower limbs in participants with and without musculoskeletal injury and in the subgroup analysis (including only individuals without injury), there was also no clinical effect (Z = 1.50, 95%CI = 0.31[-0.10-0.71] p = 0.13, I2 = 0%) of KT for muscle strength. CONCLUSIONS: KT does not contribute to muscle strength gain in athletes with and without musculoskeletal injuries. PROSPERO: CRD42020139822. (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=139822) (29 July 2020).

[Head injuries: What the team physician needs to know]. / Kopfverletzungen: Was der Teamarzt wissen sollte.

A concussion is the mildest form of a mild traumatic brain injury (tbi) and resembles the most prevalent type of sports associated tbi. Diffuse axonal injuries, the main pathophysiological mechanism of concussion, leads to disruption of communication between different brain areas. The resulting clinical symptoms may relate to several clinical domains (cognition, fatigue, anxiety disorders, headaches/migraines or vestibulo-ocular problems), all of which need to be assessed in a clinical screening during an evaluation for possible concussion. Appropriate and consensus-based protocols to conduct clinical exams are provided by the Concussion in Sport Group (Sport Concussion Assessment Tool (SCAT), Sport Concussion Office Assessment Tool (SCOAT)) and should be used in the most up-to-date version. Therapeutically, slowly and incrementally increasing sub symptomatic activation consisting of daily routine activities, aerobic and cognitive exercises should be introduced early after the trauma. Education about concussion should be geared towards target audiences and will then greatly contribute to adherence and acceptance of medical management.

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.

Gender differences in concussion-related knowledge, attitudes and reporting behaviors of varsity athletes.

BACKGROUND: Concussion is a pathophysiological process that occurs due to a traumatic biomechanical force. Concussions are an "invisible" and common traumatic brain injury with symptoms that may be underestimated. This necessitates fundamental improvements in public knowledge specifically addressing young university athletes and different genders. This cross-sectional study aimed to explore the possibility of gender differences with respect to university student athletes' concussion knowledge, attitude and reporting behaviors. We hypothesized that there should be no significant difference in concussion knowledge among male and female student athletes; however, females would show a more positive attitude and more reporting behaviors than male student athletes. METHODS: Overall, 115 university athlete students completed a survey questionnaire; we eliminated some participants based on required inclusion criteria of Rosenbaum Concussion Knowledge and Attitude Survey-student version (RoCKAS-ST). Our final analysis consisted of 96 participants: 20 males (mean age 21.15 years) and 75 females (mean age 22.36 years). This study included questions about the athletes' given reasons for reporting or not reporting a concussion. Additionally, 33 RoCKAS-ST questions on Concussion Knowledge Index (CKI) with fair test-retest reliability (r=0.67) and 15 items on Concussion Attitude Index (CAI) with satisfactory test-retest reliability (r=0.79) were provided. RESULTS: Males reported more sources for learning about concussions and more sport-related reasons for reporting a concussion than females (P<0.05). Both genders provided equal numbers of reasons for neglecting a concussion report or not disclosing a concussion for the sake of others (i.e., family, teammates or the coach). Out of 16 given reasons for not reporting a concussion, males significantly chose sport-related reasons over female athletes (P<0.05). Additionally, by looking at the two components of RoCKAS-ST, the independent t-test results showed no significant gender-based differences in concussion knowledge and attitude indices (P>0.05). Nevertheless, females were less optimistic about evaluating other athletes' attitude over concussion reporting (P<0.05). CONCLUSIONS: Our study indicated that concussion knowledge is not gender biased among Canadian university athletes; however, more investigation is required to learn how safe environments for concussion disclosure could encourage reporting the symptoms in varsity athletes, especially in males who are more susceptible to not reporting a concussion to not miss their sport-related goals.

Self-reported knee function and activity level are reduced after primary or additional anterior cruciate ligament injury in female football players: a five-year follow-up study.

BACKGROUND: Playing football involves a high risk of anterior cruciate ligament (ACL) injuries and these may affect knee function and activity level. OBJECTIVES: To measure changes in self-reported knee function, activity level, and satisfaction with knee function and activity level in female football players with or without an ACL-reconstructed knee. METHODS: Female football players, age 19.9 (SD 2.6) years, with either a primary ACL-reconstruction 1.6 (SD 0.7) years after ACL-reconstruction (n = 186) or no ACL injury (n = 113) were followed prospectively for five years. Self-reported data collected at baseline and follow-up included knee function (International Knee Documentation Committee Subjective Knee Form [IKDC-SKF]), activity level (Tegner Activity Scale), and satisfaction with knee function (Likert scale 1=happy; 7=unhappy) and activity level (1-10 scale). Information on any new ACL injury during the follow-up period was collected. RESULTS: Players with ACL-reconstruction at baseline who either did (n = 56) or did not (n = 130) sustain an additional ACL injury, and players with no injury at baseline who remained injury free (n = 101) had a lower Tegner score at follow-up. Players with additional ACL injury had lower IKDC-SKF score (mean difference: -11.4, 95% CI: -16.0, -6.7), and satisfaction with activity level (mean difference: -1.5, 95% CI: -2.3, -0.7) at follow-up. Players with no additional ACL injury had higher satisfaction with knee function (mean difference: 0.6, 95% CI: 0.3, 0.9) at follow-up. Players with no ACL injury had lower satisfaction with activity level (mean difference: -0.7, 95% CI: -1.1, -0.3) at follow-up. Players with additional ACL injury had larger decreases in all variables measured compared to the two other groups. CONCLUSION: Primary, and even more so additional, ACL injuries decreased self-reported knee function, activity level, and satisfaction with knee function and activity level in female football players.

Auxetic structures used in kinesiology tapes can improve form-fitting and personalization.

Each year 65% of young athletes and 25% of physically active adults suffer from at least one musculoskeletal injury that prevents them from continuing with physical activity, negatively influencing their physical and mental well-being. The treatment of musculoskeletal injuries with the adhesive elastic kinesiology tape (KT) decreases the recovery time. Patients can thus recommence physical exercise earlier. Here, a novel KT based on auxetic structures is proposed to simplify the application procedure and allow personalization. This novel KT exploits the form-fitting property of auxetics as well as their ability to simultaneously expand in two perpendicular directions when stretched. The auxetic contribution is tuned by optimizing the structure design using analytical equations and experimental measurements. A reentrant honeycomb topology is selected to demonstrate the validity of the proposed approach. Prototypes of auxetic KT to treat general elbow pains and muscle tenseness in the forearm are developed.

The Relationship Between Performance and Injury in Junior Australian Football Athletes.

PURPOSE: Determine the impact of preseason and between-seasons changes in individual physical performance on injury risk in elite junior Australian football players and if injuries sustained during a season impact subsequent-season performance improvement. METHODS: This prospective cohort study assessed individual performance measures (sprint speed, jump, agility, and aerobic endurance) during preseason over 4 consecutive seasons. Injury status (injured/not injured) was tracked weekly to determine the relationship between individual performance and in-season injury occurrence. Mixed models were used to determine the relationship between physical performance and injury, and the effect of injury on physical performance improvement. RESULTS: A total of 206 players played 2 consecutive seasons and were included (17.6 y, 181.9 cm, 75.7 kg). Faster players during preseason experienced higher injury incidence (injuries/season) during that playing season (incidence rate ratio = 0.127; P = .034). Injury incidence was not influenced by between-seasons change in any performance measure. Players injured during their first season maintained their aerobic fitness, which declined in noninjured players (d = 0.39; P = .013). Players who sustained a lower-limb injury during their first season saw smaller improvements in sprint speed than players who did not get injured (d = 0.39; P = .035). CONCLUSION: Faster players experience higher injury incidence than slower players and may require specific prevention interventions. Players who experience a lower-limb injury during the playing season do not improve sprint speed between seasons to the same extent as players who do not get injured, highlighting the need for targeted high-speed running ability development as part of rehabilitation.

Acute Physical and Mental Activity Influence on Concussion Recovery.

INTRODUCTION: Physical activity (PA) and mental activity (MA) postconcussion has received renewed attention to improve concussion management; however, most protocols start after several days and do not assess the acute window. Therefore, the purpose of this study was to assess PA and MA in the first 48 h postconcussion on the time to symptom-free status and return to play. METHODS: We recruited 78 NCAA Division I athletes (male, 51.3%; age, 19.6 ± 1.4 yr; height, 173.7 ± 11.5 cm; weight, 80.1 ± 23.2 kg) who were diagnosed with a sports-related concussion. Participants completed a 0-5 PA and MA scale daily until fully cleared for return to participation (mean, 15.1 ± 6.9 d). A quadratic model regression assessed PA and MA over the first 2 d (acute) postconcussion on to time to symptom-free status and return to play. RESULTS: The overall model was significant for both time to symptom free (r2 = 0.27, P = 0.004) and return to play (r2 = 0.23, P = 0.019). Reported PA was the only significant predictor for time to symptom-free (P = 0.002) and return-to-participation (P = 0.006) day. Reported MA was not associated either outcome. CONCLUSIONS: The primary finding of this study was that mild to moderate PA acutely postconcussion was associated with reduced time to symptom free and return to participation as opposed to either lower or higher levels of PA. Conversely, acute MA was not associated with recovery outcomes. These results further elucidate the role of postconcussion PA.

Use of Mayer wave activity to demonstrate aberrant cardiovascular autonomic control following sports concussion injury.

Dysregulation of cardiovascular autonomic control is gaining recognition as a prevailing consequence of concussion injury. Characterizing the presence of autonomic dysfunction in concussed persons is inconsistent and conventional metrics of autonomic function cannot differentiate the presence/absence of injury. Mayer wave (MW) activity originates through baroreflex adjustments to blood pressure (BP) oscillations that appear in the low-frequency (LF: 0.04-0.15 Hz) band of the BP and heart rate (HR) power spectrum after a fast Fourier transform. We prospectively explored MW activity (∼0.1 Hz) in 19 concussed and 19 noninjured athletes for 5 min while seated at rest within 48 h and 1 week of injury. MW activity was derived from the LF band of continuous digital electrocardiogram and beat-to-beat BP signals (LFHR, LF-SBP, MWHR, and MW-SBP, respectively); a proportion between MWBP and MWHR was computed (cMW). At 48 h, the concussion group had a significantly lower MWBP and cMW than controls; these differences were gone by 1 week. MWHR, LFHR, and LF-SBP were not different between groups at either visit. Attenuated sympathetic vasomotor tone was present and the central autonomic mechanisms regulating MW activity to the heart and peripheral vasculature became transiently discordant early after concussion with apparent resolution by 1 week.

Vestibular-Evoked Myogenic Potential Outcomes Associated with Pediatric Sports-Related Concussion.

OBJECTIVES/HYPOTHESIS: To 1) characterize vestibular-evoked myogenic potential responses in children and young adults with sports-related concussion (SRC) histories as compared with a normal healthy control group, and 2) correlate VEMP characteristics to SRC/sport history outcomes. STUDY DESIGN: Prospective cohort study. METHODS: Seventy-six children and young adults with and without a history of SRC received cervical and ocular VEMP testing using a 500 Hz tone burst air conduction stimuli. VEMP response parameters (response rates, peak latencies, and peak-to-peak amplitudes) were assessed. Other clinical vestibular measures were performed. In the SRC group, sport history outcomes including number of SRC sustained over a lifetime, years of playing contact sports, and length of time playing contact sports were collected via in-person questionnaire. RESULTS: Children and young adults with SRC had significantly reduced oVEMP responses and peak-to-peak amplitudes and greater amplitude response asymmetries between left and right ear. There was no effect of group on cVEMP findings. A greater frequency of SRCs sustained throughout a lifetime, a greater number of contact sports played, and a longer duration of playing a contact sport correlated with significantly poorer VEMP response characteristics. CONCLUSIONS: Our results suggest that SRC and repeated subclinical head impact events have an effect on oVEMP outcomes. SRC may affect the utricle, superior vestibular nerve, and/or brainstem-mediated vestibular-ocular-reflex pathway. The prevalence of post-concussion-related dizziness is becoming increasingly common in a pediatric-otology clinic, thus performing VEMP testing in youth post-SRC provides an objective, noninvasive, and cost-effective method for monitoring the effects of sports-related impact on the vestibular system and related neural pathways. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:436-442, 2022.

Increased short interval intracortical inhibition in participants with previous hamstring strain injury.

PURPOSE: Cortical mechanisms may contribute to weakness in participants with previous hamstring strain injury. This study aims to examine intra-cortical inhibition (SICI) and corticospinal excitability in previously injured participants. METHODS: In this cross-sectional study, TMS was used to examine SICI, silent period, silent period: MEP ratios and area under the stimulus response curve in the biceps femoris and medial hamstrings. Comparisons were made between participants with (n = 10) and without (n = 10) previous hamstring strain injury. Motor threshold and isometric knee flexor strength were also compared between participants and the relationship between strength and SICI in control and previously injured participants was examined. RESULTS: Isometric knee flexor strength was lower in previously injured limbs compared with control limbs (mean difference = - 41 Nm (- 26%) [95% CI = - 80 to - 2 Nm], p = 0.04, Cohen's d = - 1.27) and contralateral uninjured limbs (mean difference = - 23 Nm (- 17%), [95% CI = - 40 to - 6 Nm], p = 0.01, Cohen's d = - 0.57). Previously injured limbs exhibited smaller responses to paired pulse stimulation (i.e. greater levels of SICI) in the biceps femoris compared with control limbs (mean difference = - 19%, [95% CI = - 34 to - 5%], p = 0.007, Cohen's d = - 1.33). Isometric knee flexor strength was associated with the level of SICI recorded in the biceps femoris in previously injured participants (coefficient = 23 Nm [95% CI = 7-40 Nm], adjusted R2 = 0.31, p = 0.01). There were no differences in markers of corticospinal excitability between previously injured and control limbs (all p > 0.24, all Cohen's d < 0.40). CONCLUSION: Athletes with previous injury in the biceps femoris exhibit increased SICI in this muscle compared with control participants. Increased SICI is related to lower levels of hamstring strength, and rehabilitation programs targeting the removal of intra-cortical inhibition should be considered.

Cervical Muscle Activation Characteristics and Head Kinematics in Males and Females Following Acoustic Warnings and Impulsive Head Forces.

Sex, head and neck posture, and cervical muscle preparation are contributing factors in the severity of head and neck injuries. However, it is unknown how these factors modulate the head kinematics. In this study, twenty-four (16 male and 8 female) participants experienced 50 impulsive forces to their heads with and without an acoustic warning. Female participants demonstrated a 71 ms faster (p = 0.002) muscle activation onset compared to males after warning. The magnitude of muscle activation was not significant between sexes. Females exhibited 21% (p < 0.008) greater peak angular velocity in all force directions and 18% (p < 0.04) greater peak angular acceleration in sagittal plane compared to males. Females exhibited 15% (p = 0.03) greater peak linear acceleration compared to males only in sagittal flexion. Preparation attenuated head kinematics significantly (p < 0.03) in 11 out of 18 investigated head kinematics for both sexes. A warning eliciting a startle response 420 ms prior to the impact resulted in significant attenuation of all measured head kinematics in sagittal extension (p < 0.037). In conclusion, both sex and warning type were significant factors in head kinematics. These data provide insight into the complex relationship of muscle activation and sex, and may help identify innovative strategies to reduce head and neck injury risk in sports.

Searching for the Holy Grail: A Systematic Review of Health-Related Quality of Life Measures for Active Youth.

OBJECTIVE: To identify the most suitable existing generic and condition-specific health-related quality of life (HRQoL) patient-reported outcome measures (PROMs) for active youth with and without a musculoskeletal injury, based on measurement properties, interpretability, and feasibility. DESIGN: Systematic review of clinimetrics. LITERATURE SEARCH: We searched MEDLINE, Embase, CINAHL, SPORTDiscus, PsycINFO, and Scopus from inception to April 30, 2020. STUDY SELECTION CRITERIA: Records with original data describing the evaluation of a PROM or PROM subscale in active youth (15-24 years old) with or without a musculoskeletal injury were included. Non-English studies and those including individuals with a cognitive, developmental, or systemic condition were excluded. DATA SYNTHESIS: This review was conducted according to the COSMIN user manual for systematic reviews of PROMs and the PRISMA guidelines. The COSMIN user manual guided our measurement property evaluation and interpretability and feasibility description. RESULTS: Of 6931 potential records, 21 studies were included. Eleven generic and 7 condition-specific PROMs were identified. No PROM received a final COSMIN recommendation of "A" because all lacked sufficient content validity. The 8-item Disablement in the Physically Active scale-mental summary component Short Form (DPA-MSC SF-8), Quality of Life Survey, and Functional Arm Scale for Throwers (FAST) were the most suitable existing PROMs, given their high-quality evidence for sufficient structural validity and internal consistency. CONCLUSION: No definitively robust PROM for measuring generic or condition-specific HRQoL of active youth was identified. Until one exists, we recommend the DPA-MSC SF-8, the Quality of Life Survey, or the FAST and applying mixed methods to best characterize the HRQoL of active youth. J Orthop Sports Phys Ther 2021;51(10):478-491. doi:10.2519/jospt.2021.10412.