Link Between the Female Athlete Triad and Gymnastics-Related Injury in Retired Collegiate Gymnasts.

OBJECTIVES: To compare gymnastics-related injuries between former collegiate gymnasts who did and did not report components of the female athlete triad (Triad) during college, including disordered eating or menstrual irregularity. We hypothesized that athletes reporting these 2 triad symptoms would have higher rates of time loss injury and injuries requiring surgery. DESIGN: Retrospective case-control. SETTING: Online survey. PATIENTS: Four hundred seventy former collegiate gymnasts. INTERVENTIONS: Athletes completed online survey distributed through social media. MAIN OUTCOME MEASURES: Participants were grouped based on self-reported menstrual irregularity and disordered eating during college. We compared time loss injuries, injuries resulting in surgery, and injury locations between the groups using χ2 analyses. RESULTS: Seventy percent (n = 328) of participants in this study reported a time loss college injury without surgery, and 42% (n = 199) reported an injury during college that required surgical treatment. A significantly greater proportion of gymnasts with only disordered eating reported a time loss gymnastics injury (without surgery) compared with those who reported only menstrual irregularity during college (79% vs 64%; P =0 .03). A significantly greater proportion of the disordered eating-only group reported a spine injury compared with the menstrual irregularity-only group (P = 0.007) and the group who reported neither menstrual irregularity nor disordered eating (P = 0.006). CONCLUSIONS: College gymnasts who experienced disordered eating were more likely to experience a nonsurgical time loss injury while in college, as well as spine injury compared with those with menstrual irregularity. Sports medicine providers should be aware of the association between injuries and individual components of Triad in gymnasts beyond bone stress injuries.

Comparison of Braces for Treatment of Sever's Disease (Calcaneal Apophysitis) in Barefoot Athletes: A Randomized Clinical Trial.

CONTEXT: Sever's disease (calcaneal apophysitis) is a common condition in youth athletes, including those who participate in barefoot sports. Health care professionals often recommend that young athletes with Sever's disease wear heel cups in their shoes while active, but barefoot athletes are unable to use heel cups. OBJECTIVE: To compare the efficacy of 2 braces used by barefoot athletes with Sever's disease. DESIGN: Randomized controlled clinical trial. SETTING: Pediatric sports medicine clinic. PATIENTS OR OTHER PARTICIPANTS: A total of 43 barefoot athletes aged 7 to 14 years were enrolled, and 32 completed the study (age = 10.3 ± 1.6 years; 29 girls, 3 boys). INTERVENTION(S): Participants were randomized to the Tuli's Cheetah heel cup (n = 16) or Tuli's The X Brace (n = 16) group for use during barefoot sports over the 3-month study period. MAIN OUTCOME MEASURE(S): Participants completed self-reported assessments after diagnosis (baseline) and 1, 2, and 3 months later. The primary outcome was the Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) physical score (3 months postenrollment). The secondary outcomes were OxAFQ-C school or play and emotional scores and the visual analog scale pain score. RESULTS: The percentage of time wearing the brace during barefoot sports was not different between the Cheetah heel cup and The X Brace groups (82% versus 64% of the time in sports; P = .08). At 3 months, we observed no differences for the OxAFQ-C physical (0.79 versus 0.71; P = .80; Hedges g = 0.06), school or play (0.94 versus 1.00; P = .58; Hedges g = 0.26), or emotional (1.00 versus 1.00; P = .85; Hedges g = 0.21) score. Visual analog scale pain scores during activities of daily living and sports were lower (better) at the 2- and 3-month time points than at baseline (P < .001). CONCLUSIONS: Both groups demonstrated improvements in ankle and foot function across time, but no between-groups differences were seen at 3 months. Given these results, barefoot athletes with Sever's disease may consider using either brace with barefoot activity to help improve pain and functional status.

Training volume recommendations and psychosocial outcomes in adolescent athletes.

OBJECTIVES: Researchers have recommended that youth athletes limit their practice volume to the number of hours/week that they are old in years. We examined sport perceptions, burnout, anxiety, and depressive symptoms among youth athletes who did and did not report playing more hours/week of organized sports than their age. METHODS: Uninjured athletes aged 13-18 years old completed questionnaires documenting demographics, sport participation volume, health and injury history, depressive symptoms, anxiety, burnout, and sport perceptions during a pre-participation physical examination. We grouped participants as those who reported more hours/week in organized sports than their age (exceeds age/volume recommendation) vs. those who reported equal/less hours/week in organized sports than their age (meets age/volume recommendation). RESULTS: Of 161 participants, 21% (n = 33) were in the 'exceeds age/volume recommendation' group (age = 15.2 ± 1.3 years; 55% female; 18.7 ± 4.0 hours/week) and 79% (n = 128) were in the 'meets age/volume recommendation' group (age = 15.6 ± 1.2 years; 50% female; 10.2 ± 3.4 hours/week). A higher proportion of the 'exceeds age/volume recommendation' group agreed with the statement 'youth in my sport play too many games before college' than the 'meets age/volume recommendation' group (33% vs. 16%; p = 0.03). After adjusting for the effect of age, sport specialization level, and weight, exceeding age/volume recommendations was associated with the perception that youth in sports play too many games before college (aOR = 3.24; 95% CI = 1.26, 8.29; p = 0.01), while burnout (aOR = 0.99; 95% CI = 0.94, 1.06; p = 0.93), anxiety (aOR = 0.97; 95% CI = 0.84, 1.11; p = 0.65), and depressive symptoms (aOR = 0.90; 95% CI = 0.74, 1.10; p = 0.30) were not significantly related. CONCLUSION: Athletes who spend more hours in sport than their age appear to perceive their competition load during youth sports to be excessive. Coaches and providers should monitor athlete's training hours and perceptions of competition load to offer support and potentially prevent burnout development.

BefA, a microbiota-secreted membrane disrupter, disseminates to the pancreas and increases ß cell mass.

Microbiome dysbiosis is a feature of diabetes, but how microbial products influence insulin production is poorly understood. We report the mechanism of BefA, a microbiome-derived protein that increases proliferation of insulin-producing ß cells during development in gnotobiotic zebrafish and mice. BefA disseminates systemically by multiple anatomic routes to act directly on pancreatic islets. We detail BefA's atomic structure, containing a lipid-binding SYLF domain, and demonstrate that it permeabilizes synthetic liposomes and bacterial membranes. A BefA mutant impaired in membrane disruption fails to expand ß cells, whereas the pore-forming host defense protein, Reg3, stimulates ß cell proliferation. Our work demonstrates that membrane permeabilization by microbiome-derived and host defense proteins is necessary and sufficient for ß cell expansion during pancreas development, potentially connecting microbiome composition with diabetes risk.

Understanding the Cheerleader as an Orthopaedic Patient: An Evidence-Based Review of the Literature.

Cheerleading is a highly popular youth sport in the United States and has been increasingly recognized in recent years for its athleticism and competitive nature. The sport has changed dramatically since its inception. When the sport of cheerleading was first developed, its primary purpose was to entertain crowds and support other athletes. Today, cheerleaders are competitive athletes themselves. Cheerleaders, most of whom are in the pediatric age group, and their parents commonly approach orthopaedic surgeons and sports medicine physicians with questions regarding the risks associated with participation in the sport. Appropriate clinical guidance is especially important for athletes returning to the sport after an injury. However, unlike other popular sports (eg, football, basketball, and volleyball), the intricacies of cheerleading are not well-known to those outside the sport, including many health care providers. Previous studies have reported on the epidemiological patterns of injuries associated with cheerleading and how such aesthetic sports affect the body, finding that fractures and concussions are prevalent and that catastrophic injuries are more common than in most other sports. Here, we provide an evidence-based discussion of 10 pertinent topics regarding cheerleading and its risks to the musculoskeletal system. The purpose of this review is to provide a comprehensive resource for orthopaedic surgeons and sports medicine physicians who care for these athletes.

Intersection of surgical injuries and pain interference among former female collegiate gymnasts.

BACKGROUND: Gymnastics is a competitive sport with numerous health benefits. However, few data exist that examine the lasting effects of injuries in retired gymnasts. OBJECTIVE: To examine pain interference among former collegiate gymnasts. Specifically, we focused on the relationship between gymnastics-related injuries sustained during middle/high school or college that required surgery and former collegiate gymnasts' current pain. We hypothesized that injuries requiring surgery would be associated with increased pain and reduced function after retirement. DESIGN: Cross-sectional survey. SETTING: An online questionnaire was distributed to former female collegiate gymnasts via social media. PARTICIPANTS: A total of 447 former female collegiate gymnasts completed the survey and were grouped according to whether they indicated an injury during their middle/high school or collegiate gymnastics career that required surgery. MAIN OUTCOME MEASURES: The association between current pain interference (Patient-Reported Outcomes Measurement Information System [PROMIS] scale) and injuries in middle/high school or college that resulted in surgery. Pain interference elements included current enjoyment of life, ability to concentrate, participation in day-to-day activities, enjoyment of recreational activities, ability to perform errands, and ability to socialize with others. RESULTS: Those who reported an injury that resulted in surgery (n = 260; mean current age ± SD = 32.8 ± 9.5 years) were younger than those who did not at the time of survey completion (n = 187; current age: 37.0 ± 11.0 years) and reported beginning gymnastics at an earlier age (4.4 ± 2.0 years vs. 5.1 ± 2.5 years; p = .001). There were no statistically significant differences between the groups on any PROMIS questions. In secondary analyses, we found a small but significant association between beginning gymnastics at an earlier age and the odds of requiring surgery (odds ratio = 1.11, 95% confidence interval [CI] = 1.02-1.21; p = .02). CONCLUSIONS: Most retired gymnasts reported a gymnastics-related injury that required surgery. Gymnasts who start gymnastics at a younger age were more likely to sustain an injury that required surgery, but surgery was not associated with higher levels of pain interference.

The dCache Chemoreceptor TlpA of Helicobacter pylori Binds Multiple Attractant and Antagonistic Ligands via Distinct Sites.

The Helicobacter pylori chemoreceptor TlpA plays a role in dampening host inflammation during chronic stomach colonization. TlpA has a periplasmic dCache_1 domain, a structure that is capable of sensing many ligands; however, the only characterized TlpA signals are arginine, bicarbonate, and acid. To increase our understanding of TlpA's sensing profile, we screened for diverse TlpA ligands using ligand binding arrays. TlpA bound seven ligands with affinities in the low- to middle-micromolar ranges. Three of these ligands, arginine, fumarate, and cysteine, were TlpA-dependent chemoattractants, while the others elicited no response. Molecular docking experiments, site-directed point mutants, and competition surface plasmon resonance binding assays suggested that TlpA binds ligands via both the membrane-distal and -proximal dCache_1 binding pockets. Surprisingly, one of the nonactive ligands, glucosamine, acted as a chemotaxis antagonist, preventing the chemotaxis response to chemoattractant ligands, and acted to block the binding of ligands irrespective of whether they bound the membrane-distal or -proximal dCache_1 subdomains. In total, these results suggest that TlpA senses multiple attractant ligands as well as antagonist ones, an emerging theme in chemotaxis systems. IMPORTANCE Numerous chemotactic bacterial pathogens depend on the ability to sense a diverse array of signals through chemoreceptors to achieve successful colonization and virulence within their host. The signals sensed by chemoreceptors, however, are not always fully understood. This is the case for TlpA, a dCache_1 chemoreceptor of H. pylori that enables the bacterium to induce less inflammation during chronic infections. H. pylori causes a significant global disease burden, which is driven by the development of gastric inflammation. Accordingly, it is essential to understand the processes by which H. pylori modulates host inflammation. This work uncovers the signals that TlpA can sense and highlights the underappreciated ability to regulate chemotactic responses by antagonistic chemoreceptor ligands, which is an emerging theme among other chemotactic systems.

Host-emitted amino acid cues regulate bacterial chemokinesis to enhance colonization.

Animal microbiomes are assembled predominantly from environmental microbes, yet the mechanisms by which individual symbionts regulate their transmission into hosts remain underexplored. By tracking the experimental evolution of Aeromonas veronii in gnotobiotic zebrafish, we identify bacterial traits promoting host colonization. Multiple independently evolved isolates with increased immigration harbored mutations in a gene we named sensor of proline diguanylate cyclase enzyme (SpdE) based on structural, biochemical, and phenotypic evidence that SpdE encodes an amino-acid-sensing diguanylate cyclase. SpdE detects free proline and to a lesser extent valine and isoleucine, resulting in reduced production of intracellular c-di-GMP, a second messenger controlling bacterial motility. Indeed, SpdE binding to amino acids increased bacterial motility and host colonization. Hosts serve as sources of SpdE-detected amino acids, with levels varying based on microbial colonization status. Our work demonstrates that bacteria use chemically regulated motility, or chemokinesis, to sense host-emitted cues that trigger active immigration into hosts.

Single season re-injury risk after concussion and lower extremity injury among male, collision sport, high school athletes.

OBJECTIVES: Research suggests that a recent concussion increases subsequent lower extremity injury risk; however, data in high school athletes is limited. This study evaluates the association between concussion and subsequent injury risk among male, collision sport, high school athletes over a single season. DESIGN: Retrospective cohort study. METHODS: Data were obtained from 2005/06-2014/15 in the High School Reporting Information Online database. A two stage, multi-method matching process was used to identify athletes who suffered multiple injuries over a single athletic season. Demographics and injury characteristics were compared with Chi square and Student's t-tests. Multiple Cox Proportional Hazards regression analysis was used to test whether index injury type was associated with hazard of subsequent injury following return to play from index injury. RESULTS: Overall 1364 HS athletes sustained 2 injuries over a single athletic season (subsequent injury within 45 days of the index injury). Index injuries included 686 (50.2%) lower extremity injuries, 417 (30.6%) upper extremity injuries, and 261 (19.1%) concussions. Hazard of subsequent concussion was increased in the index concussion group relative to the index lower extremity injury group [hazard ratio (HR): 1.60, 95% CI: 1.15-2.23, p = 0.0052]. Hazard of a subsequent lower extremity injury was not significantly different for the index lower extremity injury group relative to the index concussion group [HR: 1.27, 95% CI: 0.98-1.65, p = 0.0728]. CONCLUSIONS: History of recent concussion or recent lower extremity injury are both risk factors for subsequent lower extremity injury in male, collision sport, high school athletes.

Acute Knee Injuries in Children and Adolescents: A Review.

Importance: Knee injuries in children and adolescents are exceedingly common. When an active youth presents complaining of knee pain, the treating pediatrician should be comfortable with forming a working differential diagnosis and should be able to manage many such injuries or recognize when it is necessary to make an appropriate referral. Observations: Knee injuries typically present after acute trauma. Appreciating the likely etiologies pertaining to a particular case is best achieved with a thorough history and physical examination. This review discusses the etiologies of acute injuries including fractures that are unique to skeletally immature individuals, patellar dislocations, ligamentous injuries, and meniscal tears. Imaging findings and management of these conditions are also reviewed. Conclusions and Relevance: This review summarizes the more common acute knee injuries seen in active children and adolescents. Given how frequently such conditions present, this overview of diagnosis and management will provide a useful resource for the nonspecialist.

Presence and Perceptions of Menstrual Dysfunction and Associated Quality of Life Measures Among High School Female Athletes.

CONTEXT: Adolescent female athletes are at risk for menstrual dysfunction in the setting of exercise and low energy availability. Education regarding menstrual dysfunction and its associated consequences is important to promote athlete wellbeing. OBJECTIVE: The primary aim was to determine the prevalence and characteristics of female athletes who believed that losing their period was a normal response to high training demands. The secondary aim was to explore the relationship between menstrual dysfunction and patient-reported quality of life measures. DESIGN: Cross-sectional study. SETTING: Preparticipation evaluations for a local high school district. PATIENTS OR OTHER PARTICIPANTS: Female athletes, 13-18 years old (n = 90). MAIN OUTCOME MEASURE(S): Health history, family affluence, and patient-reported quality of life measures. RESULTS: Forty four percent (n = 40) of 90 adolescent athletes answered that losing their period was a normal response to a high level of training, and this group had a lower body mass index, were less likely to report being worried about their current weight, and had a higher family affluence level than those who answered that losing their period was not a normal response to training. The overall prevalence of menstrual dysfunction was 28%. After adjusting for age and body mass index, we found that menstrual dysfunction was significantly associated with higher levels of anxiety, fatigue, and pain interference. CONCLUSIONS: Nearly half of our sample of adolescent female athletes perceived losing their period was a normal response to high training demands. Females with menstrual dysfunction reported higher levels of anxiety, fatigue, and pain interference than those without menstrual dysfunction. Understanding adolescent perceptions of menstrual dysfunction and the characteristics of those with menstrual dysfunction can guide the development of future educational interventions aimed at athletes at risk for the female athlete triad.

Comparison of pediatric sports fracture outcomes based on provider type.

Objective: Pediatric primary care sports medicine physicians and pediatric sports medicine orthopedic surgeons, in conjunction with physician assistants (PAs), often manage patients with fractures. We sought to determine if pediatric patients with fractures seen by primary care sports medicine physicians had similar outcomes and satisfaction as those seen by orthopedic surgeons. Methods: We performed a retrospective chart review of four to 18-year-old patients who were treated by a sports medicine provider (primary care or orthopedic surgeon/PA) for a fracture of the radius, ulna, tibia, or fibula. Patients or their parents completed a patient satisfaction survey (Short Assessment of Patient Satisfaction [SAPS]) and an injury location-specific patient-reported functional outcome tool: the Foot and Ankle Ability Measure (FAAM) or the Disabilities of the Arm, Shoulder, and Hand (DASH) Scale. Results: Fifty-seven (70%) of the 82 patients were treated by pediatric primary care sports medicine physicians and 25 (30%) were treated by a pediatric sports medicine orthopedic surgeon or surgical PA. The median time from injury to clinically confirmed healing was similar between the two groups (47 vs 60.5 days; p = 0.54), as was the patient satisfaction (SAPS median score = 26 [range = 19-28] vs 24 [range = 9-28]; p = 0.12). Patient-reported outcomes did not differ significantly between groups for the functional outcome tools. Conclusions: Patients seen by pediatric primary care sports medicine physicians and sports medicine orthopedic surgeons have similar patient-reported fracture outcomes and similar satisfaction with care. Pediatric patients with fractures will likely have favorable outcomes when cared for by either of these subspecialty providers.

Health outcomes among former female collegiate gymnasts: the influence of sport specialization, concussion, and disordered eating.

Objective: Gymnastics is a popular sport with high injury rates, especially at the collegiate level. There is limited evidence, however, regarding the risks of early specialization in this sport, the rate of concussions in gymnasts, and the long-term effects of disordered eating in gymnasts. We sought to describe health-related outcomes of former collegiate gymnasts and the association with early sport specialization, concussion history, and disordered eating.Methods: We distributed an online survey through social media outlets. A total of 473 former female collegiate gymnasts completed the survey and were grouped according to early (<14 years) specialization, presence or absence of concussion history, and history of disordered eating. We determined the number of participants who had time-loss injuries, injuries requiring surgery, and injuries resulting in retirement. We also evaluated menstrual history, reasons for sport retirement, functional outcome measures, and mental health.Results: The median age of gymnastics specialization was 8 years [interquartile range = 6-11 years]. The proportion of injuries sustained during college did not significantly differ by specialization age. A significantly greater proportion of early specializers required surgery for college sports-related injuries (60% vs. 44%; p = 0.02). Forty-two percent of the respondents reported concussion history, and a greater proportion of those with concussion history reported seeking mental health treatment during college (32% vs. 23%; p = 0.03), and anxiety disorder diagnosis (16% vs. 9%; p = 0.01). Disordered eating history was reported by 34% of the respondents, and this group had a higher proportion of time-loss injury (78% vs 65%; p = 0.004), and osteoporosis (4% vs 0%; p = 0.003) during college, and worse current pain (11.5 vs 10.2; p = 0.007) and physical function (12.2 vs 11.0; p = 0.01) than those without disordered eating.Conclusion: Athletes and clinicians should be aware of the long-term effects of early specialization, concussions, and disordered eating in gymnastics as these issues are common in female collegiate gymnasts.

Overuse Knee Pain in the Pediatric and Adolescent Athlete.

Overuse knee pain is common in young athletes. There are many potential overuse injuries which present with insidious onset of pain that can challenge sports medicine providers, including Osgood-Schlatter's disease, patellofemoral syndrome, osteochondritis dissecans, and stress fractures. The differential diagnosis of insidious onset knee pain also includes malignancies, infections, and rheumatologic issues. A thorough history and physical examination can guide the treating provider in making a diagnosis and appropriate treatment plan. Although not always necessary, imaging is often helpful in overuse knee pain, and laboratory workup may be necessary. Conservative treatment is often the first recommendation in the management of overuse knee pain in young athletes, and this may include activity modification, ice, anti-inflammatory medications, bracing, and physical therapy. This review summarizes common overuse knee injuries seen in pediatric and adolescent athletes.

Symptom profiles and postural control after concussion in female artistic athletes.

OBJECTIVES: The purpose of our investigation was to compare post-concussion symptom profiles and postural control measures among female youth artistic athletes (gymnasts and cheerleaders) relative to female ball sport athletes (volleyball or basketball). METHODS/FINDINGS: We compared 27 artistic athletes (median age = 15.0 years; evaluated median = 13 days post-injury) and 49 ball sport athletes (median age = 15.3 years; evaluated median = 10 days post-injury) within 21 days of sustaining a concussion on measures of symptom profiles and postural control (Balance Error Scoring System [BESS]), tandem gait, and Romberg tests. After adjusting for the independent effect of time from injury-evaluation, concussion history, and pre-morbid migraine history, we observed that artistic athletes performed the BESS tandem stance foam condition with fewer errors than ball sport athletes (ß = -2.4; 95% CI = -4.7, -0.2; p = .03). Artistic athletes demonstrated a higher, yet not statistically significant, headache severity than ball sport athletes (median = 4.5 vs 4.0, p = .07). CONCLUSIONS: Overall, artistic athletes had similar symptom profiles to ball sport athletes. Postural control measures, other than the BESS tandem stance foam condition, were not significantly different from ball sport athletes. This suggests that although their sports may require higher levels of balance, artistic athletes' performance on post-concussion balance tests may be similar to athletes of other disciplines.

Peak sagittal plane spine kinematics in female gymnasts with and without a history of low back pain.

BACKGROUND: Female gymnasts have a greater prevalence of back pain compared to other female athletes. There is little evidence that female artistic gymnasts with and without back pain demonstrate different movement patterns during gymnastics skills. The purpose of this study was to determine if there were differences in back movements during back walkovers and back handsprings among female artistic gymnasts. METHODS: Female artistic gymnasts (8-18 years old) with and without back pain wore inertial sensors on their torso, arms, and legs while performing back walkovers (N = 14) and back handsprings (N = 15) on the floor and balance beam at their training gymnastics facilities. FINDINGS: Gymnasts with back pain had similar spine peak extension, peak flexion, and range of motion during back walkovers and back handsprings compared to gymnasts without back pain. Additionally, no differences in sagittal plane spine kinematics were found between the groups at any specific time point during either the back walkover or back handspring skills. However, a large portion of the data collected was excluded during quality assurance, thus our final sample sizes are small. INTERPRETATION: These findings suggest that gymnasts with back pain have similar sagittal plane movements to those without back pain. The relationship between back pain and gymnastics training load/intensity is currently unclear. We suggest future studies to investigate common artistic gymnastics skills and back pain prevalence with more participants, full-body motion analysis with kinetic measurement capabilities, and longitudinally for those demonstrating back pain.

Sleep Quality and Quality of Life Among Healthy High School Athletes.

We examined the association between sleep quality and quality of life (QOL) among uninjured high school athletes. Participants completed the Pittsburgh Sleep Quality Index (PSQI) and the Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Profile 25 questionnaire. One hundred ten athletes reported poor sleep quality (mean PSQI: 6.6 ± 2.0; mean age: 15.3 ± 1.1; 62% female); 162 athletes reported good sleep quality (mean PSQI: 2.3 ± 1.3; mean age: 15.1 ± 1.7; 33% female). After adjusting for sex and age, worse sleep quality was associated with higher physical function/mobility (ß = 0.034; 95% confidence interval [CI] = 0.007-0.060; P = .01), anxiety (ß= 0.391; 95% CI = 0.263-0.520; P < .001), depressive symptom (ß = 0.456; 95% CI = 0.346-0.565; P < .001), fatigue (ß = 0.537; 95% CI = 0.438-0.636; P < .001), pain interference (ß = 0.247; 95% CI = 0.119-0.375; P < .001), and pain intensity (ß = 0.103; 95% CI = 0.029-0.177; P = .006) ratings. Poor self-reported sleep quality among adolescent athletes was associated with worse QOL ratings. Clinicians should consider assessing sleep hygiene to provide guidance on issues pertaining to reduced QOL.

Association Between Flexibility and Low Back Pain in Female Adolescent Gymnasts.

OBJECTIVE: To determine the relationship between low back pain (LBP), flexibility, and individual demographic characteristics in competitive adolescent female gymnasts. DESIGN: Cross-sectional observational study. SETTING: Gymnastics facilities in Colorado. PARTICIPANTS: Six- to 18-year-old gymnasts who participate in the USA Gymnastics Women's Artistic Junior Olympic Program levels 3 to 10. INDEPENDENT VARIABLES: Demographic data included height, weight, menstrual status, gymnastics level, and participation hours per week. Flexibility measurements were obtained on the gymnasts. Gymnasts also completed a questionnaire documenting LBP in the past 12 months. Univariable (t test and χ) analyses were used to assess between-group differences; multivariable logistic regression model was used to assess the association between LBP, flexibility, and demographics/injury history. MAIN OUTCOME MEASURES: Low back pain within the past 12 months. RESULTS: Thirty (45%) of 67 gymnasts reported LBP within the past year. Those who reported LBP were older (11.7 vs 13.7 years, P = 0.005), heavier (37.5 vs 43.4 kg, P = 0.049), and participated in gymnastics more often (19.1 vs 22.4 h/wk, P = 0.017). A greater proportion of gymnasts with LBP had experienced menarche compared with those without LBP (47% vs 16%; P = 0.008). On multivariable analysis, gymnasts with LBP were less likely to have left Iliotibial (IT) band tightness compared with those without LBP [adjusted odds ratio (aOR) = 0.186; 95% confidence interval (CI), 0.04-0.82] and more likely to have experienced menarche (aOR = 8.0; 95% CI, 1.2-50.9). CONCLUSIONS: Low back pain is more common in gymnasts who experienced menarche, whereas limited joint flexibility does not seem to be associated with LBP in this population.

Agent-Based Modeling Demonstrates How Local Chemotactic Behavior Can Shape Biofilm Architecture.

Bacteria are often found living in aggregated multicellular communities known as biofilms. Biofilms are three-dimensional structures that confer distinct physical and biological properties to the collective of cells living within them. We used agent-based modeling to explore whether local cellular interactions were sufficient to give rise to global structural features of biofilms. Specifically, we asked whether chemorepulsion from a self-produced quorum-sensing molecule, autoinducer-2 (AI-2), was sufficient to recapitulate biofilm growth and cellular organization observed for biofilms of Helicobacter pylori, a common bacterial resident of human stomachs. To carry out this modeling, we modified an existing platform, Individual-based Dynamics of Microbial Communities Simulator (iDynoMiCS), to incorporate three-dimensional chemotaxis, planktonic cells that could join or leave the biofilm structure, and cellular production of AI-2. We simulated biofilm growth of previously characterized H. pylori strains with various AI-2 production and sensing capacities. Using biologically plausible parameters, we were able to recapitulate both the variation in biofilm mass and cellular distributions observed with these strains. Specifically, the strains that were competent to chemotax away from AI-2 produced smaller and more heterogeneously spaced biofilms, whereas the AI-2 chemotaxis-defective strains produced larger and more homogeneously spaced biofilms. The model also provided new insights into the cellular demographics contributing to the biofilm patterning of each strain. Our analysis supports the idea that cellular interactions at small spatial and temporal scales are sufficient to give rise to larger-scale emergent properties of biofilms.IMPORTANCE Most bacteria exist in aggregated, three-dimensional structures called biofilms. Although biofilms play important ecological roles in natural and engineered settings, they can also pose societal problems, for example, when they grow in plumbing systems or on medical implants. Understanding the processes that promote the growth and disassembly of biofilms could lead to better strategies to manage these structures. We had previously shown that Helicobacter pylori bacteria are repulsed by high concentrations of a self-produced molecule, AI-2, and that H. pylori mutants deficient in AI-2 sensing form larger and more homogeneously spaced biofilms. Here, we used computer simulations of biofilm formation to show that local H. pylori behavior of repulsion from high AI-2 could explain the overall architecture of H. pylori biofilms. Our findings demonstrate that it is possible to change global biofilm organization by manipulating local cell behaviors, which suggests that simple strategies targeting cells at local scales could be useful for controlling biofilms in industrial and medical settings.

Low back pain in female adolescent gymnasts and functional pain scales.

OBJECTIVES: To determine the scores of gymnasts with low back pain (LBP) on two functional pain scales: the Micheli Functional Scale (MFS) and the Oswestry Low Back Pain Disability Questionnaire (ODQ). DESIGN: Cross-sectional study. SETTING: Gymnastics facilities. PARTICIPANTS: Female gymnasts aged 7-18 years. MAIN OUTCOME MEASURES: We grouped gymnasts into those having pain affecting gymnastics and those with pain not affecting gymnastics and then compared MFS and ODQ scores for various activities. RESULTS: Eleven of the 29 participants (38%) endorsed LBP during gymnastics and 18 had LBP not affecting gymnastics. There were no demographic differences between the two groups. A significantly greater proportion of gymnasts who had pain during gymnastics reported pain with jumping (N = 11, 100% vs N = 8, 44%, p = 0.003) and lifting weights (N = 4, 36% vs N = 0, p = 0.016) compared to those not having pain during gymnastics. There were no significant differences between the two groups for pain with spine flexion or extension or for hip flexibility. CONCLUSIONS: Although gymnastics requires extreme flexion and extension of the spine, gymnasts whose pain affects them during gymnastics do not endorse more pain with these movements. Gymnasts with LBP during gymnastics are more likely to have pain with jumping and with lifting weights.