45 results on '"Swartz EE"'
Search Results
2. Advantages of the prone Lachman test.
- Author
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Norkus SA, Swartz EE, and Floyd RT
- Abstract
Factors involved in the accurate performance of the Lachman test and its interpretation are numerous and include examiner hand size, individual knee size, examiner psychomotor skill, relaxation, and examiner appreciation of anterior translation and end feel.The prone Lachman test has been shown to be an acceptable alternative in determination of ACL disruption and might have numerous advantages over the standard Lachman test. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
3. Observed Hand Placement Patterns Of Certified Athletic Trainers While Using Various Facemask Removal Tools
- Author
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Brown, A, Swartz, EE, Armstrong, CW, Rankin, J, and Rogers, B
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Athletic trainers -- Evaluation ,Tools -- Usage ,Sports -- Equipment and supplies - Published
- 2001
4. A Three Dimensional Analysis Of Facemask Removal Tools In Inducing Head Movement
- Author
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Swartz, EE, Armstrong, CW, Rankin, J, and Rogers, B
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Vertebrae, Cervical -- Injuries ,Sports medicine -- Research ,Athletes -- Injuries ,Tools -- Research ,Football -- Equipment and supplies - Published
- 2001
5. A Comparison Of The Three-Dimensional Characteristics Of A Full-Effort Overhand Throw And The Throwing Motions Involved In A Rehabilitative Throwing Program
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Norkus, SA, Armstrong, CW, Campbell, BM, Swartz, EE, Tucker, WS, Rankin, JM, and Skelly, WA
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Throwing -- Physiological aspects ,Human mechanics -- Research ,Exercise therapy -- Research ,Baseball players - Published
- 2001
6. TIME, MOVEMENT, AND SUCCESS WHEN USING A CORDLESS SCREWDRIVER FOR FACEMASK REMOVAL
- Author
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Swartz Ee, Ensor Hd, and Norkus Sa
- Subjects
Orthodontics ,Cordless ,Computer science ,Physical Therapy, Sports Therapy and Rehabilitation ,Orthopedics and Sports Medicine ,Movement (clockwork) - Published
- 2003
7. Cervical spine injury management in the helmeted athlete.
- Author
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Waninger KN and Swartz EE
- Published
- 2011
- Full Text
- View/download PDF
8. National athletic trainers' association position statement: acute management of the cervical spine-injured athlete.
- Author
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Swartz EE, Boden BP, Courson RW, Decoster LC, Horodyski M, Norkus SA, Rehberg RS, and Waninger KN
- Abstract
OBJECTIVE: To provide certified athletic trainers, team physicians, emergency responders, and other health care professionals with recommendations on how to best manage a catastrophic cervical spine injury in the athlete. BACKGROUND: The relative incidence of catastrophic cervical spine injury in sports is low compared with other injuries. However, cervical spine injuries necessitate delicate and precise management, often involving the combined efforts of a variety of health care providers. The outcome of a catastrophic cervical spine injury depends on the efficiency of this management process and the timeliness of transfer to a controlled environment for diagnosis and treatment. RECOMMENDATIONS: Recommendations are based on current evidence pertaining to prevention strategies to reduce the incidence of cervical spine injuries in sport; emergency planning and preparation to increase management efficiency; maintaining or creating neutral alignment in the cervical spine; accessing and maintaining the airway; stabilizing and transferring the athlete with a suspected cervical spine injury; managing the athlete participating in an equipment-laden sport, such as football, hockey, or lacrosse; and considerations in the emergency department. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
9. Combined tool approach is 100% successful for emergency football face mask removal.
- Author
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Copeland AJ, Decoster LC, Swartz EE, Gattie ER, and Gale SD
- Published
- 2007
- Full Text
- View/download PDF
10. The influence of various factors on high school football helmet face mask removal: a retrospective, cross-sectional analysis.
- Author
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Swartz EE, Decoster LC, Norkus SA, and Cappaert TA
- Abstract
Context: Most research on face mask removal has been performed on unused equipment.Objective: To identify and compare factors that influence the condition of helmet components and their relationship to face mask removal.Design: A cross-sectional, retrospective study.Setting: Five athletic equipment reconditioning/recertification facilities.Participants: 2584 helmets from 46 high school football teams representing 5 geographic regions.Intervention(s): Helmet characteristics (brand, model, hard-ware components) were recorded. Helmets were mounted and face mask removal was attempted using a cordless screwdriver. The 2004 season profiles and weather histories were obtained for each high school.Main Outcome Measure(s): Success and failure (including reason) for removal of 4 screws from the face mask were noted. Failure rates among regions, teams, reconditioning year, and screw color (type) were compared. Weather histories were compared. We conducted a discriminant analysis to determine if weather variables, region, helmet brand and model, reconditioning year, and screw color could predict successful face mask removal. Metallurgic analysis of screw samples was per-formed.Results: All screws were successfully removed from 2165 (84%) helmets. At least 1 screw could not be removed from 419 (16%) helmets. Significant differences were found for mean screw failure per helmet among the 5 regions, with the Midwest having the lowest failure rate (0.08 +/- 0.38) and the Southern (0.33 +/- 0.72), the highest. Differences were found in screw failure rates among the 46 teams (F1445 = 9.4, P < .01). Helmets with the longest interval since last reconditioning (3 years) had the highest failure rate, 0.47 +/- 0.93. Differences in success rates were found among 4 screw types (chi2[1,4] = 647, P < .01), with silver screws having the lowest percentage of failures (3.4%). A discriminant analysis (Delta = .932, chi 2[14,n=2584 = 175.34, P < .001) revealed screw type to be the strongest predictor of successful removal.Conclusions: Helmets with stainless steel or nickel-plated carbon steel screws reconditioned in the previous year had the most favorable combination of factors for successful screw removal. T-nut spinning at the side screw locations was the most common reason and location for failure. [ABSTRACT FROM AUTHOR]
- Published
- 2007
11. A comparison of head movement during back boarding by motorized spine-board and log-roll techniques.
- Author
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Swartz EE, Nowak J, Shirley C, and Decoster LC
- Abstract
Context: In a patient with a potential cervical spine injury, minimizing or eliminating movement at the head and neck during stabilization and transport is paramount because movement can exacerbate the condition. Any equipment or technique creating less movement will allow for a more effective and safe stabilization of an injured patient, reducing the likelihood of movement and potential secondary injury. Objective: To compare the amount of head movement created during the log-roll and motorized spine-board (MSB) stabilization techniques. Design: A 2-condition, repeated-measures design. Setting: Laboratory. Patients or Other Participants: Thirteen certified athletic trainers, emergency first responders, and emergency medical technicians (6 men, 7 women). Intervention(s): Subjects rotated through 4 positions for the log roll and 2 positions for the MSB. Each subject performed 3 trials while maintaining manual, inline stabilization of the model's head for each condition. Main Outcome Measure(s): Three-dimensional head movement was measured and expressed as degrees of motion. Results:The log roll created significantly more motion in the frontal and transverse planes compared with the MSB ( P = .001 for both measures). No significant difference was noted for sagittal-plane motion ( P= .028). Conclusions:The MSB created less movement at the head than did the log roll in 2 planes of motion and created slightly more motion in 1 plane, although this difference was not significant. The MSB may provide emergency responders with an appropriate alternative method for stabilizing and transporting a supine injured athlete without requiring a log roll. [ABSTRACT FROM AUTHOR]
- Published
- 2005
12. Cervical spine functional anatomy and the biomechanics of injury due to compressive loading.
- Author
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Swartz EE, Floyd RT, and Cendoma M
- Abstract
Objective: To provide a foundation of knowledge concerning the functional anatomy, kinematic response, and mechanisms involved in axial-compression cervical spine injury as they relate to sport injury. Data Sources: We conducted literature searches through the Index Medicus, SPORT Discus, and PubMed databases and the Library of Congress from 1975-2003 using the key phrases cervical spine injury, biomechanics of cervical spine, football spinal injuries, kinematics of the cervical spine, and axial load. Data Synthesis: Research on normal kinematics and minor and major injury mechanisms to the cervical spine reveals the complex nature of movement in this segment. The movement into a single plane is not the product of equal and summative movement between and among all cervical vertebrae. Instead, individual vertebrae may experience a reversal of motion while traveling through a single plane of movement. Furthermore, vertebral movement in 1 plane often requires contributed movement in 1 or 2 other planes. Injury mechanisms are even more complex. The reaction of the cervical spine to an axial-load impact has been investigated using cadaver specimens and demonstrates a buckling effect. Impact location and head orientation affect the degree and level of resultant injury. Conclusions/Recommendations: As with any joint of the body, our understanding of the mechanisms of cervical spine injury will ultimately serve to reduce their occurrence and increase the likelihood of recognition and immediate care. However, the cervical spine is unique in its normal kinematics compared with joints of the extremities. Injury biomechanics in the cervical spine are complex, and much can still be learned about mechanisms of the cervical spine injury specific to sports. [ABSTRACT FROM AUTHOR]
- Published
- 2005
13. Effects of developmental stage and sex on lower extremity kinematics and vertical ground reaction forces during landing.
- Author
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Swartz EE, Decoster LC, Russell PJ, and Croce RV
- Abstract
Context: The presence or absence of biomechanical differences between the sexes before puberty may provide clues about the onset of adult landing pattern differences, which may help to explain the greater number of anterior cruciate ligament injuries in females than in males and provide the basis for interventions to reduce those injuries. Objective: To identify developmental sex-related and biomechanical differences during vertical jump landings. Design: A 2 x 2 developmental stage (prepubescent or postpubescent) 3 sex (male or female) between-subjects design. Setting: Controlled laboratory setting. Patients or Other Participants: Thirty prepubescent subjects (15 boys, age = 9.63 +/- 0.95 years; 15 girls, age = 9.19 +/- 1.00 years) and 28 postpubescent subjects (14 men, age = 23.57 +/- 3.23 years; 14 women, age = 24.22 +/- 2.27 years). Intervention: Subjects performed a vertical jump to a target set at 50% of their maximum vertical jump height ability. Main Outcome Measure(s):Hip and knee kinematics of the dominant lower extremity and vertical ground reaction forces during impact were analyzed. Results:We found significant main effects for developmental stage. Children demonstrated greater knee valgus and less hip flexion at initial contact and at maximum vertical force, less knee flexion at maximum vertical force, greater maximum vertical force and impulse, and a shorter time to maximum vertical force than the adults. No sex differences were found among the biomechanical variables measured. Conclusions:The presence of significant biomechanical differences between children and adults suggests that physical development influences landing patterns. Sex does not appear to influence landing patterns during a 50% maximum vertical jump landing. These findings add to the body of knowledge regarding developmental and sex comparisons in a functional landing task. [ABSTRACT FROM AUTHOR]
- Published
- 2005
14. Face-mask removal: movement and time associated with cutting of the loop straps.
- Author
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Swartz EE, Norkus SA, Armstrong CW, and Kleiner DM
- Abstract
OBJECTIVE: To quantify the amount of helmet movement, time for task completion, tool satisfaction, and overall efficiency for various face-mask removal tools during football helmet face-mask removal. DESIGN AND SETTING: Each subject performed one trial with the anvil pruner (AP), Face Mask Extractor (FME), PVC pipe cutter (PVC), and Trainer's Angel (TA). Each subject cut through 4 loop straps and removed the face mask while kneeling behind the athlete's head. SUBJECTS: Twenty-nine certified athletic trainers (age = 29.5 +/- 6.2 years, athletic training experience = 6.3 +/- 5.0 years). MEASUREMENTS: Time to complete the task was recorded. Total range of motion and total movement of the helmet were assessed using a 6-camera, 3-dimensional motion-capture system. Satisfaction scores were measured for each subject for each tool. Efficiency scores were calculated using time and total helmet-movement data. RESULTS: When using the FME, subjects were significantly faster than with all other tools (P <.05), and when using the AP and TA, they were significantly faster than with the PVC. No differences were noted between tools in either movement variable. Significant differences were noted for satisfaction (P <.05) for all comparisons except TA versus AP. Efficiency scores were FME, 11.6; AP, 14.3; TA, 14.5; and PVC, 22.9, with lower scores identifying increased efficiency. CONCLUSIONS: In general, subjects using the FME were superior in all variables except the movement variables. Future researchers should assess the removal task using specific protocols to determine whether the tools truly differ in terms of the movement created. [ABSTRACT FROM AUTHOR]
- Published
- 2003
15. A 3-dimensional analysis of face-mask removal tools in inducing helmet movement [corrected] [published erratum appears in J ATHLETIC TRAIN 2003 Jan-Mar;38(1):83].
- Author
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Swartz EE, Armstrong CW, Rankin JM, and Rogers B
- Abstract
Objective: To evaluate the performance of specific facemask removal tools during football helmet face-mask retraction using 3-dimensional (3-D) video.Design and Setting: Four different tools were used: the anvil pruner (AP), polyvinyl chloride pipe cutters (PVC), Face Mask (FM) Extractor (FME), and Trainer's Angel (TA). Subjects retracted a face mask once with each tool.Subjects: Eleven certified athletic trainers served as subjects and were recruited from among local sports medicine professionals.Measurements: We analyzed a sample of movement by 3D techniques during the retraction process. Movement of the head in 3 planes and time to retract the face mask were also assessed. All results were analyzed with a simple repeated-measures one-way multivariate analysis of variance. An overall efficiency score was calculated for each tool.Results: The AP allowed subjects to perform the face-mask removal task the fastest. Face mask removal with the AP was significantly faster than with the PVC and TA and significantly faster with the TA than the PVC. The PVC and AP created significantly more movement than the FME and TA when planes were combined. No significant differences were noted among tools for flexion-extension, rotation, or lateral flexion. The AP had an efficiency score of 14; FME, 15; TA, 18; and PVC, 35.Conclusions: The subjects performed the face-mask removal task in the least amount of time with the AP. They completed the task with the least amount of combined movement using the FME. The AP and FME had nearly identical overall efficiency scores for movement and time. [ABSTRACT FROM AUTHOR]
- Published
- 2002
16. Football face-mask removal with a cordless screwdriver on helmets used for at least one season of play.
- Author
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Decoster LC, Shirley CP, and Swartz EE
- Abstract
Context: The Inter-Association Task Force for the Appropriate Care of the Spine-Injured Athlete recommends leaving a football player's helmet in place and removing the face mask from the helmet 'as quickly as possible and with as little movement of the head and neck as possible' Although 2 groups have studied face-mask removal from new equipment, to our knowledge no researchers have investigated equipment that has been previously used. A full season of play may have a significant effect on football equipment and its associated hardware. Countless impacts, weather, playing surfaces, sweat, and other unforeseen or unknown variables might make the face-mask removal process more difficult on equipment that has been used. Objective: To determine the percentage of face masks that we could unscrew, with a cordless screwdriver, from football helmets used for a full season. Design: Cross-sectional. Setting: Three New England high schools. Patients or Other Participants: All football helmets used at 3 local high schools were tested (n = 222, mean games, 9.7 +/- 1.2; mean practice weeks, 13.7 +/- 1.2). Intervention(s): Each helmet was secured to a board, and a cordless screwdriver was used to attempt to remove all 4 screws attaching the face mask to the helmet. Main Outcome Measure(s): Variables included overall success or failure, time required for face-mask removal, and success by screw location. Data were analyzed with chi2, analysis of variance, and Tamhane post hoc tests. Results: Overall, 832 (94%) of 885 screws were unscrewed, and 183 (82.4%) of 222 face masks were removed. Mean removal time was 26.9 +/- 5.83 seconds. Face-mask removal success was significantly different between school 1 (24 [52.2%] of 46) and schools 2 (84 [91.3%] of 92) and 3 (75 [89.3%] of 84; F[2,219] = 24.608; P< .001). The removal success rate was significantly higher at top screws (98%) than at screws adjacent to ear holes (90%) ( P< .001). Conclusions: Based on our results and previous findings that demonstrated quicker access time and reduced head movement associated with the use of the screwdriver compared with cutting tools, the former may be a good tool for face-mask removal. However, an appropriate cutting tool must be immediately available should the screwdriver fail. Helmet hardware adjacent to ear holes was more vulnerable to failure, perhaps because it is protected by less padding than the top hardware. Possible causes of the higher failure rate at school 1 are the use of hardware materials subject to rust and corrosion and differences in helmet brand; these areas warrant future research and rules consideration. [ABSTRACT FROM AUTHOR]
- Published
- 2005
17. Head Impact Exposure in Hawaiian High School Football: Influence of Adherence Rates on a Helmetless Tackling and Blocking Training Intervention.
- Author
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Swartz EE, Myers JL, Lee JS, Broglio SP, Furutani T, Oshiro R, Gioia GA, Brothers D, Glodowski K, Lloansi I, Meyer L, and Murata N
- Abstract
Context: High school football remains a popular, physically demanding sport despite the known risks for acute brain and neck injury. Impacts to the head also raise concerns about their cumulative effects and long-term health consequences., Objective: To examine the effectiveness of a helmetless tackling training program to reduce head impact exposure in football participants., Design: A three-year, quasi-experimental, prospective cohort (clinicaltrials.gov #NCTXXX) study., Setting: Honolulu (XXX, XXX) area public and private secondary schools with varsity and junior varsity football., Patients or Other Participants: Football participants (n=496) ages 14 to 18 years old. Intervention(s) Participants wore new football helmets furnished with head impact sensor technology. Teams employed a season-long helmetless tackling and blocking intervention in Years 2 and 3 consisting of a 3-phase, systematic progression of 10 instructional drills., Main Outcome Measure(s): Head impact frequency per athlete exposure (ImpAE), location, and impact magnitude per participant intervention adherence levels (60% and 80%)., Results: An overall regression analysis revealed a significant negative association between ImpAE and adherence (p=0.003, beta=-1.21, SE=0.41). In year 3, a longitudinal data analysis of weekly ImpAE data resulted in an overall difference between the adherent and non-adherent groups (p=0.040 at 80%; p=0.004 at 60%), mainly due to decreases in top and side impacts. Mean cumulative impact burden for the adherent group (n=131: 2,105.84g ± 219.76,) was significantly (p=0.020) less than the non-adherent group (n=90: 3,158.25g ± 434.80) at the 60% adherence level., Conclusions: Participants adhering to the intervention on at least a 60% level experienced a 34% to 37% significant reduction in the number of head impacts (per exposure) through the season. These results provide additional evidence that a helmetless tackling and blocking training intervention (utilizing the HuTT® program) reduces head impact exposure in high school football players. Adherence to an intervention is crucial for achieving intended outcomes.
- Published
- 2024
- Full Text
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18. National Athletic Trainers' Association Position Statement: Reducing Intentional Head-First Contact Behavior in American Football Players.
- Author
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Swartz EE, Register-Mihalik JK, Broglio SP, Mihalik JP, Myers JL, Guskiewicz KM, Bailes J, and Hoge M
- Subjects
- Humans, Athletic Injuries epidemiology, Brain Concussion epidemiology, Football injuries, Spinal Injuries complications
- Abstract
Objective: To provide evidence-based recommendations for reducing the prevalence of head-first contact behavior in American football players with the aim of reducing the risk of head and neck injuries., Background: In American football, using the head as the point of contact is a persistent, well-documented, and direct cause of catastrophic head and cervical spine injury. Equally concerning is that repeated head-impact exposures are likely to result from head-first contact behavior and may be associated with long-term neurocognitive conditions such as dementia, depression, and chronic traumatic encephalopathy., Conclusions: The National Athletic Trainers' Association proposes 14 recommendations to help the certified athletic trainer, allied health care provider, coach, player, parent, and broader community implement strategies for reducing the prevalence of head-first contact in American football., (© by the National Athletic Trainers' Association, Inc.)
- Published
- 2022
- Full Text
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19. Consensus Recommendations on the Prehospital Care of the Injured Athlete With a Suspected Catastrophic Cervical Spine Injury.
- Author
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Mills BM, Conrick KM, Anderson S, Bailes J, Boden BP, Conway D, Ellis J, Feld F, Grant M, Hainline B, Henry G, Herring SA, Hsu WK, Isakov A, Lindley T, McNamara L, Mihalik JP, Neal TL, Putukian M, Rivara FP, Sills AK, Swartz EE, Vavilala MS, and Courson R
- Subjects
- Athletic Injuries prevention & control, Delphi Technique, Device Removal, Emergency Medical Services standards, Emergency Responders education, Head Protective Devices, Humans, Protective Devices, Restraint, Physical, Spinal Injuries prevention & control, Transportation of Patients, United States, Athletic Injuries therapy, Emergency Medical Services methods, Spinal Injuries therapy
- Abstract
Introduction: Sports participation is among the leading causes of catastrophic cervical spine injury (CSI) in the United States. Appropriate prehospital care for athletes with suspected CSIs should be available at all levels of sport. The goal of this project was to develop a set of best-practice recommendations appropriate for athletic trainers, emergency responders, sports medicine and emergency physicians, and others engaged in caring for athletes with suspected CSIs., Methods: A consensus-driven approach (RAND/UCLA method) in combination with a systematic review of the available literature was used to identify key research questions and develop conclusions and recommendations on the prehospital care of the spine-injured athlete. A diverse panel of experts, including members of the National Athletic Trainers' Association, the National Collegiate Athletic Association, and the Sports Institute at UW Medicine participated in 4 Delphi rounds and a 2-day nominal group technique (NGT) meeting. The systematic review involved 2 independent reviewers and 4 rounds of blinded review., Results: The Delphi process identified 8 key questions to be answered by the systematic review. The systematic review comprised 1544 studies, 49 of which were included in the final full-text review. Using the results of the systematic review as a shared evidence base, the NGT meeting created and refined conclusions and recommendations until consensus was achieved., Conclusions: These conclusions and recommendations represent a pragmatic approach, balancing expert experiences and the available scientific evidence.
- Published
- 2020
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20. A helmetless-tackling intervention in American football for decreasing head impact exposure: A randomized controlled trial.
- Author
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Swartz EE, Myers JL, Cook SB, Guskiewicz KM, Ferrara MS, Cantu RC, Chang H, and Broglio SP
- Subjects
- Adolescent, Head, Humans, Male, Athletic Injuries prevention & control, Craniocerebral Trauma prevention & control, Football injuries, Head Protective Devices, Physical Conditioning, Human methods
- Abstract
Objectives: To evaluate a behavioral intervention to reduce head impact exposure in youth playing American football., Design: Nested randomized controlled trial., Methods: Participants, ages 14-17 years, wore head impact sensors (SIM-G™) during two seasons of play. Those randomized to the intervention group underwent weekly tackling/blocking drills performed without helmets (WoH) and shoulder pads while the control group trained as normal, matching frequency and duration. Research personnel provided daily oversight to maintain fidelity. Head impact frequency (≥10g) per athlete exposure (ImpAE) was analyzed over time (two 11-week seasons) using mixed effect models or ANCOVA. Secondary outcomes included exposure-type (training, game) and participation level (entry-level versus upper-level secondary education)., Results: One-hundred fifteen participants (59 WoH, 56 control) met compliance criteria, contributing 47,382 head impacts and 10,751 athlete exposures for analysis. WoH had fewer ImpAE during games compared to control participants at weeks 4 (p=0.0001 season 1, p=0.0005 season 2) and 7 (p=0.0001 both seasons). Upper-level WoH participants had less ImpAE during games than their matched controls at weeks 4 (p=0.017 and p=0.026) and 7 (p=0.037 and p=0.014) in both seasons, respectively. Upper-level WoH also had fewer ImpAE during training at week 7 (p=0.015) in season one., Conclusions: Tackling and blocking drills performed without a helmet during training reduced the frequency of head impacts during play, especially during games. However, these differences disappeared by the end of the season. Future research should explore the frequency of behavioral intervention and a dose-response relationship considering years of player experience., Trial Registration: ClinicalTrials.gov # NCT02519478., (Copyright © 2019 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2019
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21. Prehospital Cervical Spine Motion: Immobilization Versus Spine Motion Restriction.
- Author
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Swartz EE, Tucker WS, Nowak M, Roberto J, Hollingworth A, Decoster LC, Trimarco TW, and Mihalik JP
- Subjects
- Adult, Cervical Vertebrae physiopathology, Cross-Over Studies, Emergency Medical Services, Humans, Immobilization adverse effects, Male, Patient Simulation, Range of Motion, Articular physiology, Spinal Injuries physiopathology, Young Adult, Cervical Vertebrae injuries, Immobilization methods, Spinal Injuries therapy, Transportation of Patients methods
- Abstract
Objective: This study aims to evaluate the efficacy of two different spinal immobilization techniques on cervical spine movement in a simulated prehospital ground transport setting., Methods: A counterbalanced crossover design was used to evaluate two different spinal immobilization techniques in a standardized environment. Twenty healthy male volunteers (age = 20.9 ± 2.2 yr) underwent ambulance transport from a simulated scene to a simulated emergency department setting in two separate conditions: utilizing traditional spinal immobilization (TSI) and spinal motion restriction (SMR). During both transport scenarios, participants underwent the same simulated scenario. The main outcome measures were cervical spine motion (cumulative integrated motion and peak range of motion), vital signs (heart rate, blood pressure, oxygen saturation), and self-reported pain. Vital signs and pain were collected at six consistent points throughout each scenario., Results: Participants experienced greater transverse plane cumulative integrated motion during TSI compared to SMR (F
1,57 = 4.05; P = 0.049), and greater transverse peak range of motion during participant loading/unloading in TSI condition compared to SMR (F1,57 = 17.32; P < 0.001). Pain was reported by 40% of our participants during TSI compared to 25% of participants during SMR (χ2 = 1.29; P = 0.453)., Conclusions: Spinal motion restriction controlled cervical motion at least as well as traditional spinal immobilization in a simulated prehospital ground transport setting. Given these results, along with well-documented potential complications of TSI in the literature, SMR is supported as an alternative to TSI. Future research should involve a true patient population.- Published
- 2018
- Full Text
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22. Delivering Chest Compressions and Ventilations With and Without Men's Lacrosse Equipment.
- Author
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Clark MD, Davis MP, Petschauer MA, Swartz EE, and Mihalik JP
- Subjects
- Adult, Cross-Sectional Studies, Female, Head Protective Devices adverse effects, Humans, Male, Pressure, Protective Clothing adverse effects, Thorax, Ventilation, Athletes, Cardiopulmonary Resuscitation methods, Death, Sudden, Cardiac prevention & control, Racquet Sports, Sports Equipment adverse effects
- Abstract
Context: Current management recommendations for equipment-laden athletes in sudden cardiac arrest regarding whether to remove protective sports equipment before delivering cardiopulmonary resuscitation are unclear., Objective: To determine the effect of men's lacrosse equipment on chest compression and ventilation quality on patient simulators., Design: Cross-sectional study., Setting: Controlled laboratory., Patients or Other Participants: Twenty-six licensed athletic trainers (18 women, 8 men; age = 25 ± 7 years; experience = 2.1 ± 1.6 years)., Intervention(s): In a single 2-hour session, participants were block randomized to 3 equipment conditions for compressions and 6 conditions for ventilations on human patient simulators., Main Outcome Measure(s): Data for chest compressions (mean compression depth, compression rate, percentage of correctly released compressions, and percentage of optimal compressions) and ventilations (ventilation rate, mean ventilation volume, and percentage of ventilations delivering optimal volume) were analyzed within participants across equipment conditions., Results: Keeping the shoulder pads in place reduced mean compression depth (all P values < .001, effect size = 0.835) and lowered the percentages of both correctly released compressions ( P = .02, effect size = 0.579) and optimal-depth compressions (all P values < .003, effect size = 0.900). For both the bag-valve and pocket masks, keeping the chinstrap in place reduced mean ventilation volume (all P values < .001, effect size = 1.323) and lowered the percentage of optimal-volume ventilations (all P values < .006, effect size = 1.038). Regardless of equipment, using a bag-valve versus a pocket mask increased the ventilation rate (all P values < .003, effect size = 0.575), the percentage of optimal ventilations (all P values < .002, effect size = 0.671), and the mean volume ( P = .002, effect size = 0.598) across all equipment conditions., Conclusions: For a men's lacrosse athlete who requires cardiopulmonary resuscitation, the shoulder pads should be lifted or removed to deliver chest compressions. The facemask and chinstrap, or the entire helmet, should be removed to deliver ventilations, preferably with a bag-valve mask.
- Published
- 2018
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23. Cervical spine trauma: prevention strategies.
- Author
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Swartz EE
- Subjects
- Humans, Athletic Injuries complications, Cervical Vertebrae injuries, Spinal Injuries etiology, Spinal Injuries prevention & control
- Abstract
Participation in any sport activity carries risk of cervical spine trauma, but certain activities have a higher risk than others, and hence, demand concerted efforts in developing prevention strategies. Prevention often includes efforts surrounding education of stakeholders, creating or modifying rules, and specific policies adopted for decreasing such risk. Stakeholders include sport clinicians, participants, coaches, parents, league administrators, officials, and the public. Thus, both athlete-specific and setting-specific factors must be considered and controlled to the extent possible for a multipronged approach for decreasing cervical spine injury risk. The effectiveness of certain strategies put into place in collision sports, such as American football, rugby, and ice hockey, is reviewed to illustrate this approach. Some research evidence exists that either has informed a strategy, or validated its effectiveness after the fact. More research of a higher level needs to be conducted in all sports to continue to contain the risk of cervical spine trauma to the fullest extent possible., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2018
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24. Asymmetry of lower extremity force and muscle activation during knee extension and functional tasks.
- Author
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Bond CW, Cook SB, Swartz EE, and Laroche DP
- Subjects
- Adult, Female, Humans, Lower Extremity physiology, Male, Middle Aged, Functional Laterality physiology, Isometric Contraction physiology, Knee Joint physiology, Muscle Strength physiology, Muscle, Skeletal physiology
- Abstract
Introduction: Strength and power asymmetries of >10% may negatively impact physical function., Methods: Twenty-four healthy participants, 30-60 years of age, were assessed for muscle power asymmetry during isokinetic knee extension and ground reaction force asymmetry during chair-rise and vertical jump tasks. Neuromuscular activation asymmetry and coactivation of vastus lateralis (VL) and biceps femoris (BF) were assessed in each condition. Symmetric (SG) and asymmetric (AG) groups were identified using a 10% knee extension power asymmetry criterion., Results: The AG had greater chair-rise rate of force development asymmetry (P = 0.003, d = 1.29), but a similar chair-rise and vertical jump peak force asymmetry as the SG. Large group effects were found for VL activation asymmetry during knee extension (P = 0.047, d = 0.87), BF activation asymmetry during vertical jump (P = 0.015, d = 1.12), and strong leg coactivation during vertical jump (P = 0.028, d = 0.96)., Conclusions: Compensation for muscle power asymmetry may occur during functional tasks, potentially through differential activation of strong and weak leg muscles. Muscle Nerve 56: 495-504, 2017., (© 2017 Wiley Periodicals, Inc.)
- Published
- 2017
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25. Football Equipment Removal Improves Chest Compression and Ventilation Efficacy.
- Author
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Mihalik JP, Lynall RC, Fraser MA, Decoster LC, De Maio VJ, Patel AP, and Swartz EE
- Subjects
- Adult, Athletes, Cervical Vertebrae injuries, Female, Football, Head Protective Devices, Humans, Male, Patient Simulation, Pressure, Athletic Injuries therapy, Cardiopulmonary Resuscitation methods, Emergency Medical Services methods, Respiration, Artificial methods, Spinal Injuries therapy
- Abstract
Objective: Airway access recommendations in potential catastrophic spine injury scenarios advocate for facemask removal, while keeping the helmet and shoulder pads in place for ensuing emergency transport. The anecdotal evidence to support these recommendations assumes that maintaining the helmet and shoulder pads assists inline cervical stabilization and that facial access guarantees adequate airway access. Our objective was to determine the effect of football equipment interference on performing chest compressions and delivering adequate ventilations on patient simulators. We hypothesized that conditions with more football equipment would decrease chest compression and ventilation efficacy., Methods: Thirty-two certified athletic trainers were block randomized to participate in six different compression conditions and six different ventilation conditions using human patient simulators. Data for chest compression (mean compression depth, compression rate, percentage of correctly released compressions, and percentage of adequate compressions) and ventilation (total ventilations, mean ventilation volume, and percentage of ventilations delivering adequate volume) conditions were analyzed across all conditions., Results: The fully equipped athlete resulted in the lowest mean compression depth (F5,154 = 22.82; P < 0.001; Effect Size = 0.98) and delivery of adequate compressions (F5,154 = 15.06; P < 0.001; Effect Size = 1.09) compared to all other conditions. Bag-valve mask conditions resulted in delivery of significantly higher mean ventilation volumes compared to all 1- or 2-person pocketmask conditions (F5,150 = 40.05; P < 0.001; Effect Size = 1.47). Two-responder ventilation scenarios resulted in delivery of a greater number of total ventilations (F5,153 = 3.99; P = 0.002; Effect Size = 0.26) and percentage of adequate ventilations (F5,150 = 5.44; P < 0.001; Effect Size = 0.89) compared to one-responder scenarios. Non-chinstrap conditions permitted greater ventilation volumes (F3,28 = 35.17; P < 0.001; Effect Size = 1.78) and a greater percentage of adequate volume (F3,28 = 4.85; P = 0.008; Effect Size = 1.12) compared to conditions with the chinstrap buckled or with the chinstrap in place but not buckled., Conclusions: Chest compression and ventilation delivery are compromised in equipment-intense conditions when compared to conditions whereby equipment was mostly or entirely removed. Emergency medical personnel should remove the helmet and shoulder pads from all football athletes who require cardiopulmonary resuscitation, while maintaining appropriate cervical spine stabilization when injury is suspected. Further research is needed to confirm our findings supporting full equipment removal for chest compression and ventilation delivery.
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- 2016
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26. Head and Trunk Acceleration During Intermediate Transport on Medical Utility Vehicles.
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Tucker WS, Swartz EE, and Hornor SD
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- Accelerometry, Healthy Volunteers, Humans, Immobilization, Male, Surface Properties, Young Adult, Acceleration, Head, Off-Road Motor Vehicles, Torso, Transportation of Patients
- Abstract
Objective: To compare head and trunk acceleration during transport on 2 medical utility vehicles., Design: Within subject., Setting: Controlled laboratory., Participants: Nineteen male volunteers (21.8 ± 1.4 years, 176.5 ± 5.5 cm, 90.3 ± 16.1 kg)., Interventions: Participants were secured to a spineboard and stretcher on the Husqvarna HUV 4421DXL ambulance (HUV) and modified John Deere Gator TH (Gator) and driven over synthetic field turf transitioning to concrete slab (interval 1) and concrete slab transitioning to natural grass (interval 2). Three-dimensional (x, y, and z) accelerometers recorded head and trunk acceleration. At each data point, acceleration of the trunk was subtracted from the acceleration of the head and the peak acceleration difference was determined. Independent variables were vehicle (HUV, Gator) and interval (interval 1, interval 2)., Main Outcome Measures: The average peak acceleration differences in 3 directions (x, y, z) were analyzed using a 2-factor within analysis of variance (P ≤ 0.05)., Results: For x, Gator in interval 2 (28.34 ± 7.45 m/s/s) was greater than HUV in interval 2 (21.87 ± 6.28 m/s/s), and HUV (11.05 ± 3.29 m/s/s) and Gator (12.56 ± 4.32 m/s/s) in interval 1. The HUV in interval 2 was greater than HUV and Gator in interval 1. For z, Gator in interval 2 (22.12 ± 4.8 m/s/s) was greater than HUV in interval 2 (15.21 ± 2.84 m/s/s), and HUV (9.51 ± 3.01 m/s/s) and Gator (12.5 ± 3.78 m/s/s) in interval 1. The HUV in interval 2 was greater than HUV and Gator in interval 1. Gator in interval 1 was greater than HUV in interval 1., Conclusions: Varying head and trunk accelerations exist in healthy spine-boarded participants during transport on medical utility vehicles dependent on surface and vehicle type., Clinical Relevance: Intermediate transport vehicles vary in their ability to mitigate perturbations conveyed to the patient from the terrain travelled over.
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- 2016
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27. Early Results of a Helmetless-Tackling Intervention to Decrease Head Impacts in Football Players.
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Swartz EE, Broglio SP, Cook SB, Cantu RC, Ferrara MS, Guskiewicz KM, and Myers JL
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- Acceleration, Head Protective Devices, Humans, Male, Prospective Studies, Universities, Craniocerebral Trauma prevention & control, Football injuries, Physical Education and Training methods
- Abstract
Objective: To test a helmetless-tackling behavioral intervention for reducing head impacts in National Collegiate Athletic Association Division I football players., Design: Randomized controlled clinical trial., Setting: Football field., Patients or Other Participants: Fifty collegiate football players (intervention = 25, control = 25)., Intervention(s): The intervention group participated in a 5-minute tackling drill without their helmets and shoulder pads twice per week in the preseason and once per week through the season. During this time, the control group performed noncontact football skills., Main Outcome Measure(s): Frequency of head impacts was recorded by an impact sensor for each athlete-exposure (AE). Data were tested with a 2 × 3 (group and time) repeated-measures analysis of variance. Significant interactions and main effects (P < .05) were followed with t tests., Results: Head impacts/AE decreased for the intervention group compared with the control group by the end of the season (9.99 ± 6.10 versus 13.84 ± 7.27, respectively). The intervention group had 30% fewer impacts/AE than the control group by season's end (9.99 ± 6.10 versus 14.32 ± 8.45, respectively)., Conclusion: A helmetless-tackling training intervention reduced head impacts in collegiate football players within 1 season.
- Published
- 2015
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28. Cold-Water Immersion for Hyperthermic Humans Wearing American Football Uniforms.
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Miller KC, Swartz EE, and Long BC
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- Body Temperature physiology, Body Temperature Regulation physiology, Cold Temperature, Cross-Over Studies, Exercise physiology, Heat Stroke physiopathology, Heat Stroke therapy, Hot Temperature, Humans, Male, Skin Temperature physiology, United States, Young Adult, Clothing, Cryotherapy methods, Fever therapy, Football physiology, Immersion physiopathology, Water
- Abstract
Context: Current treatment recommendations for American football players with exertional heatstroke are to remove clothing and equipment and immerse the body in cold water. It is unknown if wearing a full American football uniform during cold-water immersion (CWI) impairs rectal temperature (Trec) cooling or exacerbates hypothermic afterdrop., Objective: To determine the time to cool Trec from 39.5°C to 38.0°C while participants wore a full American football uniform or control uniform during CWI and to determine the uniform's effect on Trec recovery postimmersion., Design: Crossover study., Setting: Laboratory., Patients or Other Participants: A total of 18 hydrated, physically active, unacclimated men (age = 22 ± 3 years, height = 178.8 ± 6.8 cm, mass = 82.3 ± 12.6 kg, body fat = 13% ± 4%, body surface area = 2.0 ± 0.2 m(2))., Intervention(s): Participants wore the control uniform (undergarments, shorts, crew socks, tennis shoes) or full uniform (control plus T-shirt; tennis shoes; jersey; game pants; padding over knees, thighs, and tailbone; helmet; and shoulder pads). They exercised (temperature approximately 40°C, relative humidity approximately 35%) until Trec reached 39.5°C. They removed their T-shirts and shoes and were then immersed in water (approximately 10°C) while wearing each uniform configuration; time to cool Trec to 38.0°C (in minutes) was recorded. We measured Trec (°C) every 5 minutes for 30 minutes after immersion., Main Outcome Measure(s): Time to cool from 39.5°C to 38.0°C and Trec., Results: The Trec cooled to 38.0°C in 6.19 ± 2.02 minutes in full uniform and 8.49 ± 4.78 minutes in control uniform (t17 = -2.1, P = .03; effect size = 0.48) corresponding to cooling rates of 0.28°C·min(-1) ± 0.12°C·min(-1) in full uniform and 0.23°C·min(-1) ± 0.11°C·min(-1) in control uniform (t17 = 1.6, P = .07, effect size = 0.44). The Trec postimmersion recovery did not differ between conditions over time (F1,17 = 0.6, P = .59)., Conclusions: We speculate that higher skin temperatures before CWI, less shivering, and greater conductive cooling explained the faster cooling in full uniform. Cooling rates were considered ideal when the full uniform was worn during CWI, and wearing the full uniform did not cause a greater postimmersion hypothermic afterdrop. Clinicians may immerse football athletes with hyperthermia wearing a full uniform without concern for negatively affecting body-core cooling.
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- 2015
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29. Emergent Access to the Airway and Chest in American Football Players.
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Swartz EE, Mihalik JP, Decoster LC, Al-Darraji S, and Bric J
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- Adult, Athletes, Cross-Over Studies, Device Removal, Equipment Safety, Female, Humans, Male, Motion, Time Factors, United States, Airway Management methods, Emergency Treatment methods, Football injuries, Head Protective Devices, Protective Clothing
- Abstract
Context: American football has the highest rate of fatalities and catastrophic injuries of any US sport. The equipment designed to protect athletes from these catastrophic events challenges the ability of medical personnel to obtain neutral spine alignment and immobilization during airway and chest access for emergency life-support delivery., Objective: To compare motion, time, and difficulty during removal of American football helmets, face masks, and shoulder pads., Design: Quasi-experimental, crossover study., Setting: Controlled laboratory., Patients or Other Participants: We recruited 40 athletic trainers (21 men, 19 women; age = 33.7 ± 11.2 years, height = 173.1 ± 9.2 cm, mass = 80.7 ± 17.1 kg, experience = 10.6 ± 10.4 years)., Intervention(s): Paired participants conducted 16 trials in random order for each of 4 helmet, face-mask, and shoulder-pad combinations. An 8-camera, 3-dimensional motion-capture system was used to record head motion in live models wearing properly fitted helmets and shoulder pads., Main Outcome Measure(s): Time and perceived difficulty (modified Borg CR-10)., Results: Helmet removal resulted in greater motion than face-mask removal, respectively, in the sagittal (14.88°, 95% confidence interval [CI] = 13.72°, 16.04° versus 7.04°, 95% CI = 6.20°, 7.88°; F(1,19) = 187.27, P < .001), frontal (7.00°, 95% CI = 6.47°, 7.53° versus 4.73°, 95% CI = 4.20°, 5.27°; F1,19 = 65.34, P < .001), and transverse (7.00°, 95% CI = 6.49°, 7.50° versus 4.49°, 95% CI = 4.07°, 4.90°; F(1,19) = 68.36, P < .001) planes. Face-mask removal from Riddell 360 helmets took longer (31.22 seconds, 95% CI = 27.52, 34.91 seconds) than from Schutt ION 4D helmets (20.45 seconds, 95% CI = 18.77, 22.12 seconds) or complete ION 4D helmet removal (26.40 seconds, 95% CI = 23.46, 29.35 seconds). Athletic trainers required less time to remove the Riddell Power with RipKord (21.96 seconds, 95% CI = 20.61°, 23.31° seconds) than traditional shoulder pads (29.22 seconds, 95% CI = 27.27, 31.17 seconds; t(19) = 9.80, P < .001)., Conclusions: Protective equipment worn by American football players must eventually be removed for imaging and medical treatment. Our results fill a gap in the evidence to support current recommendations for prehospital emergent management in patients wearing protective football equipment. Helmet face masks and shoulder pads with quick-release designs allow for clinically acceptable removal times without inducing additional motion or difficulty.
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- 2015
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30. A novel sensorimotor movement and walking intervention to improve balance and gait in women.
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Cook SB, LaRoche DP, Swartz EE, Hammond PR, and King MA
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- Adult, Aged, Aged, 80 and over, Female, Humans, Middle Aged, Quality of Life psychology, Exercise Therapy methods, Gait physiology, Postural Balance physiology, Walking physiology
- Abstract
Purpose: This study evaluated the effectiveness of a 5-day mind-body exercise (MBE) program on measures of quality of life, balance, balance confidence, mobility and gait in community-dwelling women., Methods: The MBE program was a 5-day retreat where multiple sessions of Feldenkrais(®)-based sensorimotor movement training and walking were performed daily. Forty-six women aged 40-80 years old participated in either the MBE program or maintained normal daily activity. Two-footed eyes-closed balance, gait characteristics, mobility via the Timed Up and Go test, balance confidence and quality of life were assessed before and after the intervention., Results: Women in the MBE group experienced improvements in mobility (6%; p = 0.01), stride length (3%; p = 0.008), single limb support time (1.3%; 0.006), balance confidence (5.2%; p < 0.001) and quality of life (p < 0.05) while the control group did not change., Conclusion: This short-term intensive program may be beneficial to women at risk of mobility limitations., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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31. Face mask removal is safer than helmet removal for emergent airway access in American football.
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Swartz EE, Mihalik JP, Beltz NM, Day MA, and Decoster LC
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- Adult, Athletes, Cohort Studies, Female, Humans, Male, Motion, United States, Airway Management methods, Athletic Injuries therapy, Football, Head Protective Devices, Masks, Spinal Injuries therapy
- Abstract
Background Context: In cases of possible cervical spine injury, medical professionals must be prepared to achieve rapid airway access while concurrently restricting cervical spine motion. Face mask removal (FMR), rather than helmet removal (HR), is recommended to achieve this. However, no studies have been reported that compare FMR directly with HR., Purpose: The purpose of this study was to compare motion, time, and perceived difficulty in two commonly used American football helmets between FMR and HR techniques, and when helmet air bladders were deflated before HR compared with inflated scenarios., Study Design/setting: The study incorporated a repeated measures design and was performed in a controlled laboratory setting., Participants: Participants included 22 certified athletic trainers (15 men and seven women; mean age, 33.9±10.5 years; mean experience, 11.4±10.0 years; mean height, 172±9.4 cm; mean mass, 76.7±14.9 kg). All participants were free from upper extremity or central nervous system pathology for 6 months and provided informed consent., Outcome Measures: Dependent variables included head excursion in degrees (computed by subtracting the minimum position from the maximum position) in each of the three planes (sagittal, frontal, transverse), time to complete the required task, and ratings of perceived exertion. To address our study purposes, we used two-by-two repeated-measures analysis of variance (removal technique×helmet type, helmet type×deflation status) for each dependent variable., Methods: Independent variables consisted of removal technique (FMR and HR), helmet type (Riddell Revolution IQ [RIQ] and VSR4), and helmet deflation status (deflated [D], inflated, [I]). After familiarization, participants conducted two successful trials for each of six conditions in random order (RIQ-FMR, VSR4-FMR, RIQ-HR-D, VSR4-HR-D, RIQ-HR-I, and VSR4-HR-I). Face masks, helmets, and shoulder pads were removed from a live model wearing a properly fitted helmet and shoulder pads. The participant and an investigator stabilized the model's head. A six-camera three-dimensional motion system and a three-point one-segment marker set were used to record motion of the head., Results: Face mask removal resulted in less motion in all three planes, required less completion time, and was easier to perform than HR. The RIQ helmet resulted in less frontal plane motion and less time to task completion, and was easier to remove than VSR4 helmets. Inflated helmets-regardless of helmet type-required less removal time but did not result in greater cervical spine motion or difficulty., Conclusions: It is safer to remove the face mask in the prehospital setting for the potential spine-injured American football player than to remove the helmet, based on results from both a traditional and newer football helmet designs. Deflating the air bladder inside the helmet does not provide an advantage., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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32. A study of emergency American football helmet removal techniques.
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Swartz EE, Mihalik JP, Decoster LC, and Hernandez AE
- Subjects
- Adult, Biomechanical Phenomena, Female, Head Movements, Humans, Male, Motion Pictures, Emergency Medical Services methods, Football injuries, Head Protective Devices
- Abstract
Purpose: The purpose was to compare head kinematics between the Eject Helmet Removal System and manual football helmet removal., Basic Procedures: This quasi-experimental study was conducted in a controlled laboratory setting. Thirty-two certified athletic trainers (sex, 19 male and 13 female; age, 33 ± 10 years; height, 175 ± 12 cm; mass, 86 ± 20 kg) removed a football helmet from a healthy model under 2 conditions: manual helmet removal and Eject system helmet removal. A 6-camera motion capture system recorded 3-dimensional head position. Our outcome measures consisted of the average angular velocity and acceleration of the head in each movement plane (sagittal, frontal, and transverse), the resultant angular velocity and acceleration, and total motion. Paired-samples t tests compared each variable across the 2 techniques., Main Findings: Manual helmet removal elicited greater average angular velocity in the sagittal and transverse planes and greater resultant angular velocity compared with the Eject system. No differences were observed in average angular acceleration in any single plane of movement; however, the resultant angular acceleration was greater during manual helmet removal. The Eject Helmet Removal System induced greater total head motion., Principal Conclusions: Although the Eject system created more motion at the head, removing a helmet manually resulted in more sudden perturbations as identified by resultant velocity and acceleration of the head. The implications of these findings relate to the care of all cervical spine-injured patients in emergency medical settings, particularly in scenarios where helmet removal is necessary., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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33. Maintaining neutral sagittal cervical alignment after football helmet removal during emergency spine injury management.
- Author
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Decoster LC, Burns MF, Swartz EE, Murthi DS, Hernandez AE, Vailas JC, and Isham LL
- Subjects
- Adult, Cervical Vertebrae diagnostic imaging, Humans, Male, Radiography, Spinal Injuries diagnostic imaging, Cervical Vertebrae injuries, Football injuries, Head Protective Devices, Immobilization methods, Spinal Injuries therapy
- Abstract
Study Design: Descriptive laboratory study., Objective: To determine whether the placement of padding beneath the occiput after helmet removal is an effective intervention to maintain neutral sagittal cervical spine alignment in a position comparable with the helmeted condition., Summary of Background Data: Current on-field recommendations for managing football athletes with suspected cervical spine injuries call for face mask removal, rather than helmet removal, because the combination of helmet and shoulder pads has been shown to maintain neutral cervical alignment. Therefore, in cases when helmet removal is required, recommendations also call for shoulder pad removal. Because removal of equipment causes motion, any technique that postpones the need to remove the shoulder pads would reduce prehospital motion., Methods: Four lateral radiographs of 20 male participants were obtained (age = 23.6 ± 2.7 years). Radiographs of participants wearing shoulder pads and helmet were first obtained. The helmet was removed and radiographs of participants with occipital padding were obtained immediately and 20 minutes later and finally without occipital padding. Cobb angle measurements for C2-C6 vertebral segments were determined by an orthopedic spine surgeon blinded to the study's purpose. Intraobserver reliability was determined using intraclass coefficient analysis. Measurements were analyzed using a 1×4 repeated-measures analysis of variance and post hoc pairwise comparisons with Bonferroni correction., Results: Intraobserver analysis showed excellent reliability (intraclass correlation = 1.0; 95% confidence interval [CI], 0.999-1.0). Repeated-measures analysis of variance detected significant differences (F(3,17) = 13.34; P < 0.001). Pairwise comparisons revealed no differences in cervical alignment (all measurements reported reflect lordosis) when comparing the baseline helmeted condition (10.1° ± 8.7°; 95% CI, 6.0-14.1) with the padded conditions. Measurements taken after removal of occipital padding (14.4° ± 8.1°; 95% CI, 10.6-18.2) demonstrated a significant increase in cervical lordosis compared with the immediate padded measurement (9.5° ± 6.9°; 95% CI, 6.3-12.7; P = 0.011) and the 20-minute padded measurement (6.5° ± 6.8°; 95% CI, 3.4-9.7; P < 0.001)., Conclusion: Although face mask removal remains the standard, if it becomes necessary to remove the football helmet in the field, occipital padding (along with full body/head immobilization techniques) may be used to limit cervical lordosis, allowing safe delay of shoulder pad removal.
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- 2012
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34. National athletic trainers' association position statement: preventing sudden death in sports.
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Casa DJ, Guskiewicz KM, Anderson SA, Courson RW, Heck JF, Jimenez CC, McDermott BP, Miller MG, Stearns RL, Swartz EE, and Walsh KM
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- Athletes, Craniocerebral Trauma mortality, Craniocerebral Trauma prevention & control, Diabetes Mellitus mortality, Emergency Medical Services, Heart Arrest mortality, Heart Arrest prevention & control, Heat Stroke mortality, Heat Stroke prevention & control, Humans, Hyponatremia mortality, Hyponatremia prevention & control, Spinal Injuries mortality, Spinal Injuries prevention & control, Athletic Injuries mortality, Athletic Injuries prevention & control, Death, Sudden prevention & control, Sports
- Abstract
Objective: To present recommendations for the prevention and screening, recognition, and treatment of the most common conditions resulting in sudden death in organized sports., Background: Cardiac conditions, head injuries, neck injuries, exertional heat stroke, exertional sickling, asthma, and other factors (eg, lightning, diabetes) are the most common causes of death in athletes., Recommendations: These guidelines are intended to provide relevant information on preventing sudden death in sports and to give specific recommendations for certified athletic trainers and others participating in athletic health care.
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- 2012
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35. In vivo biomechanical measurements of a football player's C6 spine fracture.
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Broglio SP, Swartz EE, Crisco JJ, and Cantu RC
- Subjects
- Acceleration, Adolescent, Biomechanical Phenomena, Head Protective Devices, Humans, Male, Telemetry, Cervical Vertebrae injuries, Football injuries, Spinal Fractures physiopathology
- Published
- 2011
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36. Prehospital emergency removal of football helmets using two techniques.
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Swartz EE, Hernandez AE, Decoster LC, Mihalik JP, Burns MF, and Reynolds C
- Subjects
- Adult, Analysis of Variance, Athletic Injuries, Cervical Vertebrae injuries, Equipment Design, Female, Health Status Indicators, Humans, Male, Spinal Injuries, Sports Medicine instrumentation, Craniocerebral Trauma, Emergency Medical Services methods, Football injuries, Head Protective Devices, Neck Injuries, Sports Medicine methods
- Abstract
Objective: To compare the Eject Helmet Removal (EHR) System with manual football helmet removal., Methods: This quasiexperimental counterbalanced study was conducted in a controlled laboratory setting. Thirty certified athletic trainers (17 men and 13 women; mean ± standard deviation age: 33.03 ± 10.02 years; height: 174.53 ± 12.04 cm; mass: 85.19 ± 19.84 kg) participated after providing informed consent. Participants removed a Riddell Revolution IQ football helmet from a healthy model two times each under two conditions: manual helmet removal (MHR) and removal with the EHR system. A six-camera, three-dimensional motion capture system was used to record range of motion (ROM) of the head. A digital stopwatch was used to time trials and to record a split time associated with EHR system bladder insertion. A modified Borg CR10 scale was used to measure the rating of perceived exertion (RPE). Mean values were created for each variable. Three pairwise t-tests with Bonferroni-corrected alpha levels tested for differences between time for removal, split time, and RPE. A 2 x 3 (condition x plane) totally within-subjects repeated-measures design analysis of variance (ANOVA) tested for differences in head ROM between the sagittal, frontal, and transverse planes. Analyses were performed using SPSS (version 18.0) (alpha = 0.05)., Results: There was no statistically significant difference in perceived difficulty between EHR (RPE = 2.73) and MHR (RPE = 2.55) (t(29) = 0.76; p = 0.45; d = 0.20). Manual helmet removal was, on average, 28.95 seconds faster than EHR (t(29) = 11.44; p < 0.001). Head ROM was greater during EHR compared with MHR in the sagittal (t(29) = 4.57; p < 0.001), frontal (t(29) = 5.90; p < 0.001), and transverse (t(29) = 8.34; p < 0.001) planes. Head ROM was also greater during the helmet-removal portion of EHR in the frontal (t(29) = 4.44; p < 0.001) and transverse (t(29) = 5.99; p < 0.001) planes, compared with MHR. Regardless of technique, sagittal-plane head ROM was greater than frontal- and transverse-plane movements (F(2,58) = 241.47; p < 0.001)., Conclusions: Removing a helmet manually is faster and creates slightly less motion than removing a helmet using the Eject system. Both techniques were equally easy to use. Future research should analyze the performance of the Eject system in other styles of football helmets and in helmets used in other sports such as lacrosse, motorsports, and ice hockey.
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- 2011
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37. Prevalence and characteristics of general and football-specific emergency medical service activations by high school and collegiate certified athletic trainers: a national study.
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Decoster LC, Swartz EE, Cappaert TA, and Hootman JM
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- Adult, Certification, Craniocerebral Trauma therapy, Cross-Sectional Studies, Female, Health Care Surveys statistics & numerical data, Humans, Male, Middle Aged, Neck Injuries therapy, Prevalence, Retrospective Studies, United States epidemiology, Craniocerebral Trauma epidemiology, Emergency Medical Services statistics & numerical data, Football injuries, Neck Injuries epidemiology
- Abstract
Objective: To describe frequency and characteristics of emergency medical services (EMS) activations by certified athletic trainers (ATs) and effects of pre-season planning meetings on interactions between ATs and EMS both generally and specifically during football head/neck emergencies., Design: Retrospective cross-sectional survey., Setting: 2009 Web-based survey., Participants: Athletic trainers (n = 1884; participation rate, 28%) in high school and collegiate settings., Independent Variables: Athletic trainer work setting, AT demographics, history of pre-season planning meetings., Main Outcome Measures: Proportions and 95% confidence intervals (CIs) estimated the prevalence of EMS activation, planning meetings, and characteristics of AT-EMS interactions (eg, episodes of AT-perceived inappropriate care and on-field disagreements). Chi square tests tested differences (P < 0.05) in proportions. Associations (odds ratio = OR and 95% CI) between work setting, demographics, preseason meetings and fall 2008 1) episodes of AT-perceived inappropriate care, and 2) on-field disagreements were assessed using multivariate logistic regression., Results: High school ATs activated EMS more frequently than collegiate ATs (eg, fall 2008 EMS activation for football injury, 59.9% vs 27.5%; P < 0.01) and reported fewer pre-season planning meetings (eg, met with EMS to practice, 38.1% vs 55.8%; P < 0.01). During the Fall 2008 football season, high school ATs perceived more episodes of inappropriate care (10.4% vs 3.9%; P < 0.01) and on-field disagreements (5.4 vs 2.2%; P < 0.01) than collegiate ATs. High school work setting was independently associated with episodes of AT-perceived inappropriate care (adjusted OR = 2.76; 95% CI, 1.65-4.62) and on-field disagreements (adjusted OR = 2.33; 95% CI, 1.17-4.64)., Conclusions: Athletic trainer-EMS interactions are common and sometimes involve AT-perceived episodes of inappropriate care and on-field disagreements between emergency care providers.
- Published
- 2010
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38. Emergency face-mask removal effectiveness: a comparison of traditional and nontraditional football helmet face-mask attachment systems.
- Author
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Swartz EE, Belmore K, Decoster LC, and Armstrong CW
- Subjects
- Acceleration, Adult, Analysis of Variance, Athletic Injuries etiology, Athletic Injuries prevention & control, Biomechanical Phenomena, Exercise, Facial Injuries etiology, Facial Injuries prevention & control, Female, Humans, Male, Reproducibility of Results, Spinal Cord Injuries etiology, Spinal Cord Injuries prevention & control, Statistics as Topic, Time Factors, United States epidemiology, Athletic Injuries epidemiology, Facial Injuries epidemiology, Football injuries, Head Protective Devices, Spinal Cord Injuries epidemiology, Sports Medicine
- Abstract
Context: Football helmet face-mask attachment design changes might affect the effectiveness of face-mask removal., Objective: To compare the efficiency of face-mask removal between newly designed and traditional football helmets., Design: Controlled laboratory study., Setting: Applied biomechanics laboratory., Participants: Twenty-five certified athletic trainers., Intervention(s): The independent variable was face-mask attachment system on 5 levels: (1) Revolution IQ with Quick Release (QR), (2) Revolution IQ with Quick Release hardware altered (QRAlt), (3) traditional (Trad), (4) traditional with hardware altered (TradAlt), and (5) ION 4D (ION). Participants removed face masks using a cordless screwdriver with a back-up cutting tool or only the cutting tool for the ION. Investigators altered face-mask hardware to unexpectedly challenge participants during removal for traditional and Revolution IQ helmets. Participants completed each condition twice in random order and were blinded to hardware alteration., Main Outcome Measure(s): Removal success, removal time, helmet motion, and rating of perceived exertion (RPE). Time and 3-dimensional helmet motion were recorded. If the face mask remained attached at 3 minutes, the trial was categorized as unsuccessful. Participants rated each trial for level of difficulty (RPE). We used repeated-measures analyses of variance (α = .05) with follow-up comparisons to test for differences., Results: Removal success was 100% (48 of 48) for QR, Trad, and ION; 97.9% (47 of 48) for TradAlt; and 72.9% (35 of 48) for QRAlt. Differences in time for face-mask removal were detected (F(4,20) = 48.87, P = .001), with times ranging from 33.96 ± 14.14 seconds for QR to 99.22 ± 20.53 seconds for QRAlt. Differences were found in range of motion during face-mask removal (F(4,20) = 16.25, P = .001), with range of motion from 10.10° ± 3.07° for QR to 16.91° ± 5.36° for TradAlt. Differences also were detected in RPE during face-mask removal (F(4,20) = 43.20, P = .001), with participants reporting average perceived difficulty ranging from 1.44 ± 1.19 for QR to 3.68 ± 1.70 for TradAlt., Conclusions: The QR and Trad trials resulted in superior results. When trials required cutting loop straps, results deteriorated.
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- 2010
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39. Summary of the National Athletic Trainers' Association position statement on the acute management of the cervical spine-injured athlete.
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Swartz EE, Decoster LC, Norkus SA, Boden BP, Waninger KN, Courson RW, Horodyski M, and Rehberg RS
- Subjects
- Humans, Athletic Injuries therapy, Cervical Vertebrae injuries, Emergency Medicine, Spinal Injuries therapy, Sports Medicine
- Abstract
The incidence of catastrophic cervical spine injury in sports is low compared with other injuries. However, cervical spine injuries necessitate delicate and precise management, often involving the combined efforts of a variety of health care providers. The outcome of a catastrophic cervical spine injury depends on the efficiency of this management process and timeliness of transfer to a controlled environment for diagnosis and treatment. The objective of the National Athletic Trainers' Association (NATA) position statement on the acute care of the cervical spine-injured athlete is to provide the certified athletic trainer, team physician, emergency responder, and other health care professionals with recommendations on how to best manage a catastrophic cervical spine injury in an athlete. Recommendations are based on current evidence pertaining to prevention strategies to reduce the incidence of cervical spine injuries in sport; emergency planning and preparation to increase management efficiency; maintaining or creating neutral alignment in the cervical spine; accessing and maintaining the airway; stabilizing and transferring the athlete with a suspected cervical spine injury; managing the athlete participating in an equipment-laden sport such as football, hockey, or lacrosse; and imaging considerations in the emergency department.
- Published
- 2009
- Full Text
- View/download PDF
40. Cervical spine alignment during on-field management of potential catastrophic spine injuries.
- Author
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Swartz EE and Del Rossi G
- Abstract
Context: When cervical spine injuries are suspected, the cervical spine should be immobilized in a neutral position and neck motion controlled in preparation for transport to an emergency facility. Protocols for emergency transport utilizing common devices (cervical collars) and methods (transfer techniques) during these procedures are not entirely evidence based., Evidence Acquisition: The medical literature search covered the time period of January 1966 to June 2008 using the following keywords, either alone or in combination: extrication collars, cervical collars, spine orthoses, spinal immobilization, spine board, spinal board, transfer techniques, and back board. Biomedical databases searched included Medline, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL [1982 to 2008]). The reference lists of all trials identified were also searched for additional trials., Methods: Only trials that directly compared the efficacy or safety of transfer methods and/or immobilization devices were included. Studies that measured voluntary head movement after the fitting of the cervical orthoses and those that did not evaluate motion across individual spinal segments were not included., Results: A lift-and-slide transfer method with a full body immobilization device creates less motion than a log-roll maneuver. Extrication-type cervical immobilization collars are limited in their ability to control neck motion in the injured cadaveric model., Conclusion: Allied health professionals responsible for the management of the cervical spine-injured patient should become familiar with and employ a lift-and-slide transfer technique in appropriate situations and should not rely exclusively on extrication-type collars to immobilize the neck.
- Published
- 2009
- Full Text
- View/download PDF
41. Electromyography of 3 scapular muscles: a comparative analysis of the cuff link device and a standard push-up.
- Author
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Tucker WS, Campbell BM, Swartz EE, and Armstrong CW
- Subjects
- Adolescent, Adult, Algorithms, Exercise Test, Female, Humans, Male, Muscle, Skeletal innervation, Reference Values, Young Adult, Electromyography instrumentation, Isometric Contraction physiology, Muscle, Skeletal physiology, Scapula innervation, Scapula physiology, Shoulder Injuries, Weight-Bearing physiology
- Abstract
Context: The Cuff Link is a closed kinetic chain rehabilitation apparatus for the upper extremity. Limited research has established its effectiveness to elicit muscle activation of the scapular muscles., Objective: To determine if scapular muscle activation differs in response to 2 upper extremity closed kinetic chain exercises: Cuff Link and standard push-up., Design: A single-group, repeated-measures design., Setting: Controlled laboratory., Patients or Other Participants: Twenty-eight healthy individuals (13 women: age = 19.69 +/- 1.55 years, height = 167.44 +/- 9.52 cm, mass = 61.00 +/- 8.79 kg; 15 men: age = 22.00 +/- 3.91 years, height = 181.44 +/- 6.60 cm, mass = 82.36 +/- 13.23 kg) with no history of shoulder or low back injury volunteered to participate in this study., Intervention(s): Participants performed 10 trials of complete revolutions on the Cuff Link and 10 full-weight-bearing push-ups. We controlled trial velocity and randomized order. Trunk and shoulder positions were normalized to the participant's height. Using surface electromyography, we recorded muscle activity of the serratus anterior, middle trapezius, and lower trapezius. Rectified and smoothed electromyography data for the serratus anterior, middle trapezius, and lower trapezius were normalized as a percentage of the maximal voluntary isometric contractions (%MVIC)., Main Outcome Measure(s): Mean muscle activity of the serratus anterior, middle trapezius, and lower trapezius. We used paired-samples t tests to analyze the mean data for each condition. The alpha level was adjusted to .016 to avoid a type I error., Results: Middle trapezius %MVIC was greater during push-ups (27.01 +/- 20.40%) than during use of the Cuff Link (11.49 +/- 9.46%) (P = .001). Lower trapezius %MVIC was greater during push-ups (36.07 +/- 18.99%) than during use of the Cuff Link (16.29 +/- 8.64%) (P = .001). There was no difference in %MVIC for the serratus anterior between conditions., Conclusions: The push-up demonstrated greater middle trapezius and lower trapezius activation levels compared with the Cuff Link. However, the push-up had a high participant failure rate. Because serratus anterior activation levels were similar, the Cuff Link may be an appropriate alternative for individuals lacking the upper body strength to perform a push-up.
- Published
- 2008
- Full Text
- View/download PDF
42. The combined tool approach for face mask removal during on-field conditions.
- Author
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Gale SD, Decoster LC, and Swartz EE
- Subjects
- Adult, Airway Obstruction, Humans, Male, Cervical Vertebrae injuries, Emergency Medical Services, Football injuries, Head Protective Devices, Spinal Injuries prevention & control, Sports Equipment, Sports Medicine
- Abstract
Context: An effective approach to emergency removal of the face mask (FM) from a football helmet should include successful removal of the FM and limitation of both the time required and the movement created during the process. Current recommendations and practice are to use a cutting tool to remove the FM. Researchers recently have suggested an alternate approach that combines the use of a cordless screwdriver and a cutting tool. This combined tool approach has not been studied, and FM removal has not been studied in a practical setting., Objective: To investigate the effectiveness and speed of using a combined tool approach to remove the FMs from football helmets during on-field conditions throughout the course of a football season., Design: Randomized multigroup design., Setting: Practice field of 1 National Collegiate Athletic Association Division II football college., Patients or Other Participants: Eighty-four members of 1 football team., Intervention(s): We used a battery-operated screwdriver for FM removal and resorted to using a cutting tool as needed., Main Outcome Measure(s): We tracked FM removal success and failure and trial time and compared results based on helmet characteristics, weather variables, and the seasonal timing of the removal trial., Results: Of the 84 players, 76 were available for data-collection trials. Overall, 98.6% (75/76) of FM removal trials were successful and resulted in a mean removal time of 40.09 +/- 15.1 seconds. We found no differences in FM removal time throughout the course of the season. No differences in effectiveness or trial time were found among helmet characteristics, weather variables, or the timing of the trial., Conclusions: Combining the cordless screwdriver and cutting tool provided a fast and reliable means of on-field FM removal in this Division II setting. Despite the excellent overall result, 1 FM was not removed in a timely manner. Therefore, we recommend that athletic trainers practice helmet removal to be prepared should FM removal fail.
- Published
- 2008
- Full Text
- View/download PDF
43. Knee-muscle activation during landings: developmental and gender comparisons.
- Author
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Russell PJ, Croce RV, Swartz EE, and Decoster LC
- Subjects
- Adolescent, Adult, Anterior Cruciate Ligament physiology, Biomechanical Phenomena, Child, Female, Growth and Development, Humans, Knee growth & development, Male, Task Performance and Analysis, United States, Knee physiology, Muscle Contraction, Weight-Bearing physiology
- Abstract
Purpose: This study determined anteroposterior knee-joint muscle activation differences among children and adult males and females landing from a self-initiated vertical jump (VJ) under normal and offset-target conditions to further understand physical maturation's influence on anterior cruciate ligament (ACL) injury risk., Methods: Fifty-five recreationally active volunteer subjects grouped by age (children = 9.5 +/- 0.9 yr; adult = 23.9 +/- 2.8 yr) and gender (females = 28; males = 27) completed motion analysis, ground reaction force, and surface electromyography (SEMG) data collection during a two-footed landing under straight (midline-target) and offset-target (adult = 45.7 cm; child = 30.5 cm) conditions. Target height was 50% of maximum VJ height. Co-contraction ratios (CCR) (hamstrings (HAMS)/vastus medialis (VM) activity) from normalized SEMG root mean squares were analyzed in the prelanding (PRE) (100 ms before initial contact (IC)), reflexive (REF) (100 ms after IC), and voluntary (VOL) (end of REF to maximum knee flexion) muscle activity phases. Repeated-measures statistical analyses determined significant gender, physical maturation, and target differences (P < 0.05) in CCR and associated HAMS and VM activity across landing phases., Results: A significant interaction (P < 0.0001) indicated similar CCR for children and adults during the REF and VOL phases, but during the PRE phase adult CCR (619.04 + 52.01) were two times greater than children's (308.32 +/- 51.04). Significantly more HAMS activity, not less VM activity, increased adult PRE-CCR. Gender and target CCR differences were absent., Conclusions: Children's decreased preparatory co-contraction about the knee does not seem to be linked to increased ACL injury risk. Thus, adults may strive for preparatory co-contraction levels about the knee that permit adaptability to varied landing tasks.
- Published
- 2007
- Full Text
- View/download PDF
44. Football equipment design affects face mask removal efficiency.
- Author
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Swartz EE, Norkus SA, Cappaert T, and Decoster LC
- Subjects
- Adult, Device Removal, Equipment Design, Female, Hand Strength, Humans, Male, Football, Head Protective Devices
- Abstract
Background: Researchers have investigated the performance of face mask removal tools for spine injury management in football but not the effects of football equipment design., Hypotheses: Various styles or designs of football helmet equipment (helmets, face masks, loop straps) affect face mask removal efficiency. A cordless screwdriver performs more efficiently than do cutting tools., Study Design: Controlled laboratory study., Methods: Nineteen certified athletic trainers were randomly assigned to group 1 (cordless screwdriver and the FM Extractor) or group 2 (cordless screwdriver and the Trainer's Angel). Subjects randomly performed face mask removal for 6 conditions composed of helmet (3), face mask (3), and loop strap (5) combinations. Time, head movement, perceived difficulty, and success rates were measured., Results: Multiple significant differences were found in time, movement, and perceived difficulty between the 6 helmet equipment conditions. The Shockblocker loop strap was consistently superior in all variables regardless of the tool used or the helmet it was attached to. The cordless screwdriver created less movement (mean range from any one plane, 2.8 degrees -13.3 degrees ), was faster (mean range, 42.1-68.8 seconds), and was less difficult (mean rating of perceived exertion range, 1.4-2.9) compared to cutting tools (ranges, 4.4 degrees -18.4 degrees in any one plane, 71-174 seconds, rating of perceived exertion, 2.8-7.7). Trial failure was more common with cutting tools than with the screwdriver., Conclusion: Differences in football helmet equipment affect face mask removal. The cordless screwdriver is more efficient than the FM Extractor and Trainer's Angel., Clinical Relevance: Professionals responsible for the care of football athletes must be knowledgeable in the types of equipment used and the best option available for effective airway access.
- Published
- 2005
- Full Text
- View/download PDF
45. Knee muscular response strategies differ by developmental level but not gender during jump landing.
- Author
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Croce RV, Russell PJ, Swartz EE, and Decoster LC
- Subjects
- Adult, Age Factors, Child, Electromyography, Female, Humans, Male, Reflex physiology, Sex Factors, Knee Joint physiology, Motor Activity physiology, Muscle, Skeletal physiology
- Abstract
The purpose of this investigation was to determine differences between pre- and post-pubescent males and females in quadriceps (vastus medialis; VM) and hamstrings (medial hamstrings and biceps femoris; HAMS) muscular activation patterns via the root mean square of surface electromyography (SEMG) during self-initiated vertical jump landing. Fifty-eight subjects, divided into age and gender groupings, were compared on kinematic variables during pre-landing (100 msec preceeding initial ground contact), post-landing (100 msec following initial ground contact), and initial-contact-to-maximum-knee-flexion stages. Kinematic variables investigated were (1) SEMG values during each stage of the vertical-jump landing; (2) Co-contraction ratios (CCR), which represented the ratio of normalized hamstrings' activity to normalized quadriceps' activity; and, (3) knee angle at initial contact. Results indicated (1) no significant gender differences in variables measured; and, (2) significant developmental level differences. Post-pubescent subjects displayed greater HAMS acitivity and CCR values in the pre-landing stage relative to post-landing stages, indicating that post-pubescent subjects had a greater level of hamstrings co-contraction prior to landing than pre-pubescent subjects. Conversely, pre-pubescent subjects displayed greater post-landing and initial-contact-to-maximum-knee-flexion ratios, indicating a greater level of hamstrings' co-contraction during post-landing stages than post-pubescent subjects. There were no significant differences in knee angle at initial contact. The greater level of hamstrings' co-activation prior to landing by post-pubescent subjects indicated that they used a strategy of pre-tuning the hamstrings prior to landing (more CNS pre-activation) to control the ground reaction forces and anterior tibial displacement experienced by the knee during landing. On the other hand, pre-pubescent subjects controlled these forces by having a greater level of hamstrings' co-activation during landing, which represents more of a reflexive activation in response to ground impact.
- Published
- 2004
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