Year

2008

Degree Name

Master of Science - Research

Department

School of Health Sciences - Health & Behavioural Sciences

Abstract

With the older adult representing an increasingly large percentage of the Western world, attempts are being sought to improve their healthy aging through various modes of prevention. The age-associated declines that occur in the physiological and functional systems along with levels of physical activity and quality of life have the potential to be attenuated and ameliorated with various forms of health-related interventions. It has been suggested that intake of dietary protein in the elderly may be too low to sustain normal muscle mass and red meat intake declines in the over 65 y age group in Australia.

The present study examined the effects of a high-intensity resistance training program and two levels of red meat intake on skeletal muscle strength, body composition and other health-related markers in healthy, community-dwelling older adults. Twenty-eight healthy male and female subjects with mean age (±SD) of 67 ±3 y and randomized to either a moderate (400g/wk) or high (800g/wk) red meat diet, completed a supervised twice weekly, twelve week high-intensity resistance training program of the lower extremities. The moderate meat diet represented the usual intake for older Australians over 65 y. Diet histories, body composition assessments, mid-thigh CT scans, grip strength, lower extremity performance, physical activity levels, one-mile walk test, fasted blood samples and morning urine samples were taken at baseline and twelve weeks. Four repetition maximum strength testing of the lower extremity was undertaken at pre-, mid- and postintervention.

Leg strength was greater in males than in females and this was strongly associated with their muscle mass and stature independent of gender. Age related declines in grip strength and leg muscle strength were evident at baseline. Resistance training significantly increased leg muscle strength >50% (p<0.001) irrespective of gender and age but grip strength (not targeted by the training program) remained unchanged. In subjects on the higher meat diet, mid-intervention leg press strength improvements were greater than those seen with the moderate meat diet (p<0.01), although significant differences between diets were not sustained at week twelve. The sum of seven skinfolds (mm) decreased significantly in all subjects with training (131.2±8.8 to 119.9±7.3, p<0.001) and significant improvement to the proportion of cross-sectional area of thigh muscle and thigh fat were measured in the non-dominant leg (p<0.05). Physical activity levels and lower extremity performance remained unchanged. The high red meat diet provided additional short-term benefits for building muscle strength without compromising cardiovascular disease risk factors, but in the longer term had no additional beneficial effects to strength and functional parameters.

In summary, healthy older adults exhibit an age related decline in strength, yet all have the capacity to greatly increase strength with muscle specific exercise training. Marked increases in strength can be rapidly achieved with short term high intensity resistance training. Resistance training is well tolerated and can be recommended for improving strength and enhancing other health-related parameters as part of a prevention based healthy aging strategy.

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.