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Concept: Analysis of variance


Study Design Cross-sectional repeated measures. Background Rehabilitation of diastasis rectus abdominis (DRA) generally aims to reduce the inter-rectus distance (IRD). We tested the hypothesis that activation of the transversus abdominis (TrA) before a curl-up would reduce IRD narrowing, with less linea alba (LA) distortion/deformation, which may allow better force transfer between sides of the abdominal wall. Objectives This study investigated behavior of the LA and IRD during curl-ups performed naturally and with preactivation of the TrA. Methods Curl-ups were performed by 26 women with DRA and 17 healthy control participants using a natural strategy (automatic curl-up) and with TrA preactivation (TrA curl-up). Ultrasound images were recorded at 2 points above the umbilicus (U point and UX point). Ultrasound measures of IRD and a novel measure of LA distortion (distortion index: average deviation of the LA from the shortest path between the recti) were compared between 3 tasks (rest, automatic curl-up, TrA curl-up), between groups, and between measurement points (analysis of variance). Results Automatic curl-up by women with DRA narrowed the IRD from resting values (mean U-point between-task difference, -1.19 cm; 95% confidence interval [CI]: -1.45, -0.93; P<.001 and mean UX-point between-task difference, -0.51 cm; 95% CI: -0.69, -0.34; P<.001), but LA distortion increased (mean U-point between-task difference, 0.018; 95% CI: 0.0003, 0.041; P = .046 and mean UX-point between-task difference, 0.025; 95% CI: 0.004, 0.045; P = .02). Although TrA curl-up induced no narrowing or less IRD narrowing than automatic curl-up (mean U-point difference between TrA curl-up versus rest, -0.56 cm; 95% CI: -0.82, -0.31; P<.001 and mean UX-point between-task difference, 0.02 cm; 95% CI: -0.22, 0.19; P = .86), LA distortion was less (mean U-point between-task difference, -0.025; 95% CI: -0.037, -0.012; P<.001 and mean UX-point between-task difference, -0.021; 95% CI: -0.038, -0.005; P = .01). Inter-rectus distance and the distortion index did not change from rest or differ between tasks for controls (P≥.55). Conclusion Narrowing of the IRD during automatic curl-up in DRA distorts the LA. The distortion index requires further validation, but findings imply that less IRD narrowing with TrA preactivation might improve force transfer between sides of the abdomen. The clinical implication is that reduced IRD narrowing by TrA contraction, which has been discouraged, may positively impact abdominal mechanics. J Orthop Sports Phys Ther 2016;46(7):580-589. doi:10.2519/jospt.2016.6536.

Concepts: Scientific method, Transversus abdominis muscle, Absolute deviation, Standard deviation, Abdomen, Analysis of variance, Rectus abdominis muscle, Linea alba


AIM: The purpose of this study was to determine the changes in running mechanics that occur when highly trained runners run barefoot and in a minimalist shoe, and specifically if running in a minimalist shoe replicates barefoot running. METHODS: Ground reaction force data and kinematics were collected from 22 highly trained runners during overground running while barefoot and in three shod conditions (minimalist shoe, racing flat and the athlete’s regular shoe). Three-dimensional net joint moments and subsequent net powers and work were computed using Newton-Euler inverse dynamics. Joint kinematic and kinetic variables were statistically compared between barefoot and shod conditions using a multivariate analysis of variance for repeated measures and standardised mean differences calculated. RESULTS: There were significant differences between barefoot and shod conditions for kinematic and kinetic variables at the knee and ankle, with no differences between shod conditions. Barefoot running demonstrated less knee flexion during midstance, an 11% decrease in the peak internal knee extension and abduction moments and a 24% decrease in negative work done at the knee compared with shod conditions. The ankle demonstrated less dorsiflexion at initial contact, a 14% increase in peak power generation and a 19% increase in the positive work done during barefoot running compared with shod conditions. CONCLUSIONS: Barefoot running was different to all shod conditions. Barefoot running changes the amount of work done at the knee and ankle joints and this may have therapeutic and performance implications for runners.

Concepts: Knee, Force, Classical mechanics, Analysis of variance, Running, Reaction, Ground reaction force, Barefoot running


As part of an ongoing research program into the relationship between cannabis use and emotion processing, participants were assessed on their level of cannabis exposure using the Recreational Cannabis Use Examination, a measure developed specifically to assess cannabis use in Colorado post state legalization. Three groups were created based on self-reported use: a control group who have never used, a casual user group and a chronic user group. Each participant also completed two measures of mood assessment, the Center for Epidemiologic Studies Depression Scale and the State-Trait Anxiety Inventory. Relationships between cannabis use groups and scores on these measures were then analyzed using both correlations and multivariate analysis of variance. Results indicate a relationship between casual cannabis use and scoring highly for depressive symptomatology on the Center for Epidemiologic Studies Depression Scale. There were no significant relationships between cannabis use and scores on the State-Trait Anxiety Inventory.

Concepts: Psychology, Assessment, Psychometrics, Normal distribution, Selective serotonin reuptake inhibitor, Bipolar disorder, Analysis of variance, Emotion


Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors - including socio-economic status, maternal education and calorie availability - a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue.

Concepts: Regression analysis, Public health, Statistics, Statistical significance, Monte Carlo, Analysis of variance, Statistical terminology, Percentage point


Exercise has been shown to improve postischemia perfusion of normal tissues; we investigated whether these effects extend to solid tumors. Estrogen receptor-negative (ER-, 4T1) and ER+ (E0771) tumor cells were implanted orthotopically into syngeneic mice (BALB/c, N = 11-12 per group) randomly assigned to exercise or sedentary control. Tumor growth, perfusion, hypoxia, and components of the angiogenic and apoptotic cascades were assessed by MRI, immunohistochemistry, western blotting, and quantitative polymerase chain reaction and analyzed with one-way and repeated measures analysis of variance and linear regression. All statistical tests were two-sided. Exercise statistically significantly reduced tumor growth and was associated with a 1.4-fold increase in apoptosis (sedentary vs exercise: 1544 cells/mm(2), 95% CI = 1223 to 1865 vs 2168 cells/mm(2), 95% CI = 1620 to 2717; P = .048), increased microvessel density (P = .004), vessel maturity (P = .006) and perfusion, and reduced intratumoral hypoxia (P = .012), compared with sedentary controls. We also tested whether exercise could improve chemotherapy (cyclophosphamide) efficacy. Exercise plus chemotherapy prolonged growth delay compared with chemotherapy alone (P < .001) in the orthotopic 4T1 model (n = 17 per group). Exercise is a potential novel adjuvant treatment of breast cancer.

Concepts: DNA, Cancer, Breast cancer, Oncology, Chemotherapy, Tumor, Neoplasm, Analysis of variance


In humans, the personality dimension ‘sensory processing sensitivity (SPS)’, also referred to as “high sensitivity”, involves deeper processing of sensory information, which can be associated with physiological and behavioral overarousal. However, it has not been studied up to now whether this dimension also exists in other species. SPS can influence how people perceive the environment and how this affects them, thus a similar dimension in animals would be highly relevant with respect to animal welfare. We therefore explored whether SPS translates to dogs, one of the primary model species in personality research. A 32-item questionnaire to assess the “highly sensitive dog score” (HSD-s) was developed based on the “highly sensitive person” (HSP) questionnaire. A large-scale, international online survey was conducted, including the HSD questionnaire, as well as questions on fearfulness, neuroticism, “demographic” (e.g. dog sex, age, weight; age at adoption, etc.) and “human” factors (e.g. owner age, sex, profession, communication style, etc.), and the HSP questionnaire. Data were analyzed using linear mixed effect models with forward stepwise selection to test prediction of HSD-s by the above-mentioned factors, with country of residence and dog breed treated as random effects. A total of 3647 questionnaires were fully completed. HSD-, fearfulness, neuroticism and HSP-scores showed good internal consistencies, and HSD-s only moderately correlated with fearfulness and neuroticism scores, paralleling previous findings in humans. Intra- (N = 447) and inter-rater (N = 120) reliabilities were good. Demographic and human factors, including HSP score, explained only a small amount of the variance of HSD-s. A PCA analysis identified three subtraits of SPS, comparable to human findings. Overall, the measured personality dimension in dogs showed good internal consistency, partial independence from fearfulness and neuroticism, and good intra- and inter-rater reliability, indicating good construct validity of the HSD questionnaire. Human and demographic factors only marginally affected the HSD-s suggesting that, as hypothesized for human SPS, a genetic basis may underlie this dimension within the dog species.

Concepts: Psychology, Psychometrics, Sense, Analysis of variance, Dog, Internal consistency, Dog health, Highly sensitive person


Ferley, DD, Osborn, RW, and Vukovich, MD. The effects of uphill vs. level-grade high-intensity interval training on V[Combining Dot Above]O2max, Vmax, VLT, and Tmax in well-trained distance runners. J Strength Cond Res 27(6): 1549-1559, 2013-Uphill running represents a frequently used and often prescribed training tactic in the development of competitive distance runners but remains largely uninvestigated and unsubstantiated as a training modality. The purpose of this investigation included documenting the effects of uphill interval training compared with level-grade interval training on maximal oxygen consumption (V[Combining Dot Above]O2max), the running speed associated with V[Combining Dot Above]O2max (Vmax), the running speed associated with lactate threshold (VLT), and the duration for which Vmax can be sustained (Tmax) in well-trained distance runners. Thirty-two well-trained distance runners (age, 27.4 ± 3.8 years; body mass, 64.8 ± 8.9 kg; height, 173.6 ± 6.4 cm; and V[Combining Dot Above]O2max, 60.9 ± 8.5 ml·min·kg) received assignment to an uphill interval training group (GHill = 12), level-grade interval training group (GFlat = 12), or control group (GCon = 8). GHill and GFlat completed 12 interval and 12 continuous running sessions over 6 weeks, whereas GCon maintained their normal training routine. Pre- and posttest measures of V[Combining Dot Above]O2max, Vmax, VLT, and Tmax were used to assess performance. A 3 × 2 repeated measures analysis of variance was performed for each dependent variable and revealed a significant difference in Tmax in both GHill and GFlat (p < 0.05). With regard to running performance, the results indicate that both uphill and level-grade interval training can induce significant improvements in a run-to-exhaustion test in well-trained runners at the speed associated with V[Combining Dot Above]O2max but that traditional level-grade training produces greater gains.

Concepts: Variance, Analysis of variance, High-intensity interval training, Running, VO2 max, Interval training, Excess post-exercise oxygen consumption, Long slow distance


Purpose To assess intracranial visual system changes of newly diagnosed Parkinson disease in drug-naïve patients. Materials and Methods Twenty patients with newly diagnosed Parkinson disease and 20 age-matched control subjects were recruited. Magnetic resonance (MR) imaging (T1-weighted and diffusion-weighted imaging) was performed with a 3-T MR imager. White matter changes were assessed by exploring a white matter diffusion profile by means of diffusion-tensor imaging-based parameters and constrained spherical deconvolution-based connectivity analysis and by means of white matter voxel-based morphometry (VBM). Alterations in occipital gray matter were investigated by means of gray matter VBM. Morphologic analysis of the optic chiasm was based on manual measurement of regions of interest. Statistical testing included analysis of variance, t tests, and permutation tests. Results In the patients with Parkinson disease, significant alterations were found in optic radiation connectivity distribution, with decreased lateral geniculate nucleus V2 density (F, -8.28; P < .05), a significant increase in optic radiation mean diffusivity (F, 7.5; P = .014), and a significant reduction in white matter concentration. VBM analysis also showed a significant reduction in visual cortical volumes (P < .05). Moreover, the chiasmatic area and volume were significantly reduced (P < .05). Conclusion The findings show that visual system alterations can be detected in early stages of Parkinson disease and that the entire intracranial visual system can be involved. (©) RSNA, 2017 Online supplemental material is available for this article.

Concepts: Statistics, Cerebrum, Visual perception, Visual system, Analysis of variance, Thalamus, Lateral geniculate nucleus, Optic nerve


Objective: Cardiac rehabilitation (CR) is routinely prescribed for patients with cardiovascular disease (CVD), but data indicate that 20% to 50% of patients do not adhere to CR. Studies have focused on the impact of depression on CR adherence, but results have been equivocal. Irrational health beliefs are related to adherence among diabetes patients, but have not been examined among cardiac patients. This study examined depression and irrational health beliefs as predictors of CR adherence. Method: Sixty-one participants (30% female; mean age = 59.9 ± 11.8; 72% Caucasian), recruited at the outset of an outpatient CR program, completed a baseline questionnaire including measures of depression and irrational health beliefs. CR adherence was defined as the percentage of CR exercise sessions completed. Pearson correlations and analysis of variance determined demographic factors related to adherence. Hierarchical regression analyses examined irrational health beliefs and depression as predictors of CR adherence. Results: Older age (p < .05) and higher income (p < .05) were associated with better CR adherence, but CR adherence was lower among African Americans than Caucasians (p < .01). Depression was not related to adherence (p = .78), but irrational health beliefs predicted CR adherence, after controlling for race/ethnicity, income, and age (β = -.290, ΔR2 = .074, ΔF[1,55] = 5.50, p < .05). Conclusions: Irrational health beliefs predicted CR adherence but depression did not. Thus, poorer adherence to CR was associated with endorsing beliefs that are not based in medical evidence. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Concepts: Regression analysis, Prediction, Futurology, Illness, Pearson product-moment correlation coefficient, Analysis of variance, All rights reserved, Caucasian


Ryan, EJ, Kim, C-H, Fickes, EJ, Williamson, M, Muller, MD, Barkley, JE, Gunstad, J, and Glickman, EL. Caffeine gum and cycling performance: A timing study. J Strength Cond Res 27(1): 259-264, 2013-The purpose of this study was to determine the most efficacious time to administer caffeine (CAF) in chewing gum to enhance cycling performance. Eight male cyclists participated in 5 separate laboratory sessions. During the first visit, the subjects underwent a graded exercise test to determine maximal oxygen consumption (V[Combining Dot Above]O2max). During the next 4 visits, 3 pieces of chewing gum were administered at 3 time points (120-minute precycling, 60-minute precycling, and 5-minute precycling). In 3 of the 4 visits, at 1 of the time points mentioned previously, 300 mg of CAF was administered. During the fourth visit, placebo gum was administered at all 3 time points. The experimental trials were defined as follows: trial A (-120), trial B (-60), trial C (-5), and trial D (Placebo). After baseline measurements, time allotted for gum administration, and a standard warm-up, the participants cycled at 75% V[Combining Dot Above]O2max for 15 minutes then completed a 7-kJ·kg cycling time trial. Data were analyzed using a repeated measures analysis of variance. Cycling performance was improved in trial C (-5), but not in trial A (-120) or trial B (-60), relative to trial D (Placebo). CAF administered in chewing gum enhanced cycling performance when administered immediately prior, but not when administered 1 or 2 hours before cycling.

Concepts: Variance, Physical exercise, Exercise, Analysis of variance, VO2 max, Physical fitness, Chewing gum, Individual time trial