Influence of training on the biokinematics in trotting Andalusian horses.

The aim of this study was to determine the influence of a 10-month training programme on the linear, temporal and angular characteristics of the fore and hind limbs at the trot in the Andalusian horse, using standard computer-aided videography. Sixteen male Andalusian horses were observed before and after training. Six strides were randomly selected for analysis in each horse and linear, temporal and angular parameters were calculated for fore and hind limbs. The training programme used here produced significant changes in kinematic parameters, such as shortening of stride length, and increase in swing duration and a decrease in hind limb stance percentage. No significant differences were recorded in the angular values for the forelimb joints. In trained horses, the more proximal joints of the hind limb, especially the hip and stifle, had a greater flexion while the fetlock showed a smaller extension angle. At the beginning of the swing phase, hip and stifle joints presented angles that were significantly more flexed. When the hind limbs came into contact with the ground, all the joints presented greater flexion after training.

Effects of a 3 month endurance training programme on skeletal muscle histochemistry in Andalusian, Arabian and Anglo-Arabian horses.

Twenty adult (5 to 14 years old) sedentary stallions of several breeds (8 Andalusians, 7 Arabians and 5 Anglo-Arabians) were endurance-trained for 3 months. Duplicate biopsies from 2 different depths (20 mm, superficial sampling site; 60 mm, deep sampling site) of the gluteus medius muscle were collected before and after training and after 3 months of detraining. Few significant changes in muscle fibre type composition were recorded in response to training. The percentage of type I fibres in the deep sampling site of the muscle in Andalusian horses and of type IIB oxidative fibres in the superficial region in Anglo-Arabians had increased significantly (P < 0.05) after training. The mean type I and IIA cross-sectional area was increased significantly (range P < 0.05 to P < 0.01) after 3 months' training in the deep site of the muscle in Arabian and Andalusian horses, but not in Anglo-Arabians. The changes seen in fibre sizes disappeared after the detraining period. The mean number of capillaries adjacent to type I fibres in the superficial sampling site of the muscle had increased significantly (P < 0.05) in response to training in Andalusian and Arabian horses. However, a significant decrease in the mean number of capillaries in contact with each fibre type relative to the mean area of that fibre type was observed associated with training in the deep region of the muscle for type I and IIA fibres in Arabians (P < 0.01) and for type I fibres in Andalusian horses (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Sexual models in adolescents and adults]. / Modelos sexuales en jóvenes y adultos.

Findings of a research that has been carried over among 13- to 19-year-old young people, their parents, and their teachers with regard to sex models of all involved are presented. Subjects were from the city of Buenos Aires, Argentina. Social representations of the three subject samples involved about sex behavior, certain values linked to sexuality, and certain gender patterns are discussed.

Modelos sexuales en jóvenes y adultos. / [Sexual models in adolescents and adults]

Findings of a research that has been carried over among 13- to 19-year-old young people, their parents, and their teachers with regard to sex models of all involved are presented. Subjects were from the city of Buenos Aires, Argentina. Social representations of the three subject samples involved about sex behavior, certain values linked to sexuality, and certain gender patterns are discussed.

Intramuscular distribution of fibre types in the gluteus medius of the horse: a histochemical analysis.

The results from a recent study by Bruce and Schurg (1990) indicate that the gluteus medius (Gm) of the horse is a complex muscle subdivided by an internal tendinous sheet into two regions (dorsal and ventral) which may subserve different functions. In the present study, both regions were found to contain a similar proportion of histochemically-determined muscle fibre types. Fibre type composition did not generally vary over the length of the muscle at the same relative depth. In contrast, there was a significant tendency for the percentage of type I fibres to increase gradually in accordance with depth. These histochemical results do not suggest that the two regions of the Gm assume distinct functional roles; they do, however, indicate that at a given relative depth the muscle fibre type distribution is relatively uniform over the length of the muscle. Nevertheless, care should be exercised in sampling and interpreting data obtained from limited biopsy of equine Gm, due to the substantial histochemical variation of fibre type composition as a function of sampling depth.

Changes in cross-sectional area and capillary supply of the muscle fiber population in equine gluteus medius muscle as a function of sampling depth.

The right and left gluteus medius muscles of 4 mature Andalusian stallions were examined by repeated needle biopsy over a specific area and depth, as well as at different depths, to determine whether the cross-sectional area and capillary supply of the various fiber types are homogeneous throughout the muscle. The muscle biopsy specimens were histochemically analyzed for fiber types (myofibrillar adenosine triphosphatase) and capillaries (amylase-periodic acid-Schiff method). Differences between contralateral sites were not identifiable for any of the analyzed variables. Differences between sampling depths were larger than those between sample sites. The percentage of type-1 fibers increased, and that of type-2B fibers decreased as a function of increased sampling depth, but the relative frequency of type-2A fibers did not change with depth. The mean cross-sectional area of type-1 and type-2A fibers increased significantly, and that of type-2B fibers decreased between the most superficial and the deepest sampling sites. The capillary density and the mean number of capillaries per fiber increased as a function of sampling depth, but significant changes were not recorded between sampling depths for overall mean fiber area. The mean number of capillaries in contact with fibers of each histochemical type increased significantly with increasing sampling depth only for type-1 fibers. However, the number of capillaries in contact with fibers changed significantly, relative to the fiber area, as a function of sampling depth; for type-2B fibers this variable increased, whereas for type-2A and type-1 fibers, it decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Variability of muscle fibre composition and fibre size in the horse gluteus medius: an enzyme-histochemical and morphometric study.

To determine the variability in fibre types and fibre sizes in the equine gluteus medius muscle, biopsy specimens were removed from 5 sites, at 4 different depths, within the right and left muscles of 3 Andalusian stallions. The percentage, lesser fibre diameter and cross-sectional area of the various fibre types were measured systematically in myosin ATPase and NADH-tetrazolium reductase-stained, serial cryostat sections of these multiple samples. Significant differences in muscle fibre type composition were recorded, with a lower percentage of type I fibres (high myosin ATPase activity at pH 4.5) being observed towards superficial regions of the muscle and a greater percentage towards the deep areas. Type II B fibres (moderate myosin ATPase activity at pH 4.5), including both II B nonoxidative (low NADH-TR activity) and II B oxidative (moderate NADH-TR activity), displayed the opposite tendency, and the percentage of type II A fibres (low myosin ATPase activity at pH 4.5) did not change with depth. Types I and II A fibres in the deep regions were larger than superficially, whereas the II B fibres in the deep regions were smaller than in the superficial parts of the muscle. The results also imply that type I fibres tend to be larger than type II fibres in the deep regions. The size of type I fibres is more homogeneous in the deep parts than in the superficial regions of the muscle, while II B fibres vary more in size in the peripheral portions than in deep regions. A single biopsy taken from the gluteus medius muscle of the horse is therefore a poor representative of the whole muscle and care should be exercised in sampling and interpreting data obtained from limited biopsy of this muscle. The pattern of variation in fibre types and fibre sizes between the different depths of the muscle probably reflect different functional demands on the gluteus medius muscle.