List of Records in School of Human Movement Studies Publications - UQ eSpace

A birth-weight questionnaire indicated that life style modifies the birth weight and metabolic syndrome relationship at age 36

2009-04-02T14:49:32Z

Able athletes with disabilities: Issues and group work

Hanrahan, S.J. — 2007-08-14T12:16:46Z

Abnormal tenocyte morphology is more prevalent than collagen disruption in asymptomatic athletes' patellar tendons

2009-03-10T12:02:15Z

This study investigated the prevalence of each of the four features of patellar tendinosis in asymptomatic athletic subjects undergoing patellar tendon anterior cruciate ligament (ACL) reconstruction. Fifty subjects (39 males and 11 females) undergoing ACL reconstruction using a patellar tendon graft were screened for previous tendon symptoms, training and playing history and had their patellar tendons examined with ultrasound prior to surgery. During surgery, a small piece of proximal posterocentral tendon was harvested, fixed and examined under light microscopy. Histopathological changes were graded for severity. Results demonstrate that 18 tendons were abnormal on light microscopy and 32 were normal. There were no differences between subjects with and without pathology in respect of training, recovery after surgery and basic anthropometric measures. Three tendons were abnormal on ultrasound but only one had proximal and central changes. Tendons showed a consistent series of changes. Tenocyte changes were found in all but one of the abnormal tendons. In all but one of the tendons with increased ground substance there were tenocyte changes, and collagen separation was always associated with both tenocyte changes and increased ground substance. No tendons demonstrated neovascularization. It appears that cellular changes must be present if there is an increase in ground substance, or collagen and vascular changes. Further research is required to confirm these findings. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved

A brief on school-linked mental health services

Lawson, H. — 2009-03-09T13:43:45Z

Absence of an increase in the soleus H-reflex with increasing voluntary drive during shortening contractions in man

Oya, T. og Cresswell, A — 2007-08-23T22:08:49Z

Absorption and pharmacokinetics of bilirubin and biliverdin administration in the rat

2009-10-21T14:40:19Z

Abstract motor programming in prehension: Normal and pathological performance

Tresilian, J. R. — 2008-06-10T14:07:09Z

Abstract: The Embodiment of Learning: What the Sociology of Education Doesn't Say about 'Risk' in Going to School

2009-03-03T15:07:37Z

Despite burgeoning interests in "the body" as a topic of sociological interest and analysis in recent decades, with few notable exceptions, the sociology of education has not taken as seriously as it might how "embodied subjectivities" both shape and are framed by contexts of teaching and learning. There are processes of formal education that may either damage, or richly reward and sustain individual identities, by culture and class. This article suggests that embracing issues of corporeality in analyses of schooling may help us to better understand not only the complexity and importance of "emotions" (or rather the affective dimensions of corporeality) in teaching and learning, but also the immense "risks" involved, for some children, in displaying them when cultures of "performativity" dominate and prevail in schools. Our analysis highlights ways in which powerful discursive tendencies around body perfection, health and performance permeate schools, and influence how and what teachers and pupils think and learn about their identity and self-worth. Informed by data drawn from an ongoing study of the relationships between education, eating disorders and "obesity discourse", our analyses illustrate the complexity of such processes, while also highlighting the merits of embracing "embodiment" in theories of learning, teaching, social reproduction and change.

A case for intervention? Sedentary behaviour in a sample of middle-to-high income Mexicans

Gilson, N. D. — 2009-02-19T13:04:45Z

Gilson evaluates the need for physical activity (PA) intervention in a select group of urban, middle-to-high income men and women from the Northeast of Mexico. This was undertaken by assessing the extent to which the sample fulfilled contemporary PA criteria. Results show that all subjects reported an income greater than 5 times the national minimum, classifying the sample within the middle-to-high socio-economic cohort of Mexico.

Accelerometer Data Reduction: A Comparison of Four Reduction Algorithms on Select Outcome Variables

2009-03-10T15:18:58Z

Purpose: Accelerometers are recognized as a valid and objective tool to assess free-living physical activity. Despite the widespread use of accelerometers, there is no standardized way to process and summarize data from them, which limits our ability to compare results across studies. This paper a) reviews decision rules researchers have used in the past, b) compares the impact of using different decision rules on a common data set, and c) identifies issues to consider for accelerometer data reduction. Methods: The methods sections of studies published in 2003 and 2004 were reviewed to determine what decision rules previous researchers have used to identify wearing period, minimal wear requirement for a valid day, spurious data, number of days used to calculate the outcome variables, and extract bouts of moderate to vigorous physical activity (MVPA). For this study, four data reduction algorithms that employ different decision rules were used to analyze the same data set. Results: The review showed that among studies that reported their decision rules, much variability was observed. Overall, the analyses suggested that using different algorithms impacted several important outcome variables. The most stringent algorithm yielded significantly lower wearing time, the lowest activity counts per minute and counts per day, and fewer minutes of MVPA per day. An exploratory sensitivity analysis revealed that the most stringent inclusion criterion had an impact on sample size and wearing time, which in turn affected many outcome variables. Conclusions: These findings suggest that the decision rules employed to process accelerometer data have a significant impact on important outcome variables. Until guidelines are developed, it will remain difficult to compare findings across studies.

Access to physical activity: The stories of six young women negotiating a physically active lifestyle

Hunt, K. B. og Lee, J. T. og Macdonald, D. — 2007-08-24T01:46:10Z

Accumulating Brisk Walking for Fitness, Cardiovascular Risk, and Psychological Health

2009-03-03T10:14:10Z

MURPHY, M., A. NEVILL, C. NEVILLE, S. BIDDLE, and A. HARDMAN. Accumulating brisk walking for fitness, cardiovascular risk, and psychological health. Med. Sci. Sports Exerc., Vol. 34, No. 9, pp. 1468–1474, 2002. Purpose: To compare the effects of different patterns of regular brisk walking on fitness, risk factors for cardiovascular disease, and psychological well-being in previously sedentary adults. Methods: Twenty-one subjects (14 women), aged 44.5 ± 6.1 yr (mean ± SD) were randomly assigned to two different, 6-wk programs of brisk walking in a cross-over design, with an interval of 2 wk. One program comprised one 30-min walk per day, 5 d·wk-1 (long bout) and the other three 10-min walks per day, also 5 d·wk-1 (short bouts). All walking was at 70–80% of predicted maximal heart rate. Maximal oxygen uptake ([latin capital V with dot above]O2max), body composition, resting arterial blood pressure, fasting plasma lipoprotein variables, and psychological parameters were assessed before and after each program. Results: Overall, subjects completed 88.2 ± 1.1% and 91.3 ± 4.1% of prescribed total walking time in the short- and long-bout programs, respectively. Both programs increased plasma concentrations of high-density lipoprotein cholesterol, and decreased concentrations of triacylglycerol and total cholesterol (all P < 0.05). There were no changes in body mass, but the sum of four skinfolds, waist circumference, and hip circumference were decreased after both walking programs (all P < 0.05). Predicted [latin capital V with dot above]O2max increased with both programs (P < 0.05), but this increase was greater with the program based on short bouts (P < 0.05). Both walking patterns resulted in similar decreases in tension/anxiety (P < 0.05). Conclusion: These findings suggest that three short bouts (10 min) of brisk walking accumulated throughout the day are at least as effective as one continuous bout of equal total duration in reducing cardiovascular risk and improving aspects of mood in previously sedentary individuals.

Accuracy of DXA scanning of the thoracic spine: cadaveric studies comparing BMC, areal BMD and geometric estimates of volumetric BMD against ash weight and CT measures of bone volume

2009-03-10T15:17:52Z

Biomechanical studies of the thoracic spine often scan cadaveric segments by dual energy X-ray absorptiometry (DXA) to obtain measures of bone mass. Only one study has reported the accuracy of lateral scans of thoracic vertebral bodies. The accuracy of DXA scans of thoracic spine segments and of anterior-posterior (AP) thoracic scans has not been investigated. We have examined the accuracy of AP and lateral thoracic DXA scans by comparison with ash weight, the gold-standard for measuring bone mineral content (BMC). We have also compared three methods of estimating volumetric bone mineral density (vBMD) with a novel standard–ash weight (g)/bone volume (cm3) as measured by computed tomography (CT). Twelve T5–T8 spine segments were scanned with DXA (AP and lateral) and CT. The T6 vertebrae were excised, the posterior elements removed and then the vertebral bodies were ashed in a muffle furnace. We proposed a new method of estimating vBMD and compared it with two previously published methods. BMC values from lateral DXA scans displayed the strongest correlation with ash weight (r=0.99) and were on average 12.8% higher (p<0.001). As expected, BMC (AP or lateral) was more strongly correlated with ash weight than areal bone mineral density (aBMD; AP: r=0.54, or lateral: r=0.71) or estimated vBMD. Estimates of vBMD with either of the three methods were strongly and similarly correlated with volumetric BMD calculated by dividing ash weight by CT-derived volume. These data suggest that readily available DXA scanning is an appropriate surrogate measure for thoracic spine bone mineral and that the lateral scan might be the scan method of choice.

Accuracy of pQCT for evaluating the aged human radius: an ashing, histomorphometry and failure load investigation

2009-03-13T13:09:07Z

Introduction: Quantifying the determinants of bone strength is essential to understanding if or how the structure will fail under load. Determining failure requires knowledge of material and geometric properties. However, characterizing the relative contributions of geometric parameters of bone to overall bone strength has been difficult to date because of limitations in imaging technology. Peripheral quantitative computed tomography (pQCT) uses digital images to derive estimates of bone strength in the peripheral skeleton and is a relatively safe technique to differentiate cortical from trabecular bone and assess bone geometry and density. However, in a compromised osteoporotic bone, thin cortices and low scan resolution can limit accurate analysis. Methods: Therefore, in this two-part investigation we scanned ten pairs (n=20) of fresh-frozen radial specimens [female, mean (SD) age 79(6) years] using pQCT (XCT 2000) at the 4 and 30% sites of the distal radius. We investigated the accuracy of four different acquisition resolutions (200, 300, 400, 500 μm) and several analysis modes and thresholds. We evaluated (1) the accuracy of the Norland/Stratec XCT 2000 pQCT in assessing low-density bones by comparing pQCT outcomes to ashing and histomorphometry and (2) the association of geometric parameters by pQCT and areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) to failure load at the distal radius. Results: Using histomorphometry and ashing as reference standards, we found that pQCT scans varied systematically and underestimated or overestimated total area and mineral content at the radial midshaft depending on the analysis algorithm and selected threshold. Overall, most pQCT analysis modes were accurate. In the mechanical testing studies, bone mineral content and cortical bone content at the midshaft were strongly associated with failure load. The pQCT parameters that best accounted for failure load were total content at the 4% site and cortical thickness at the 30% site and they accounted for up to 81% of the variance. The best DXA predictor of failure load was total density at the distal third site and it explained 75% of the variance. Conclusions: In summary, analysis mode, resolution and thresholding affected pQCT outputs at the radial midshaft. This study extends our understanding of pQCT analysis and provides important data regarding determinants of bone strength at the distal radius

Accuracy of SRM and power tap power monitoring systems for bicycling

2007-08-15T03:18:46Z

Purpose: Although manufacturers of bicycle power monitoring devices SRM and Power Tap (PT) claim accuracy to within 2.5%, there are limited scientific data available in support. The purpose of this investigation was to assess the accuracy of SRM and PT under different conditions. Methods: First, 19 SRM were calibrated, raced for 11 months, and retested using a dynamic CALRIG (50-1000 W at 100 rpm). Second, using the same procedure, five PT were repeat tested on alternate days. Third, the most accurate SRM and PT were tested for the influence of cadence (60, 80, 100, 120 rpm), temperature (8 and 21degreesC) and time (1 h at similar to300 W) on accuracy. Finally, the same SRM and PT were downloaded and compared after random cadence and gear surges using the CALRIG and on a training ride. Results: The mean error scores for SRM and PT factory calibration over a range of 50-1000 W were 2.3 +/- 4.9% and -2.5 +/- 0.5%, respectively. A second set of trials provided stable results for 15 calibrated SRM after 11 months (-0.8 +/- 1.7%), and follow-up testing of all PT units confirmed these findings (-2.7 +/- 0.1%). Accuracy for SRM and PT was not largely influenced by time and cadence; however. power output readings were noticeably influenced by temperature (5.2% for SRM and 8.4% for PT). During field trials, SRM average and max power were 4.8% and 7.3% lower, respectively, compared with PT. Conclusions: When operated according to manufacturers instructions, both SRM and PT offer the coach, athlete, and sport scientist the ability to accurately monitor power output in the lab and the field. Calibration procedures matching performance tests (duration, power, cadence, and temperature) are, however, advised as the error associated with each unit may vary.

Achievement goal orientations, attributional style, and motivational climate as predictors of performance and persistance

Hanrahan, S.J. og Cerin, E. og Hartel, C. — 2007-08-24T02:25:50Z

Achievement Goal Profiles in School Physical Education: Differences in Self-determination, Sport Ability Beliefs, and Physical Activity

2009-02-27T11:54:10Z

Background: Physical activity is a major public health issue as trends show inadequate levels of physical activity for health and rising levels of obesity. Understanding motivation for physical activity in youth by assessing their motivational profiles associated with school physical education could inform future interventions. Aims: To investigate goal orientation and perceived competence profiles in young adolescents and to test the nature of differences between clusters on motivational and physical activity measures. Sample: Boys (N = 427) and girls (N = 391), aged 11-14 years, from two comprehensive schools in England. Method: Cross-sectional survey using cluster analysis. Results: Clusters reflecting 'highly', 'moderately', and 'lowly' motivated youth were found. Physical activity, incremental sport ability beliefs, and self-determined motivation were highest in the highly motivated cluster. Girls were under-represented in this cluster. Conclusions: High motivation towards physical activity is characterised by high task and high ego orientation, and high perceived competence. With only 38% of this group being girls, interventions are required to boost motivation for girls based on goal and self-determination approaches

A circle is a wheel is a circle

Minniti, A. M. — 2008-06-10T13:53:25Z

A Community-Based Fitness and Mobility Exercise Program for Older Adults with Chronic Stroke: A Randomized, Controlled Trial

2009-03-10T13:48:22Z

Objectives: To examine the effects of a community-based group exercise program for older individuals with chronic stroke. Design: Prospective, single-blind, randomized, controlled intervention trial. Setting: Intervention was community-based. Data collection was performed in a research laboratory located in a rehabilitation hospital. Participants: Sixty-three older individuals (aged≥50) with chronic stroke (poststroke duration≥1 year) who were living in the community. Intervention: Participants were randomized into intervention group (n=32) or control group (n=31). The intervention group underwent a fitness and mobility exercise (FAME) program designed to improve cardiorespiratory fitness, mobility, leg muscle strength, balance, and hip bone mineral density (BMD) (1-hour sessions, three sessions/week, for 19 weeks). The control group underwent a seated upper extremity program. Measurements: Cardiorespiratory fitness (maximal oxygen consumption), mobility (6-minute walk test), leg muscle strength (isometric knee extension), balance (Berg Balance Scale), activity and participation (Physical Activity Scale for Individuals with Physical Disabilities), and femoral neck BMD (using dual-energy x-ray absorptiometry). Results: The intervention group had significantly more gains in cardiorespiratory fitness, mobility, and paretic leg muscle strength than controls. Femoral neck BMD of the paretic leg was maintained in the intervention group, whereas a significant decline of the same occurred in controls. There was no significant time-by-group interaction for balance, activity and participation, nonparetic leg muscle strength, or nonparetic femoral neck BMD. Conclusion: The FAME program is feasible and beneficial for improving some of the secondary complications resulting from physical inactivity in older adults living with stroke. It may serve as a good model of a community-based fitness program for preventing secondary diseases in older adults living with chronic conditions.

A comparison of muscle damage and systematic inflammatory responses to submaximal versus maximal eccentric exercise

2007-08-23T22:09:04Z

A comparison of muscle damage and systemic inflammatory responses to submaximal versus maximal eccentric exercise

2007-08-23T22:09:22Z

A comparison of peak power in the shoulder press and shoulder throw

2007-08-14T17:57:25Z

The ability to generate peak power is central for performance in many sports. Currently two distinct resistance training methods are used to develop peak power, the heavy weight/slow velocity and light weight/fast velocity regimes. When using the light weight/fast velocity power training method it was proposed that peak power would be greater in a shoulder throw exercise compared with a normal shoulder press. Nine males performed three lifts in the shoulder press and shoulder throw at 30% and 40% of their one repetition maximum (1RM). These lifts were performed identically, except for the release of the bar in the throw condition. A potentiometer attached to the bar measured displacement and duration of the lifts. The time of bar release in the shoulder throw was determined with a pressure switch. ANOVA was used to examine statistically significant differences where the level of acceptance was set at p <0.05. Peak power was found to be significantly greater in the shoulder throw at 30% of 1 RM condition [F, (1, 23) =2.325 p <0.05) and at 40% of 1 RM [F, (1, 23) =2.905 p <0.05) compared to values recorded for the respective shoulder presses. Peak power was also greater in the 30% of 1 RM shoulder throw (510 +/- 103W) than in the 40% of 1 RM shoulder press (471 +/- 96W). Peak power was produced significantly later in the shoulder throw versus the shoulder press. This differing power reflected a greater bar velocity of the shoulder throw at both assigned weights compared with the shoulder press.

A comparison of posture and muscle activity during tablet computer, desktop computer and paper use by young children

2009-03-05T12:13:06Z

A comparison of the cycling performance of cyclists and triathletes

2007-08-15T01:33:14Z

The aim of this study was to compare the cycling performance of cyclists and triathletes. Each week for 3 weeks, and on different days, 25 highly trained male cyclists and 18 highly trained male triathletes performed: (1) an incremental exercise test on a cycle ergometer for the determination of peak oxygen consumption ((V) over dot O-2peak), peak power output and the first and second ventilatory thresholds, followed 15 min later by a sprint to volitional fatigue at 150% of peak power output; (2) a cycle to exhaustion test at the (V) over dot O-2peak power output; and (3) a 40-km cycle time-trial. There were no differences in (V) over dot O-2peak, peak power output, time to volitional fatigue at 150% of peak power output or time to exhaustion at (V) over dot O-2peak power output between the two groups. However, the cyclists had a significantly faster time to complete the 40-km time-trial (56:18 +/- 2:31 min:s; mean +/- s) than the triathletes (58:57 +/- 3:06 min:s; P < 0.01), which could be partially explained (r = 0.34-0.51; P < 0.05) by a significantly higher first (3.32 +/- 0.36 vs 3.08 +/- 0.36 l . min(-1)) and second ventilatory threshold (4.05 +/- 0.36 vs 3.81 +/- 0.29 l . min(-1); both P < 0.05) in the cyclists compared with the triathletes. In conclusion, cyclists may be able to perform better than triathletes in cycling time-trial events because they have higher first and second ventilatory thresholds.

A comparison of the physiological demands of well-trained cyclists to field and laboratory mountain bike race simulation

2009-03-04T15:39:27Z

A comparison of two methods for the calculation of accumulated oxygen deficit

2007-08-15T01:33:10Z

The aim of this study was to compare accumulated oxygen deficit data derived using two different exercise protocols with the aim of producing a less time-consuming test specifically for use with athletes. Six road and four track male endurance cyclists performed two series of cycle ergometer tests. The first series involved five 10 min sub-maximal cycle exercise bouts, a (V) over dotO(2peak) test and a 115% (V) over dotO(2peak) test. Data from these tests were used to estimate the accumulated oxygen deficit according to the calculations of Medbo et al. (1988). In the second series of tests, participants performed a 15 min incremental cycle ergometer test followed, 2 min later, by a 2 min variable resistance test in which they completed as much work as possible while pedalling at a constant rate. Analysis revealed that the accumulated oxygen deficit calculated from the first series of tests was higher (P< 0.02) than that calculated from the second series: 52.3 +/- 11.7 and 43.9 +/- 6.4 ml . kg(-1), respectively (mean +/- s). Other significant differences between the two protocols were observed for (V) over dot O-2peak, total work and maximal heart rate; all were higher during the modified protocol (P<0.01 and P< 0.02, respectively). Oxygen kinetics were also significantly faster during the modified 2 min maximal test. We conclude that the difference in accumulated oxygen deficit between protocols was probably due to a reduced oxygen uptake, possibly caused by a slower oxygen on-response during the 115% (V) over dot O-2peak test in the first series, and (V) over dot O-2-power output regression differences caused by an elevated (V) over dot O-2 during the early stages of the second series.

A Complex Partnership to Optimize and Stabilize the Public Child Welfare Workforce

2009-03-06T16:08:22Z

This article introduces a complex partnership developed in a Northeastern state. Its aim is to optimize and stabilize the public child welfare workforce and thereby improve outcomes for clients as well as results for country and borough agencies. To achieve this aim, this partnership has implemented a comprehensive, multi‐faceted strategy. Intermediaries play pivotal roles in this partnership system. Originating with a focus on social work education, this partnership quickly focused on research. Participatory workforce research aimed at understanding turnover led to a hybrid, complex intervention involving team‐driven articipatory action research and learning in local agencies. These design teams, facilitated by social workers, connect professional development and organizational development to retention planning and ultimately, to workforce optimization initiatives. (Author abstract)

A conceptual understanding of motivation

Mallett, C. J. — 2007-08-15T02:29:49Z

A cost-benefit analysis of early specialization

Cote, Jean — 2009-03-03T16:34:35Z

Acquisition of skill

Abernethy, A.B. — 2007-08-14T10:57:52Z

A Critical Appraisal of Narrative in Sport History: Reading the Surf Lifesaving Debate

Phillips, Murray G. — 2007-03-22T08:58:21Z

All debates in history—who started the Cold War, how successful were the Chartists in achieving their aims, to what extent was the recession of the American frontier culturally significant in American history— are debates between competing narrative interpretations. Moreover, because the historical imagination itself exists intertextually within our own social and political environment, the past is never discovered set aside from everyday life. History is designed and composed in the here and now.

A critical discourse analysis of the Queensland 1-10 Health and Physical Education syllabus and support materials: Reviewing the emancipatory agenda

Rossi, A.J. — 2007-08-23T20:47:50Z

A cross-cultural investigation of the use of teaching styles

2007-08-15T06:01:47Z

Teacher beliefs are a major influence on teacher actions. Because context influences beliefs, it was the purpose of this study to explore teachers' beliefs about Mosston's Spectrum of Teaching Styles from an international perspective. Over 1,400 teachers from 7 countries completed a survey related to their self-reported use of and beliefs about various teaching styles. Data suggested a shared core of reproduction teaching style use. The use of and beliefs about the production styles of teaching were more varied. Teachers' use of styles was significantly related to their beliefs about the styles. [PUBLICATION ABSTRACT]

Action Schools! BC: A Socioecological Approach to Modifying Chronic Disease Risk Factors in Elementary School Children

2009-03-26T17:57:32Z

Active Australian children - A health and education challenge for families, schools and communities

2007-08-24T01:46:37Z

Actively tracking 'passive' stability in a ball bouncing task

2007-10-17T12:16:51Z

This study investigates the control involved in a task where subjects rhythmically bounce a ball with a hand-held racket as regularly as possible to a prescribed amplitude. Stability analyses of a kinematic model of the ball-racket system revealed that dynamically stable solutions exist if the racket hits the ball in its decelerating upward movement phase. Such solutions are resistant to small perturbations obviating explicit error corrections. Previous studies reported that subjects' performance was consistent with this 'passive' stability. However, some 'active' control is needed to attune to this passive stability. The present study investigates this control by confronting subjects with perturbations where stable behavior cannot be maintained solely from passive stability. Six subjects performed rhythmic ball bouncing in a virtual reality set-up with and without perturbations. In the perturbation trials the coefficient of restitution of the ball-racket contact was changed at every fifth contact leading to unexpected ball amplitudes. The perturbations were compensated for within 2-3 bouncing cycles such that ball amplitudes decreased to initial values. Passive stability was reestablished as indicated by negative racket acceleration. Results revealed that an adjustment of the racket period ensured that the impacts occurred at a phase associated with passive stability. These findings were implemented in a model consisting of a neural oscillator that drives a mechanical actuator (forearm holding the racket) to bounce the ball. Following the perturbation, the oscillator's period is adjusted based on the perceived ball velocity after impact. Simulation results reproduced the major aspects of the experimental results. (C) 2003 Elsevier B.V. All rights reserved.

A curious illusion suggests complex cue interactions in distance perception

Tresilian, J. R. og Mon-Williams, M. — 2008-06-10T14:07:12Z

Binocular perception of the distance to, and between, paint light targets depends on vergence angle: Increasing vergence angle decreases apparent distance and vice versa. Placing a prism base out requires increased convergence for target fixation; base in requires decreased convergence: The triangulation account of distance perception predicts that apparent target distance should decrease and increase respectively. It was found that the results predicted from the triangulation account were not observed. Egocentric target distance was judged to be greater regardless of prism orientation or target distance. A heuristic model provided an explanation for this phenomenon and allowed for the prediction of modulations of the overestimate with simple manipulations of the viewing environment. Further experiments confirmed these predictions and demonstrated that the effects of the prism could be greatly attenuated by adding additional distance cues.

Acute adaptation to low volume eccentric exercise

Paddon-Jones, D. og Abernethy, P. J. — 2007-08-14T15:50:49Z

Purpose: Many symptoms of eccentric muscle damage can be substantially reduced if a similar eccentric bout is repeated within several weeks of the initial bout. The purpose of this study was to determine whether a nondamaging, low repetition, low volume eccentric exercise bout could also provide a protective/adaptive effect. h Methods: Subjects were assigned to a control (CON), eccentric exercise (ECC), or low volume familiarized eccentric exercise group (LV+ECC). Before the study, the LV+ECC group performed six maximal eccentric contractions during two familiarization sessions. The main eccentric bout targeted the elbow flexor muscle group and consisted of 36 maximal eccentric contractions. Muscle soreness, upper arm girth, elbow angle. creatine kinase activity, isometric torque, and concentric and eccentric torque at 0.52 and 3.14 rad s(-1) were assessed 0. 1, 2, 3. 4, 7, and 10 d postexercise. Results: No evidence of muscle damage was observed as a result of the low volume eccentric bouts. Nevertheless, with the exception of muscle soreness and concentric torque, all variables recovered more rapidly in the LV+ECC group (P < 0.05). Conclusion: Adaptation to eccentric exercise can occur in the absence of significant muscle damage. Exposure to a small number of nondamaging eccentric contractions can significantly improve recovery after a subsequent damaging eccentric bout. Furthermore, this adaptation appears to be mode-specific and not applicable to concentric contractions.

Acute effects of high-intensity endurance exercise on subsequent resistance activity

Leveritt, M. og Abernethy, P. J. — 2008-06-10T13:54:07Z

This study investigated the effect of high-intensity endurance on subsequent isoinertial and isokinetic resistance exercise. One woman and five men (mean 6 SD: age 5 20.3 6 2.5 years; body mass 5 75.1 6 10.2 kg; height 5 177.8 6 10.3 cm) performed isoinertial and isokinetic resistance exercise under control conditions (no experimental intervention) and after an acute bout of high-intensity endurance exercise. Endurance exercise consisted of five 5-minute bouts of incremental cycle exercise at between 40 and 100% of peak cycle ergometer oxygen consumption (peak V˙ O2). Isoinertial resistance exercise consisted of three sets of squats with a load of 80% of one repetition maximum. Isokinetic resistance exercise consisted of five repetitions of leg extensions performed at five different contractile speeds (1.05, 2.09, 3.14, 4.19, and 5.24 rad•s21). Significant reductions in isokinetic torque at 0.52 rad from full extension (T30) were observed after high-intensity endurance exercise. Endurance exercise also caused significant reductions in the number of isoinertial squat lifts performed. Plasma lactate values, measured before subjects performed resistance activity, were significantly higher after high intensity endurance exercise (6.16 6 2.28 mmol•L21) when compared with the control condition (0.50 6 0.45 mmol•L21). It was concluded that an acute bout of high-intensity endurance exercise may inhibit performance in a subsequent bout of resistance activity.

Acute exercise and T-lymphocyte expression of the early activation marker CD69

2009-03-04T16:00:23Z

This study aimed to determine the effect of acute exercise on the proliferation and expression of activation markers on T-lymphocytes.

Acute exercise response of blood glucose to short-term exercise training in patients with type 2 diabetes

2008-04-22T21:49:46Z

Acute exposure to cyclosporine does not increase plasma homocysteine in rats

2007-08-15T06:37:05Z

There is interest in the postulate that cyclosporine a (CsA) contributes to the elevated homocysteine levels seen in organ transplant recipients, as hyperhomocysteinemia is now considered an independent risk factor for cardiovascular disease (CVD) and may partially explain the increased prevalence of CVD in this population. The main purpose of this investigation was to determine the effect of CsA administration on plasma homocysteine. Eighteen female Sprague Dawley rats (4 months old) were randomly assigned to either a treatment or a control group. For 18 days the treatment group received of CsA (25 mg/kg/d) while the control group received the same volume of the vehicle. Blood samples obtained following sacrifice to measure CsA, total homocysteine, and plasma creatinine. There were no significant differences in plasma homocysteine (mean values SD: treatment = 4.79 +/- 0.63 mu mol/L, control = 4.46 +/- 0.75 mu mol/L; P = .37). Homocysteine was not significantly correlated with final CsA concentrations (r = .17; P = .69). There was a significant difference in plasma creatinine values between the two groups (treatment = 60.44 +/- 7.68 mu mol/L, control = 46.33 +/- 1.66 mu mol/L; P < .001). Furthermore, plasma homocysteine and creatinine were positively correlated with the treatment group (r = .73; P < .05) but not the controls (r = -.10; P = .81). In conclusion, CsA does not influence plasma homocysteine concentrations in rats.

Acute exposure to cyclosprine A does not increase plasma homocysteine in rats

2007-08-24T01:18:27Z

Acute high-intensity interval training improves T-vent and peak power output in highly trained males.

2007-08-13T13:07:46Z

This study examined the effects of four high-intensity interval-training (HIT) sessions performed over 2 weeks on peak volume of oxygen uptake (VO2peak), the first and second ventilatory thresholds (UT VT2) and peak power output (PPO) in highly trained cyclists. Fourteen highly trained male cyclists (VO2peak = 67.5 +/- 3.7 ml . kg(-1) . min(-1)) performed a ramped cycle test to determine VO2peak VT1 VT2, and PPO. Subjects were divided equally into a HIT group and a control group. The HIT group performed four HIT sessions (20 x 60 s at PPO, 120 s recovery); the V-02peak test was repeated <I wk after the HIT program. Control subjects maintained their regular training program and were reassessed under the same timeline. There was no change in V0(2peak) for either group; however, the HIT group showed a significantly greater increase in VT1, (+22% vs. -3%), VT2 (+15% vs. -1%), and PPO (+4.3 vs. -.4%) compared to controls (all P <.05). This study has demonstrated that HIT can improve VT1, VT2,, and PPO, following only four HIT sessions in already highly trained cyclists.

Acute weight loss followed by an aggressive nutritional recovery strategy has little impact on on-water rowing performance

2007-08-15T09:58:58Z

Objectives: To assess the influence of moderate, acute weight loss on on-water rowing performance when aggressive nutritional recovery strategies were used in the two hours between weigh in and racing. Methods: Competitive rowers (n=17) undertook three on-water 1800 m time trials under cool conditions ( mean (SD) temperature 8.4 (2.0)degrees C), each separated by 48 hours. No weight limit was imposed for the first time trial-that is, unrestricted body mass (UNR1). However, one of the remaining two trials followed a 4% loss in body mass in the previous 24 hours (WT-4%). No weight limit was imposed for the other trial (UNR2). Aggressive nutritional recovery strategies (WT-4%, 2.3 g/kg carbohydrate, 34 mg/kg Na+, and 28.4 ml/kg fluid; UNR, ad libitum) were used in the first 90 minutes of the two hours between weigh in and performance trials. Results: WT-4% had only a small and statistically non-significant effect on the on-water time trial performance ( mean 1.0 second, 95% confidence interval (CI) 20.9 to 2.8; p=0.29) compared with UNR. This was despite a significant decrease in plasma volume at the time of weigh in for WT-4% compared with UNR (-9.2%, 95% CI -12.8% to -5.6%; p<0.001). Conclusions: Acute weight loss of up to 4% over 24 hours, when combined with aggressive nutritional recovery strategies, can be undertaken with minimal impact on on-water rowing performance, at least in cool conditions.

Adaptation to chronic eccentric exercise in humans: the influence of contraction velocity

2007-08-14T15:52:35Z

We compared changes in muscle fibre composition and muscle strength indices following a 10 week isokinetic resistance training programme consisting of fast (3.14 rad(.)s(-1)) or slow (0.52 rad(.)s(-1)) velocity eccentric muscle contractions. A group of 20 non-resistance trained subjects were assigned to a FAST (n = 7), SLOW (n = 6) or non-training CONTROL (n = 7) group. A unilateral training protocol targeted the elbow flexor muscle group and consisted of 24 maximal eccentric isokinetic contractions (four sets of six repetitions) performed three times a week for 10 weeks. Muscle biopsy samples were obtained from the belly of the biceps brachii. Isometric torque and concentric and eccentric torque at 0.52 and 3.14 rad(.)s(-1) were examined at 0, 5 and 10 weeks. After 10 weeks, the FAST group demonstrated significant [mean (SEM)] increases in eccentric [29.6 (6.4)%] and concentric torque [27.4 (7.3) %] at 3.14 rad(.)s(-1), isometric torque [21.3 (4.3)%] and eccentric torque [25.2 (7.2) %] at 0.52 rad(.)s(-1). The percentage of type I fibres in the FAST group decreased from [53.8 (6.6)% to 39.1 (4.4)%] while type lib fibre percentage increased from [5.8 (1.9)% to 12.9 (3.3)%; P < 0.05]. In contrast. the SLOW group did not experience significant changes in muscle fibre type or muscle torque. We conclude that neuromuscular adaptations to eccentric training stimuli may be influenced by differences in the ability to cope with chronic exposure to relatively fast and slow eccentric contraction velocities. Possible mechanisms include greater cumulative damage to contractile tissues or stress induced by slow eccentric muscle contractions.

A Descriptive Epidemiology of Screen-based Media Use in Youth: A Review and Critique

2009-03-03T10:47:23Z

The purpose of this systematic review was to (i) estimate the prevalence and dose of television (TV) viewing, video game playing and computer use, and (ii) assess age-related and (iii) secular trends in TV viewing among youth (less-than-or-equals, slant18 yr). Ninety studies published in English language journals between 1949 and 2004 were included, presenting data from 539 independent samples (the unit of analysis). Results suggest contemporary youth watch on average 1.8–2.8 h of TV per day, depending on age and gender. Most (66%) are ‘low users’ (<2 h day−1) of TV but 28% watch more than 4 h day−1. Boys and girls with access to video games spend approximately 60 and 23 min day−1, respectively, using this technology. Computer use accounts for an additional 30 min day−1. Age-specific data suggest TV viewing decreases during adolescence, but those considered ‘high users’ at young ages are likely to remain high users when older. For children with access to a television set, the number of hours spent viewing does not appear to have increased over the past 50 years.

Adherence to mental health guidelines by Dutch occupational physicians

2009-04-01T17:14:01Z

Background In 2000, the Dutch Association of Occupational Physicians published a national guideline for the management of employees with mental health problems. Objectives To examine predictors of adherence to this guideline by Dutch occupational physicians (OPs). Methods Using the Theory of Planned Behaviour, a questionnaire was developed about self-reported guideline adherence of OPs and possible predictors of this behaviour. A total of 165 OPs were approached to complete the questionnaire and registration forms of first consultations of workers with mental health problems. Performance indicators based on the guideline were developed to calculate performance rates of guideline adherence by OPs. Results Eighty of 165 (48%) OPs approached completed the questionnaire. Fifty-six OPs returned one or more registration forms, totalling 344 consultations. On a five-point Likert scale, ranging from never (1) to always (5), the mean score on self-reported guideline adherence was 2.35, compared to a mean score of 4.06 on the intention to comply with the guideline. The mean performance rate of OPs ranging from 0 to 2 was 1.27 on diagnosis and 0.60 on guidance. No relation was found between self-reported guideline adherence and performance rates. Self-reported guideline adherence correlated significantly with perceived behaviour control (r = 0.48, P < 0.05), subjective norms (r = 0.33, P < 0.05) and positive job stress (r = 0.35, P < 0.05). Conclusions Guideline adherence by Dutch OPs lags behind its acceptance. Further implementation efforts need to focus on diminishing barriers and enhancing social norms of OPs to work according to the guideline.

Adherence Within and Between Lifestyle Physical Activity Groups in Project PRIME

2009-01-12T16:40:55Z

Background: Interventions that teach strategies for integrating physical activity into a person's daily routine are becoming more common. These interventions have been found to increase physical activity behavior, although the increases have not been large. The small to moderate changes in physical activity can result from participants having insufficient adherence to the intervention protocol to produce an intervention effect. Given that adherence is likely to affect the power to find a treatment effect, it should be tracked. This study examined changes in adherence over 6 months for a lifestyle physical activity intervention. Methods: Participants were 244 sedentary adults who took part in the Project PRIME lifestyle physical activity intervention. Adherence was assessed separately for a group-based intervention (PRIME G) and a telephone- and mail-based intervention (PRIME C). Markers of adherence were completion of homework, self-monitoring of physical activity, attendance at class (PRIME G only), and completion of monthly telephone calls (PRIME C only). Changes over time in adherence markers and differences between intervention groups for homework completion and adherence to self-monitoring were modeled with generalized estimating equations (GEE). Results: The probability of attending class, completing the telephone calls, and completing the homework decreased significantly over 6 months. Participants only self-monitored an average of 5 to 6 days each calendar month. Participants in the group-based intervention were more likely than those in the telephone- and mail-delivered intervention to complete the homework throughout the study. Conclusions: The findings suggest that individuals are willing to adhere with a telephone call protocol over 6 months. They are less willing to complete homework and attend class over this same time period. Most are not willing to self-monitor their lifestyle physical activities more than a few days a month

Adipokine levels in a large pedigree of indigenous Australians with high prevalence of type 2 diabetes mellitus and central obesity

2007-08-23T21:38:58Z