PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 7824824

Perspectives on activity.

N S Redeker·D J Mason
View original source ↗Export metadata ↓

Abstract

Activity is integral to human health, well-being, development, and functioning. Despite its importance to health, there have been few efforts to develop conceptual definitions of activity as a basis for nursing research in this area. The purposes of this paper are to review the major attributes of physical activity found in the nursing and health care literature, to formulate a comprehensive definition of activity based on the literature, and to suggest directions for future research.

Explore related subjects

Energy MetabolismGoalsHumansModels, NursingMotionMotor ActivityNursing ResearchJournal ArticleReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

N S Redeker, D J Mason. 1994. Perspectives on activity.. https://pubmed.ncbi.nlm.nih.gov/7824824/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2000

The role of gravity in human walking: pendular energy exchange, external work and optimal speed.

During walking on Earth, at 1.0 g of gravity, the work done by the muscles to maintain the motion of the centre of mass of the body (W(ext)) is reduced by a pendulum-like exchange between gravitational potential energy and kinetic energy. The weight-specific W(ext) per unit distance attains a minimum of 0.3 J x kg(-1) x m(-1) at about 4.5 km x h(-1) in adults. The effect of a gravity change has been studied during walking on a force platform fixed to the floor of an aircraft undergoing flight profiles which resulted in a simulated gravity of 0.4 and 1.5 times that on Earth. At 0.4 g, such as on Mars, the minimum W(ext) was 0.15 J x kg(-1) x m(-1), half that on Earth and occurred at a slower speed, about 2.5 km x h(-1). The range of walking speeds is about half that on Earth. At 1.5 g, the lowest value of W(ext) was 0.60 J x kg(-1) x m(-1), twice that on Earth; it was nearly constant up to about 4.3 km x h(-1) and then increased with speed. The range of walking speeds is probably greater than that on Earth. A model is presented in which the speed for an optimum exchange between potential and kinetic energy, the 'optimal speed', is predicted by the balance between the forward deceleration due to the lift of the body against gravity and the forward deceleration due to the impact against the ground. In conclusion, over the range studied, gravity increases the work required to walk, but it also increases the range of walking speeds.

Energy Metabolism↗
PubMed2000

The mechanism of the proton transfer: an outline.

A brief summary of the principal notions of the quantum-mechanical theory of the charge transfer reactions has been presented. In the framework of this theory, the mechanism of the proton transfer consists in the classical medium reorganization that equalizes the proton energy levels in the initial and final states, and a consequent proton transfer via a quantum-mechanical underbarrier transition. On the basis of this mechanism, factors influencing the proton transfer probability, and hence kinetic isotope effect, have been discussed; among them are the optimum tunneling distance, the involvement of the excited vibrational states, etc. Semi-classical and quantum-mechanical treatments of the Swain-Schaad relations have been compared. Some applications to enzymatic proton-transfer reactions have been described.

Energy Metabolism↗