Search Results

You are looking at 1 - 10 of 35 items for

  • Author: Roy J. Shephard x
Clear All Modify Search
Restricted access

Roy J. Shephard

This paper examines the postmodernist critique of the scientific method in the specific context of adapted physical activity. Particular assumptions identified include (a) that truth must be approached through testing hypotheses, with acceptance of the most plausible explanation, (b) that underlying laws have general (if not universal) application, and (c) that the observer approaches an experiment free of bias and without interacting with the subject. Postmodernists also argue, less convincingly, that users of the scientific method are committed to reductionism, are tyrannized by the mean, and are unable to quantitate important components of disability. The overall critique raises consciousness regarding the limitations of scientific methodology and points to ways this methodology can be improved. But too often, postmodernists offer few viable alternatives to the scientific method. Too often, those who espouse postmodernism resort to convoluted semantics, using poorly defined words of uncertain etymology. Such an approach does little to help the human condition and should be rejected as a new gnostic heresy.

Restricted access

Roy J. Shephard

The Journal of Physical Activity and Health seems likely to develop as a vehicle for practical, evidence-based answers to problems concerning physical activity and health, issues that have important implications for public health policy. There is strong epidemiological evidence for an association between the regular practice of physical activity and preventive or therapeutic benefit in a wide range of chronic health conditions,1-4 and already many professional groups have been eager to pre¬pare position statements, indicating their assessments of an appropriate minimum weekly dose of physical activity to maintain health.5 Unfortunately, there have been substantial discrepancies between successive recommendations, and uncertainties in the message are one probable factor, limiting its acceptance by both the general public and immediate health-care providers.6,7 The purpose of this brief commentary is to suggest some areas of investigation that would help in formulating a clear and consistent message. Topics discussed include the desired health outcome, the shape of the dose–response relationship, the impact of confounding variables, the quality of the evidence accepted, the basis for shaping the message, and the need for multiple messages.

Restricted access

Roy J. Shephard

This paper offers a brief response to the article of Bouffard (2001), which in itself was a reaction to two earlier papers published by the present author (Shephard, 1998, 1999). Bouffard makes a vigorous attack on his perceptions of my observations concerning the use of jargon, the primacy of the scientific method, and postmodernism. Unfortunately, his perceptions of my arguments are not always substantiated by a careful reading of the text. Many of the world’s social ills are rashly attributed uniquely to rationalism. No viable alternatives to the scientific method are suggested, and self-criticism of the postmodern approach is less than optimal. Nevertheless, the paper is to be welcomed, both as a challenge to continuing perfection of evidence-based science and as providing an insight into the thinking of those who espouse the postmodernist philosophy.

Restricted access

Roy J. Shephard

Attention is drawn to specific practical and ethical concerns that may arise when researchers study responses to vigorous exercise in populations with disabilities. It is argued that the study of such individuals can provide important information regarding responses to exercise by nondisabled people. This thesis is illustrated by selected examples relating to (a) central versus peripheral limitation of oxygen transport, (b) the contribution of muscle pumping to venous return during vigorous exercise, (c) the contribution of sympathetic innervation to aerobic training responses, (d) the ceiling of muscle fiber hypertrophy, (e) the functional demands of daily living, and (f) the responsiveness of young children to aerobic training. It is concluded that exercise physiologists have already learned much about normal reactions to exercise by studies involving those disabilities, but there remains scope for many further investigations exploiting the special characteristics of such populations.

Restricted access

Roy J. Shephard

Restricted access

Roy J. Shephard

The pediatric sports physician faces an epidemic of obesity. A preliminary triage of individual patients can be based on the body mass index (BMI). The 80th and 95th percentiles of age-specific BMI suggest overweight and obesity, respectively; the diagnosis is confirmed by measurements of triceps and subscapular skinfolds. Over the last twenty years, the proportions of overweight and obese children have increased in both indigenous populations and most developed societies. The increase in body fat content seems to be associated with a decline in daily energy expenditure. Immediate health consequences include an increased prevalence of atherosclerotic plaques, hypertension, and an adverse lipid profile; in addition, the resulting poor self-image limits sport participation. Many obese children become obese adults, facing increased risks of cardiovascular and all-cause deaths. A combination of increased lifestyle activities, behavioral modification techniques to reduce sedentary behavior, and an appropriate diet seems to be the most effective approach to both prevention and treatment of obesity. Such initiatives should be supported by quality daily physical education and changes in the urban environment that encourage an active lifestyle.

Restricted access

Roy J. Shephard

A quantitative hypothetico-deductive approach has continued to contribute greatly to advances in biological and medical science. Quantitative methods are adopted over other approaches primarily because they contribute the most new knowledge about biological processes. Nevertheless, investigators make many assumptions when testing a biological hypothesis quantitatively. These assumptions may become invalid unless experiments are designed with great care. Problems arise in relation to formulating appropriate hypotheses, using volunteer samples, controlling the experimental intervention and potentially interfering behaviors, reaching an acceptable level of proof, excluding alternative hypotheses, and generalizing findings beyond the immediate experimental sample. When biologists are aware of these issues, they can take appropriate countermeasures and reach valid conclusions. However, the issues become more critical and resolution is less clear-cut when the same methods are extended from biology to psychology and the social sciences, and from general to special populations. In such situations, case studies and single-subject designs may have continuing relevance.

Restricted access

Roy J. Shephard

Autonomic dysreflexia is a common response to painful stimuli following high level spinal injuries. Loss of normal control of sympathetic reflexes leads to large increases in blood pressure, accompanied by headache and occasional more dangerous sequelae. Although now officially banned, intentional dysreflexia ("boosting") is still exploited by some competitors to gain an unfair advantage. It is thus important to consider physiological mechanisms, consequences for health and performance, and methods of controlling this abuse. Boosters perceive the practice as frequent, performance enhancing, and of low immediate risk. Effective methods of eliminating the practice may include more stringent control of competitors, evaluating and publicizing short-and long-term risks, and countering arguments that boosting is an ethically acceptable method of restoring a normal physiological response.

Restricted access

Roy J. Shephard

During the 1970s, the U.S. policy of requiring a negative exercise stress test for all adults >35 years old proved expensive. It also discouraged exercise adoption, was ineffective in detecting high-risk individuals, and led to much iatrogenic disease. In the age range of 15–69 years, a better alternative is triage, based on responses to the revised Physical Activity Readiness Questionnaire (PAR-Q), supplemented by considerations of age and cardiac risk factors. But most people older than 70 years have one or more clinical conditions; in this age group, any potential system of triage excludes an excessive proportion of potential exercisers and thus does not appear warranted. An increase in habitual physical activity increases quality-adjusted life span, and it might also enhance total longevity. Restriction of physical activity remains advisable in a few individuals, but they are already under medical care. The one small group who need medical clearance includes those who decide to prepare themselves for some high-performance event. They are highly motivated, and their activity will not be discouraged by the need for a careful clinical examination.

Restricted access

Roy J. Shephard

Background:

Traditional approaches to exercise prescription have included a preliminary medical screening followed by exercise tests of varying sophistication. To maximize population involvement, qualified fitness and exercise professionals (QFEPs) have used a self-administered screening questionnaire (the Physical Activity Readiness Questionnaire, PAR-Q) and a simple measure of aerobic performance (the Canadian Aerobic Fitness Test, CAFT). However, problems have arisen in applying the original protocol to those with chronic disease. Recent developments have addressed these issues.

Methods:

Evolution of the PAR-Q and CAFT protocol is reviewed from their origins in 1974 to the current electronic decision tree model of exercise screening and prescription.

Results:

About a fifth of apparently healthy adults responded positively to the original PAR-Q instrument, thus requiring an often unwarranted referral to a physician. Minor changes of wording did not overcome this problem. However, a consensus process has now developed an electronic decision tree for stratification of exercise risk not only for healthy individuals, but also for those with various types of chronic disease.

Conclusions:

The new approach to clearance greatly reduces physician referrals and extends the role of QFEPs. The availability of effective screening and simple fitness testing should contribute to the goal of maximizing physical activity in the entire population.