Effect of nitrate supplementation on skeletal muscle motor unit activity during isometric blood flow restriction exercise.

BACKGROUND: Nitrate (NO3-) supplementation has been reported to lower motor unit (MU) firing rate (MUFR) during dynamic resistance exercise; however, its impact on MU activity during isometric and ischemic exercise is unknown. PURPOSE: To assess the effect of NO3- supplementation on knee extensor MU activities during brief isometric contractions and a 3 min sustained contraction with blood flow restriction (BFR). METHODS: Sixteen healthy active young adults (six females) completed two trials in a randomized, double-blind, crossover design. Trials were preceded by 5 days of either NO3- (NIT) or placebo (PLA) supplementation. Intramuscular electromyography was used to determine the M. vastus lateralis MU potential (MUP) size, MUFR and near fibre (NF) jiggle (a measure of neuromuscular stability) during brief (20 s) isometric contractions at 25% maximal strength and throughout a 3 min sustained BFR isometric contraction. RESULTS: Plasma nitrite (NO2-) concentration was elevated after NIT compared to PLA (475 ± 93 vs. 198 ± 46 nmol L-1, p < 0.001). While changes in MUP area, NF jiggle and MUFR were similar between NIT and PLA trials (all p > 0.05), MUP duration was shorter with NIT compared to PLA during brief isometric contractions and the sustained ischemic contraction (p < 0.01). In addition, mean MUP duration, MUP area and NF jiggle increased, and MUFR decreased over the 3 min sustained BFR isometric contraction for both conditions (all p < 0.05). CONCLUSIONS: These findings provide insight into the effect of NO3- supplementation on MUP properties and reveal faster MUP duration after short-term NO3- supplementation which may have positive implications for skeletal muscle contractile performance.

Physical therapy of patients undergoing first-time lumbar discectomy: a survey of current UK practice.

BACKGROUND: The type, timing, and extent of provision of rehabilitation for lumbar discectomy patients in the UK are currently unknown. The aim of this study was to determine the provision and type of rehabilitation for patients undergoing lumbar discectomy in UK neurosurgical centers. METHOD: Physical therapists involved in treating lumbar discectomy patients in UK neurosurgery centers were invited to complete an online survey that asked about the type, timing (preop, postop), and rehabilitation content for patients undergoing lumbar discectomy. RESULTS: Seventeen UK neurosurgery centers completed the survey. Twelve (36%) responded from the 33 centers targeted as well as an additional five private centers. All participating centers provided a rehabilitation service for lumbar discectomy patients. Rehabilitation was provided preoperatively in n = 6 (35%) centers, postoperatively as an inpatient in all centers, and postoperatively as an outpatient in n = 14 (82%) centers. Factors that influenced the decision to provide rehabilitation included both external and internal or patient-related factors. Preoperative rehabilitation focused mainly on education, whilst postoperative outpatient rehabilitation focused more on exercises. Rehabilitation consistently included mobility, functional task training, and exercise prescription. CONCLUSIONS: Whilst all neurosurgical centers in this survey provided some form of rehabilitation for patients undergoing LD surgery, the approach remains inconsistent. Rehabilitation was delivered most frequently postoperatively, with one in three centers providing it preoperatively. Rehabilitation content also varied depending on when it was provided. Further research is needed to determine the optimum timing, contents, and target of rehabilitation for patients undergoing LD surgery.

REPORT-PFP: a consensus from the International Patellofemoral Research Network to improve REPORTing of quantitative PatelloFemoral Pain studies.

Patellofemoral pain is a common and often debilitating musculoskeletal condition. Clinical translation and evidence synthesis of patellofemoral pain research are compromised by heterogenous and often inadequately reported study details. This consensus statement and associated checklist provides standards for REPORTing of quantitative PatelloFemoral Pain (REPORT-PFP) research to enhance clinical translation and evidence synthesis, and support clinician engagement with research and data collection. A three-stage Delphi process was initiated at the 2015 International Patellofemoral Research Network (iPFRN) retreat. An initial e-Delphi activity (n=24) generated topics and items, which were refined at the 2017 iPFRN retreat, and voted on prior to and following the 2019 iPFRN retreat (n=51 current and past retreat participants). Voting criteria included 'strongly recommended' (essential), 'recommended' (encouraged) and uncertain/unsure. An item was included in the checklist if ≥70% respondents voted 'recommended'. Items receiving ≥70% votes for 'strongly recommended' were labelled as such. The final REPORT-PFP checklist includes 31 items (11 strongly recommended, 20 recommended), covering (i) demographics (n=2,4); (ii) baseline symptoms and previous treatments (n=3,7); (iii) outcome measures (2,4); (iv) outcomes measure description (n=1,2); (v) clinical trial methodology (0,3) and (vi) reporting study results (n=3,0). The REPORT-PFP checklist is ready to be used by researchers and clinicians. Strong stakeholder engagement from clinical academics during development means consistent application by the international patellofemoral pain research community is likely. Checklist adherence will improve research accessibility for clinicians and enhance future evidence synthesis.

Measurement of synovial tissue volume in knee osteoarthritis using a semiautomated MRI-based quantitative approach.

PURPOSE: Synovitis is common in knee osteoarthritis and is associated with both knee pain and progression of disease. Semiautomated methods have been developed for quantitative assessment of structure in knee osteoarthritis. Our aims were to apply a novel semiautomated assessment method using 3D active appearance modeling for the quantification of synovial tissue volume (STV) and to compare its performance with conventional manual segmentation. METHODS: Thirty-two sagittal T1 -weighted fat-suppressed contrast-enhanced MRIs were assessed for STV by a single observer using 1) manual segmentation and 2) a semiautomated approach. We compared the STV analysis using the semiautomated and manual segmentation methods, including the time taken to complete the assessments. We also examined the reliability of STV assessment using the semiautomated method in a subset of 12 patients who had participated in a clinical trial of vitamin D therapy in knee osteoarthritis. RESULTS: There was no significant difference in STV using the semiautomated quantitative method compared to manual segmentation, mean difference = 207.2 mm3 (95% confidence interval -895.2 to 1309.7). The semiautomated method was significantly quicker than manual segmentation (18 vs. 71 min). For the semiautomated method, intraobserver agreement was excellent (intraclass correlation coefficient (3,1) = 0.99) and interobserver agreement was very good (intraclass correlation coefficient (3,1) = 0.83). CONCLUSION: We describe the application of a semiautomated method that is accurate, reliable, and quicker than manual segmentation for assessment of STV. The method may help increase efficiency of image assessment in large imaging studies and may also assist investigation of treatment efficacy in knee osteoarthritis.

2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017.

Patellofemoral pain affects a large proportion of the population, from adolescents to older adults, and carries a substantial personal and societal burden. An international group of scientists and clinicians meets biennially at the International Patellofemoral Research Retreat to share research findings related to patellofemoral pain conditions and develop consensus statements using best practice methods. This consensus statement, from the 5th International Patellofemoral Research Retreat held in Australia in July 2017, focuses on exercise therapy and physical interventions (eg, orthoses, taping and manual therapy) for patellofemoral pain. Literature searches were conducted to identify new systematic reviews and randomised controlled trials (RCTs) published since the 2016 Consensus Statement. The methodological quality of included systematic reviews and RCTs was graded using AMSTAR and PEDro, respectively. Evidence-based statements were developed from included papers and presented to a panel of 41 patellofemoral pain experts for consensus discussion and voting. Recommendations from the expert panel support the use of exercise therapy (especially the combination of hip-focused and knee-focused exercises), combined interventions and foot orthoses to improve pain and/or function in people with patellofemoral pain. The use of patellofemoral, knee or lumbar mobilisations in isolation, or electrophysical agents, is not recommended. There is uncertainty regarding the use of patellar taping/bracing, acupuncture/dry needling, manual soft tissue techniques, blood flow restriction training and gait retraining in patients with patellofemoral pain. In 2017, we launched the International Patellofemoral Research Network (www.ipfrn.org) to consolidate and grow our patellofemoral research community, facilitate collaboration and disseminate patellofemoral pain knowledge to clinicians and the general public. The 6th International Patellofemoral Research Retreat will be held in Milwaukee, Wisconsin, USA, in October 2019.

Memory and adaptive behavior in population dynamics: anti-predator behavior as a case study.

Memory allows organisms to forecast the future on the basis of experience, and thus, in some form, is important for the development of flexible adaptive behavior by animal communities. To model memory, we use the concept of hysteresis, which mathematically is described by the Preisach operator. As a case study, we consider anti-predator adaptation in the classic Lotka-Volterra predator-prey model. Despite its simplicity, the model allows us to naturally incorporate essential features of an adaptive system and memory. Our analysis and simulations show that a system with memory can have a continuum of equilibrium states with non-trivial stability properties. The main factor that determines the actual equilibrium state to which a trajectory converges is the maximal number achieved by the population of predator along this trajectory.

With a biomechanical treatment in knee osteoarthritis, less knee pain did not correlate with synovitis reduction.

BACKGROUND: Braces are used to treat pain in patellofemoral joint osteoarthritis (PFJOA). In a trial, we previously reported pain improvement after 6-weeks brace use. The pain reduction did not correlate with changes in Magnetic Resonance Imaging (MRI) assessed Bone Marrow Lesion volume or static synovial volume. Studies show that changes in the synovium on dynamic contrast enhanced (DCE) MRI are more closely associated with symptom change than static synovial volume changes. We hypothesised change in synovitis assessed using dynamic imaging could explain the reduction in pain. METHOD: One hundred twenty-six men and women aged 40-70 years with painful radiographically confirmed PFJOA were randomised to either brace wearing or no brace for 6-weeks. Pain assessment and DCE-MRI were performed at baseline and 6 weeks. DCE data was analysed using Tofts's equation. Pain measures included a VAS of pain on nominated aggravating activity (VASNA), and the KOOS pain subscale. Paired t-tests were used to determine within person change in outcome measures and Spearman's correlation coefficients were used to determine the correlation between change in pain and change in the DCE parameters. RESULTS: Mean age of subjects was 55.5 years (SD = 7.5) and 57% were female. There was clear pain improvement in the brace users compared to controls (VASNA - 16.87 mm, p = <0.001). There was no significant change to the dynamic synovitis parameters among brace users nor was pain change correlated with change in dynamic synovitis parameters. CONCLUSION: The reduction in knee pain following brace wearing in patients with PFJOA is not explained by changes in synovitis. TRIAL REGISTRATION: Trial registration number UK. ISRCTN50380458 /Registered 21.5.2010.

A prospective, observational cohort study of patients presenting to an emergency department with acute shoulder trauma: the Manchester emergency shoulder (MESH) project.

BACKGROUND: Fracture and dislocation of the shoulder are usually identifiable through the use of plain radiographs in an emergency department. However, other significant soft tissue injuries can be missed at initial presentation. This study used contrast enhanced magnetic resonance arthrography (MRA) to determine the pattern of underlying soft tissue injuries in patients with traumatic shoulder injury, loss of active range of motion, and normal plain radiography. METHODS: A prospective, observational cohort study. Twenty-six patients with acute shoulder trauma and no identifiable radiograph abnormality were screened for inclusion. Those unable to actively abduction their affected arm to 90° at initial presentation and at two week's clinical review were consented for MRA. RESULTS: Twenty patients (Mean age 44 years, 4 females) proceeded to MRA. One patient had no abnormality, three patients showed minimal pathology. Four patients had an isolated bony/labral injury. Eight patients had injuries isolated to the rotator cuff. Four patients had a combination of bony and rotator cuff injury. Four patients were referred to a specialist shoulder surgeon following MRA and underwent surgery. CONCLUSIONS: Significant soft tissue pathology was common in our cohort of patients with acute shoulder trauma, despite the reassurance of normal plain radiography. These patients were unable to actively abduct to 90° both at initial presentation and at two week's post injury review. A more aggressive management and diagnostic strategy may identify those in need of early operative intervention and provide robust rehabilitation programmes.

Recommendations for the conduct of efficacy trials of treatment devices for osteoarthritis: a report from a working group of the Arthritis Research UK Osteoarthritis and Crystal Diseases Clinical Studies Group.

OBJECTIVE: There are unique challenges to designing and carrying out high-quality trials testing therapeutic devices in OA and other rheumatic diseases. Such challenges include determining the mechanisms of action of the device and the appropriate sham. Design of device trials is more challenging than that of placebo-controlled drug trials. Our aim was to develop recommendations for designing device trials. METHODS: An Arthritis Research UK study group comprised of 30 rheumatologists, physiotherapists, podiatrists, engineers, orthopaedists, trialists and patients, including many who have carried out device trials, met and (using a Delphi-styled approach) came to consensus on recommendations for device trials. RESULTS: Challenges unique to device trials include defining the mechanism of action of the device and, therefore, the appropriate sham that provides a placebo effect without duplicating the action of the active device. Should there be no clear-cut mechanism of action, a three-arm trial including a no-treatment arm and one with presumed sham action was recommended. For individualized devices, generalizable indications and standardization of the devices are needed so that treatments can be generalized. CONCLUSION: A consensus set of recommendations for device trials was developed, providing a basis for improved trial design, and hopefully improvement in the number of effective therapeutic devices for rheumatic diseases.

Patellofemoral pain.

Patellofemoral pain refers to pain behind or around the patella (also known as patellofemoral pain syndrome, anterior knee pain, runner's knee, and, formerly, chondromalacia patellae). Patellofemoral pain is common, accounting for 11-17% of all knee pain presentations to general practice.(1 2) While it typically occurs in physically active people aged <40 years, it also affects people of all activity levels and ages.(1 2) Patellofemoral pain can be diagnosed in the clinic, and evidence based treatments can reduce pain and improve function, allowing patients to maintain a physically active lifestyle.

A randomised trial of a brace for patellofemoral osteoarthritis targeting knee pain and bone marrow lesions.

OBJECTIVE: Braces used to treat (PF) osteoarthritis (OA) may reduce contact stress across the PF joint. We hypothesised that in PF OA, braces would decrease knee pain and shrink PF bone marrow lesions (BMLs). METHODS: Eligible subjects had painful PF OA. Subjects were randomly allocated to brace or no brace for 6 weeks. Knee MRIs were acquired at baseline and 6 weeks. We measured BMLs on post-contrast fat suppressed sagittal and proton density weighted axial images. The primary symptom outcome was change in pain at 6 weeks during a preselected painful activity, and the primary structural outcome was BML volume change in the PF joint. Analyses used multiple linear regression. RESULTS: We randomised 126 subjects aged 40-70 years (mean age 55.5  years; 72 females (57.1%)). Mean nominated visual analogue scale (0-10 cm) pain score at baseline was 6.5 cm. 94 knees (75%) had PF BMLs at baseline. Subjects wore the brace for a mean of 7.4 h/day. 6 subjects withdrew during the trial. After accounting for baseline values, the brace group had lower knee pain than the control group at 6 weeks (difference between groups -1.3 cm, 95% CI -2.0 to -0.7; p<0.001) and reduced PF BML volume (difference -490.6 mm(3), 95% CI -929.5 to -51.7; p=0.03) but not tibiofemoral volume (difference -53.9 mm(3), 95% CI -625.9 to 518.2; p=0.85). CONCLUSIONS: A PF brace reduces BML volume in the targeted compartment of the knee, and relieves knee pain. TRIAL REGISTRATION NUMBER: UK. ISRCTN50380458.

Adaptive behaviour and multiple equilibrium states in a predator-prey model.

There is evidence that multiple stable equilibrium states are possible in real-life ecological systems. Phenomenological mathematical models which exhibit such properties can be constructed rather straightforwardly. For instance, for a predator-prey system this result can be achieved through the use of non-monotonic functional response for the predator. However, while formal formulation of such a model is not a problem, the biological justification for such functional responses and models is usually inconclusive. In this note, we explore a conjecture that a multitude of equilibrium states can be caused by an adaptation of animal behaviour to changes of environmental conditions. In order to verify this hypothesis, we consider a simple predator-prey model, which is a straightforward extension of the classic Lotka-Volterra predator-prey model. In this model, we made an intuitively transparent assumption that the prey can change a mode of behaviour in response to the pressure of predation, choosing either "safe" of "risky" (or "business as usual") behaviour. In order to avoid a situation where one of the modes gives an absolute advantage, we introduce the concept of the "cost of a policy" into the model. A simple conceptual two-dimensional predator-prey model, which is minimal with this property, and is not relying on odd functional responses, higher dimensionality or behaviour change for the predator, exhibits two stable co-existing equilibrium states with basins of attraction separated by a separatrix of a saddle point.

Prem Baby Triple P: a randomised controlled trial of enhanced parenting capacity to improve developmental outcomes in preterm infants.

BACKGROUND: Very preterm birth (<32 weeks gestation) is associated with motor, cognitive, behavioural and educational problems in children and maternal depression and withdrawal. Early interventions that target parenting have the greatest potential to create sustained effects on child development and parental psychopathology. Triple P (Positive Parenting Program) has shown positive effects on child behaviour and adjustment, parenting practices and family functioning. Baby Triple P for Preterm infants, has been developed to target parents of very preterm infants. This study tests the effectiveness of Baby Triple P for Preterm infants in improving child and parent/couple outcomes at 24 months corrected age (CA). METHODS/DESIGN: Families will be randomised to receive either Baby Triple P for Preterm infants or Care as Usual (CAU). Baby Triple P for Preterm infants involves 4 × 2 hr group sessions at the hospital plus 4 × 30 min telephone consultations soon after transfer (42 weeks C.A.). After discharge participants will be linked to community based Triple P and intervention maintenance up to 24 months C.A. Assessments will be: baseline, post-intervention (6 weeks C.A.), at 12 and 24 months C.A. The primary outcome measure is the Infant Toddler Social & Emotional Assessment (ITSEA) at 24 months C.A. Child behavioural and emotional problems will be coded using the mother-toddler version of the Family Observation Schedule at 24 months C.A. Secondary outcome will be the Bayley Scales of Infant and Toddler Development (BSID III) cognitive development, language and motor abilities. Proximal targets of parenting style, parental self-efficacy, parental mental health, parental adjustment, parent-infant attachment, couple relationship satisfaction and couple communication will also be assessed. Our sample size based on the ITSEA, has 80% power, predicted effect size of 0.33 and an 85% retention rate, requires 165 families are required in each group (total sample of 330 families). DISCUSSION: This protocol presents the study design, methods and intervention to be analysed in a randomised trial of Baby Triple P for Preterm infants compared to Care as Usual (CAU) for families of very preterm infants. Publications of all outcomes will be published in peer reviewed journals according to CONSORT guidelines. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12612000194864.

Predictors of response to intra-articular steroid injections in knee osteoarthritis--a systematic review.

OBJECTIVE: IA steroid injections (IASIs) have been shown to relieve pain in knee OA and are widely used in clinical practice. There is, however, evidence of some variation in response. Knowledge of predictors of response could aid in the selection of patients for this therapy. The aim of this systematic review was to determine factors associated with response to IASI in knee OA. METHODS: Medline, Embase, AMED, CINAHL, Web of Science and Cochrane Central Registers for Controlled Trials up to January 2012 were searched with additional hand searches of relevant articles. Studies included were those that involved adults diagnosed with knee OA in whom IASIs were administered and factors that predicted treatment response were investigated. RESULTS: Eleven publications meeting these criteria were reviewed and relevant information extracted. It was not possible to pool the results because of the different predictors studied, variable outcome measures, different criteria for symptom change and missing data. Given the relative paucity of data and small heterogeneously designed studies, it was difficult to identify predictors of response. Data from individual publications, although not consistent across studies, suggest that the presence of effusion, withdrawal of fluid from the knee, severity of disease, absence of synovitis, injection delivery under US guidance and greater symptoms at baseline may all improve the likelihood of response to IASI. CONCLUSION: Further larger-scale studies using standardized methods are required to characterize predictors of response and should focus on synovitis, effusion, pain and structural severity of disease. Such data would help in better targeting therapy to those most likely to benefit.

Change in maternal body mass index is associated with offspring body mass index: a 21-year prospective study.

PURPOSE: To examine whether changes in maternal overweight and obesity from pre-pregnancy to two decades postpartum predict the body mass index (BMI) of adult offspring. METHODS: We used a subsample of 1997 mother-offspring pairs from the 7,223 original cohorts of women who gave birth in Brisbane, Australia, between 1981 and 1984. Multiple linear regression and multinomial logistic regression were used to examine the relationship between change in maternal BMI from pre-pregnancy to 21-year postpartum, and offspring BMI at 21-year, adjusting for potential confounding factors. RESULTS: At 21-year postpartum, 31.15 % mothers were overweight and a further 30.80 % were obese. Mothers gained a mean weight of 16.07 kg over the 21 year. We found that the offspring of mothers who became overweight or remained overweight at 21-year postpartum were at greater risk of being overweight and obese at 21 years. In the adjusted model, offspring of mothers who had normal BMI before pregnancy but became overweight by 21-year postpartum were (odds ratio) 1.72 (95 % CI = 1.20, 2.47) times more likely to be overweight. Compared to offspring of mothers who maintained normal weight over two decades, offspring of mothers who remained persistently overweight were (odds ratio) 5.39 (95 % CI = 3.50, 8.30) times more likely to be obese by age 21 year. CONCLUSIONS: The findings of this study suggest that long-term changes in maternal BMI from pre-pregnancy to 21-year postpartum are independently associated with BMI in their young adult offspring.

Television watching from adolescence to adulthood and its association with BMI, waist circumference, waist-to-hip ratio and obesity: a longitudinal study.

OBJECTIVE: To examine the prospective association of television (TV) watching from adolescence to young adulthood with BMI, waist circumference (WC), waist-to-hip ratio (WHR) and obesity. DESIGN: A community-based longitudinal cohort study. SETTING: Mater-University of Queensland Study of Pregnancy (MUSP) Cohort, Brisbane, Australia. SUBJECTS: A sub-sample of 2439 children was followed up at ages 14 years and 21 years as part of a population-based birth cohort. Offspring reported the number of TV viewing hours each day at 14 and 21 years. BMI, WC and WHR were measured at 21 years. RESULTS: In the adjusted model, offspring who watched TV for <3 h/d at 14 years but for ≥ 3 h/d at 21 years, or who watched TV for ≥ 3 h/d at 14 and 21 years, had greater BMI, WC and WHR at 21 years. Offspring who watched TV for ≥ 3 h/d at 14 years but for <3 h/d at 21 years had similar mean BMI, WC and WHR at 21 years to those who watched TV for <3 h/d at 14 and 21 years. Those offspring who reduced their TV watching hours to <3 h/d during the transition from adolescence into young adulthood were at less risk of becoming obese and those who continued or increased their TV watching to ≥ 3 h/d were at greater risk of becoming obese. This association remained independent of the potential confounding factors considered. CONCLUSIONS: The present findings suggest that our efforts to decrease obesity by reducing TV watching hours among adults should consider interventions to reduce TV time among adolescents.

Chaos in a seasonally perturbed SIR model: avian influenza in a seabird colony as a paradigm.

Seasonality is a complex force in nature that affects multiple processes in wild animal populations. In particular, seasonal variations in demographic processes may considerably affect the persistence of a pathogen in these populations. Furthermore, it has been long observed in computer simulations that under seasonal perturbations, a host-pathogen system can exhibit complex dynamics, including the transition to chaos, as the magnitude of the seasonal perturbation increases. In this paper, we develop a seasonally perturbed Susceptible-Infected-Recovered model of avian influenza in a seabird colony. Numerical simulations of the model give rise to chaotic recurrent epidemics for parameters that reflect the ecology of avian influenza in a seabird population, thereby providing a case study for chaos in a host- pathogen system. We give a computer-assisted exposition of the existence of chaos in the model using methods that are based on the concept of topological hyperbolicity. Our approach elucidates the geometry of the chaos in the phase space of the model, thereby offering a mechanism for the persistence of the infection. Finally, the methods described in this paper may be immediately extended to other infections and hosts, including humans.

Fitness limitations in non-disabled extremely low birthweight adolescents.

AIM: This study aims to compare non-disabled otherwise healthy extremely low birthweight (ELBW) (<1000 g) children and term-born peers in an investigation of relationship between cardiorespiratory endurance and parent report of competence. METHODS: Forty-eight of 105 eligible ELBW 11- to 13-year-old children (27 male) and 55 term-born school peers (28 male) completed a 20-m shuttle run, anthropometric measures, respiratory function tests and the Motor Assessment Battery for Children. Parents completed the Child Behavior Checklist (CBCL). RESULTS: The ELBW group had poorer cardiorespiratory endurance (P = 0.002), growth (P = 0.002), respiratory function (P = 0.003) and motor ability (P < 0.001) than term-born peers. Parents reported the ELBW children to be less competent than term-born peers: CBCL total T score mean difference -9, 95% confidence interval -14, -5 (P < 0.001). Cardiorespiratory endurance predicted competence (regression coefficient 0.865; 95% confidence interval 0.352, 1.378; P = 0.001) independent of prematurity, growth, respiratory function, motor score, gender and socio-economic status. Cardiorespiratory endurance had association with social competence for all participating children, but was related to CBCL Activities Competence only for the ELBW children who were the significantly less fit group. CONCLUSIONS: The poor cardiorespiratory endurance prevalent in non-disabled otherwise healthy ELBW children is associated with general competence independent of prematurity and of the impact of other mild physical deficits, gender or socio-economic status. The relationship demonstrated between cardiorespiratory endurance and competence to engage in general activities of daily living, seen only in the less fit ELBW children, identifies the fitness levels in non-disabled ELBW children as a barrier to participation.