Identifying Risk Factors for Preexisting or Developing Low Back Pain in Youth, High School, and Collegiate Lacrosse Players Using 3-Dimensional Motion Analysis.

Background: Low back pain (LBP) is a common condition that can affect athletes of all ages. The risk factors for LBP onset and worsening associated with the lacrosse shooting motion are not yet known. Purpose: To identify training and biomechanical factors associated with preexisting LBP and development of LBP over 6 months in youth, high school, and collegiate lacrosse players. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 128 lacrosse players were enrolled in this study between January 2016 and January 2019. Player characteristics, lacrosse experience, and participation in other sports were self-reported. At baseline and 2-, 4-, and 6-month follow-ups, the players self-rated the presence and severity of LBP using a numeric pain rating scale (0-10 points). Participants were grouped according to LBP symptoms: no LBP at any time point (n = 102), preexisting LBP (n = 17), or developed LBP within the 6-month period (n = 9). The lacrosse shooting motion was captured via 3-dimensional motion analysis, and kinematic and kinetic variables were recorded. A Low Back Stress Index was used to estimate lumbar stress as a function of pelvic acceleration at the time of maximum lateral trunk lean during the shot. Univariate analyses of covariance and logistic regression models were used to address study aims. Results: Compared with the no-LBP group, the preexisting LBP group demonstrated 13.9% to 22.9% lower maximum angular velocities at the pelvis, trunk, and shoulders in the transverse plane (P < .05), 19.3% less collective pelvis-shoulder rotation in the transverse plane (P = .015), and 4.5% more knee flexion excursion (P = .063). The developed-LBP group produced 2.3% to 11.1% higher angular velocities in the pelvis, trunk, and shoulder and generated maximum pelvic acceleration values 36% to 42% higher than the remaining groups (P < .05 for both). Mean Low Back Stress Index values were not statistically significant among the groups (no LBP: 12,504 ± 13,076 deg2/s2; preexisting LBP: 8808 ± 10,174 deg2/s2; developed LBP: 19,389 ± 13,590 deg2/s2; P = .157). Conclusion: Preexisting LBP was associated with significantly restricted motion of the pelvis, trunk, and shoulders during a lacrosse shot. Excessive pelvic acceleration may be related to the development of LBP in lacrosse players.

Preseason lower extremity range of motion, flexibility, and strength in relation to in-season injuries in NCAA division I gymnasts.

OBJECTIVES: To determine if preseason lower extremity ROM, flexibility, and strength differ in collegiate gymnasts (NCAA Division 1) who do or do not sustain an injury during the competitive season. METHODS: Over four seasons, a total of 15 female gymnasts (age = 20.5 ± 1.0 years) underwent preseason screening (30 gymnast-season). We tested joint ROM (hip: flexion, internal and external rotation; ankle: weightbearing dorsiflexion), muscle flexibility (passive straight leg raise, Thomas,' Ober's, Ely's tests) and strength (hip extensors, abductors, and flexors isometric strength via a handheld dynamometer; knee: quadriceps and hamstring isokinetic strength at 60°/sec). The team athletic trainer tracked overuse lower extremity injuries (restricted gymnasts from full participation, occurred as from participation in organized practice or competition, and required medical attention) during each season. For athletes that tested multiple seasons, each encounter was considered independent, and each preseason assessment was linked to overuse injuries sustained during the same competitive season. Gymnasts were dichotomized into injured and non-injured groups. An independent t-test was used to measure differences in preseason outcomes between injured and non-injured groups. RESULTS: During four years, we recorded 23 overuse lower extremity injuries. Gymnasts that sustained an in-season overuse injury demonstrated significantly lower hip flexion ROM (mean difference: -10.6°; 95% confidence interval: -16.5, -4.6; p < 0.01) and lower hip abduction strength (mean difference: -4.7% of body weight; 95% confidence interval: -9.2, -0.3; p = 0.04). CONCLUSION: Gymnasts who sustain an in-season overuse lower extremity injury have significant preseason deficit of hip flexion ROM and weakness in the hip abductors. These findings indicate potential impairments in the kinematic & kinetic chains responsible for skill performance and energy absorption during landing.

Characteristics and reported injuries of recreational and competitive archers.

BACKGROUND: The aim of this cross-sectional study was to describe basic characteristics of archery athletes and examine injuries reported among archers of a variety of demographic and experience levels. METHODS: Participants at various archery competitions were asked to complete a 27-item survey that included demographics, bow type, archery experience, archery training patterns and volume, and injury incidence and anatomical location. RESULTS: Two hundred and thirty-four complete surveys were included in the analysis. No significant differences were noted between archery experience groups for age, height, weight, or draw length. A significant difference for draw weight was noted between beginners and advanced level (P=0.045) and between intermediate and advanced archers (P=0.013). Expert level archers reported participating in archery the most days per week (4.9±1.6) and months per year (11.6±0.9) out of all experience levels. Archers using recurve bow types reported more injuries (54 in total) than archers using compound bows (that were 47). The highest percentage of injuries due to archery was found at the expert/professional level with 50% of that group acquiring an injury. The shoulder was the most reported anatomical site of injury (with a total of 69 cases) followed by the back (30 cases) and elbow (19 in total). CONCLUSIONS: Injury rates in archery are comparable to other sports such as golf and tennis, thus establishing archery as a sport with legitimate risks to athletes. Also, there are several factors within the sport that predispose participants to injury. It is crucial that participants are informed of these risks and that appropriate training and equipment decisions are made to optimize the reduction of injury prevalence.

Swing Type and Batting Grip Affect Peak Pressures on the Hook of Hamate in Collegiate Baseball Players.

BACKGROUND: Bat swing and grip type may contribute to hook of hamate fractures in baseball players. PURPOSE: To compare the effects of swing type and batting grip on the pressure and rate of pressure development over the hook of hamate in collegiate baseball players. STUDY DESIGN: Descriptive laboratory study. Level of evidence, 3. METHODS: This was an experimental quasi-randomized study of bat grip and swing differences in National Collegiate Athletic Association Division I baseball players (N = 14; age, 19.6 ± 1.1 years [mean ± SD]). All participants performed swings under 6 combinations: 3 grip types (all fingers on the bat shaft [AO], one finger off the bat shaft [OF], and choked up [CU]) and 2 swing types (full swing and check swing). Peak pressure and rate of pressure generation over the area of the hamate were assessed using a pressure sensor fitted to the palm of the bare hand over the area of the hamate. Wrist angular velocities and excursions of radial ulnar deviation were obtained using 3-dimensional motion analysis. RESULTS: The OF-check swing combination produced the highest peak pressure over the hamate (3.72 ± 2.64 kg/cm2) versus the AO-full swing (1.36 ± 0.73 kg/cm2), OF-full swing (1.68 ± 1.17 kg/cm2), and CU-full swing (1.18 ± 0.96 kg/cm2; P < .05 for all). There was a significant effect of condition on rate of pressure development across the 6 conditions (P = .023). Maximal wrist angular velocities were 44% lower in all check swing conditions than corresponding full swing conditions (P < .0001). The time to achieve the maximal wrist angular velocity was longest with the AO-full swing and shortest with the CU-check swing (100.1% vs 7.9% of swing cycle; P = .014). CONCLUSION: The OF-check swing condition produced the highest total pressure reading on the hook of hamate. Check swing conditions also had the steepest rate of pressure development as compared with the full swing conditions. CLINICAL RELEVANCE: Batters who frequently check their swings and use an OF or AO grip may benefit from bat modifications or grip adjustment to reduce stresses over the hamate. Athletic trainers and team physicians should be aware of these factors to counsel players in the context of previous or ongoing hand injury.

Shoulder and Hip Range of Motion and Strength Changes Throughout a Season in College Softball Players.

BACKGROUND: Many studies have been done on the strength and mobility of the shoulder and hip in baseball players, but fewer studies have examined these metrics in softball players. PURPOSE: The purpose of this study was to observe and analyze changes in range of motion (ROM) and strength at the hip and shoulder that occur over the course of a competitive season, to describe preseason ROM and strength at the hip and shoulder in healthy college softball players through side-to-side comparison, and to compare measurements between pitchers and position players. STUDY DESIGN: Descriptive Cohort Study. METHODS: Data was collected over the course of six seasons, and a total of fifty-four healthy softball athletes (including pitchers and postiion players) who completed at least one set of preseason and postseason measurements were included. Subjects underwent passive ROM (External rotation [ER], internal rotation [IR], total arc of motion [TAM]) and strength (ER/IR at the shoulder, abduction/extension at the hip) measurements at preseason and postseason timepoints. RESULTS: Over a season, position players demonstrated an increase in all ROM metrics in both shoulders, except dominant IR, and a decrease in ER strength at the shoulder bilaterally (p<0.05). They also showed decreased ROM in all metrics across both hips (p<0.05). Pitchers had increased IR and TAM ROM in the dominant shoulder, decreased strength in both shoulders (ER throwing; ER and IR non-throwing), decreased ROM in both hips, and decreased abduction strength in the non-dominant hip (p<0.05). Position players showed less preseason IR in the dominant shoulder compared to non-dominant IR (Dominant: 31.7 ± 1.6°, Non-dominant: 37.0 ± 2.3°; p<0.05). CONCLUSION: Softball pitchers and position players both show increased ROM at the shoulder and decreased ROM at the hip over the course of a season. Position players demonstrated side-to-side discrepancies and seasonal changes at the throwing shoulder similar to those seen in baseball players. The preseason mobility of the dominant shoulder of pitchers increased over the season while strength of hip abduction in the non-dominant side was reduced. LEVEL OF EVIDENCE: 3.

Screening by Self-Report Underestimates Sickle Cell Trait in High-School Athletes.

BACKGROUND:  Sickle cell trait (SCT) has received attention as a cause of death in college athletes, leading to mandatory lab SCT screening in National Collegiate Athletic Association (NCAA) athletes. High-school athletes are commonly screened by self-report. There are no known studies for evaluating whether this method is effective as a screening tool. HYPOTHESIS:  The local prevalence rate of SCT as self-reported on the preparticipation evaluation (PPE) forms would be lower than the national accepted average. METHODS: PPE forms from the Department of Orthopedics and Rehabilitation of the University of Florida (UF) were reviewed between January 1, 2017, and April 30, 2018. The Florida High School PPE form includes a yes/no question to assess the diagnosis of SCT. The prevalence established by self-report was then compared with the national prevalence for SCT in the comparable race/ethnicity groups reported by the CDC. The response rate of SCT questions was also compared to other common cardiac screening questions. RESULTS:  A total of 401 forms were reviewed. Six (1.5%) students answered "yes," 351 answered "no," and 44 left the SCT question blank. All six athletes who self-reported "yes" were Black and made up 3.7% of the 162 known Black respondents. This self-report rate for Black/African Americans was well below the expected 7.3% described by the CDC. Response rates were also lower than the comparable cardiac screening questions. CONCLUSIONS:  Self-report SCT status rates are lower than the accepted prevalence in a similar population. Significant inconsistencies in reporting were also determined. CLINICAL RELEVANCE:  This is a rare study to evaluate the self-reported prevalence of SCT in high-school athletes. Below average reporting of SCT and inconsistency in completion of the forms increase the concern for accuracy and effectiveness of current high-school SCT screening methods relying on self-report.

Sufficient Cartilage for Most Talar Articular Defects Can Be Harvested From the Non-Loadbearing Talus: A Cadaveric Analysis.

PURPOSE: To assess the quantity of morselized cartilage that can be harvested from the non-load-bearing portion of the talus for immediate reimplantation. METHODS: Non-load-bearing talar cartilage was harvested from 5 cadaveric specimens using a standard arthroscopic approach. Cartilage was separated from the talus in maximum dorsiflexion at the junction of the talar head and neck, grasped, and morselized into a graft using a cartilage particulator. The volume of reclaimed cartilage was measured, and the extrapolated area of coverage was compared to average osteochondral lesions of the talus previously reported. RESULTS: The total yield of cartilage graft following processing that was obtained from 5 ankle joints ranged from 0.3 mL to 2.1 mL with a mean volume of 1.3 ± 0.7 mL, yielding a theoretical 13.2 ± 7.1 cm2 coverage with a 1-mm monolayer. While the average size of osteochondral lesions of the talus is difficult to estimate, they may range from 0.5 cm2 to 3.7 cm2 according to the literature. CONCLUSIONS: This study validated that it is possible to harvest sufficient amount of cartilage for an autologous morselized cartilage graft via a single-stage, single-site surgical and processing technique to address most talar articular cartilage defects. CLINICAL RELEVANCE: Particulated cartilage autografts have shown promise in surgical management of cartilage defects. A single-site, single-staged procedure that uses a patient's autologous talar cartilage from the same joint has the potential to reduce morbidity associated with multiple surgical sites, multistaged procedure, or nonautologous tissue in ankle surgery.

A Biomechanical Comparison Shows No Difference Between Two Knee Braces used for Medial Collateral Ligament Injuries.

PURPOSE: The purpose of this study was to assess the ability of 2 commonly used knee braces to control knee valgus motion and subsequent strain on the medial collateral ligament (MCL) in a laboratory-controlled environment. METHODS: Twenty healthy individuals (6 male, 14 female; mean age, 23 ± 3 years) with no history of knee injury or brace use performed a jump landing task while wearing either no brace or 1 of 2 braces: the Playmaker and Total Range of Motion . Three-dimensional joint kinematics and kinetics were measured in our biomechanics laboratory. RESULTS: Significantly less knee dynamic valgus angulation was noted when using either brace (-0.51° ± 3.9° and -1.3° ± 3.2°) compared no brace (4.8° ± 3.0°). Dynamic valgus angulation did not differ significantly between the 2 braces tested, which were both not statistically different from baseline alignment. There were significant differences seen in peak knee flexion angle between each brace (77.9° ± 8.8°and 83.1° ± 8.4°), as well as between both braces and no brace (90.6° ± 11.1°). There was no significant difference in knee frontal plane moment or peak vertical ground reaction force loading among all 3 testing conditions. CONCLUSIONS: Compared to no brace, both braces allowed significantly less dynamic valgus angulation of the knee under physiological vertical loads but were not significantly different from one another. CLINICAL RELEVANCE: Knee braces are commonly used to protect the MCL when placed under physiological loads. It is important to know which braces effectively reduce valgus stress to provide the best outcomes.

Youth Baseball Caregiver Understanding of Safe Pitching Guidelines and Player Injury.

BACKGROUND: As more athletes participate in youth baseball, there has been an associated increase in upper extremity injuries. Knowledge of baseball injury prevention guidelines continues to be developed and defined as throwing-related injuries rise. The purpose of this study was to evaluate how knowledgeable youth baseball caregivers were about safe pitching guidelines and secondarily determine pitching practices which may be associated with increased risk of player injury. METHODS: A twenty-two question survey comprised of demographic data, knowledge of overhead throwing guidelines, pitching history, presence of risk factors associated with overhead throwing and pitching habits was distributed to the caregivers of youth baseball pitchers in North Central Florida. RESULTS: Eighty-three percent (81/98) of those polled were unaware of the existence of safe pitching guidelines, regardless of the pitcher's playing experience (p > 0.05). Those who pitched more than six months out of the year were significantly more prone to experience throwing arm pain after a performance (p < 0.05). Fifty-two percent (51/98) of the caregivers recalled their child having throwing arm pain as a direct result of pitching, with twenty-six percent (25/98) of pitchers having to miss either a game or a pitching appearance. Twenty-seven percent (26/98) of all players went on to seek medical evaluation for arm discomfort due to pitching. Pitchers 13 years of age and older were more likely to throw curveballs and miss games because of throwing arm pain (p < 0.05). CONCLUSION: Despite implementation and accessibility of safe pitching guidelines, a large portion of those surveyed were unaware or noncompliant with these established recommendations. Given the results of this study, further measures need to be taken to improve caregivers' understanding of current guidelines to help increase compliance and protect youth pitchers. LEVEL OF EVIDENCE: Cross-sectional survey study, 3b.

The Relationship Between Hip Range of Motion and Pitching Kinematics Related to Increased Elbow Valgus Loads in Collegiate Baseball Pitchers: A Pilot Study.

BACKGROUND: Hip range of motion (ROM) during baseball pitching is associated with trunk rotation and shoulder kinematics, which has shown to influence medial elbow valgus loading and pitching performance. The purpose of this study was to measure the relationship between hip rotational ROM and kinematic variables that influence elbow valgus loads in Division 1 collegiate pitchers. STUDY DESIGN: Descriptive laboratory study. METHODS: Three-dimensional pitching motion (Motion Analysis Corp, Santa Rosa, California) analyses were captured for seven Division 1 baseball pitchers. Six kinematic measurements related to medial elbow valgus loading were calculated while the pitchers threw fastballs. Inclinometer measurements were used to measure hip internal (IR), external (ER) ROM, and total rotational arc at the hip (IR + ER ROM). Correlations were used to evaluate the association between hip IR, ER, and total rotational arc ROM (TRARC) and six kinematic variables. RESULTS: Trunk angular velocity was correlated to trail hip ER and TRARC (p <0.01). Lead hip total arc ROM was associated with maximum shoulder ER (p < 0.01). Lead hip IR was correlated to elbow flexion angle at ball release (p < 0.01). CONCLUSION: Hip ROM during pitching is associated with trunk angular velocity, maximum shoulder ER and elbow flexion angle at ball release. Alterations in hip TRARC appears to influence trunk rotation velocity leading to dependence on increased shoulder ROM and decreased elbow flexion angle at ball release which is associated with diminished pitching performance and excessive medial elbow valgus loads. LEVEL OF EVIDENCE: level 3.

Preseason Upper Extremity Range of Motion and Strength in Relation to In-Season Injuries in NCAA Division I Gymnasts.

BACKGROUND: Gymnastics is a demanding sport that places unique forces on the upper extremity. The repetitive nature of the sport and the high-impact forces involved may predispose the gymnast to overuse injuries. Risk factors for injuries in gymnastics are not well understood. PURPOSE/HYPOTHESIS: The purpose of this study was to ascertain whether preseason upper extremity range of motion (ROM) and strength differ between National Collegiate Athletic Association (NCAA) Division I collegiate gymnasts who sustain an in-season upper extremity injury and those who do not. We hypothesized that gymnasts who sustain an upper extremity injury would demonstrate reduced ROM and strength compared with noninjured gymnasts. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Over 4 seasons, from 2014 to 2018, a total of 15 female NCAA Division I collegiate gymnasts underwent preseason upper extremity ROM (shoulder: flexion, internal and external rotation; elbow: extension; wrist: extension) and strength (shoulder: internal and external rotation, and middle and lower trapezius) testing. Overuse upper extremity injuries were tracked in each subsequent season. Gymnasts were dichotomized into injured and noninjured groups, and a 2 × 2 analysis of variance was used to measure differences in preseason measures between the groups as well as within arms (injured vs noninjured arm for the injured group; dominant vs nondominant arm for the noninjured group). RESULTS: A total of 12 overuse upper extremity injuries (10 shoulders; 2 wrist/forearm) occurred during 31 gymnast-seasons. There were no significant interactions for preseason ROM and strength measurements between groups (injured vs noninjured) or within arms (injured and noninjured arm for the injured group; dominant and nondominant arm for the noninjured group; P = .07). CONCLUSION: Preseason upper extremity ROM and strength were not different between gymnasts who sustained an in-season upper extremity overuse injury and those who did not. It is possible that ROM and strength measures used to screen other overhead athletes may not capture the unique features and requirements of gymnastics. Further, it may be challenging to discern differences in clinical measures of ROM and strength in gymnastics populations owing to the bilateral nature of the sport.

Traumatic Obturator Internus and Quadratus Femoris Injury in a Pediatric Patient: A Case Report.

We present the case of a 11-year-old White female patient with a traumatic quadratus femoris and obturator internus tear after a sprint while at school. She felt immediate pain, swelling, and point tenderness in her posterosuperior thigh with a severely antalgic gait. Magnetic resonance imaging demonstrated a quadratus femoris tear, obturator internus tear, and ischial spine avulsion fracture. Although a less common etiology for acute hip pain in the pediatric population, traumatic injury to the short external rotators should not be excluded. The prognosis is favorable with a full return to previous activities expected using an appropriate rehabilitation program.

Assessment of Safe Cartilage Harvesting Quantity in the Shoulder: A Cadaveric Study.

PURPOSE: To evaluate the volume and yield of morselized cartilage that can be harvested from the shoulder for immediate reimplantation and repair. METHODS: A standard arthroscopic approach was used to harvest non-load-bearing cartilage from 5 cadaveric shoulder specimens. Cartilage was separated from the humerus, grasped, added to the cartilage particulator, and morselized to form a cartilage paste. The volume of reclaimed cartilage was measured and compared with average humeral and glenoid defects. RESULTS: The total yield of cartilage paste following tissue processing that was obtained from the 5 glenohumeral joints ranged from 1.0 mL to 2.4 mL with a mean volume of 1.9 ± 0.5 mL, yielding a theoretical 18.6 cm2 ± 5.2 cm2 of coverage with a 1-mm monolayer. Previously reported mean glenoid defect size ranges from 1.12 cm2 to 2.73 cm2, while the mean humeral defect size ranges from 4.22 cm2 to 6.00 cm2. CONCLUSIONS: This study validated that through a single-stage surgical and processing technique it is possible to obtain a sufficient volume for re-implantable autologous morselized cartilage graft to address most glenohumeral articular cartilage defects. CLINICAL RELEVANCE: Chondrocyte grafts have been shown to be effective in cartilage repair. A single-site, single-staged procedure that uses a patient's autologous shoulder cartilage from the same joint has the potential to reduce morbidity associated with multiple surgical sites, multistaged procedures, or nonautologous tissue in shoulder surgery.

Musculoskeletal pain in lacrosse officials impacts function on the field.

This study determined the prevalence of joint pain among lacrosse officials and described the impact of pain thereof on current officiating duties on the field. Members of the US Lacrosse Officials Development Programme were provided with an electronic survey (a 15.7% response rate resulted in N = 1,441 of completed surveys). Pain sites and severity, previous injuries and current impact of musculoskeletal pain on officiating duties were captured. Pain was present in 18.1-40.1% of respondents at the foot, shoulder, back and knee. A total of 437 officials reported diagnoses of osteoarthritis ([OA]; knee 48.7%, hip 10.5%, spine 10.1%, shoulder 8.0%) and 247 reported OA in more than one joint (p < .05). Officials with OA or previous lacrosse-related injuries reported frequent difficulty with running the entire field distance (p < 0.0001), starting and stopping on the field (p < 0.0001), keeping pace (p < 0.0001), focusing on multiple actions of players at once (p < 0.0001), and enjoyment (all p < 0.0001). Musculoskeletal pain is a common, unrecognized issue in this population that interferes with sport officiating functions. Additional study is needed to objectively determine the impact of OA pain and musculoskeletal injuries on measurable performance outcomes on the field and subjective measures of focus, attention and enjoyment.

Volleyball-related injuries in adolescent female players: an initial report.

OBJECTIVE: To determine the prevalence and risk factors associated with musculoskeletal injuries sustained in female adolescent volleyball players. METHODS: Volleyball players (n = 276; 13-18 years), with any level of volleyball experience, were recruited. Participants completed a study-specific survey about their overall sport(s) involvement, training modalities, volleyball experience (beginner, intermediate, advanced), annual volume of volleyball play, injuries accrued during volleyball, and care received for injury. RESULTS: Annual volume of volleyball play was higher in advanced than beginner/intermediate players (490.0 hr/yr versus 302.3 hr/yr; p < 0.0001). Nearly 67% (188/276) of participants incurred one or more volleyball-related injuries over the last year. The ankle (40.6%), fingers (36.6%), knee (21.2%), and shoulder (15.5%) were the most frequently reported injury. Injury prevalence was higher in advanced than beginner/intermediate players (73.5% versus 62.0%; p = 0.04). Beginner/intermediate players have significantly higher odds ratio (OR) of sustaining an elbow injury than advanced players (OR 5.88; p = 0.025). 21.5% of injured players missed more than one month of play. CONCLUSION: More competitive and experienced adolescent female players may incur injuries due to progressively higher volumes of play as experience and competition level increase. Players who have committed to only playing volleyball participated in greater volumes of volleyball play, which increases the odds of sustaining an injury. CLINICAL RELEVANCE: Understanding injury risk factors may improve clinical management and injury prevention.

Emergency Medical Service Directors' Protocols for Exertional Heat Stroke.

Background and Objectives: Emergency Medical Service (EMS) protocols vary widely and may not implement best practices for exertional heat stroke (EHS). EHS is 100% survivable if best practices are implemented within 30 min. The purpose of this study is to compare EMS protocols to best practices for recognizing and treating EHS. Materials and Methods: Individuals (n = 1350) serving as EMS Medical or Physician Director were invited to complete a survey. The questions related to the EHS protocols for their EMS service. 145 individuals completed the survey (response rate = 10.74%). Chi-Squared Tests of Associations (χ2) with 95% confidence intervals (CI) were calculated. Prevalence ratios (PR) with 95% CI were calculated to determine the prevalence of implementing best practices based on location, working with an athletic trainer, number of EHS cases, and years of directing. All PRs whose 95% CIs excluded 1.00 were considered statistically significant; Chi-Squared values with p values < 0.05 were considered statistically significant. Results: A majority of the respondents reported not using rectal thermometry for the diagnosis of EHS (n = 102, 77.93%) and not using cold water immersion for the treatment of EHS (n = 102, 70.34%). If working with an athletic trainer, EMS is more likely to implement best-practice treatment (i.e., cold-water immersion and cool-first transport-second) (69.6% vs. 36.9%, χ2 = 8.480, p < 0.004, PR = 3.15, 95% CI = 1.38, 7.18). Conclusions: These findings demonstrate a lack of implementation of best-practice standards for EHS by EMS. Working with an athletic trainer appears to increase the likelihood of following best practices. Efforts should be made to improve EMS providers' implementation of best-practice standards for the diagnosis and management of EHS to optimize patient outcomes.

Impact of Body Mass Index on Biomechanics of Recreational Runners.

BACKGROUND: Some recreational runners with obesity successfully train or compete without musculoskeletal injury. Insight into the key kinetic strategies of injury-free heavier runners is necessary to appropriately guide development of safe training programs for this population. OBJECTIVE: To determine key biomechanical strategies of running in individuals with body mass index (BMI) values above and equal to and higher than 30 kg/m2 . DESIGN: This was a case-control study. PARTICIPANTS: Runners with obesity (n =18; 42.7 years, 38.9% women) who were matched by sex, age, footstrike type, footwear characteristics, and running speed with healthy runners (n = 36; 41.7 years, 32.5% women). SETTING: Research laboratory affiliated with an academic medical center. METHODS: A seven-camera optical motion analysis system was used to capture running kinematics and an instrumented treadmill captured kinetic data. MAIN OUTCOMES: Main outcomes were temporal spatial parameters, joint excursions, peak ground reaction forces (GRFs), joint moments, vertical average loading rate (VALR), impulses, and vertical stiffness (Kvert ). RESULTS: Runners with obesity demonstrated 15% less vertical excursion of the center of mass, 18% wider strides, and 3% longer stance times than nonobese runners (P < .05). Normalized peak GRFs and VALRs were higher in the nonobese group. GRF impulse was higher in the group with obesity compared to the nonobese group (means ± SD; 339.6 ± 55.2 Ns vs. 255.0 ± 45.8 Ns; P = .0001). Kvert was higher in the obese group compared to the nonobese group (238.6 ± 50.3 N/cm vs. 183.1 ± 29.4 N/cm; P = .0001). Peak hip moments were higher in runners with obesity in the sagittal and frontal planes (P < .05). CONCLUSION: Runners with obesity dampened impact forces and controlled loading rate more than nonobese runners by increasing lower body stiffness and constraining vertical displacement.

Comparison of wet bulb globe temperature measured on-site vs estimated and the impact on activity modification in high school football.

Exertional heat stroke is one of the top three causes of death in young athletes, particularly high school football players. Despite evidence that these deaths are completely avoidable with appropriate prevention and treatment, deaths still occur at an alarming rate. Wet bulb globe temperature (WBGT) is the preferred method of both the National Athletic Trainers' Association and American College of Sports Medicine to measure heat intensity. Based on the WBGT, activity modification guidelines (AMG) dictate work-to-rest ratios, activity levels and duration, protective equipment worn, and length and frequency of hydration breaks. Due to the cost of handheld WBGT monitors, smartphone apps that estimate WBGT have been considered an alternative. However, it is unclear how WBGT values estimated by these smartphone apps compare to those measured on-site using handheld WBGT monitors. We compared WBGT values estimated by a commercial smartphone app to those taken on-site at the same time and place. Thirteen athletic trainers measured WBGT in the field during high school football practices over a three-month season in North Central Florida. A paired sample t-test indicated the smartphone app significantly overestimated WBGT (29.0°C ± 4.1°C) compared to on-site measures (26.4°C ± 3.2°C) ( r =0.580; t(943)=-23.38, p <0.0001). The smartphone app-estimated values were consistently greater than on-site measures, resulting in potentially unnecessary activity modifications and cancellations if the app was used in place of on-site handheld WBGT monitors. Despite being significantly cheaper than handheld WBGT monitors, at this time, smartphone apps are not ready for widespread use to guide activity modification decisions.

Cadence impact on cardiopulmonary, metabolic and biomechanical loading during downhill running.

BACKGROUND: Distance runners can approach long descents with slow cadence and long steps, or a fast cadence with shorter steps. These approaches differentially affect mechanical loading and energy demand. RESEARCH QUESTION: This study determined the cadence range in which biomechanical loads, caloric unit cost and energy cost were simultaneously minimized during downhill running (DR). METHODS: Trained runners (N = 40; 25.6 ± 7.2 yr; 42.5% female) participated in this experimental study. Participants ran on an instrumented treadmill while wearing a portable gas analyzer during six conditions: control normal level running (LR) at 0 deg inclination (CON-0); control DR -6 deg inclinaton (CON-6); DR at cadences +/-5% and +/-10% different from CON-6. A motion analysis system was used to capture running motion, and an instrumented treadmill captured force data. Cardiopulmonary measures, rating of perceived exertion (RPE), and biomechanical measures (temporal spatial parameters, peak ground reaction forces [GRF], vertical average loading rate [VALR], impulses) were calculated. Caloric unit cost and energy costs were standardized per unit distance. RESULTS: Running at -10% cadence increased HR by 10 bpm compared to CON-6 (p < 0.0001). Vertical excursion of the center of mass and step length were greatest in the cadence -10% and least in the cadence +10% conditions (both p < 0.0001). RPEs were higher among all cadence conditions compared to CON-0 (p < 0.0001). Caloric unit costs were lowest in CON-6, and +/5% cadence conditions compared to the CON-0 and +/-10% conditions (-2.1% to -12.3%, respectively; p < 0.05). Peak GRF and VALR were not different among conditions; vertical impulses were greatest in the -10% condition compared to CON-0, CON-6 and +5% and +10% by 11.3-14.5% (p < .001). SIGNIFICANCE: Changing cadence across level and downhill stretches is likely not necessary and may actually increase perceived effort of running. Running downhill at cadences that range +/-5% of preferred simultaneously minimize caloric unit cost and impulse loading.

Comparison of Autonomic Control of Blood Pressure During Standing and Artificial Gravity Induced via Short-Arm Human Centrifuge.

Autonomic control of blood pressure is essential toward maintenance of cerebral perfusion during standing, failure of which could lead to fainting. Long-term exposure to microgravity deteriorates autonomic control of blood pressure. Consequently, astronauts experience orthostatic intolerance on their return to gravitational environment. Ground-based studies suggest sporadic training in artificial hypergravity can mitigate spaceflight deconditioning. In this regard, short-arm human centrifuge (SAHC), capable of creating artificial hypergravity of different g-loads, provides an auspicious training tool. Here, we compare autonomic control of blood pressure during centrifugation creating 1-g and 2-g at feet with standing in natural gravity. Continuous blood pressure was acquired simultaneously from 13 healthy participants during supine baseline, standing, supine recovery, centrifugation of 1-g, and 2-g, from which heart rate (RR) and systolic blood pressure (SBP) were derived. The autonomic blood pressure regulation was assessed via spectral analysis of RR and SBP, spontaneous baroreflex sensitivity, and non-linear heart rate and blood pressure causality (RR↔SBP). While majority of these blood pressure regulatory indices were significantly different (p < 0.05) during standing and 2-g centrifugation compared to baseline, no change (p > 0.05) was observed in the same indices during 2-g centrifugation compared to standing. The findings of the study highlight the capability of artificial gravity (2-g at feet) created via SAHC toward evoking blood pressure regulatory controls analogous to standing, therefore, a potential utility toward mitigating deleterious effects of microgravity on cardiovascular performance and minimizing post-flight orthostatic intolerance in astronauts.