The relationship between sagittal curvature and extensor muscle volume in the lumbar spine.

This is the peer reviewed version of the article, which has been published in final form at doi: 10.1111/joa.12047. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.A previous modelling study predicted that the forces applied by the extensor muscles to stabilise the lumbar spine would be greater in spines that have a larger sagittal curvature (lordosis). Because the force-generating capacity of a muscle is related to its size, it was hypothesised that the size of the extensor muscles in a subject would be related to the size of their lumbar lordosis. Magnetic resonance imaging (MRI) data were obtained, together with age, height, body mass and back pain status, from 42 female subjects. The volume of the extensor muscles (multifidus and erector spinae) caudal to the mid-lumbar level was estimated from cross-sectional area measurements in axial T1-weighted MRIs spanning the lumbar spine. Lower lumbar curvature was determined from sagittal T1-weighted images. A stepwise linear regression model was used to determine the best predictors of muscle volume. The mean lower lumbar extensor muscle volume was 281 cm(3) (SD = 49 cm(3)). The mean lower lumbar curvature was 30 ° (SD = 7 °). Five subjects reported current back pain and were excluded from the regression analysis. Nearly half the variation in muscle volume was accounted for by the variables age (standardised coefficient, B = -3.2, P = 0.03) and lower lumbar curvature (B = 0.47, P = 0.002). The results support the hypothesis that extensor muscle volume in the lower lumbar spine is related to the magnitude of the sagittal curvature; this has implications for assessing muscle size as an indicator of muscle strength

Short-term Precision Error in Dual Energy X-Ray Absorptiometry, Bone Mineral Density and Trabecular Bone Score Measurements; and Effects of Obesity on Precision Error.

This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Introduction: Bone mineral density (BMD) measured by dual energy x-ray absorptiometry (DXA) is the primary screening tool for diagnosis of osteopenia and osteoporosis. BMD alone does not provide information regarding the structural characteristics of bone and this limitation has been a driver for the development of techniques, including trabecular bone score (TBS) software, to assess bone microarchitecture. Precision error in DXA is important for accurately monitoring changes in BMD and it has been demonstrated that BMD precision error increases with increasing body mass index (BMI). Information on in vivo precision error for TBS is very limited. This study evaluated short-term precision error (STPE) of lumbar spine BMD & TBS measurement, and investigated the effect of obesity on DXA precision error. Method: DXA lumbar spine scans (L1-L4) were performed using GE Lunar Prodigy. STPE was measured in ninety-one women at a single visit by duplicating scans with repositioning in-between. Precision error was calculated as the percentage coefficient of variation. Participants were sub-divided into four groups based on BMI to assess the effect of obesity on STPE. Results: STPE is poorer for TBS than for BMD. STPE is adversely affected for both BMD and TBS measurements by increasing BMI but this effect is mitigated for TBS in the highest BMI category where use of the thick scanning mode improves signal to noise ratio. Conclusion: Results from serial BMD and TBS measurements should take account of differences in precision error in the two techniques and in different BMI categories.Society and College of Radiographers Industry Partnership Scheme (CORIPS

The feasibility of using citizens to segment anatomy from medical images: Accuracy and motivation

This is the final version. Available from Public Library of Science via the DOI in this record.Data cannot be shared publicly because participants did not consent for their data to be made publicly available, however, consent was granted to make the data available to researchers for use in related studies. Further information about the data and details of how to request access are available from the University of Exeter's institutional repository at: https://doi.org/10.24378/exe.1703.The development of automatic methods for segmenting anatomy from medical images is an important goal for many medical and healthcare research areas. Datasets that can be used to train and test computer algorithms, however, are often small due to the difficulties in obtaining experts to segment enough examples. Citizen science provides a potential solution to this problem but the feasibility of using the public to identify and segment anatomy in a medical image has not been investigated. Our study therefore aimed to explore the feasibility, in terms of performance and motivation, of using citizens for such purposes. Public involvement was woven into the study design and evaluation. Twenty-nine citizens were recruited and, after brief training, asked to segment the spine from a dataset of 150 magnetic resonance images. Participants segmented as many images as they could within three one-hour sessions. Their accuracy was evaluated by comparing them, as individuals and as a combined consensus, to the segmentations of three experts. Questionnaires and a focus group were used to determine the citizens’ motivation for taking part and their experience of the study. Citizen segmentation accuracy, in terms of agreement with the expert consensus segmentation, varied considerably between individual citizens. The citizen consensus, however, was close to the expert consensus, indicating that when pooled, citizens may be able to replace or supplement experts for generating large image datasets. Personal interest and a desire to help were the two most common reasons for taking part in the study.Wellcome Trus

Combining behavioural activation with physical activity promotion for adults with depression: findings of a parallel-group pilot randomised controlled trial (BAcPAc)

BACKGROUND: Depression is associated with physical inactivity, which may mediate the relationship between depression and a range of chronic physical health conditions. However, few interventions have combined a psychological intervention for depression with behaviour change techniques, such as behavioural activation (BA), to promote increased physical activity. METHODS: To determine procedural and clinical uncertainties to inform a definitive randomised controlled trial (RCT), a pilot parallel-group RCT was undertaken within two Improving Access to Psychological Therapies (IAPT) services in South West England. We aimed to recruit 80 adults with depression and randomise them to a supported, written self-help programme based on either BA or BA plus physical activity promotion (BAcPAc). Data were collected at baseline and 4 months post-randomisation to evaluate trial retention, intervention uptake and variance in outcomes to inform a sample size calculation. Qualitative data were collected from participants and psychological wellbeing practitioners (PWPs) to assess the acceptability and feasibility of the trial methods and the intervention. Routine data were collected to evaluate resource use and cost. RESULTS: Sixty people with depression were recruited, and a 73 % follow-up rate was achieved. Accelerometer physical activity data were collected for 64 % of those followed. Twenty participants (33 %) attended at least one treatment appointment. Interview data were analysed for 15 participants and 9 study PWPs. The study highlighted the challenges of conducting an RCT within existing IAPT services with high staff turnover and absences, participant scheduling issues, PWP and participant preferences for cognitive focussed treatment, and deviations from BA delivery protocols. The BAcPAc intervention was generally acceptable to patients and PWPs. CONCLUSIONS: Although recruitment procedures and data collection were challenging, participants generally engaged with the BAcPAc self-help booklets and reported willingness to increase their physical activity. A number of feasibility issues were identified, in particular the under-use of BA as a treatment for depression, the difficulty that PWPs had in adapting their existing procedures for study purposes and the instability of the IAPT PWP workforce. These problems would need to be better understood and resolved before proceeding to a full-scale RCT. TRIAL REGISTRATION: ISRCTN74390532 . Registered on 26 March 2013

Influence of training status and exercise modality on pulmonary O2 uptake kinetics in pre-pubertal girls

The limited available evidence suggests that endurance training does not influence the pulmonary oxygen uptake (V(O)(2)) kinetics of pre-pubertal children. We hypothesised that, in young trained swimmers, training status-related adaptations in the V(O)(2) and heart rate (HR) kinetics would be more evident during upper body (arm cranking) than during leg cycling exercise. Eight swim-trained (T; 11.4 +/- 0.7 years) and eight untrained (UT; 11.5 +/- 0.6 years) girls completed repeated bouts of constant work rate cycling and upper body exercise at 40% of the difference between the gas exchange threshold and peak V(O)(2). The phase II V(O)(2) time constant was significantly shorter in the trained girls during upper body exercise (T: 25 +/- 3 vs. UT: 37 +/- 6 s; P < 0.01), but no training status effect was evident in the cycle response (T: 25 +/- 5 vs. UT: 25 +/- 7 s). The V(O)(2) slow component amplitude was not affected by training status or exercise modality. The time constant of the HR response was significantly faster in trained girls during both cycle (T: 31 +/- 11 vs. UT: 47 +/- 9 s; P < 0.01) and upper body (T: 33 +/- 8 vs. UT: 43 +/- 4 s; P < 0.01) exercise. The time constants of the phase II V(O)(2)and HR response were not correlated regardless of training status or exercise modality. This study demonstrates for the first time that swim-training status influences upper body V(O)(2) kinetics in pre-pubertal children, but that cycle ergometry responses are insensitive to such differences

Aerobic capacity, activity levels and daily energy expenditure in male and female adolescents of the kenyan nandi sub-group

The relative importance of genetic and socio-cultural influences contributing to the success of east Africans in endurance athletics remains unknown in part because the pre-training phenotype of this population remains incompletely assessed. Here cardiopulmonary fitness, physical activity levels, distance travelled to school and daily energy expenditure in 15 habitually active male (13.9±1.6 years) and 15 habitually active female (13.9±1.2) adolescents from a rural Nandi primary school are assessed. Aerobic capacity ([Formula: see text]) was evaluated during two maximal discontinuous incremental exercise tests; physical activity using accelerometry combined with a global positioning system; and energy expenditure using the doubly labelled water method. The [Formula: see text] of the male and female adolescents were 73.9±5.7 ml(.) kg(-1.) min(-1) and 61.5±6.3 ml(.) kg(-1.) min(-1), respectively. Total time spent in sedentary, light, moderate and vigorous physical activities per day was 406±63 min (50% of total monitored time), 244±56 min (30%), 75±18 min (9%) and 82±30 min (10%). Average total daily distance travelled to and from school was 7.5±3.0 km (0.8-13.4 km). Mean daily energy expenditure, activity-induced energy expenditure and physical activity level was 12.2±3.4 MJ(.) day(-1), 5.4±3.0 MJ(.) day(-1) and 2.2±0.6. 70.6% of the variation in [Formula: see text] was explained by sex (partial R(2) = 54.7%) and body mass index (partial R(2) = 15.9%). Energy expenditure and physical activity variables did not predict variation in [Formula: see text] once sex had been accounted for. The highly active and energy-demanding lifestyle of rural Kenyan adolescents may account for their exceptional aerobic fitness and collectively prime them for later training and athletic success

The influence of body weight on the pulmonary oxygen uptake kinetics in pre-pubertal children during moderate- and heavy intensity treadmill exercise

To assess the influence of obesity on the oxygen uptake (V˙O2) kinetics of pre-pubertal children during moderate- and heavy intensity treadmill exercise. We hypothesised that obese (OB) children would demonstrate significantly slower V˙O2 kinetics than their normal weight (NW) counterparts during moderate- and heavy intensity exercise. 18 OB (9.8 ± 0.5 years; 24.1 ± 2.0 kg m2) and 19 NW (9.7 ± 0.5 years; 17.6 ± 1.0 kg m2) children completed a graded-exercise test to volitional exhaustion and two submaximal constant work rate treadmill tests at moderate (90 % gas exchange threshold) and heavy (∆40 %) exercise intensities. Bodyweight significantly influenced the V˙O2 kinetics during both moderate- and heavy exercise intensities (P < 0.05). During moderate intensity exercise, the phase II τ (OB: 30 ± 13 cf. NW: 22 ± 7 s), mean response time (MRT; OB: 35 ± 16 cf. NW: 25 ± 10 s), phase II gain (OB: 156 ± 21 cf. NW: 111 ± 18 mLO2 kg−1 km−1) and oxygen deficit (OB: 0.36 ± 0.11 cf. NW: 0.20 ± 0.06 L) were significantly higher in the OB children (all P < 0.05). During heavy intensity exercise, the τ (OB: 33 ± 9 cf. NW: 27 ± 6 s; P < 0.05) and phase II gain (OB: 212 ± 61 cf. NW: 163 ± 23 mLO2 kg−1 km−1; P < 0.05) were similarly higher in the OB children. A slow component was observed in all participants during heavy intensity exercise, but was not influenced by weight status. In conclusion, this study demonstrates that weight status significantly influences the dynamic V˙O2 response at the onset of treadmill exercise in children and highlights that the deleterious effects of being obese are already manifest pre-puberty

Association between preoperative haemoglobin concentration and cardiopulmonary exercise variables: a multicentre study

Background: Preoperative anaemia and low exertional oxygen uptake are both associated with greater postoperative morbidity and mortality. This study reports the association among haemoglobin concentration ([Hb]), peak oxygen uptake (V_O2 peak) and anaerobic threshold (AT) in elective surgical patients. Methods: Between 1999 and 2011, preoperative [Hb] and cardiopulmonary exercise tests were recorded in 1,777 preoperative patients in four hospitals. The associations between [Hb], V_O2 peak and AT were analysed by linear regression and covariance. Results: In 436 (24.5%) patients, [Hb] was <12 g dl-1 and, in 83 of these, <10 g dl-1. Both AT and V_O2 peak rose modestly with increasing [Hb] (r2 = 0.24, P <0.0001 and r2 = 0.30, P <0.0001, respectively). After covariate adjustment, an increase in [Hb] of one standard deviation was associated with a 6.7 to 9.7% increase in V_O2 peak, and a rise of 4.4 to 6.0% in AT. Haemoglobin concentration accounted for 9% and 6% of the variation in V_O2 peak and AT respectively. Conclusions: To a modest extent, lower haemoglobin concentrations are independently associated with lower oxygen uptake during preoperative cardiopulmonary exercise testing. It is unknown whether this association is causative