BackgroundIncreased maximal oxygen uptake (V?O-2max) is beneficial in children with cystic fibrosis (CF) but remains lower compared to healthy peers. Intrinsic metabolic deficiencies within skeletal muscle (muscle "quality") and skeletal muscle size (muscle "quantity") are both proposed as potential causes for the lower V?O-2max, although exact mechanisms remain unknown. This study utilises gold-standard methodologies to control for the residual effects of muscle size from V?O-2max to address this "quality" vs. "quantity" debate.MethodsFourteen children (7 CF vs. 7 age- and sex-matched controls) were recruited. Parameters of muscle size - muscle cross-sectional area (mCSA) and thigh muscle volume (TMV) were derived from magnetic resonance imaging, and V?O-2max obtained via cardiopulmonary exercise testing. Allometric scaling removed residual effects of muscle size, and independent samples t-tests and effect sizes (ES) identified differences between groups in V?O-2max, once mCSA and TMV were controlled for.ResultsV?O-2max was shown to be lower in the CF group, relative to controls, with large ES being identified when allometrically scaled to mCSA (ES = 1.76) and TMV (ES = 0.92). Reduced peak work rate was also identified in the CF group when allometrically controlled for mCSA (ES = 1.18) and TMV (ES = 0.45).ConclusionsA lower V?O-2max was still observed in children with CF after allometrically scaling for muscle size, suggesting reduced muscle "quality" in CF (as muscle "quantity" is fully controlled for). This observation likely reflects intrinsic metabolic defects within CF skeletal muscle.

Breathlessness is a universal experience during exercise and has relevance in the assessment and management of paediatric respiratory disease. Understanding breathlessness is underpinned by knowledge of the mechanics and neurological control of breathing. Respiratory disease may lead to breathlessness at lower levels of physical activity than in health. However, many factors influence an individual's perception of breathlessness and there is overlap between physiologically explained breathlessness and psychological comorbidity. There are both subjective and objective ways of assessing of breathlessness but discordance between these measures requires explanation. Practical guidelines for managing breathlessness may help maintain a young person's physical activity and health. Rather than relying on the extrapolation of adult research, more studies in children are required to progress our understanding and management of this important symptom.

BACKGROUND:The Cystic Fibrosis Trust recently published a standards of care document which stated that patients should be given a physical activity (PA) programme based on their motivations, fitness, and willingness to be active. However, there remains much debate regarding the roles and responsibilities for PA promotion, as well as "optimal" recommendations and advice. This study aimed to qualitatively explore cystic fibrosis (CF) multidisciplinary teams (MDTs) advice, recommendations and practices relating to PA promotion for adolescents with CF.METHOD:Semi-structured interviews were conducted with fifteen members of CF MDTs (11 physiotherapists, two dieticians and two paediatricians). Thematic analysis was used to analyse the data.RESULTS:Major themes identified were: (1) structure of MDTs, (2) recommendations relating to intensities, durations and types of PA, and (3) use of exercise testing. Participants reported variation between MDTs in terms of who is responsible for promoting and supporting PA, the nature of advice given to patients, and the use of exercise testing. Participants consistently lacked confidence in their own or others' knowledge to provide standardised recommendations to patients and highlighted that PA promotion and support was often overlooked during busy periods.CONCLUSIONS:Despite its importance, PA support and promotion is not always prioritised. MDTs lack confidence in their ability to promote PA. Standardised advice and training relating to optimal intensities, durations and types of PA would provide a baseline from which to individualise advice to each patient and could increase confidence in PA promotion among MDTs.

Cardiopulmonary exercise testing (CPET) is viewed by many as the gold standard for assessing exercise capacity in CF, being recommended on an annual basis. However, not all patients undergo CPET for varying reasons. This service evaluation retrospectively reviewed data from 179 (92 male) patients in a single CF centre in the UK to identify such reasons. A total of 75/179 patients underwent CPET, whilst 104/179 did not. Of these 104, 41 patients were ≤ 11 years of age. Of the remaining 63 patients, 26 did not undergo CPET for clinical reasons including needing IV antibiotics, musculoskeletal issues and obesity. Seventeen refused to undergo CPET because of reasons such as an unwillingness to travel and dislike of CPET. Twenty did not undergo CPET for miscellaneous reasons including difficulty contacting patients. Individuals with FEV 1 < 40% predicted were 85.7% less likely to undertake a CPET than individuals with FEV 1 ≥ 70% predicted . Understanding these challenges will assist clinical teams with future implementation of CPET into routine care, by identifying areas for improvement and establishing strategies for enhancing future provision of the test.

Abstract Estimating muscle volume (MV) using variable numbers of cross-sectional area (CSA) slices obtained from magnetic resonance imaging (MRI) introduces an error that is known in adults, but not in children and adolescents, whereby body sizes differ due to growth and maturation. Therefore, 15 children and adolescents (11 males, 14.8 ± 2.1 years) underwent MRI scans of the right thigh using a 1.5 T scanner to establish this error. A criterion MV was determined by tracing around and summing all CSAs, with MV subsequently estimated using every second, third, fourth and fifth CSA slice. Bland-Altman plots identified mean bias and limits of agreement (LoA) between methods. Error rates between 1.0 and 10.4% were seen between criterion and estimated MV. Additional analyses identified an impact of formulae selection, with a cylindrical formula preferred to a truncated cone. To counter high error between criterion and estimated MV due to the discrepancies in the number of CSA slices analysed, length-matched criterion volumes were established, with reduced error rates (0.5-2.0%) being produced as a result. CSA at 50% thigh-length also predicted MV, producing a high error (13.8-39.6%). Pearson's correlation coefficients determined relationships between error and measures of body size/composition, with all body size/composition measures being correlated (r = -0.78-0.86, p < 0.05) with the error between criterion and estimated MV. To conclude, MV can be accurately estimated using fewer CSA slices. However, the associated error must be considered when calculating MV in children and adolescents, as body size biases estimates.

posture exercises, and appropriate precautions.In April 2019, a retrospective audit of exercise tests in this 20-month period (n = 88) was performed.Post exercise test, patients continuing to exercise completed a questionnaire to assess attendance rate, value of the exercise guidelines, and benefits felt from exercise.Results: Post-exercise test 53% (n = 47) patients were interested in receiving exercise guidelines for an exercise scheme, independent gym, personal trainer, or hospital-based programme, with 66% (n = 31) completing the audit questionnaire.Of audited patients, 71% (n = 22) attended an exercise scheme, 13% (n = 4) attended a hospital based programme, 10% (n = 3) an independent gym, 3% (n = 1) acquired a personal trainer, and 3% (n = 1) didn't start exercise.Average length of attendance was 6 weeks.Of the 20 (67%) patients who received exercise guidelines, 80% (n = 16) stated they were useful.The majority of patients, 70% (n = 21) felt benefit from their exercise programme, 20% (n = 6) felt no benefit, and 10% (n = 3) failed to comment.Conclusions: Over half the patients attending exercise tests in our centre took up the offer of commencing an exercise routine for an average of 6 weeks post-test.Most patients who received exercise guidelines felt they were useful and over two thirds of the patients felt benefit from their exercise routine.

Objectives: Cardiopulmonary exercise testing (CPET) is a fundamental component of CF care, with endorsement by the European Cystic Fibrosis Society.Aerobic fitness (VO 2max ) is a primary outcome and has been shown to be prognostically associated with risk of mortality and hospitalisation in patients with CF.Whilst bacterial infection and antibiotic treatments are associated with decreased aerobic fitness, no study has yet analysed the relationship between baseline CPET outcomes, and subsequent days receiving intravenous antibiotics (IVAbx).This study utilised annual review and CPET outcomes to predict prospective 12 month IVAbx usage in a single CF centre in the United Kingdom.Methods: CPET (VO 2max (mL•kg -1 •min -1 ), peak VE/VO2, peak VE/VCO2, peak PETCO2) and clinical (age, sex, FEV 1 % predicted , and BMI) data was collected at annual review from 64 patients with CF (21 paediatric, mean age 26.02 ± 12.85 years).Prospective IVAbx days were collected from annual review data from the following year, and equated to 12-month scores to account for differences in time between annual reviews.All variables were individually entered into univariate regression model to predict 12 month IVAbx days.Significant variables were subsequently entered into a stepwise multiple regression model.Results: BMI, FEV 1 % predicted , VE/VCO2, and VO 2max (mL•kg -1 •min -1 ) were included in the final predictive model for the entire dataset.Only CPET variables and BMI were significant predictors of IVAbx days amongst adults.FEV 1 % predicted was the only significant variable in the paediatric model.These models accounted for 41 (Standard Error Estimate 14.77), 49 (13.63) and 33 (16.02) % of the variance in IV days respectively.Conclusion: This is the first study to identify the association between CPET outcomes and prospective IVAbx usage in CF, showing that an increased VO 2max is associated with fewer IV days.

Rationale, aims and objectives: Physical activity (PA) and exercise are important in maintaining and improving health and wellbeing in people with cystic fibrosis (CF) and measures of exercise capacity are useful outcomes in monitoring disease progression. The roles and responsibilities of CF multi-disciplinary team (MDT) members in supporting PA and exercise have yet to be fully defined. This communication reports on national meetings of CF MDT staff whose interest is to improve and standardise person-centered exercise provision and testing as part of routine CF care. We also introduce the role of the physiotherapy technician in supporting PA interventions.Meetings: The two meetings covered a range of presentations, discussions and workshops, focusing on the role of exercise and PA in CF management. Forty people from 15 NHS Hospital Trusts and 3 universities were asked to provide feedback via a questionnaire.Results: The common roles and responsibilities of clinical staff involved in exercise testing and prescription are described, with a wide range of duties identified. In addition, physiotherapists were reported as the main MDT member responsible for exercise provision. The majority of teams reported discussing exercise at every clinical visit (57%) and felt confident in discussing exercise with patients (67%).Conclusions: While this report highlights the current provision of exercise in CF MDTs, it also provides insight into the resources MDTs may require in order to enhance the profile of exercise within CF services, including enhanced training, guidelines and standardised clinical roles.

This study characterised oxygen uptake efficiency (OUE) in children with mild-to-moderate cystic fibrosis (CF). Specifically, it investigated (1) the utility of OUE parameters as potential submaximal surrogates of peak oxygen uptake (\(\dot {V}{{\text{O}}_{2{\text{peak}}}}\)), and (2) the relationship between OUE and disease severity.

Maximal cardiopulmonary exercise testing is recommended on an annual basis for children with cystic fibrosis (CF), due to clinically useful prognostic information provided by maximal oxygen uptake (V̇O2max). However, not all patients are able, or willing, to reach V̇O2max, and therefore submaximal alternatives are required. This study explored the validity of the oxygen uptake efficiency slope (OUES) as a submaximal measure of V̇O2max in children and adolescents with CF.

Letter to the EditorMeasurement of V̇o2max in clinical groups is feasible and necessaryCraig Anthony Williams, Zoe L. Saynor, Alan R. Barker, Patrick J. Oades, and Owen W. TomlinsonCraig Anthony WilliamsChildren’s Health and Exercise Research Centre, Sport and Health Sciences, University of Exeter, Exeter, Devon, United Kingdom; Paediatric Unit, Royal Devon and Exeter National Health Service Foundation Trust, Exeter, Devon, United Kingdom, Zoe L. SaynorDepartment of Sport and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom; and , Alan R. BarkerChildren’s Health and Exercise Research Centre, Sport and Health Sciences, University of Exeter, Exeter, Devon, United Kingdom; , Patrick J. OadesPaediatric Unit, Royal Devon and Exeter National Health Service Foundation Trust, Exeter, Devon, United Kingdom, and Owen W. TomlinsonChildren’s Health and Exercise Research Centre, Sport and Health Sciences, University of Exeter, Exeter, Devon, United Kingdom; Paediatric Unit, Royal Devon and Exeter National Health Service Foundation Trust, Exeter, Devon, United KingdomPublished Online:26 Oct 2017https://doi.org/10.1152/japplphysiol.00538.2017MoreSectionsPDF (28 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat to the editor: We commend the recent CORP statement by Poole and Jones (1) in which they advocate the use of a supramaximal bout to verify maximal oxygen uptake (V̇o2max) obtained during incremental exercise. The authors cite research that supports this approach, particularly in clinical populations, where exercise testing provides important prognostic information, such as individuals with cystic fibrosis (CF).However, subsequent correspondence from van Breda et al. (3) concluded that “the short constant-work rate verification phase after the steep-ramp test . . . is, at least in a clinical setting, unrealistic and unethical in certain patient populations” (pp. 1370). We disagree with this statement, because evidence has consistently shown that a verification phase is crucial if clinicians are to have confidence in the determination of V̇o2max. In pediatric patients with CF, we have shown that a further increase in V̇o2 can be elicited by performing supramaximal verification (2), which also improves test-retest reliability and eliminates dependence on secondary criteria (heart rate, respiratory exchange ratio, blood lactate, etc.). Our group has been using cardiopulmonary exercise testing (CPET) with supramaximal verification in our routine adult and pediatric clinical practice for over 5 years. It is included in our portfolio of annual review investigations and we have performed 110 in the last 2 yr. We are aware that the two-stage protocol is preferred in a further three UK CF Centers, and others have expressed interest in adopting the same methodology. The supramaximal protocol is affordable, accepted by patients, and most importantly safe when performed correctly. We have not had any adverse events with any of our CPET testing across a full range of clinical severity.Given the prognostic value of V̇o2max being able to discriminate between “day-to-day variation” and clinically meaningful changes due to disease progression and/or therapeutic intervention is essential. Indeed, previous clinical studies have suggested their own conclusions may be limited by the lack of supramaximal verification testing, highlighting the need to heed the advice presented in the CORP statement (1).We agree with van Breda et al. (3) that “the concepts of aerobic/anaerobic and ventilatory thresholds encompass important clinical information”. However, it should be noted such parameters should be normalized to a percentage of V̇o2max, which therefore warrants accurate determination.In clinical practice, tracking changes in aerobic capacity over time will have more precision and meaning if the most accurate methodology is used. It is for this very reason that our group and associated clinical teams fully support the methodological recommendation of using supramaximal verification as part of CPET.AUTHOR CONTRIBUTIONSC.A.W. drafted manuscript; C.A.W., Z.L.S., A.R.B., P.J.O., and O.W.T. edited and revised manuscript; C.A.W., Z.L.S., A.R.B., P.J.O., and O.W.T. approved final version of manuscript.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the authors.References1. Poole DC, Jones AM. Measurement of the maximum oxygen uptake V̇o2max: V̇o2peak is no longer acceptable. J Appl Physiol (1985) 122: 997–1002, 2017. doi:10.1152/japplphysiol.01063.2016. Link | ISI | Google Scholar2. Saynor ZL, Barker AR, Oades PJ, Williams CA. A protocol to determine valid VO2max in young cystic fibrosis patients. J Sci Med Sport 16: 539–544, 2013. doi:10.1016/j.jsams.2013.01.010. Crossref | PubMed | ISI | Google Scholar3. van Breda E, Schoffelen PFM, Plasqui G. Clinical V̇o2peak is “part of the deal”. J Appl Physiol (1985) 122: 1370, 2017. doi:10.1152/japplphysiol.00187.2017. Link | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence C. A. Williams, Children’s Health and Exercise Research Centre, Sport and Health Sciences, University of Exeter, Exeter, Devon, United Kingdom (e-mail: c.a.[email protected]ac.uk). Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Collections More from this issue > Volume 123Issue 4October 2017Pages 1017-1017 Copyright & PermissionsCopyright © 2017 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00538.2017PubMed29074571History Received 7 June 2017 Accepted 28 June 2017 Published online 26 October 2017 Published in print 1 October 2017 Metrics

PURPOSE:The aim of this study was to describe the relationship between body size and oxygen uptake efficiency slope (OUES) in pediatric patients with cystic fibrosis (CF) and healthy controls (CON), to identify appropriate scaling procedures to adjust the influence of body size upon OUES. METHODS:The OUES was derived using maximal and submaximal points from cardiopulmonary exercise testing in 72 children (36 CF and 36 CON). OUES was subsequently scaled for stature, body mass (BM), and body surface area (BSA) using ratio-standard (Y/X) and allometric (Y/X) methods. Pearson's correlation coefficients were used to determine the relationship between body size and OUES. RESULTS:When scaled using the ratio-standard method, OUES had a significant positive relationship with stature (r = 0.54, P < 0.001) and BSA (r = 0.25, P = 0.031) and significant negative relationship with BM (r = -0.38, P = 0.016) in the CF group. Combined allometric exponents (b) for CF and CON were stature 3.00, BM 0.86, and BSA 1.40. A significant negative correlation was found between OUES and stature in the CF group when scaled allometrically (r = -0.37, P = 0.027). Nonsignificant (P > 0.05) correlations for the whole group were found between OUES and allometrically scaled BM (CF r = -0.25, CON, r = 0.15) and BSA (CF r = -0.27, CON r = 0.13). CONCLUSIONS:Only allometric scaling of either BM or BSA, and not ratio-standard scaling, successfully eliminates the influence of body size upon OUES. Therefore, this enables a more direct comparison of the OUES between patients with CF and healthy controls.