Effect of 15% body weight support on exercise capacity of adults without impairments

BACKGROUND AND PURPOSE

External support of body weight, a technique used for the gait training of patients with neurologic conditions, may also be beneficial for tests of exercise capacity in people whose impairments in motor function and balance have traditionally precluded such testing. The purpose of this study was to investigate the effect of using external support of 15% of body mass during treadmill exercise testing of adults without impairments.

SUBJECTS AND METHODS

Seven men and 8 women (mean age=55.2 years, SD=11.3, range=43-82) performed 3 treadmill tests with random assignment of testing condition: (1) no body weight support (BWS)-standard test, (2) 0% BWS-harness in place but no use of external support, and (3) 15% BWS-use of external support for 15% of body mass. Expired gas was analyzed to determine oxygen uptake, carbon dioxide production, minute ventilation, tidal volume, heart rate, and respiratory exchange ratio.

RESULTS

Use of external support for 15% of body mass did not affect the end-expiratory gas exchange variables, although the time to achieve peak values was lengthened. Maximal tidal volume was lower in the 15% BWS test, but maximal minute ventilation was not different.

DISCUSSION AND CONCLUSION

Because 15% BWS did not affect the exercise capacity of adults without known impairments, future study of its application to testing of patients with neurologic injuries is warranted.

Myocardial infarction: survivors' and spouses' stress, coping, and support

Despite evidence that spouses play an important role in the recovery of MI survivors, there have been few studies of pertinent psychosocial factors from the perspectives of both survivors and spouses. Accordingly, the aim of this study was to describe stress, coping strategies and social support experienced by survivors and spouses. This study was limited to first-time MI to focus on a time of uncertainty and transition. Twenty-eight persons (14 couples) participated. Both survivors and their spouses reported similar post-MI stresses: emotional impact, lifestyle changes, encounters with health professionals, and their partners' reactions. Spouses and survivors used diverse strategies to cope with the stresses of MI. Seeking informational support was prevalent. Both spouses and survivors engaged in 'protective buffering' of their partners. Couples described deficient support, conflict and miscarried helping efforts within their relationships. Spouses and survivors referred to inadequate informational support from health professionals.

A cardiovascular health needs assessment of university students living in residence

The purpose of this study was to determine the cardiovascular health needs of university students living in residence. A survey was administered to students living in residence at a university in Nova Scotia, Canada to identify eating patterns, physical activity, smoking behaviours and perceived stress. Data were analyzed using descriptive statistics and chi-square tests of association. Qualitative data were collected using focus group interviews. Results showed that fewer than half of the students participated in exercise three or more times per week, and 82% are less than the recommended amount of fruits and vegetables. As perceived knowledge of CVD increased so did level of physical activity and consumption of fruits and vegetables. Fifty-six percent of students rated their stress as high or very high; exams and course assignments are a major cause of this stress. Fifteen percent of the university students surveyed were daily smokers. Barriers to a healthy lifestyle include time constraints and limited food choices in the residence cafeteria.

Primary care physicians and coronary heart disease prevention: a practice model

Primary care physicians have an important role in coronary heart disease prevention. This paper discusses the results of a qualitative study conducted with Nova Scotian physicians to explore the following: physicians' expectations about their role in prevention; obstacles to providing preventive care; and, mechanisms by which preventive care occurs. The second part of the paper presents a practice model which is intended as a framework by which physicians may more effectively educate and counsel their patients about health issues, such as coronary heart disease.

Stress, coping, and social support as psychosocial factors in readmissions for ischaemic heart disease

This exploratory investigation aimed to identify psychological and social factors associated with early (4 months postdischarge) readmission to hospital of persons with ischaemic heart disease (IHD). Data on stress (Stress Appraisal Scale), coping strategies (Ways of Coping Questionnaire), and social network/social support (Norbeck Social Support Questionnaire) were collected from 100 persons with the primary diagnosis of IHD prior to discharge from hospital. Twenty-four persons were readmitted during the 4-month study period. The sample was divided into two groups for analysis: (1) persons with a first admission for IHD, and (2) persons with a prior history of admission for IHD. In comparison to persons with multiple admissions for cardiac illness, first time admissions appraised their IHD as less central and threatening, perceived less affective and affirmational support from health professionals, and identified health professionals less and neighbours more as sources of support. Greater use of the coping strategy 'seeking social support' was associated with the readmission of persons who had had their first admission for IHD. Less use of the coping strategy 'accepting responsibility' was associated with the readmission of persons who had a history of prior admission for IHD.

High-intensity endurance training in 20- to 30- and 60- to 70-yr-old healthy men

Factors contributing to maximal incremental and short-term exercise capacity were measured before and after 12 wk of high-intensity endurance training in 12 old (60-70 yr) and 10 young (20-30 yr) sedentary healthy males. Peak O2 uptake in incremental cycle ergometer exercise increased from 1.60 +/- 0.073 to 2.21 +/- 0.073 (SE) l/min (38% increase) in the old subjects and from 2.54 +/- 0.141 to 3.26 +/- 0.181 l/min (29%) in the young subjects. Peak cardiac output, estimated by extrapolation from a series of submaximal measurements by the CO2 rebreathing method, increased by 30% (from 12.7 to 16.5 l/min) in the old subjects, associated with a 6% increase (from 126 to 135 ml/l) in arteriovenous O2 difference; in the young subjects there were equal 14% increases in both variables (18.0 to 20.5 l/min and 140 to 159 ml/l, respectively). Submaximal mean arterial pressure and cardiac output were lower posttraining in the old subjects; total vascular conductance and cardiac stroke volume increased. Although peak power at the start of a short-term maximal isokinetic test did not change, total work accomplished in 30 s at a pedaling frequency of 110 revolutions/min increased in both groups, from 11.2 to 12.6 kJ and from 15.7 to 16.9 kJ in the old and young, respectively; fatigue during the 30-s test was less, and postexercise plasma lactate concentrations were lower. In older subjects, increases in aerobic power after high-intensity endurance training are at least as large as in younger subjects and are associated with increases in vascular conductance, maximal cardiac output, and stroke volume.

Maximal short term exercise capacity in healthy subjects aged 15-70 years

Fifty males and 50 females, 15-71 years of age, exercised maximally for 30 s on an isokinetic ergometer at a pedalling frequency of 60 rev./min. Results were compared with maximal oxygen uptake (VO2 max.) obtained in a progressive incremental exercise test. Total work in 30 s was higher in males than females, declined linearly by about 6% per decade of age (r = -0.65), and was related closely to height (r = 0.75) and to lean thigh volume estimated anthropometrically (r = 0.84). A close association with vital capacity (r = 0.86) was also found that accounted statistically for the combined effects of age and height. The percentage decline in power during 30 s (fatigue index) was lower in subjects reporting greater leisure activity. A close relationship was found between total work in 30 s and VO2max. (r = 0.86), with vital capacity and leisure activity exerting additional influences on VO2max. (P less than 0.001; multiple r = 0.93). The well-established reduction with age in VO2max. is associated with an apparent parallel reduction in the power output capacity of large muscle groups recruited in heavy dynamic leg exercise.

Normal standards for an incremental progressive cycle ergometer test

One hundred healthy subjects (50 male and 50 female), selected to provide an even distribution of age (15 to 71 yr) and height (165 to 194 cm in males and 152 to 176 cm in females), underwent a progressively incremental (100 kpm/min each min) exercise test to a symptom-limited maximum. Measurements were made of O2 intake and CO2 output, ventilation and breathing pattern, heart rate and blood pressure, and rating of perceived exertion. The ventilatory anaerobic threshold was identified. Predictive data were derived for measurements at maximal and submaximal exercise. Maximal power output (Wmax) and oxygen intake (VO2max) varied with sex (0, male; 1, female), age (yr), and height (Ht, cm): Wmax = 20.4 (Ht) - 8.74 (Age) - 288 (Sex) - 1,909 kpm/min (SEE, 216; r, 0.858); VO2max = 0.046 (Ht) - 0.021 (Age) - 0.62 (Sex) - 4.31 L/min (SEE, 0.458; r, 0.869). The extent of leisure time activity exerted a positive influence on VO2max (r, 0.47; p less than 0.001); VO2max was also related to lean thigh volume (r, 0.79). Maximal heart rate (HR) declined as a function of age: HRmax = 202 - 0.72 (Age) beats/min (SEE, 10.3; r, 0.72). Maximal O2 pulse (O2Pmax) was related to height and was systematically higher in males than in females: O2Pmax = 0.28 (Ht) - 3.3 (Sex) - 26.7 ml/beat (SEE, 2.8; r, 0.86). Ventilation was closely related to CO2 output, and the maximal tidal volume was related to vital capacity. The VO2 increased linearly with power throughout the test; in an individual subject, the intercept of this relationship was positively influenced by weight and height.(ABSTRACT TRUNCATED AT 250 WORDS)

Research methodology and applied statistics. Part 2: the literature search

This paper presents a basic methodology for an effective and efficient retrieval and recording of written materials in a subject area. The purpose of the literature review is examined and the criteria for selection of materials for inclusion are outlined. The methodology then describes the role of the librarian, various types of information resources, how to choose appropriate indexing and abstracting services, and a simple efficient method of recording the items found. The importance and use of Medical Subject Headings for research in physiotherapy is emphasized. A survey of types of book materials and how to locate them is followed by a detailed description of the most useful indexing and abstracting services available, in particular, the publications of the National Library of Medicine, notably Index Medicus, as well as Excerpta Medica and the Science Citation Index. A discussion of on-line search services, their coverage and availability in Canada, concludes the review of information sources. Finally, guidelines for selecting and summarizing the materials located and comments on the literary style for a review are supplied.