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Edited by Thomas Rowland

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Edited by Herberta M. Lundegren

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Leslie J. Low, Mary J. Knudsen and Claudine Sherrill

In recent years, the number of individuals with dwarfism participating in sports and physical activities has increased. The Dwarf Athletic Association of America (DAAA) has grown from 30 athletes in 1985 to over 600 in 1994. This paper details the structural, intellectual, motor, orthopedic, and medical characteristics of six types of dwarfism (achondroplasia, hypochon-droplasia, cartilage-hair hypoplasia, diastrophic dysplasia, spondyloepiphyseal dysplasia tarda, and spondyloepiphyseal dysplasia congenita) seen in individuals currently participating in eight DAAA-sanctioned sports. Implications and modifications for participation in physical activity, physical education, and sport are included.

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Dirk Pette and Dejan Škorjanc

We compared responses of the fast extensor digitorum longus (EDL) and tibialis anterior (TA) muscles in young (15-week) and aging (101-week) male Brown Norwegian rats to 50 days of chronic low-frequency stimulation (CLFS, 10 Hz, 10 hours/day). After 50 days of CLFS, the EDL muscles of the young (22-week) and aging (108-week) rats displayed similar increases in type IIA fibers, relative concentration of myosin heavy chain MHCIIa, elevations in mitochondrial citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities, and similar decreases in glycolytic enzyme activities (glyceraldehydephosphate dehydrogenase, lactate dehydrogenase). TA muscle in young rats contained a few cytochrome c oxidase negative (COX) type I fibers. Their number was ~2-fold elevated by CLFS. Conversely, aging muscle, which contained a slightly higher amount of COX fibers than young TA muscle, responded to CLFS with a significant decrease in COX− fibers. The appearance of small COX-positive type I fibers in stimulated aging muscle indicated that regenerating type I fibers “diluted” the COX-deficient fiber population.

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S. Tolomio, A. Ermolao, G. Travain and M. Zaccaria

Background and aims:

It is known that people affected by osteopenia/osteoporosis can benefit from an adequate amount of physical activity, counteracting the progressive loss of bone and muscle mass caused by aging. Moreover, there is increasing evidence that exercise has positive effects on bone structure. The aim of our study was to evaluate the effects on bone tissue and muscular strength of a short-term exercise program in osteopenic/osteoporotic postmenopausal women.

Methods:

Forty-nine osteopenic/osteoporotic postmenopausal women were divided into 2 groups: exercise and control. All subjects underwent 2 evaluations: before and after a training period. Bone quality was assessed by phalangeal quantitative osteosonography, and maximal strength of leg extensor muscles was also evaluated. The experimental group participated in a specific supervised 20-week physical activity program that included aerobic, balance, and strength training.

Results:

After the training period, all bone parameters and lower-limb maximal strength were significantly improved in the exercise group (P < .05), whereas no significant changes were observed in the control group.

Conclusions:

Our study showed that a broad-based training protocol, lasting 20 weeks, can improve leg strength and bone quality parameters—main determinants of fall and fracture risk, respectively.