The primary purpose of this narrative review was to evaluate the current literature and to provide further insight into the role physical inactivity plays in the development of chronic disease and premature death. We confirm that there is irrefutable evidence of the effectiveness of regular physical activity in the primary and secondary prevention of several chronic diseases (e.g., cardiovascular disease, diabetes, cancer, hypertension, obesity, depression and osteoporosis) and premature death. We also reveal that the current Health Canada physical activity guidelines are sufficient to elicit health benefits, especially in previously sedentary people. There appears to be a linear relation between physical activity and health status, such that a further increase in physical activity and fitness will lead to additional improvements in health status.

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Health benefits of physical activity: the evidence

Evidence suggests that consumers often hesitate to transact with Web-based vendors because of uncertainty about vendor behavior or the perceived risk of having personal information stolen by hackers. Trust plays a central role in helping consumers overcome perceptions of risk and insecurity. Trust makes consumers comfortable sharing personal information, making purchases, and acting on Web vendor advice--behaviors essential to widespread adoption of e-commerce. Therefore, trust is critical to both researchers and practitioners. Prior research on e-commerce trust has used diverse, incomplete, and inconsistent definitions of trust, making it difficult to compare results across studies. This paper contributes by proposing and validating measures for a multidisciplinary, multidimensional model of trust in e-commerce. The model includes four high-level constructs--disposition to trust, institution-based trust, trusting beliefs, and trusting intentions--which are further delineated into 16 measurable, literature-grounded subconstructs. The psychometric properties of the measures are demonstrated through use of a hypothetical, legal advice Web site. The results show that trust is indeed a multidimensional concept. Proposed relationships among the trust constructs are tested (for internal nomological validity), as are relationships between the trust constructs and three other e-commerce constructs (for external nomological validity)--Web experience, personal innovativeness, and Web site quality. Suggestions for future research as well as implications for practice are discussed.

Developing and Validating Trust Measures for e-Commerce: An Integrative Typology

The purpose of this Position Stand is to provide an overview of issues critical to understanding the importance of exercise and physical activity in older adult populations. The Position Stand is divided into three sections: Section 1 briefly reviews the structural and functional changes that characterize normal human aging, Section 2 considers the extent to which exercise and physical activity can influence the aging process, and Section 3 summarizes the benefits of both long-term exercise and physical activity and shorter-duration exercise programs on health and functional capacity. Although no amount of physical activity can stop the biological aging process, there is evidence that regular exercise can minimize the physiological effects of an otherwise sedentary lifestyle and increase active life expectancy by limiting the development and progression of chronic disease and disabling conditions. There is also emerging evidence for significant psychological and cognitive benefits accruing from regular exercise participation by older adults. Ideally, exercise prescription for older adults should include aerobic exercise, muscle strengthening exercises, and flexibility exercises. The evidence reviewed in this Position Stand is generally consistent with prior American College of Sports Medicine statements on the types and amounts of physical activity recommended for older adults as well as the recently published 2008 Physical Activity Guidelines for Americans. All older adults should engage in regular physical activity and avoid an inactive lifestyle.

Exercise and physical activity for older adults

As people get older, they may fall more often for a variety of reasons including problems with balance, poor vision, and dementia. Up to 30% may fall in a year. Although one in five falls may require medical attention, less than one in 10 results in a fracture.
This review looked at the healthcare literature to establish which fall prevention interventions are effective for older people living in the community, and included 159 randomised controlled trials with 79,193 participants.  
Group and home-based exercise programmes, usually containing some balance and strength training exercises, effectively reduced falls, as did Tai Chi. Overall, exercise programmes aimed at reducing falls appear to reduce fractures.
Multifactorial interventions assess an individual's risk of falling, and then carry out treatment or arrange referrals to reduce the identified risks. Overall, current evidence shows that this type of intervention reduces the number of falls in older people living in the community but not the number of people falling during follow-up. These are complex interventions, and their effectiveness may be dependent on factors yet to be determined.  
Interventions to improve home safety appear to be effective, especially in people at higher risk of falling and when carried out by occupational therapists. An anti-slip shoe device worn in icy conditions can also reduce falls.
Taking vitamin D supplements does not appear to reduce falls in most community-dwelling older people, but may do so in those who have lower vitamin D levels in the blood before treatment.  
Some medications increase the risk of falling. Three trials in this review failed to reduce the number of falls by reviewing and adjusting medications. A fourth trial involving family physicians and their patients in medication review was effective in reducing falls. Gradual withdrawal of a particular type of drug for improving sleep, reducing anxiety, and treating depression (psychotropic medication) has been shown to reduce falls.
Cataract surgery reduces falls in women having the operation on the first affected eye. Insertion of a pacemaker can reduce falls in people with frequent falls associated with carotid sinus hypersensitivity, a condition which causes sudden changes in heart rate and blood pressure.
In people with disabling foot pain, the addition of footwear assessment, customised insoles, and foot and ankle exercises to regular podiatry reduced the number of falls but not the number of people falling.
The evidence relating to the provision of educational materials alone for preventing falls is inconclusive.

Interventions for preventing falls in older people living in the community

Response representativeness is more important than response rate in survey research. However, response rate is important if it bears on representativeness. The present meta-analysis explores factors associated with higher response rates in electronic surveys reported in both published and unpublished research. The number of contacts, personalized contacts, and precontacts are the factors most associated with higher response rates in the Web studies that are analyzed.

A Meta-Analysis of Response Rates in Web- or Internet-Based Surveys

OBJECTIVE: To evaluate the effects of two exercise approaches, Tai Chi (TC) and computerized balance training (BT), on specified primary outcomes (biomedical, functional, and psychosocial indicators of frailty) and secondary outcomes (occurrence of falls).

DESIGN: The Atlanta FICSIT (Frailty and Injuries: Cooperative Studies of Intervention Techniques), a prospective, randomized, controlled clinical trial with three arms (TC, BT, and education [ED]). Intervention length was 15 weeks, with primary outcomes measured before and after intervention and at 4-month follow-up. Falls were monitored continuously throughout the study.

SETTING: Persons aged 70 and older living in the community.

PARTICIPANTS: A total of 200 participants, 162 women and 38 men; mean age was 76.2.

MEASUREMENTS: Biomedical (strength, flexibility, cardiovascular endurance, body composition), functional (IADL), and psychosocial well-being (CES-D scale, fear of falling questionnaire, self-perception of present and future health, mastery index, perceived quality of sleep, and intrusiveness) variables.

RESULTS: Grip strength declined in all groups, and lower extremity range of motion showed limited but statistically significant changes. Lowered blood pressure before and after a 12-minute walk was seen following TC participation. Fear of falling responses and intrusiveness responses were reduced after the TC intervention compared with the ED group (P = .046 and P = .058, respectively). After adjusting for fall risk factors, TC was found to reduce the risk of multiple falls by 47.5%.

CONCLUSIONS: A moderate TC intervention can impact favorably on defined biomedical and psychosocial indices of frailty. This intervention can also have favorable effects upon the occurrence of falls. Tai Chi warrants further study as an exercise treatment to improve the health of older people.

Reducing Frailty and Falls in Older Persons: An Investigation of Tai Chi and Computerized Balance Training

Foundations of Behavioral Research 2nd ed

Background and Purpose. This study explored whether two exercise programs would affect the ability to minimize postural sway of 72 relatively inactive, older subjects who participated in the Atlanta FICSIT trial. Subjects. Subjects were randomly assigned to (1) a computerized balance training group, (2) a tai chi group, or (3) an educational group serving as a control for exercise. Each group consisted of 24 members. Methods. All subjects were evaluated under four postural conditions before, immediately after, and 4 months following their respective interventions, each of which was given over 15 weeks. Results. Platform balance measures revealed greater stability after training among subjects in the balance training group but little change in stability among subjects in the tai chi and educational group. Subjects in the tai chi group were less afraid of falling after training compared with subjects in other groups with similar covariates. Conclusion and Discussion. Unlike computerized balance training, tai chi does not improve measures of postural stability. Because tai chi delayed onset to first or multiple falls in older individuals, this effect does not appear to be associated with measures of enhanced postural stability. Tai chi may gain its success, in part, from promoting confidence without reducing sway rather than primarily facilitating a reduction in sway-based measures.

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The Effect of Tai Chi Quan and Computerized Balance Training on Postural Stability in Older Subjects

were reduced after the TC intervention compared with the ED group (P 5.046 and P 5.058, respectively). After adjusting for fall risk factors, TC was found to reduce the risk of multiple falls by 47.5%. CONCLUSION: A moderate TC intervention can impact favorablyon definedbiomedicalandpsychosocial indicesof frailty. This intervention can also have favorable effects upon the occurrence of falls. TC warrants further study as an exercise treatment to improve the health of older people. J Am Geriatr Soc 51:1794–1803, 2003.

http://www.pnfchi.com/fotos/literatura/1233836450.PDF

Selected as the best paper in the 1990s: Reducing frailty and falls in older persons: an investigation of tai chi and computerized balance training.

http://www.taichifuture.com/uploads/4/6/3/7/46373393/overall_non_specific_benefits.pdf

Carol Coogler

Papers

Reducing Frailty and Falls in Older Persons: An Investigation of Tai Chi and Computerized Balance Training

Foundations of Behavioral Research 2nd ed

The Effect of Tai Chi Quan and Computerized Balance Training on Postural Stability in Older Subjects

Selected as the best paper in the 1990s: Reducing frailty and falls in older persons: an investigation of tai chi and computerized balance training.

Exploring the basis for Tai Chi Chuan as a therapeutic exercise approach