Date of Award
Doctor of Philosophy
Muscle strength and morphology were investigated in four studies in elderly men and women between the ages of 62 and 102 years. The purposes were to: (1) measure the voluntary strength in several limb muscle groups from an 'older' elderly population, (2) measure and compare the amount of muscle and non-muscle tissue (NMT) in the arms and legs of older (65 + years of age) and younger (25 to 38 years of age) males using computed tomography (CT) scans, (3) compare the CT results with measures of anthropometry in the same two groups of males, and (4) measure the electrically evoked and voluntary strength parameters in an elderly group (65 to 78 years of age) following a six month strength training program of the elbow extensors.;In the first study, the voluntary strength of several limb muscle groups was measured in 118 subjects using a modified sphygmomanometer. The device permitted a simple adaptable means of quickly testing a wide variety of muscle groups. Multiple regression analysis identified that age was the foremost explanatory variable to account for the decline in strength with age (2% to 3% per year).;In the second and third studies five nearly equidistant (CT) scans of the leg and five of the arm were taken on 7 younger (25 to 38 y) and 13 older (65 to 90 y) males. Corresponding girth and skinfold measures were also made. From the CT scans total limb area, muscle plus bone area, skin and subcutaneous area, bone area and particular muscle group areas were measured. In addition, the amount of non-muscle tissue (NMT) within a muscle group was quantified. Corresponding volumes were also estimated for the CT and anthropometry measures. Muscles of aged subjects were smaller than those of the young and contained a significantly greater proportion of NMT, particularly in the plantar flexors. Anthropometric prediction equations were developed, but predictability was not strong for individual muscle groups in the aged men.;In the fourth study, 13 elderly subjects aged 65 to 78 years were involved in a six month elbow extensor strength training program and 8 subjects served as an age and activity matched control group. Electrically evoked as well as voluntary strength measures were made at 0, 12, and 24 weeks in the experimental group. The subjects improved their voluntary strength approximately 20% in 24 weeks. Evoked tetanic torque was also increased. Temporal twitch parameters were slowed with training. The results suggest that, in response to strength training, some of the alterations in muscle properties may be related to muscle size and connective tissue changes, and not only to central neural changes.
Rice, Charles Leslie, "The Morphology And Contractile Function Of Skeletal Muscle In Aged Humans" (1989). Digitized Theses. 1797.