Group Mean Data Research Articles

Use of Theoretical Subjects to Develop a Method for Assessing Equivalence of Dietary Vitamin A in a Mixed Diet

BackgroundAlthough the vitamin A (VA) equivalency of provitamin A carotenoids from single foods or capsules has been studied using several approaches, there is currently no reliable method to determine VA equivalency for mixed diets. ObjectivesTo reach the objective of identifying a method to determine the VA equivalency of provitamin A carotenoids in mixed diets, we tested a new approach using preformed VA as proxy for provitamin A. MethodsWe studied 6 theoretical subjects who were assigned physiologically plausible values for dietary VA intake, retinol kinetic parameters, plasma retinol pool size, and VA total body stores. Using features in the Simulation, Analysis and Modeling software, we specified that subjects ingested a tracer dose of stable isotope-labeled VA on day 0 followed by 0-μg supplemental VA or 200, 400, 800, 1200, 1600, and 2000 μg VA daily from day 14 to day 28; we assigned VA absorption to be 75%. For each supplement level, we simulated plasma retinol specific activity (SAp) over time and calculated the mean decrease in SAp relative to 0 μg. Group mean data were fitted to a regression equation to calculate predicted VA equivalency at each supplement level on day 28. ResultsFor each subject, higher VA supplement loads resulted in lower SAp, with the magnitude of the decrease differing among subjects. The mean predicted amount of absorbed VA was within 25% of individual subjects’ assigned amount for 4 of the 6 subjects, and the mean ratio of predicted to assigned amount of absorbed VA over all supplement loads ranged from 0.60 to 1.50, with an overall mean ratio of 1.0. ConclusionsResults for preformed VA suggest that this protocol may be useful for determining VA equivalency of provitamin A carotenoids in free-living subjects if mixed diets with known provitamin A content were substituted for the VA supplements.

“Life-changing”: the experience of super-responders to biologics in severe asthma

BackgroundThere is limited information on the patient’s perspective of how biologic treatments impact their lives. We conducted a qualitative study to explore the patient’s experience of being considered a super-responder from a quality of life perspective.MethodsPatients with severe asthma identified as super-responders were invited to semi-structured interviews conducted online. Participants could bring a family member/friend to the interview. The interviews explored experiences of biologic treatment, were transcribed and underwent thematic analysis.ResultsTwenty-five participants took part in this study. Themes emerged on the impact of biologic treatment for participants and for their friends/family: (i) Words used to describe their often life-changing experiences and (ii) the positive changes noted. Biologic treatment stopped the disruption of family life and social life caused by exacerbations. Improvements in mental health were also noted. Marked individual variations in the way it affected their lives were noted. Most participants noticed improvements 2–3 months after starting their biologic, but some noticed improvement within a few days and others after 6 months.ConclusionsSuper-responders reported profound but heterogeneous improvements following biologic treatment beyond asthma symptoms and exacerbations including important benefits to social and family life. Improvements may be underestimated as social and family benefits are not reliably measured in current studies with implications for health economic evaluations. Not all patients are super-responders, and excellent responses may be lost in group mean data in trials. Individual time course and response patterns need further elucidation to identify who will respond best to biologics.

Quantitatively characterizing reflexive responses to pitch perturbations.

Reflexive pitch perturbation experiments are commonly used to investigate the neural mechanisms underlying vocal motor control. In these experiments, the fundamental frequency-the acoustic correlate of pitch-of a speech signal is shifted unexpectedly and played back to the speaker via headphones in near real-time. In response to the shift, speakers increase or decrease their fundamental frequency in the direction opposing the shift so that their perceived pitch is closer to what they intended. The goal of the current work is to develop a quantitative model of responses to reflexive perturbations that can be interpreted in terms of the physiological mechanisms underlying the response and that captures both group-mean data and individual subject responses. A model framework was established that allowed the specification of several models based on Proportional-Integral-Derivative and State-Space/Directions Into Velocities of Articulators (DIVA) model classes. The performance of 19 models was compared in fitting experimental data from two published studies. The models were evaluated in terms of their ability to capture both population-level responses and individual differences in sensorimotor control processes. A three-parameter DIVA model performed best when fitting group-mean data from both studies; this model is equivalent to a single-rate state-space model and a first-order low pass filter model. The same model also provided stable estimates of parameters across samples from individual subject data and performed among the best models to differentiate between subjects. The three parameters correspond to gains in the auditory feedback controller's response to a perceived error, the delay of this response, and the gain of the somatosensory feedback controller's "resistance" to this correction. Excellent fits were also obtained from a four-parameter model with an additional auditory velocity error term; this model was better able to capture multi-component reflexive responses seen in some individual subjects. Our results demonstrate the stereotyped nature of an individual's responses to pitch perturbations. Further, we identified a model that captures population responses to pitch perturbations and characterizes individual differences in a stable manner with parameters that relate to underlying motor control capabilities. Future work will evaluate the model in characterizing responses from individuals with communication disorders.

Efficacy of Hot Water Immersion versus Aerobic Exercise Training in Lowering Blood Pressure and Improving Cardiovascular Function in Adults with Untreated Hypertension

INTRODUCTIONHypertension remains among the most prevalent cardiovascular disease risk factors world‐wide. Aerobic exercise training is the current gold‐standard non‐pharmacological intervention for lowering blood pressure, yet passive heat therapy is an effective alternative means of reducing blood pressure and improving cardiovascular health for individuals that are unable or unwilling to engage in traditional exercise training. However, the effectiveness of heat therapy versus exercise training has not been compared in adults with untreated hypertension. Therefore, the purpose of this ongoing clinical trial is to compare the effectiveness of hot water immersion (HWI) versus aerobic exercise training (EX) in lowering blood pressure and improving cardiovascular function. Data presented are preliminary (mid‐point) comparisons following 15 sessions of either HWI or EX.HYPOTHESISIt was hypothesized that hot water immersion would be more effective than traditional aerobic exercise training in reducing blood pressure and improving cardiovascular function in adults with untreated hypertension.METHODSPrior to randomization, all subjects (n=6, 1F) completed resting vascular function testing, including measurements of blood pressure (automated sphygmomanometer), cardiac output (acetylene wash‐in method), and carotid‐femoral pulse wave velocity (PWV). Systemic vascular conductance (SVC) was calculated as cardiac output/mean arterial pressure (MAP). Following pre‐testing (PRE), subjects were randomized into either HWI (n=4, 1F) or EX (n=2). During HWI, subjects were immersed to the level of the sternum in 40.5°C water for 45 minutes. EX consisted of upright cycling at 60% of heart rate reserve (HRR) for 40 min, with 5 min each for warm‐up and cool‐down at 30% of HRR. Participants completed 15 sessions of either HWI or EX prior to mid‐point (MID) testing. Combined data are presented as the change from PRE as mean ± SD and were analyzed using a paired‐samples t test. Group mean data for HWI versus EX are presented as the change from PRE as means ± SD and were analyzed using an unpaired two sample t‐test.RESULTSFollowing 15 sessions of either HWI or EX, systolic blood pressure tended to be reduced (‐5±4 mmHg; p=0.10). The change in systolic blood pressure (SBP) was directionally similar between HWI and EX (∆ from PRE, HWI vs. EX; ‐3±5 vs. ‐7±7 mmHg; p=0.59), whereas the change in diastolic blood pressure (DBP) was divergent between HWI and EX (‐3±8 vs. +5±10 mmHg; p=0.43). Accordingly, changes in MAP were disparate between HWI and EX (‐3±7 vs. +2±9 mmHg; p=0.61). Cardiac output was similar between HWI and EX (‐0.09±0.71 vs. ‐0.76±1.07 L/min; p=0.53), as were changes in SVC (‐0.3±6.6 vs. ‐7.6±15.9 mL•min‐1•mmHg‐1; p=0.63). Overall, PWV was reduced by both interventions (‐0.6±0.3 m/s; p=0.01) and changes in PWV were similar between HWI and EX (‐0.6±0.4 vs. ‐0.5±0.4 m/s; p=0.72).CONCLUSIONSPreliminary data from this ongoing clinical trial suggest both hot water immersion and exercise are similarly effective in lowering systolic blood pressure and reducing arterial stiffness in people with untreated hypertension.

Reliable change and the reliable change index: still useful after all these years?

AbstractIn 1984 Jacobson and colleagues introduced the concept of reliable change, viz the amount of change on a measure that an individual needed to show to determine that it exceeded the extent of change likely due to measurement error alone. Establishing reliable change was a pre-requisite for determining clinical significance. This paper summarizes the rationale for determining reliable change as providing an individual-focused, idiographic alternative to the dominant nomothetic approach to clinical outcome research based on group mean data and statistical significance. The conventional computational steps for calculating an individual’s standardized difference (reliable change) score and the minimum raw change score on the measure (a reliable change index) required to classify individuals as reliably positively changed, indeterminate, or reliably deteriorated are described. Two methods for graphically representing reliable change are presented, and a range of possible uses in both research and practice settings are summarized. A number of issues and debates concerning the calculation of reliable change are reviewed. It is concluded that the concept of reliable change remains useful for both cognitive behavioural researchers and practitioners, but that there are options regarding methods of computation. In any use of reliable change, the rationale for selecting among method options and the exact computations used need clear and careful description so that we can continuously judge the utility and appropriateness of the use of reliable change and enhance its value to the field.Key learning aims(1)Recognizing why the concept of reliable change and the reliable change index is still important.(2)Understanding the conventional formulas for calculating reliable change and the reliable change index (the Jacobson-Truax (JT) method).(3)Seeing key ways that both researchers and practitioners can use reliable change to improve both research and practice.(4)Understanding how several issues and debates that have arisen concerning the estimation of reliable change (e.g. how to accommodate practice effects) have progressed.(5)Recognizing that there are a range of ways that reliable change may be estimated, and the need to provide full details of the method used in any particular instance of its use.

Bi-exponential modelling of W^{^{prime}} reconstitution kinetics in trained cyclists

PurposeThe aim of this study was to investigate the individual W^{^{prime}} reconstitution kinetics of trained cyclists following repeated bouts of incremental ramp exercise, and to determine an optimal mathematical model to describe W^{^{prime}} reconstitution.MethodsTen trained cyclists (age 41 ± 10 years; mass 73.4 ± 9.9 kg; dot{V}{text{O}}_{2max } 58.6 ± 7.1 mL kg min−1) completed three incremental ramps (20 W min−1) to the limit of tolerance with varying recovery durations (15–360 s) on 5–9 occasions. W^{^{prime}} reconstitution was measured following the first and second recovery periods against which mono-exponential and bi-exponential models were compared with adjusted R2 and bias-corrected Akaike information criterion (AICc).ResultsA bi-exponential model outperformed the mono-exponential model of W^{^{prime}} reconstitution (AICc 30.2 versus 72.2), fitting group mean data well (adjR2 = 0.999) for the first recovery when optimised with parameters of fast component (FC) amplitude = 50.67%; slow component (SC) amplitude = 49.33%; time constant (τ)FC = 21.5 s; τSC = 388 s. Following the second recovery, W′ reconstitution reduced by 9.1 ± 7.3%, at 180 s and 8.2 ± 9.8% at 240 s resulting in an increase in the modelled τSC to 716 s with τFC unchanged. Individual bi-exponential models also fit well (adjR2 = 0.978 ± 0.017) with large individual parameter variations (FC amplitude 47.7 ± 17.8%; first recovery: (τ)FC = 22.0 ± 11.8 s; (τ)SC = 377 ± 100 s; second recovery: (τ)FC = 16.3.0 ± 6.6 s; (τ)SC = 549 ± 226 s).ConclusionsW′ reconstitution kinetics were best described by a bi-exponential model consisting of distinct fast and slow phases. The amplitudes of the FC and SC remained unchanged with repeated bouts, with a slowing of W′ reconstitution confined to an increase in the time constant of the slow component.

Contribution of oxygen extraction fraction to maximal oxygen uptake in healthy young men.

We analysed the importance of systemic and peripheral arteriovenous O2 difference ( a-v¯O2 difference and a‐vfO2 difference, respectively) and O2 extraction fraction for maximal oxygen uptake ( V˙O2max). Fick law of diffusion and the Piiper and Scheid model were applied to investigate whether diffusion versus perfusion limitations vary with V˙O2max. Articles (n = 17) publishing individual data (n = 154) on V˙O2max, maximal cardiac output ( Q˙max; indicator‐dilution or the Fick method), a-v¯O2 difference (catheters or the Fick equation) and systemic O2 extraction fraction were identified. For the peripheral responses, group‐mean data (articles: n = 27; subjects: n = 234) on leg blood flow (LBF; thermodilution), a‐vfO2 difference and O2 extraction fraction (arterial and femoral venous catheters) were obtained. Q˙max and two‐LBF increased linearly by 4.9‐6.0 L · min–1 per 1 L · min–1 increase in V˙O2max (R 2 = .73 and R 2 = .67, respectively; both P < .001). The a-v¯O2 difference increased from 118‐168 mL · L–1 from a V˙O2max of 2‐4.5 L · min–1 followed by a reduction (second‐order polynomial: R 2 = .27). After accounting for a hypoxemia‐induced decrease in arterial O2 content with increasing V˙O2max (R 2 = .17; P < .001), systemic O2 extraction fraction increased up to ~90% ( V˙O2max: 4.5 L · min–1) with no further change (exponential decay model: R 2 = .42). Likewise, leg O2 extraction fraction increased with V˙O2max to approach a maximal value of ~90‐95% (R 2 = .83). Muscle O2 diffusing capacity and the equilibration index Y increased linearly with V˙O2max (R 2 = .77 and R 2 = .31, respectively; both P < .01), reflecting decreasing O2 diffusional limitations and accentuating O2 delivery limitations. In conclusion, although O2 delivery is the main limiting factor to V˙O2max, enhanced O2 extraction fraction (≥90%) contributes to the remarkably high V˙O2max in endurance‐trained individuals.

Effects of the Barbell Load on the Acceleration Phase during the Snatch in Elite Olympic Weightlifting.

The load-depended loss of vertical barbell velocity at the end of the acceleration phase limits the maximum weight that can be lifted. Thus, the purpose of this study was to analyze how increased barbell loads affect the vertical barbell velocity in the sub-phases of the acceleration phase during the snatch. It was hypothesized that the load-dependent velocity loss at the end of the acceleration phase is primarily associated with a velocity loss during the 1st pull. For this purpose, 14 male elite weightlifters lifted seven load-stages from 70–100% of their personal best in the snatch. The load–velocity relationship was calculated using linear regression analysis to determine the velocity loss at 1st pull, transition, and 2nd pull. A group mean data contrast analysis revealed the highest load-dependent velocity loss for the 1st pull (t = 1.85, p = 0.044, g = 0.49 [−0.05, 1.04]) which confirmed our study hypothesis. In contrast to the group mean data, the individual athlete showed a unique response to increased loads during the acceleration sub-phases of the snatch. With the proposed method, individualized training recommendations on exercise selection and loading schemes can be derived to specifically improve the sub-phases of the snatch acceleration phase. Furthermore, the results highlight the importance of single-subject assessment when working with elite athletes in Olympic weightlifting.

An individualised approach to assess the sidestep manoeuvre in male rugby union athletes

ObjectivesThis study aimed to (1) quantitatively assess external knee abduction moments between legs, and (2) qualitatively assess anterior cruciate ligament injury risk between group mean and individual athlete data during the sidestep manoeuvre. DesignDescriptive cross-sectional study. MethodsSixteen male academy-level rugby union athletes (20.4±2.7yr; 186.3±9.1cm; 99.1±14.4kg) performed three maximal effort sidesteps (>6.0ms−1) on each leg. Three-dimensional motion analysis was used to obtain external knee abduction moments, wherein the two legs were separated by the preferred and non-preferred kicking leg. Quantitative comparisons were made between legs, while qualitative comparisons were made been group mean and individual athlete data. ResultsWhen sidestepping on the non-preferred leg, athletes produced 25% greater knee abduction moments (ES=0.43) and presented modified postural adjustments associated with injury risk (extended knee [ES=−0.26; −8%], more trunk lateral flexion [ES=0.42; 17%] and more distance between the centre-of-mass and ankle-joint-centre of the stance leg [ES=0.97; 11%]) compared to the preferred leg. Individually, only 9 out of 16 athletes presented a higher abduction moment in their non-preferred leg with individual asymmetries ranging between 2.2 and 47%. ConclusionsNearly half of the athletes assessed in this study showed the potential to “slip under the radar” when using the group mean for assessment. When assessing athletes for anterior cruciate ligament injury risk factors, individual athlete data should be examined in conjunction with the group mean for a more holistic view of the data.

Hearing Aid Self-Adjustment: Effects of Formal Speech-Perception Test and Noise.

While listening to recorded sentences with a sound-field level of 65 dB SPL, 24 adults with hearing-aid experience used the “Goldilocks” explore-and-select procedure to adjust level and spectrum of amplified speech to preference. All participants started adjustment from the same generic response. Amplification was provided by a custom-built Master Hearing Aid with online processing of microphone input. Primary goals were to assess the effects of including a formal speech-perception test between repeated self-adjustments and of adding multitalker babble (signal-to-noise ratio +6 dB) during self-adjustment. The speech test did not affect group-mean self-adjusted output, which was close to the National Acoustics Laboratories’ prescription for Non-Linear hearing aids. Individuals, however, showed a wide range of deviations from this prescription. Extreme deviations at the first self-adjustment fell by a small but significant amount at the second. The multitalker babble had negligible effect on group-mean self-selected output but did have predictable effects on word recognition in sentences and on participants’ opinion regarding the most important subjective criterion guiding self-adjustment. Phoneme recognition in monosyllabic words was better with the generic starting response than without amplification and improved further after self-adjustment. The findings continue to support the efficacy of hearing aid self-fitting, at least for level and spectrum. They do not support the need for inclusion of a formal speech-perception test, but they do support the value of completing more than one self-adjustment. Group-mean data did not indicate a need for threshold-based prescription as a starting point for self-adjustment.

Inter-individual variability in load carriage economy and comparisons between different load conditions

Equivocal findings exist for the economy associated with load carried close to the body's centre of mass. Individual variation could explain some of the equivocal findings. This research aimed to examine the extent of individual variation in loaded walking economy.Eighteen females carried load on the back, head and split between the front and back. Individual variation in relative load carriage economy (ELI) was primarily assessed using standard deviation, coefficients of variation (CV) and intraclass correlation coefficients (ICC).There was large inter-individual variation in ELI values with highest mean CV's of 16%, 12% and 10% for head-, back- and combined front and back-loading. Mean ELI values were not significantly different between methods.The large amount of individual variation found here suggests future load carriage research should account for individual variation, particularly when considering sample size and when making inferences on the economy associated with different types of load carriage using group mean data.

Estimating Energy Expenditure during Level, Uphill, and Downhill Walking.

The load carriage decision aid (LCDA) walking equation was developed from literature-aggregated group mean data to calculate standing and level walking energy expenditures in healthy, military-age adults. The LCDA walking equation has not been validated for use in individuals or graded walking. We aimed to validate the LCDA walking equation as a predictor of standing and level walking energy expenditure in individuals and expand to a new graded walking equation for uphill and downhill walking. We compiled standing, level walking, and graded walking energy expenditures measured in 95 participants from 11 studies. Walking speeds reached up to 1.96 m·s with grades ranging between -40% and 45%. The LCDA walking equation was validated against the aggregated standing and level walking data. The new LCDA graded walking equation was developed and cross-validated on the graded walking trials. We compared each equation against four reference predictive equations with the standard error of estimation (SEE) as the primary criterion. The LCDA walking equation accurately estimated standing and level walking energy expenditure (bias, -0.02 ± 0.20 W·kg; SEE, 0.20 W·kg). Addition of the novel grade term resulted in precise estimates of uphill and downhill walking energy expenditure (bias, 0.09 ± 0.40 W·kg; SEE, 0.42 W·kg). The LCDA walking equation is a valid predictor of standing and walking energy expenditure in healthy, military-age individuals. We developed a novel grade term for estimating both uphill and downhill walking energy expenditure with a single equation. Practitioners can use the new LCDA graded walking equation to calculate energy expenditure during standing as well as walking on level, uphill, and downhill slopes.

Incidence, profiles and correlates of the Cortisol Awakening Response in high-functioning young males with ASD

BackgroundThe Cortisol Awakening Response (CAR) is sometimes dysregulated in young people with Autism Spectrum Disorder (ASD), but previous findings are mostly based upon group mean data and do not report individual responses. In addition, investigation of the correlates of CAR dysregulation has been limited. MethodsTo provide insight into the individual profiles and correlates of the CAR in young males with ASD, 32 high-functioning male participants with ASD aged between 9 yr and 18 yr completed several measures of anxiety and mood, and provided saliva samples at waking and 30 min later for calculation of the CAR. ResultsAlthough group mean data showed an expected CAR profile, over half of the participants had a dysregulated CAR. There was a significant interaction between cortisol concentrations at waking and 30 min later and CAR presence/absence, suggestive of the presence of hyper- and hypo-cortisolism. Unlike previous data regarding CAR and mood states in young females with ASD, there were no significant associations between anxiety or depression and CAR dysregulation in this sample of boys with ASD. ConclusionsThe use of the CAR in research and clinical settings must be accompanied by an awareness of the likelihood of individual variability.

The Respiratory Compensation Point and the Deoxygenation Break Point Are Not Valid Surrogates for Critical Power and Maximum Lactate Steady State.

The Respiratory Compensation Point and the Deoxygenation Break Point Are Not Valid Surrogates for Critical Power and Maximum Lactate Steady State.

Near-infrared spectroscopy using indocyanine green dye for minimally invasive measurement of respiratory and leg muscle blood flow in patients with COPD.

Reliability of near-infrared spectroscopy, measuring indocyanine green (ICG) for minimally invasive assessment of relative muscle blood flow during exercise has been examined in fit young individuals but not in chronic obstructive pulmonary disease (COPD). Here we ask whether it could be used to evaluate respiratory and locomotor muscle perfusion in COPD patients. Vastus lateralis muscle blood flow (MBF, the reference method calculated from arterial and muscle ICG concentration curves) and a blood flow index [BFI, calculated using only the (same) muscle ICG concentration curves] were compared in 10 patients (forced expiratory volume in 1 s: 51 ± 6% predicted) at rest and during cycling at 25, 50, 75, and 100% of peak work rate (WRpeak). Intercostal muscle MBF and BFI were also compared during isocapnic hyperpnea at rest, reproducing ventilation levels up to those at WRpeak. Intercostal and vastus lateralis BFI increased with increasing ventilation during hyperpnea (from 2.5 ± 0.3 to 4.5 ± 0.7 nM/s) and cycling load (from 1.0 ± 0.2 to 12.8 ± 1.9 nM/s), respectively. There were strong correlations between BFI and MBF for both intercostal ( r = 0.993 group mean data, r = 0.872 individual data) and vastus lateralis ( r = 0.994 group mean data, r = 0.895 individual data). Fold changes from rest in BFI and MBF did not differ for either the intercostal muscles or the vastus lateralis. Group mean BFI data showed strong interrelationships with respiratory and cycling workload, and whole body metabolic demand ( r ranged from 0.913 to 0.989) simultaneously recorded during exercise. We conclude that BFI is a reliable and minimally invasive tool for evaluating relative changes in respiratory and locomotor muscle perfusion from rest to peak exercise in COPD patient groups. NEW & NOTEWORTHY We show that noninvasive near-infrared spectroscopic (NIRS) detection of indocyanine green dye (ICG) after peripheral venous injection adequately reflects intercostal and locomotor muscle perfusion during exercise and hyperpnea in patients with chronic obstructive pulmonary disease (COPD). Mean, individual, and fold change responses from rest to exercise or hyperpnea correlated closely with the reference method, which requires arterial sampling. NIRS-ICG is a reliable, robust, and essentially noninvasive tool for assessing relative changes in intercostal and locomotor muscle perfusion in COPD patient groups.

How Accurate Is the Prediction of Maximal Oxygen Uptake with Treadmill Testing?

BackgroundCardiorespiratory fitness measured by treadmill testing has prognostic significance in determining mortality with cardiovascular and other chronic disease states. The accuracy of a recently developed method for estimating maximal oxygen uptake (VO2peak), the heart rate index (HRI), is dependent only on heart rate (HR) and was tested against oxygen uptake (VO2), either measured or predicted from conventional treadmill parameters (speed, incline, protocol time).MethodsThe HRI equation, METs = 6 x HRI– 5, where HRI = maximal HR/resting HR, provides a surrogate measure of VO2peak. Forty large scale treadmill studies were identified through a systematic search using MEDLINE, Google Scholar and Web of Science in which VO2peak was either measured (TM-VO2meas; n = 20) or predicted (TM-VO2pred; n = 20) based on treadmill parameters. All studies were required to have reported group mean data of both resting and maximal HRs for determination of HR index-derived oxygen uptake (HRI-VO2).ResultsThe 20 studies with measured VO2 (TM-VO2meas), involved 11,477 participants (median 337) with a total of 105,044 participants (median 3,736) in the 20 studies with predicted VO2 (TM-VO2pred). A difference of only 0.4% was seen between mean (±SD) VO2peak for TM- VO2meas and HRI-VO2 (6.51±2.25 METs and 6.54±2.28, respectively; p = 0.84). In contrast, there was a highly significant 21.1% difference between mean (±SD) TM-VO2pred and HRI-VO2 (8.12±1.85 METs and 6.71±1.92, respectively; p<0.001).ConclusionAlthough mean TM-VO2meas and HRI-VO2 were almost identical, mean TM-VO2pred was more than 20% greater than mean HRI-VO2.

Analyzing Therapeutic Change Using Modified Brinley Plots: History, Construction, and Interpretation

The paper reviews the history, construction, and interpretation of modified Brinley plots, a scatter plot used in therapy outcome research to compare each individual participant’s scores on the same dependent variable at Time 1 (normally pretreatment baseline; x-axis), with scores at selected times during or after treatment (y-axis). Since 1965 eponymously named Brinley plots have occasionally been used in experimental psychology to display group mean data. Between 1979 and 1995 a number of clinical researchers modified Brinley plots to show individuals’ data but these plots have received little subsequent use. When constructed with orthogonal axes having the same origin and scale values, little or no change over time is shown by individuals’ data points lying on or closely about the diagonal (450o) while the magnitude and direction of any improvement (or deterioration), outliers, and the extent of replication across cases shows via dispersion of points away from 450o. Interpretation is aided by displaying reliable change boundaries, clinical cutoffs, means, variances, confidence intervals, and effect sizes directly on the graph. Modified Brinley plots are directly informative about individual change during therapy in the context of concurrent change in others in the same (or a different) condition, clearly show if outcomes are replicated and if they are clinically significant, and make nomothetic group information, notably effect sizes, directly available. They usefully complement other forms of analysis in therapy outcome research.

Further evidence of HPA-axis dysregulation and its correlation with depression in Autism Spectrum Disorders: Data from girls

To further describe Hypothalamus-Pituitary-Adrenal (HPA) axis activity in children with Autism Spectrum Disorder (ASD), the Diurnal Fluctuation (DF) and Cortisol Awakening Response (CAR) were investigated in a sample of 39 high functioning girls with ASD. Although group mean data conformed to the DF and CAR models, over half of the participants showed inverse CAR and over 14% had inverted DF cortisol concentrations. Examination of three potential sets of predictor factors (physiological, ASD-related, and mood) revealed that only self-reported Major Depressive Disorder was significantly associated with CAR status, and that the girls' concern about dying or suicide was the most powerful contributor to the variance in CAR status. These findings add to the literature regarding the HPA axis dysfunction in children with ASD.

Cannabinoids for fibromyalgia.

This review is one of a series on drugs used to treat fibromyalgia. Fibromyalgia is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue affecting approximately 2% of the general population. People often report high disability levels and poor health-related quality of life (HRQoL). Drug therapy focuses on reducing key symptoms and disability, and improving HRQoL. Cannabis has been used for millennia to reduce pain and other somatic and psychological symptoms. To assess the efficacy, tolerability and safety of cannabinoids for fibromyalgia symptoms in adults. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE to April 2016, together with reference lists of retrieved papers and reviews, three clinical trial registries, and contact with trial authors. We selected randomised controlled trials of at least four weeks' duration of any formulation of cannabis products used for the treatment of adults with fibromyalgia. Two review authors independently extracted the data of all included studies and assessed risk of bias. We resolved discrepancies by discussion. We performed analysis using three tiers of evidence. First tier evidence was derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for drop-outs; at least 200 participants in the comparison, eight to 12 weeks' duration, parallel design), second tier evidence from data that did not meet one or more of these criteria and were considered at some risk of bias but with adequate numbers (i.e. data from at least 200 participants) in the comparison, and third tier evidence from data involving small numbers of participants that were considered very likely to be biased or used outcomes of limited clinical utility, or both. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation). We included two studies with 72 participants. Overall, the two studies were at moderate risk of bias. The evidence was derived from group mean data and completer analysis (very low quality evidence overall). We rated the quality of all outcomes according to GRADE as very low due to indirectness, imprecision and potential reporting bias.The primary outcomes in our review were participant-reported pain relief of 50% or greater, Patient Global Impression of Change (PGIC) much or very much improved, withdrawal due to adverse events (tolerability) and serious adverse events (safety). Nabilone was compared to placebo and to amitriptyline in one study each. Study sizes were 32 and 40 participants. One study used a cross-over design and one used a parallel group design; study duration was four or six weeks. Both studies used nabilone, a synthetic cannabinoid, with a bedtime dosage of 1 mg/day. No study reported the proportion of participants experiencing at least 30% or 50% pain relief or who were very much improved. No study provided first or second tier (high to moderate quality) evidence for an outcome of efficacy, tolerability and safety. Third tier (very low quality) evidence indicated greater reduction of pain and limitations of HRQoL compared to placebo in one study. There were no significant differences to placebo noted for fatigue and depression (very low quality evidence). Third tier evidence indicated better effects of nabilone on sleep than amitriptyline (very low quality evidence). There were no significant differences between the two drugs noted for pain, mood and HRQoL (very low quality evidence). More participants dropped out due to adverse events in the nabilone groups (4/52 participants) than in the control groups (1/20 in placebo and 0/32 in amitriptyline group). The most frequent adverse events were dizziness, nausea, dry mouth and drowsiness (six participants with nabilone). Neither study reported serious adverse events during the period of both studies. We planned to create a GRADE 'Summary of findings' table, but due to the scarcity of data we were unable to do this. We found no relevant study with herbal cannabis, plant-based cannabinoids or synthetic cannabinoids other than nabilone in fibromyalgia. We found no convincing, unbiased, high quality evidence suggesting that nabilone is of value in treating people with fibromyalgia. The tolerability of nabilone was low in people with fibromyalgia.

The Limiting Joint During a Failed Squat: A Biomechanics Case Series.

This investigation examined the characteristics of a failed back squat. Subjects were instructed to perform 3 repetitions of a barbell squat with a 3 repetition maximum load while instrumented for biomechanical analyses and standing atop force platforms. Inverse dynamics calculations were used to determine the net joint moment (NJM) power, work, and energy of the hip, knee, and ankle. Five subjects failed to complete all 3 repetitions, allowing for comparisons between a successful and the failed repetition. Although the NJM power and work were lower at all 3 joints during the failed attempt, the only statistically significant differences were at the hip. These findings suggest that the energy generated by the hip joint NJM limited performance of the task. However, examination of the NJM energy generation over time on an individual basis uncovered some features that were masked by the aggregated group mean data. For some subjects, the knee NJM limited the movement. Additionally, negligible to modest compensations occurred between the hip and knee NJM: a decreased energy generated by one NJM was often accompanied by an increase in energy generated at the other. A limiting joint, or "weak link," may explain the failure to complete a lift. Interventions should address the limiting joint on an individual-specific basis and incorporate assistive exercises that target these deficiencies.