Showing papers by "Roy J. Shephard published in 2012"
TL;DR: Developments in the measurement of physiological responses, studies of metabolism and indirect and direct calorimetry are reviewed, as required by the applied physiologist, ergonomist, sports scientist, nutritionist and epidemiologist.
Abstract: Over the years, techniques for the study of human movement have ranged in complexity and precision from direct observation of the subject through activity diaries, questionnaires, and recordings of body movement, to the measurement of physiological responses, studies of metabolism and indirect and direct calorimetry. This article reviews developments in each of these domains. Particular reference is made to their impact upon the continuing search for valid field estimates of activity patterns and energy expenditures, as required by the applied physiologist, ergonomist, sports scientist, nutritionist and epidemiologist. Early observers sought to improve productivity in demanding employment. Direct observation and filming of workers were supplemented by monitoring of heart rates, ventilation and oxygen consumption. Such methods still find application in ergonomics and sport, but many investigators are now interested in relationships between habitual physical activity and chronic disease. Even sophisticated questionnaires still do not provide valid information on the absolute energy expenditures associated with good health. Emphasis has thus shifted to use of sophisticated pedometer/accelerometers, sometimes combining their output with GPS and other data. Some modern pedometer/accelerometers perform well in the laboratory, but show substantial systematic errors relative to laboratory reference criteria such as the metabolism of doubly labeled water when assessing the varied activities of daily life. The challenge remains to develop activity monitors that are sufficiently inexpensive for field use, yet meet required accuracy standards. Possibly, measurements of oxygen consumption by portable respirometers may soon satisfy part of this need, although a need for valid longer term monitoring will remain.
102 citations
TL;DR: The 6MWT appears reproducible and valid relative to cycle-ergometer assessments of cardiorespiratory responses, and offers a simple method of clinical assessment, and an 8-week moderate walking program improves the cardiopulmonary fitness of children with CP.
82 citations
TL;DR: Empirical data on the extent of changes in anaerobic effort, endurance performance and muscle strength might be anticipated from the decrease in muscle glycogen and body fluid reserves are considered, suggesting potential nutritional and behavioral tactics for minimizing such effects in the Muslim competitor.
Abstract: Ramadan observance requires a total abstention from food and drink from sunrise to sunset for a period of one month. Such intermittent fasting has only minor effects upon the overall nutrition and physiological responses of the general sedentary population. Larger meals are consumed at night and in the early morning. Body mass usually remains unchanged, the total energy intake remains roughly constant, and there is little alteration in the relative consumption of protein, fats and carbohydrates. However, Ramadan observance may be of greater consequence for the training and performance of the competitive athlete, particularly when the festival is celebrated in the hotter part of the year and daylight hours are long, as is the case for the 2012 Summer Olympic Games in London, England. The normal sleeping time then tends to be shortened, and blood sugar and tissue hydration decrease progressively throughout the hours of daylight. Some limitation of anaerobic effort, endurance performance and muscle strength might be anticipated from the decrease in muscle glycogen and body fluid reserves, and a reduced blood glucose may cause a depressed mood state, an increased perception of effort, and poorer team work. This review considers empirical data on the extent of such changes, and their likely effect upon anaerobic, aerobic and muscular performance, suggesting potential nutritional and behavioral tactics for minimizing such effects in the Muslim competitor.
53 citations
TL;DR: Men were more active than women at each transition except for parenthood, and promotion initiatives should target these periods to prevent the decline of PA.
Abstract: Background:Several studies have reported an age-related decline of physical activity (PA). We examined the impact of 4 important transitional periods—adolescence, the beginning of postsecondary education, entry into the labor market, and parenthood—on the PA of participants in the Trois-Rivieres quasi-experimental study. Methods:In 2008, 44 women and 42 men aged 44.0 ± 1.2 years were given a semistructured interview; the frequency and duration of physical activities were examined during each of these transition periods. Subjects had been assigned to either an experimental program [5 h of weekly physical education (PE) from Grades 1 to 6] or the standard curriculum (40 min of weekly PE) throughout primary school. Results:The percentage of individuals undertaking ≥ 5 h of PA per week decreased from 70.4% to 17.0% between adolescence and midlife. The largest decline occurred on entering the labor market (from 55.9% to 23.4%). At midlife, there were no significant differences of PA level between experimental ...
44 citations
TL;DR: The findings suggest that the abbreviated Wingate test offers a reliable and valid tool for the evaluation of PPO and MPO, at least in young physical education students.
Abstract: Repeat measurements in 69 young adults were performed to assess the test-retest reliability and the 95% confidence interval of the difference in score between paired observations (MDC95) of a Wingate test as abbreviated for field sport participants (test of a 15-second duration [15-secT]). Test-retest reliability was excellent for peak power output (PPO) and mean power output (MPO), independently of their mode of expression and was moderate for the fatigue index (FI). The standard errors of measurement (SEM) for absolute, relative, and derived PPO and MPO values ranged from 2.6 to 3.7%, all being smaller than the corresponding smallest worthwhile change (SWC). In contrast, FI values were rated as "marginal," with an SEM (9.6%) greater than the SWC (1.7). The range of MDC95 values for PPO and MPO were 9.9-10.4 and 7.37-7.42%, respectively. The absolute MPO showed the highest test-retest reliability and was the most effective in detecting real change. A second phase of the study evaluated the criterion-related validity of the 15-secT in 43 young men who performed 15-secT and standard 30-second Wingate anaerobic test (30-secT) in random order, on 2 separate occasions. There were no significant intertest differences in absolute, relative, or derived PPO. However, the FI for the 30-secT was greater than that for the 15-secT. Intertest correlations were highly significant for both MPOs and FIs. These findings suggest that the abbreviated Wingate test offers a reliable and valid tool for the evaluation of PPO and MPO, at least in young physical education students.
32 citations
TL;DR: Children with cerebral palsy can benefit significantly from cardio-respiratory training, and such training should be included in rehabilitation programs.
Abstract: Rehabilitation is a major goal for children with cerebral palsy, although the potential to enhance cardio-respiratory fitness in such individuals remains unclear. This study thus compared current cardio-respiratory status between children with cerebral palsy and able-bodied children, and examined the ability to enhance the cardio-respiratory fitness of children with cerebral palsy by cycle ergometer training. 10 children with cerebral palsy (Gross Motor Function Classification System levels I and II) participated in thrice-weekly 30 min cycle ergometer training sessions for 8 weeks (mean age: 14.2±1.9 yrs). 10 additional subjects with cerebral palsy (mean age: 14.2±1.8 yrs) and 10 able-bodied subjects (mean age: 14.1±2.1 yrs) served as controls, undertaking no training. All subjects undertook a progressive cycle ergometer test of cardio-respiratory fitness at the beginning and end of the 8-week period. Cardio-respiratory parameters [oxygen intake V˙O2), ventilation V ˙ E) and heart rate (HR)] during testing were measured by Cosmed K4 b gas analyzer. The children with cerebral palsy who engaged in aerobic training improved their peak oxygen consumption, heart rate and ventilation significantly (p<0.05) and they also showed a non-significant trend to increased peak power output. In conclusion, children with cerebral palsy can benefit significantly from cardio-respiratory training, and such training should be included in rehabilitation programs.
31 citations
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TL;DR: Diabetes mellitus is a multifaceted condition of metabolic dysregulation, manifesting as a chronically elevated blood glucose concentration with associated disturbances in carbohydrate, lipid, and protein metabolism.
Abstract: Diabetes mellitus is a multifaceted condition of metabolic dysregulation, manifesting as a chronically elevated blood glucose concentration with associated disturbances in carbohydrate, lipid, and protein metabolism. In contrast to type 2 diabetes, which is caused primarily by an obesity-associated
26 citations
TL;DR: Data show that, to assess the crossover point and LIPOX(max) values for research purposes, the protocol must be based on the measured MAP rather than on a theoretical value, which should improve individualization of training for initially sedentary subjects.
21 citations
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TL;DR: The prevalence and effects of chronic conditions of the musculoskeletal system (including arthritis, osteoporosis, and low back pain) are substantial; such conditions have strong negative effects on the lives of many Canadians, often leading them to seek medical advice.
Abstract: The prevalence and effects of chronic conditions of the musculoskeletal system (including arthritis, osteoporosis, and low back pain) are substantial; such conditions have strong negative effects on the lives of many Canadians, often leading them to seek medical advice. Over the next 10 years,
17 citations
TL;DR: In most of the situations studied to date, Ramadan observance has had only limited adverse consequences for either training or competitive performance, and more information is needed on responses in situations where protein intake is likely to be inadequate and when vigorous muscle training is in progress.
Abstract: This review examines information on the effects of Ramadan observance upon the metabolism, training and performance of athletes, with particular reference to proteins and amino acids. Increased gluconeogenesis and/or a reduced intake of protein could lead to a decrease of lean tissue, with adverse effects on muscular performance, and the lack of immediate protein ingestion could compromise responses to strength training. Actual responses vary quite widely, depending on culture and the individual's level and type of athletic involvement. In elite competitors, there is typically an increased fractional ingestion of protein with a small reduction in overall energy intake, and this may lead to small reductions of body and lean tissue mass. There are often small decreases of performance, particularly in activities requiring vigorous and/or repetitive muscular contraction. More information is needed on responses in situations where protein intake is likely to be inadequate (adolescent growth, those maintaining vegetarian diets or from poor countries and disciplines with very high overall energy needs) and when vigorous muscle training is in progress. However, in most of the situations studied to date, Ramadan observance has had only limited adverse consequences for either training or competitive performance.
14 citations
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TL;DR: Conditions such as stroke and spinal cord injury reduce the ability to activate muscle and produce movement, typically affecting a patient’s functional capacity and ability to carry out the tasks of daily living.
Abstract: Conditions such as stroke and spinal cord injury (SCI) reduce the ability to activate muscle and produce movement, typically affecting a patient’s functional capacity and ability to carry out the tasks of daily living. Mobility limitations increase the risk of other avoidable chronic conditions
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TL;DR: Chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease affect more than 3.5 million Canadians, detracting from the physical and mental health, quality of life, and functional capacity of these individuals.
Abstract: Chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) affect more than 3.5 million Canadians, detracting from the physical and mental health, quality of life, and functional capacity of these individuals.[1][1],[2][2] At least 8% of the Canadian population
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TL;DR: This poster aims to demonstrate the progress made in improving the quality of life for patients diagnosed with cancer in the United States and Canada over the past 25 years through improved diagnostic and surgical techniques.
Abstract: Cancer is an important cause of both morbidity and mortality, currently accounting for approximately 1 of every 4 deaths in North America.[1][1],[2][2] However, survival rates are continually increasing, as diagnostic and surgical techniques are improved and ever more effective local, regional, and
TL;DR: It is suggested that depression, fatigue and quality of life were more important determinants of immune profile than fitness measures, and immunological function may be enhanced more by addressing these issues than by focusing upon aerobic or resistance training.
Abstract: Purpose: Our objective was to relate immunological data for healthy but sedentary elderly women to aerobic power, strength, and mood state. Methods: We measured peak aerobic power and one-repetition maximum strength along with mood (depression and fatigue), quality of life and carbohydrate intake on 42 women aged 60–77 years. Standard immunological techniques determined natural killer cell count and cytotoxic activity (NKCA), proliferative responses to phytohemaglutinin and OKT 3 , various lymphocyte subpopulations (CD3 + , CD3 − CD19 + , CD56 + , CD4 + , CD8 + , CD56 dim and CD56 bright ), and markers of activation, maturation, down-regulation and susceptibility to apoptosis (CD25 + , CD28 + , CD45RA + , CD45RO + , CD69 + , CD95 + , HLA-DR + ). Results: Correlations of immune parameters with aerobic power and strength were very similar for absolute and relative immunological data. In the group as a whole, the only correlation with aerobic power was −0.35 (relative CD4 + CD69 + count), but in subjects with values −1 min −1 correlations ranged from −0.57 (relative CD4 + CD45RO + ) to 0.92 (absolute CD56 dim HLA-DR + ). In terms of muscle strength, univariate correlation coefficients ranged from −0.34 (relative and absolute CD3 + CD4 + CD8 + ) to +0.48 (absolute CD3 + HLA-DR + ) and +0.50 (absolute CD8 + CD45RA + CD45RO + ). Neither NKCA nor lymphocyte proliferation were correlated with aerobic power or muscle strength. Although mood state and quality of life can sometimes be influenced by an individual’s fitness level, our multivariate analyses suggested that depression, fatigue and quality of life were more important determinants of immune profile than our fitness measures. Conclusions: Psychological changes associated with aging may have a substantial adverse effect upon the immune system, and immunological function may be enhanced more by addressing these issues than by focusing upon aerobic or resistance training.
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TL;DR: The incidence of type 2 diabetes mellitus is high, primarily as a consequence of adverse health behaviour (eg, sedentarism, increased consumption of energy-dense foods), and unfortunately the incidence is expected to increase further in all age groups over the next few decades.
Abstract: The incidence of type 2 diabetes mellitus is high, primarily as a consequence of adverse health behaviour (eg, sedentarism, increased consumption of energy-dense foods), and unfortunately the incidence is expected to increase further in all age groups over the next few decades, possibly affecting 2.
TL;DR: After summarizing knowledge gaps through 2008, research on exercise commuting is reviewed for 2008–2011 and evidence has accumulated showing enhanced cardiorespiratory fitness and fewer cardiovascular risk factors among active commuters.
Abstract: After summarizing knowledge gaps through 2008, research on exercise commuting is reviewed for 2008–2011. Evidence-based reports on physical activity needs have emerged from many consensus panels. There seems potential to meet aerobic requirements by cycling to work. Rapid walking may also be effective in older adults. It remains unclear how far exercise commuting can strengthen muscle and bones, enhance flexibility and balance, and prevent obesity. Recent reports have characterized current commuters and urban design features favoring active commuting. Evidence has accumulated showing enhanced cardiorespiratory fitness and fewer cardiovascular risk factors among active commuters. The advantages of enhanced health outweigh disadvantages of cycling (air pollutant exposure and dangers from cars), but attempts to increase active commuting have had only limited success. In children, physical activity needs exceed commuting distances, and walking to school programs have done little to augment daily activity. Exercise commuting could contribute to the physical needs of adults, but further research is required to realize this potential.
TL;DR: When Hansen et al. (2011) applied their fixed-rate step test to a diverse population of ostensibly healthy adults, they noted that the work rate, as estimated relative to a cycle ergometer measurement of peak oxygen intake, averaged 85 ± 24% of these peak values; moreover, 41% of subjects reached levels that exceeded 95% of thepeak oxygen intake.
Abstract: Hansen et al. (2011) recently reported on their evaluation of a fixed-rate step test, hypothesizing that it would elicit low-to-moderate intensities (55–75% of _ VO2max). However, when they applied their test to a diverse population of ostensibly healthy adults (both men and women, ranging in age from 23 to 75 years), they noted that the work rate, as estimated relative to a cycle ergometer measurement of peak oxygen intake, averaged 85 ± 24% of these peak values; moreover, 41% of subjects reached levels that exceeded 95% of the peak oxygen intake. Note that I use the term ‘‘peak oxygen intake,’’ rather than the _ VO2max adopted by Hansen et al. (2011). The primary criterion for termination of their cycle ergometer test was subjective ((general/muscle fatigue, dyspnea), so it is likely that in many instances values were peak rather than maximal. Further, since some of the step tests of Hansen et al. (2011) had a duration as short as 45 s, alveolar oxygen concentrations will have been increasing during the measurement period, and the volume of oxygen taken into the lungs may substantially have exceeded that taken up by the circulation (Shephard 1955). Hansen et al. (2011) do not indicate what level of supervision their subjects received, but in retrospect they questioned the safety of fixed-rate testing, unless close medical supervision was available. Given the standard deviation of exercise intensities that they themselves observed (±24% of the individual’s _ VO2peak), it is almost inevitable that a proportion of their sample would have reached an intensity of effort at or above 95% of _ VO2peak; however, if their data were normally distributed, the proportion of subjects with values above 0.83 SD should have been 21% rather than 41% of test candidates (Fisher and Yates, 1957). What is more surprising is that given our current knowledge of age and sex differences in _ VO2max, an investigator would still wish to apply a fixed-intensity exercise test to a population of both men and women covering such a broad age span. On the basis of studies conducted by the International Biological Programme (IBP) Working Group on exercise testing (Shephard et al. 1968), Bailey et al. (1976) many years ago developed the Canadian aerobic fitness test (a simple, progressive stepping task that has been widely used in large-scale fitness surveys around the world). Those designing the test quickly recognized that it was important both from the viewpoint of safety and also in terms of the validity of the cardiac response that all subjects (irrespective of age or sex) should reach approximately the same relative work rate. The protocol thus set appropriate climbing rates for the Canadian test using a sequence of bands of music (originally recorded on an LP, but subsequently available on tape and CDs). The musical tempo was classified by sex and age decade into seven distinct bands. Given this precaution, all test participants were thus likely to reach approximately 75% of their personal _ VO2max in their final 3-min stage of stepping. Moreover, because Communicated by Susan A. Ward.
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TL;DR: Bone densities, measured by dual X-ray absorptiometry (lumbar vertebrae and femoral neck), did not differ significantly between experimental and control subjects, which may reflect a normal or even a faster decrease of bone mineral density in experimental subjects over the 30 years since completion of the program.
Abstract: AIM Previous studies, mainly of self-selected athletes, have suggested that childhood activities can have a prolonged influence on bone mineral density. This investigation explored whether experimentally assigned daily quality physical education (PE) during childhood influenced bone density at an age of 42.8±1.5 years. METHODS Participants from the Trois-Rivieres Longitudinal Study were divided into 4 groups: the first 2 groups (19 women and 21 men) had received 5 h/week of specialist-taught PE in primary school in 1970-1977, whereas the third and fourth groups (10 women and 10 men) had followed the standard PE programme of 40 min/week. RESULTS Bone densities, measured by dual X-ray absorptiometry (lumbar vertebrae and femoral neck), did not differ significantly between experimental and control subjects. CONCLUSION This result may reflect a normal or even a faster decrease of bone mineral density in experimental subjects over the 30 years since completion of the program, or an intervention that was designed to enhance cardiorespiratory and muscular fitness rather than bone health.
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TL;DR: Le diabete est un probleme a multiples facettes de dysregulation metabolique qui se manifeste chroniquement par une concentration elevee de glucose sanguin and des troubles inherents du metabolisme des hydrates de carbone, des lipides et des proteines.
Abstract: Le diabete est un probleme a multiples facettes de dysregulation metabolique qui se manifeste chroniquement par une concentration elevee de glucose sanguin et des troubles inherents du metabolisme des hydrates de carbone, des lipides et des proteines. Contrairement au diabete de type 2,
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TL;DR: The most widely recognized contributions of the Greek period were the Hippocratic codification of health professionals and the establishment of inter-city Games such as the Olympiad as mentioned in this paper, which quickly became corrupted by the award of major prizes, with the modern problems of age classification, doping, etc.
Abstract: This article follows the development of interest in health and fitness, looking at contributions from the Minoan, Greek and Roman cultures. The Minoan era is best known for the institution of bull vaulting, but it also opened up sports for women, and served as an important bridge for the transmission of Egyptian knowledge to Greece. Ceramics suggest that their athletes had superb physiques, but the common people suffered from rickets, scurvy, a stunted stature and a short life expectancy. The most widely recognized contributions of the Greek period were the Hippocratic codification of health professionals and the establishment of inter-city Games such as the Olympiad. The latter competitions were initially amateur and patrician, but quickly became corrupted by the award of major prizes, with the modern problems of age classification, doping,