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Biomedical subjects

R J Shephard

Publications and source records attributed to R J Shephard.

At least 289 records · Page 16Linked to original sources
PubMed1984

Cardiorespiratory and metabolic responses during Tai Chi Chuan exercise.

Tai Chi Chuan is a form of traditional Chinese exercise which has been widely practised in China for preventive and therapeutic purposes. The present study was designed to determine the physiological demands of this exercise modality. Eleven healthy males, aged 28.4 years, were studied for oxygen cost and related metabolic variables, heart rate and blood pressure during the performance of the Long-Form Tai Chi Chuan of Yang's style. Data was collected by an automated respiratory gas analyzer (Jeger Ergooxyscreen) and ECG telemetry during a 17-25 minute performance session (X = 22 minutes). The average energy cost for the Long-Form Tai Chi Chuan was 4.1 Mets, corresponding to a mean VO2 value of 1.03 l X min-1 or 14.5 ml X kg-1 X min-1. The mean peak heart rate during the exercises was 134 beats per minute. These values suggest that the Long-Form Tai Chi Chuan may be classed as moderate exercise, and its intensity does not exceed 50% of the individual's maximum oxygen intake.

Adult↗
PubMed1984

Health beliefs and exercise habits in an employee fitness programme.

A prospective study examined the attitudes, practices and physical characteristics of adults who enrolled in and adhered to a workplace fitness programme. Questionnaires on health beliefs and exercise habits were completed by 409 participants in an employee fitness programme and by 374 randomly selected non-volunteering controls. All underwent initial aerobic testing, and 20 months later 263 of the original enrollees were re-evaluated. Among the males, concern for health and belief in the health value of exercise were significantly stronger among enrollees than in controls. A higher level of perceived health and realistic expectations of the programme characterized male enrollees who went on to higher levels of exercise. For women, perceived health and belief in exercise were stronger in initial participants, but there were no clear predictors of exercise adoption. Although attitudes towards exercise generally became more positive over the programme, low-level participants came to view exercise as less "fun" and more "discipline". People who are ready for change and believe in exercise may enter a fitness programme, but adherence is influenced by personal factors such as the perceived state of health and the acceptability of the specific exercise programme.

Attitude to Health↗
PubMed1983

Characteristics that predicted recurrence of infarction within 3 years in the Ontario Exercise-Heart Collaborative Study.

Data on 13 baseline characteristics of 618 patients who had previously had a myocardial infarction and who had entered the Ontario Exercise-Heart Collaborative Study were analysed for their ability to predict recurrence of infarction within 3 years. These characteristics were age, serum levels of cholesterol and triglycerides, systolic and diastolic blood pressure, number of hours of competitive sports per week, number of hours of jogging per week, angina, type of occupation, smoking, cough and phlegm production, personality type and the number of previous infarctions. The characteristics showing independent statistical significance (p less than 0.05) were smoking and blue-collar occupation, with estimated adjusted relative odds of 2.3 and 2.1 respectively.

Adult↗
PubMed1983

Physical activity and the healthy mind.

Physicians should seek to enhance the quality rather than the quantity of human life. Physical activity programs can increase life satisfaction through an immediate increase of arousal and a long-term enhancement of self-esteem and body image. In the young child competition can cause excessive arousal, but long-term adverse effects are rare. In the adult a reduction of anxiety and stress and a general feeling of well-being reduce the frequency of minor medical complaints, generating important economic benefits. Physical activity programs also help to correct the reactive depression that accompanies conditions such as myocardial infarction. Interest in physical activity should be stimulated from the earliest years of primary school. The allocation of curricular time to physical education does not hamper academic achievement. Rather, through its impact on psychomotor learning, it enhances the total process of intellectual and psychomotor development.

Aged↗
PubMed1983

Field testing: assessment of physical fitness of disabled adults.

The objectives of this investigation were (i) to develop simple field-test procedures for examining the cardio-respiratory and muscular strength fitness of lower-limb disabled individuals and (ii) to compare fitness levels across disabilities and physical activity levels. Forty-nine disabled adults (42 males and 7 females) were classified according to (i) functional and/or muscular deficit and, (ii) level of habitual physical activity. A forearm ergometer test was used to determine peak oxygen intake (VO2 peak). Sex-specific regression equations developed from the direct test were used in conjunction with a modified Astrand-Ryhming equation to predict VO2 peak from sub-maximal test results. Likewise, an equation was developed to predict isokinetic upper body strength (UBS) from cable tensiometry and hand grip force. The predictive power of the sub-maximal ergometer test was fair (r = 0.67), while the isometric strength measurements were relatively effective in predicting isokinetic total UBS (r = 0.82). Class 1 differed significantly from all other classes with respect to VO2 peak and UBS. The more active individuals also achieved significantly higher scores (p less than 0.05) for both variables. This study shows that an estimate of peak oxygen intake and UBS can be obtained from simple field tests and that active disabled individuals are more fit than their inactive counterparts.

Adolescent↗
PubMed1983

Interaction of ozone and cigarette smoke exposure.

Possible interactions of ozone and cigarette smoke exposure have been tested in 2-hr chamber exposures of 26 male and 6 female subjects, all of whom were habitual smokers. Treatment conditions were air alone, air + cigarette smoking, ozone alone, and ozone + cigarette smoking. Ozone levels were increased progressively over four trials (0.37 ppm, 0.75 ppm, 0.50 ppm + intermittent exercise, and 0.75 ppm + intermittent exercise); exercise (50 W for 15 min alternating with 15-min rest) was intended to increase ventilation by a factor of 2.5. Ozone exposure reduced the carbon monoxide intake normally seen with smoking, as judged from smaller increments of blood carboxyhemoglobin readings. Ozone exposure alone gave rise to a decrease of lung function (forced vital capacity (VC), 1-sec forced expiratory volume, and maximum flow rates at 25 and 50% of VC), but the onset was slower and the response less dramatic than previously seen in nonsmokers, suggesting that the chronic effect of smoking may be to delay bronchial irritation by ozone. Smoking increased heart rate both at rest and during exercise, but this response was not materially influenced by simultaneous ozone exposure. It is concluded that over an acute 2-hr exposure, there is no appreciable interaction between cigarette smoking and responses to ozone.

Adult↗
PubMed1983

Employee health and fitness: the state of the art.

Health care and health promotion measures currently are undergoing critical cost/benefit or cost/effectiveness scrutiny. An employee fitness program offers a convenient means for realizing community goals of lifestyle change but also has the potential to augment worker productivity. The costs of exercise testing and program development for an employee program ($100-$350 per participant year, measured in 1982 U.S. dollars) compare favorably with nonoccupational approaches to the promotion of fitness and a healthy lifestyle. The combined savings from a reduction of appraised age, improvement in lifestyle, decreased use of hospital and physician services, decrease in absenteeism and employee turnover, improved productivity, and decreased need for geriatric care substantially exceed the likely outlay. Given a 20% participation rate, the order of benefit from these factors is over $700 per year for each member of the labor force. In a company employing 1,000 people, a cost of perhaps $40,000 for 200 participants would yield a dividend of $650-$700,000 per year. Arguments continue on the specificity of exercise-induced gains in health and performance, but the burden of proof rests with those who maintain that equal benefits could be obtained from other tactics.

Absenteeism↗
PubMed1983

Equal opportunity for a geriatric labor force: some observations on marine surveying.

The issue of mandatory retirement is reviewed in the context of a physically arduous task with major implications for the safety of both life and property (marine surveying). The main physiological factor limiting the inspections of vessels and cargo is the individual's aerobic power. Over an eight-hour shift, the net energy expenditure can amount to 4 megajoule (MJ), equivalent ot 37% of aerobic power for an unfit 65-year-old employee. It is argued that the majority of marine surveyors should retire at about the age of 65 years, on grounds of (1) heavy physical demand, (2) ensuring continuity of operations through the recruitment of young, formally trained employees, and (3) public safety in the face of growing time pressures and a rapidly changing technology. Nevertheless, careful physiological tests may distinguish exceptional individuals who can continue with their work for a longer period.

Aged↗
PubMed1983

Exercise and nasal patency.

Nasal airflow resistances were studied in 20 healthy subjects at rest, with exercise, and during recovery from exercise. Resistances were first measured under resting conditions. As a basis for comparison 0.1% xylometazoline was applied by insufflation; it reduced nasal resistance by an average of 49%. On a subsequent occasion, the degree and time course of changes in resistance were measured 1) during 5-min exercise bouts at rest 25, 50, and 75% of predicted maximum O2 intake (VO2max), 2) during 5-, 10-, and 15-min exercise bouts at 50% of VO2max, and 3) during recovery from exercise. Resistance decreased with intensity but not duration of exercise; an initial sudden decrease was followed by a more gradual but progressive decrease, which continued for several minutes following vigorous short duration exercise. Thus following 5 min of effort at 75% of VO2max, resistance reached a nadir (46% fall) 5 min after cessation of exercise. Recovery of preexercise values required 5 min after 5 min of exercise at 25% of VO2max and 10 min after 5 min of exercise at 50% of VO2max. Some decrease persisted 15 min after 5 min of exercise at 75% of VO2max.

Adult↗
PubMed1983

The impact of physical fitness evaluation on behavioural intentions towards regular exercise.

The Fishbein model was used to assess the impact of physical fitness evaluation with subsequent counselling by professional staff on individual intentions to exercise regularly. The subjects for this study were 172 self-selected adults seeking an evaluation of their current physical fitness. Experimental subjects were given a sequence of fitness testing and counselling; however, this did not significantly change the intention to exercise relative to control subjects. The only significant differences in intentions to exercise regularly were found (i) between subjects differing in fitness level (p less than .002), and (ii) between subjects differing in current exercise behaviour (p less than .001). Thirty-five percent (35%) of the variance in intentions to exercise were explained by a combination of (i) the two components of the Fishbein model (attitude and social norm) and (ii) an index of current physical activity. Since most of our subjects reported a positive intention to exercise, the most appropriate tactic for an increase of community activity may be to initiate policy changes facilitating behaviour in accordance with existing attitudes.

Adult↗
PubMed1983

Physical fitness promotion programmes: effectiveness in modifying exercise behaviour.

Over the past decade many physical fitness promotion programmes have been developed and implemented as a means of modifying the exercise behaviour of individuals. The expectation has been that such strategies would improve community health, with a subsequent reduction in the costs of health care. The present review critically analyses published studies in the light of a theoretical framework proposed by Green (1979). Strengths and weaknesses of the designs adopted by various researchers are identified and recommendations for future studies are presented.

Canada↗
PubMed1982

Demonstration of a training response by the Canadian home fitness test.

The relative merits of the Astrand nomogram and the CHFT formula for prediction of maximum oxygen intake (VO2max) have been tested in 35 men and women during performance of the advanced version of the Canadian Home Fitness Test in a laboratory setting. Prior to training, systematic errors relative to direct treadmill measurements of maximum oxygen intake were Astrand-10.1% (male) and-1.4% (female), and CHFT 5.6% (male), and 2.2% (female), the error of the Astrand procedure being statistically significant for the men. Training was effected by a walk/jog prescription or rope-skipping and calisthenics. Following training, data analysis indicated that the CHFT prediction formula distinguished quite well between the behaviour of experimental and control subjects. The Astrand procedure showed a greater increment in VO2(max) than the CHFT formula for the experimental subjects (significantly so in the women), but it also predicted a large and spurious change in many of the controls, so that in the men responses did not differ between trained and control subjects. Further comparisons suggested that the CHFT procedure gave a closer approximation to direct treadmill estimates of training response than did the Astrand nomogram.

Adult↗
PubMed1982

Sweat composition in exercise and in heat.

Sweat samples were collected from the forearms of eight male volunteers using light gauze pads applied for 20-min periods. Preliminary trials indicated that this technique yielded realistic figures for both sweat volume and sweat composition. Tests were conducted under three conditions: a) outdoor exercise, cool environment; b) indoor exercise, normal room temperatures; and c) sauna exposure. In all environments, proximal forearm samples indicated a larger sweat secretion than distal forearm or hand samples. [Mg2+] decreased as sweat flow increased, but after allowance for interindividual differences of sweat volume, [Na+], [K+], [Ca2+], and [Cl-] were independent of sweat flow rates. The differential effect of sweat flow suggests active regulation rather than contamination. Interindividual differences of sweat composition could not be explained in terms of differences in personal fitness. Sauna bathing yielded sweat with a higher [Mg2+] and [Ca2+] content than did exercise; however, [Na+], [K+], and [Cl-] were similar for the three experimental conditions. Again, the data are best explained in terms of an active regulation of sweat composition. Total ionic losses do not seem sufficient to deplete body mineral reserves unless many days of training are undertaken in a hot climate.

Adult↗