bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying Multiplanar Knee Laxity Profiles and Associated Physical Characteristics
Authors: Shultz Sandra J. , Dudley William N. , Kong Yanfang 
Published: March 2017

Context:A single measure of knee laxity (ie, measurement of laxity in a single plane of motion) is probably inadequate to fully describe how knee joint laxity is associated with anterior cruciate ligament injury.Objective:To characterize interparticipant differences in the absolute and relative magnitudes of multiplanar knee laxity (ie, sagittal, frontal, and transverse planes) and examine physical characteristics that may contribute to these differences.Design:Descriptive laboratory study.Setting:University research laboratory.Patients or Other Participants:140 participants (90 women, 50 men).Main Outcome Measure(s):Using cluster analysis, we grouped participants into distinct multiplanar knee laxity profiles based on the absolute and relative magnitudes of their anterior knee laxity (AKL), genu recurvatum (GR), and varusvalgus (VV) and internal-external rotation (IER) knee laxity. Using multinomial logistic regression, we then examined associations between the different laxity profile clusters and physical characteristics of sex, age, activity level, general joint laxity, body mass index, thigh strength, and 8 measures of lower extremity anatomical alignment.Results:Six clusters were identified: low (LOW), moderate (MOD) and high (HIGH) laxity overall and disproportionally higher VV/IER (MODVV/IER), GR (HIGHGR), and AKL (HIGHAKL) laxity. Once all other physical characteristics were accounted for, the LOW cluster was more likely to be older, with longer femur length. Clusters with greater magnitudes of VV and IER laxity were more likely to be younger and to have lower body mass index, smaller Q-angle, and shorter femur length (MOD, HIGH, MODVV/IER) and less thigh strength (HIGH). The HIGHGR cluster was more likely to be female and to have a smaller tibiofemoral angle and longer femur length. The HIGHAKL cluster was more likely to have greater hip anteversion and navicular drop.Conclusions:The absolute and relative magnitudes of a person's multiplanar knee laxity are not always uniform across planes of motion and can be influenced by age, body composition, thigh strength, and structural alignment. Except in HIGHGR, sex was not a significant predictor of cluster membership once other physical characteristics were taken into account.
Heat Stress and Cardiovascular, Hormonal, and Heat Shock Proteins in Humans
Authors: Iguchi Masaki , Littmann Andrew E. , Chang Shuo-Hsiu , Wester Lydia A. , Knipper Jane S. , Shields Richard K. 
Published: March 2017

Context:
Conditions such as osteoarthritis, obesity, and spinal cord injury limit the ability of patients to exercise, preventing them from experiencing many well-documented physiologic stressors. Recent evidence indicates that some of these stressors might derive from exercise-induced body temperature increases.

Objective:
To determine whether whole-body heat stress without exercise triggers cardiovascular, hormonal, and extra-cellular protein responses of exercise.

Design:
Randomized controlled trial.

Setting:
University research laboratory.

Patients or Other Participants:
Twenty-five young, healthy adults (13 men, 12 women; age = 22.1 ± 2.4 years, height = 175.2 ± 11.6 cm, mass = 69.4 ± 14.8 kg, body mass index = 22.6 ± 4.0) volunteered.

Intervention(s):
Participants sat in a heat stress chamber with heat (73°C) and without heat (26°C) stress for 30 minutes on separate days. We obtained blood samples from a subset of 13 participants (7 men, 6 women) before and after exposure to heat stress.

Main Outcome Measure(s):
Extracellular heat shock protein (HSP72) and catecholamine plasma concentration, heart rate, blood pressure, and heat perception.

Results:
After 30 minutes of heat stress, body temperature measured via rectal sensor increased by 0.8°C. Heart rate increased linearly to 131.4 ± 22.4 beats per minute (F6,24 = 186, P &lt; .001) and systolic and diastolic blood pressure decreased by 16 mm Hg (F6,24 = 10.1, P &lt; .001) and 5 mm Hg (F6,24 = 5.4, P &lt; .001), respectively. Norepinephrine (F1,12 = 12.1, P = .004) and prolactin (F1,12 = 30.2, P &lt; .001) increased in the plasma (58% and 285%, respectively) (P &lt; .05). The HSP72 (F1,12 = 44.7, P &lt; .001) level increased with heat stress by 48.7% ± 53.9%. No cardiovascular or blood variables showed changes during the control trials (quiet sitting in the heat chamber with no heat stress), resulting in differences between heat and control trials.

Conclusions:
We found that whole-body heat stress triggers some of the physiologic responses observed with exercise. Future studies are necessary to investigate whether carefully prescribed heat stress constitutes a method to augment or supplement exercise.
Predicting Football Players' Dual-Energy X-Ray Absorptiometry Body Composition Using Standard Anthropometric Measures
Authors: Oliver Jonathan M. , Lambert Brad S. , Martin Steven E. , Green John S. , Crouse Stephen F. 
Published: March 2017

Context:
The recent increase in athlete size, particularly in football athletes of all levels, coupled with the increased health risk associated with obesity warrants continued monitoring of body composition from a health perspective in this population. Equations developed to predict percentage of body fat (%Fat) have been shown to be population specific and might not be accurate for football athletes.

Objective:
To develop multiple regression equations using standard anthropometric measurements to estimate dual-energy x-ray absorptiometry %Fat (DEXA%Fat) in collegiate football players.

Design:
Controlled laboratory study.

Patients and Other Participants:
One hundred fifty-seven National Collegiate Athletic Association Division IA football athletes (age  =  20 ± 1 years, height  =  185.6 ± 6.5 cm, mass  =  103.1 ± 20.4 kg, DEXA%Fat  =  19.5 ± 9.1%) participated.

Main Outcome Measure(s):
Participants had the following measures: (1) body composition testing with dual-energy x-ray absorptiometry; (2) skinfold measurements in millimeters, including chest, triceps, subscapular, midaxillary, suprailiac, abdominal (SFAB), and thigh; and (3) standard circumference measurements in centimeters, including ankle, calf, thigh, hip (AHIP), waist, umbilical (AUMB), chest, wrist, forearm, arm, and neck. Regression analysis and fit statistics were used to determine the relationship between DEXA%Fat and each skinfold thickness, sum of all skinfold measures (SFSUM), and individual circumference measures.

Results:
Statistical analysis resulted in the development of 3 equations to predict DEXA%Fat: model 1, (0.178 • AHIP) + (0.097 • AUMB) + (0.089 • SFSUM) − 19.641; model 2, (0.193 • AHIP) + (0.133 • AUMB) + (0.371 • SFAB) − 23.0523; and model 3, (0.132 • SFSUM) + 3.530. The R2 values were 0.94 for model 1, 0.93 for model 2, and 0.91 for model 3 (for all, P &lt; .001).

Conclusions:
The equations developed provide an accurate way to assess DEXA%Fat in collegiate football players using standard anthropometric measures so athletic trainers and coaches can monitor these athletes at increased health risk due to increased size.
Removal Time and Efficacy of Riddell Quick Release Face Guard Attachment System Side Clips During 1 Football Season
Authors: Gruppen Tonia , Smith Molly , Ganss Andrea 
Published: March 2017

Context
In the National Athletic Trainers' Association position statement, “Acute Management of the Cervical Spine-Injured Athlete,” the technique recommended for face-mask (FM) removal is one that “creates the least head and neck motion, is performed most quickly, is the least difficult, and carries the least chance of failure.” Industrial and technological advances in football helmet design and FM attachment systems might influence the efficacy of emergency FM removal.

Objective
To examine the removal times and success rates of the Quick Release (QR) Face Guard Attachment System (Riddell Sports, Inc, Elyria, OH) throughout and at the conclusion of 1 season of play by a National Collegiate Athletic Association Division III football team competing in the Midwest.

Design
Controlled laboratory study.

Setting
College laboratory.

Patients or Other Participants
A total of 69 randomly selected Revolution IQ (Riddell Sports, Inc) football helmets fitted with the QR system were used.

Intervention(s)
Each helmet was secured to a spine board, and investigators attempted to remove both of the QR side clips from the helmet with the Riddell insertion tool.

Main Outcome Measure(s)
Dependent variables included total time for removal of both QR side clips from the FM and success rate for removal of both side clips.

Results
The overall success rate for removal of both clips was 94.8% (164/173), whereas the mean times for removal of both clips ranged from 9.92 ± 12.06 seconds to 16.65 ± 20.97 seconds over 4 trial sessions. We found no differences among mean times for trial sessions throughout the season of play among the same helmets or among different helmets (P &gt; .05).

Conclusions
Removal time and success rate of the Riddell QR were satisfactory during and after 1 season of play despite use in various temperatures and precipitation.
Lower Extremity Muscle Activation and Knee Flexion During a Jump-Landing Task
Authors: Walsh Meghan , Boling Michelle C. , McGrath Melanie , Blackburn J. Troy , Padua Darin A. 
Published: March 2017

Context:
Decreased sagittal-plane motion at the knee during dynamic tasks has been reported to increase impact forces during landing, potentially leading to knee injuries such as anterior cruciate ligament rupture.

Objective:
To describe the relationship between lower extremity muscle activity and knee-flexion angle during a jump-landing task.

Design:
Cross-sectional study.

Setting:
Research laboratory.

Patients or Other Participants:
Thirty recreationally active volunteers (15 men, 15 women: age = 21.63 ± 2.01 years, height = 173.95 ± 11.88 cm, mass = 72.57 ± 14.25 kg).

Intervention(s):
Knee-flexion angle and lower extremity muscle activity were collected during 10 trials of a jump-landing task.

Main Outcome Measure(s):
Simple correlation analyses were performed to determine the relationship between each knee-flexion variable (initial contact, peak, and displacement) and electromyographic amplitude of the gluteus maximus (GMAX), quadriceps (VMO and VL), hamstrings, gastrocnemius, and quadriceps : hamstring (Q : H) ratio. Separate forward stepwise multiple regressions were conducted to determine which combination of muscle activity variables predicted each knee-flexion variable.

Results:
During preactivation, VMO and GMAX activity and the Q : H ratio were negatively correlated with knee-flexion angle at initial contact (VMO: r = −0.382, P = .045; GMAX: r = −0.385, P = .043; Q : H ratio: r = −0.442, P = .018). The VMO, VL, and GMAX deceleration values were negatively correlated with peak knee-flexion angle (VMO: r = −0.687, P = .001; VL: r = −0.467, P = .011; GMAX: r = −0.386, P = .043). The VMO and VL deceleration values were negatively correlated with knee-flexion displacement (VMO: r = −0.631, P = .001; VL: r = −0.453, P = .014). The Q : H ratio and GM activity predicted 34.7% of the variance in knee-flexion angle at initial contact (P = .006). The VMO activity predicted 47.1% of the variance in peak knee-flexion angle (P = .001). The VMO and VL activity predicted 49.5% of the variance in knee-flexion displacement (P = .001).

Conclusions:
Greater quadriceps and GMAX activation and less hamstrings and gastrocnemius activation were correlated with smaller knee-flexion angles. This landing strategy may predispose an individual to increased impact forces due to the negative influence on knee-flexion position.
Neuromuscular Characteristics of Individuals Displaying Excessive Medial Knee Displacement
Authors: Padua Darin A. , Bell David R. , Clark Micheal A. 
Published: March 2017

Context
Knee-valgus motion is a potential risk factor for certain lower extremity injuries, including anterior cruciate ligament injury and patellofemoral pain. Identifying neuromuscular characteristics associated with knee-valgus motion, such as hip and lower leg muscle activation, may improve our ability to prevent lower extremity injuries.

Objective
We hypothesized that hip and lower leg muscle-activation amplitude would differ among individuals displaying knee valgus (medial knee displacement) during a double-legged squat compared with those who did not display knee valgus. We further suggested that the use of a heel lift would alter lower leg muscle activation and frontal-plane knee motion in those demonstrating medial knee displacement.

Design
Descriptive laboratory study.

Setting
Research laboratory.

Patients or Other Participants
A total of 37 healthy participants were assigned to the control (n = 19) or medial-knee-displacement (n = 18) group based on their double-legged squat performance.

Main Outcome Measure(s)
Muscle-activation amplitude for the gluteus maximus, gluteus medius, adductor magnus, medial and lateral gastrocnemius, and tibialis anterior was measured during 2 double-legged squat tasks. The first task consisted of performing a double-legged squat without a heel lift; the second consisted of performing a double-legged squat task with a 2-in (5.08-cm) lift under the heels.

Results
Muscle-activation amplitude for the hip adductor, gastrocnemius, and tibialis anterior was greater in those who displayed knee valgus than in those who did not (P &lt; .05). Also, use of heel lifts resulted in decreased activation of the gluteus maximus, hip adductor, gastrocnemius, and tibialis anterior muscles (P &lt; .05). Use of heel lifts also eliminated medially directed frontal-plane knee motion in those displaying medial knee displacement.

Conclusions
Medial knee displacement during squatting tasks appears to be associated with increased hip-adductor activation and increased coactivation of the gastrocnemius and tibialis anterior muscles.
Rapid Weight Loss and the Body Fluid Balance and Hemoglobin Mass of Elite Amateur Boxers
Authors: Reljic Dejan , Hässler Eike , Jost Joachim , Friedmann-Bette Birgit 
Published: March 2017

Context
Dehydration is assumed to be a major adverse effect associated with rapid loss of body mass for competing in a lower weight class in combat sports. However, the effects of such weight cutting on body fluid balance in a real-life setting are unknown.

Objective
To examine the effects of 5% or greater loss of body mass within a few days before competition on body water, blood volume, and plasma volume in elite amateur boxers.

Design
Case-control study.

Setting
Sports medicine laboratory.

Patients or Other Participants
Seventeen male boxers (age = 19.2 ± 2.9 years, height = 175.1 ± 7.0 cm, mass = 65.6 ± 9.2 kg) were assigned to the weight-loss group (WLG; n = 10) or the control group (CON; n = 7).

Intervention(s)
The WLG reduced body mass by restricting fluid and food and inducing excessive sweat loss by adhering to individual methods. The CON participated in their usual precompetition training.

Main Outcome Measure(s)
During an ordinary training period (t-1), 2 days before competition (t-2), and 1 week after competition (t-3), we performed bioelectrical impedance measurements; calculated total body water, intracellular water, and extracellular water; and estimated total hemoglobin mass (tHbmass), blood volume, and plasma volume by the CO-rebreathing method.

Results
In the WLG, the loss of body mass (5.6% ± 1.7%) led to decreases in total body water (6.0% ± 0.9%), extracellular water (12.4% ± 7.6%), tHbmass (5.3% ± 3.8%), blood volume (7.6% ± 2.1%; P &lt; .001), and plasma volume (8.6% ± 3.9%). The intracellular water did not change (P &gt; .05). At t-3, total body water, extracellular water, and plasma volume had returned to near baseline values, but tHbmass and blood volume still were less than baseline values (P &lt; .05). In CON, we found no changes (P &gt; .05).

Conclusions
In a real-life setting, the loss of approximately 6% body mass within 5 days induced hypohydration, which became evident by the decreases in body water and plasma volume. The reduction in tHbmass was a surprising observation that needs further investigation.
Distal Biceps Tendon Repair: An Analysis of Timing of Surgery on Outcomes
Authors: Anakwenze Oke A. , Baldwin Keith , Abboud Joseph A. 
Published: March 2017

Context:
Surgical repair of the ruptured distal biceps brachaii tendon is an effective treatment in injured patients. Timing of surgery is considered an important factor when managing these patients.

Objective:
To compare our outcomes after distal biceps tendon acute (at 4 weeks or less) or chronic (greater than 4 weeks) repair.

Design:
Cohort study.

Setting:
Clinical practice.

Patients or Other Participants:
Of 18 patients in a tertiary practice who underwent distal biceps repair, 12 and 6 underwent acute or chronic repair, respectively. The average durations from injury to surgery were 15.3 (range, 9 to 25) and 50.1 (range, 29 to 75) days for the acute and chronic groups, respectively.

Intervention(s):
Distal biceps tendon repair.

Main Outcome Measure(s):
Disabilities of the Arm, Shoulder and Hand (DASH) scoring, range of motion, and clinical and radiographic complications.

Results:
No differences were noted between the groups in DASH scoring or range of motion. No complications occurred, and radiographic outcomes were satisfactory, without evidence of heterotopic ossification in any patients.

Conclusions:
Secure repair of a distal biceps tendon injury may yield similar results, whether it is performed in the acute or chronic setting.
Scapular Bracing and Alteration of Posture and Muscle Activity in Overhead Athletes With Poor Posture
Authors: Cole Ashley K. , McGrath Melanie L. , Harrington Shana E. , Padua Darin A. , Rucinski Terri J. , Prentice William E. 
Published: March 2017

Context:Overhead athletes commonly have poor posture. Commercial braces are used to improve posture and function, but few researchers have examined the effects of shoulder or scapular bracing on posture and scapular muscle activity.Objective:To examine whether a scapular stabilization brace acutely alters posture and scapular muscle activity in healthy overhead athletes with forward-head, rounded-shoulder posture (FHRSP).Design:Randomized controlled clinical trial.Setting:Applied biomechanics laboratory.Patients or Other Participants:Thirty-eight healthy overhead athletes with FHRSP.Intervention(s):Participants were assigned randomly to 2 groups: compression shirt with no strap tension (S) and compression shirt with the straps fully tensioned (S + T). Posture was measured using lateral-view photography with retroreflective markers. Electromyography (EMG) of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) in the dominant upper extremity was measured during 4 exercises (scapular punches, W's, Y's, T's) and 2 glenohumeral motions (forward flexion, shoulder extension). Posture and exercise EMG measurements were taken with and without the brace applied.Main Outcome Measure(s):Head and shoulder angles were measured from lateral-view digital photographs. Normalized surface EMG was used to assess mean muscle activation of the UT, MT, LT, and SA.Results:Application of the brace decreased forward shoulder angle in the S + T condition. Brace application also caused a small increase in LT EMG during forward flexion and Y's and a small decrease in UT and MT EMG during shoulder extension. Brace application in the S + T group decreased UT EMG during W's, whereas UT EMG increased during W's in the S group.Conclusions:Application of the scapular brace improved shoulder posture and scapular muscle activity, but EMG changes were highly variable. Use of a scapular brace might improve shoulder posture and muscle activity in overhead athletes with poor posture.
National Athletic Trainers' Association Position Statement: Evaluation of Dietary Supplements for Performance Nutrition
Authors: Buell Jackie L. , Franks Rob , Ransone Jack , Powers Michael E. , Laquale Kathleen M. , Carlson-Phillips Amanda 
Published: March 2017

ObjectivesTo help athletic trainers promote a “food-first” philosophy to support health and performance, understand federal and sport governing body rules and regulations regarding dietary supplements and banned substances, and become familiar with reliable resources for evaluating the safety, purity, and efficacy of dietary supplements.BackgroundThe dietary supplement industry is poorly regulated and takes in billions of dollars per year. Uneducated athletes need to gain a better understanding of the safety, eligibility, and efficacy concerns associated with choosing to take dietary supplements. The athletic trainer is a valuable athletic team member who can help in the educational process. In many cases, athletic trainers are asked to help evaluate the legality, safety, and efficacy of dietary supplements. For this position statement, our mission is to provide the athletic trainer with the necessary resources for these tasks.RecommendationsProper nutrition and changes in the athlete's habitual diet should be considered first when improved performance is the goal. Athletes need to understand the level of regulation (or lack thereof) governing the dietary supplement industry at the international, federal, state, and individual sport-participation levels. Athletes should not assume a product is safe simply because it is marketed over the counter. All products athletes are considering using should be evaluated for purity (ie, truth in labeling), safety, and efficacy.
Transparencia en televisiones públicas: desarrollo de indicadores y análisis de los casos de España y Chile
Authors: López-López Paulo Carlos , Puentes-Rivera Iván , Rúas-Araújo José 
Published: March 2017

El presente trabajo desarrolla y propone 29 indicadores de transparencia aplicables a las televisiones públicas, para posteriormente ensayarlos de forma experimental con la Televisión Nacional de Chile (TVN) y Televisión Española (TVE). Metodología: Siguiendo el método analítico, se aplican esos indicadores a la información disponible en las páginas web de TVN y TVE, para finalmente puntuar su nivel de transparencia dentro de una escala de 0 a 100. Resultados: La mayor transparencia se observa en relación con la producción de información y acceso a contenidos, seguido de la información económica. La mayor opacidad tiene que ver con la información institucional y la referida al personal directivo. Discusión y conclusiones: El nivel de transparencia de TVN y TVE es el mismo, ambas obtienen una puntuación de 62,069 sobre 100. Además, se demuestra la validez de los indicadores propuestos para valorar el nivel de transparencia de diferentes televisiones y establecer comparaciones equitativas y objetivas entre ellas, aunque deberán ser ampliados en el futuro