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Biomedical subjects

H Howald

Publications and source records attributed to H Howald.

At least 37 records · Page 2Linked to original sources
PubMed1989

Is excessive running predictive of degenerative hip disease? Controlled study of former elite athletes.

OBJECTIVE: To determine the effects of regular long distance running on the state of the hips in later life. DESIGN: Retrospective study of a cohort of elite athletes and a group of normal, healthy, untrained controls examined 15 years after initial testing. SETTING: Research project at school for physical education and sports. SUBJECTS: 27 Former long distance runners (mean age 42), nine former bobsleigh riders (mean age 42), and 23 normal, healthy, untrained men (mean age 35) who had been examined in 1973 and who agreed to re-examination in 1988. MAIN OUTCOME MEASURE: Radiological evidence of degenerative hip disease in 1988. RESULTS: Physiological and exercise characteristics of all subjects had been recorded in 1973, and in 1988 these measurements were repeated together with radiological examination of the hips. An additive radiological index of hip disease based on grades of subchondral sclerosis, osteophyte formation, and joint space narrowing was significantly increased among runners as compared with bobsleigh riders and untrained controls. After adjustment for age the significant effect of type of sports activity remained (p = 0.032). In multivariate analyses age and milage run in 1973 (97 km/week) emerged as independent, significant, and positive predictors of radiological signs of degenerative hip disease in 1988 (p = 0.017 and p = 0.024 respectively). Among runners alone running pace in 1973 rather than milage run was the stronger predictor of subsequent degenerative hip disease. The milage run in 1988 was not particularly predictive of the radiological index, but endurance in 1988 was inversely related to degenerative hip disease seen radiologically. CONCLUSION: Long term, high intensity, high milage running should not be dismissed as a potential risk factor for premature osteoarthritis of the hip.

Age Factors↗
PubMed1989

Growth and pubertal development of young female gymnasts and swimmers: a correlation with parental data.

Whereas intensive and regular physical training is known to alter female reproductive function, its potential role in growth is still controversial. At the beginning of a longitudinal growth study of young elite female gymnasts (n = 34, 15-25 h/wk training) and moderately trained swimmers (n = 19, 5-15 h/wk), patterns of recalled parental growth and pubertal maturation were compared with those of parents of 25 sedentary school girls. These data were also correlated to the height, weight, pubertal development as well as adult height prognosis of their daughters. Bone age was estimated using the methods of Greulich-Pyle and Tanner (RUS score) and adult height prognosis using the methods of Bayley-Pinneau (BP), Roche-Wainer-Thissen (RWT), and Tanner et al. (TW2). Parents of gymnasts were significantly lighter (fathers: P = 0.027; mothers: P = 0.038) and shorter (fathers: P = 0.034; mothers: P less than 0.001) than those of swimmers and controls. Consequently, target heights of gymnasts were also significantly shorter (P less than 0.001). Recalled menarche occurred significantly later (P = 0.030) in mothers of gymnasts who, in turn, grow much alike their mothers. At the first visit, the gymnasts were shorter and lighter for age than swimmers and controls. Their bone age (11.0 +/- 1.3 years, mean +/- SD) was retarded (P less than 0.001) when compared with chronological age (12.6 +/- 1.2 years). Adult height prognosis was lower for gymnasts than for other girls (BP: P less than 0.001; RWT: P = 0.023, TW2: P less than 0.001), but adequate for target height range.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Determination by Skeleton↗
PubMed1989

Circulatory counter-regulations induced by continuous administration of nitroglycerin.

In a placebo-controlled, double-blind, cross-over study in seven healthy volunteers, continuous transdermal administration of nitroglycerin over 48 h by means of Nitroderm TTS 10 evoked counter-regulations that interfered with the nitrate effects. These counter-regulations comprised an increase in sympathico-adrenal activity, manifested in elevated plasma levels of adrenaline and noradrenaline, and an internal hemodilution, readily perceptible from the decrease in the hematocrit readings. As a result, several of the circulatory effects of nitroglycerin were no longer in evidence, or much weaker on the second day of the study. The effects concerned were the reduction of systolic and diastolic blood pressure, the increase in heart rate, the prolongation of PEPc, and shortening of LVETc, and the change in digital-pulse morphology (increase in the a/b quotient). On the other hand, the increase in venous distensibility and the decrease in hematocrit were unaltered throughout the observation period. The attenuation of the action of nitroglycerin noticeable 24 h after application of the patches is, therefore, not indicative of any loss of effect of the substance per se, but due to the circulatory counter-regulations, which were largely confined to the arterial side of the circulation and scarcely affected the venous system. One or two hours after removal of the patches, counter-regulations had practically ceased.

Administration, Topical↗
PubMed1986

Structural changes in skeletal muscle tissue with heavy-resistance exercise.

Muscle strength, muscle cross-sectional area, fiber size, fiber type distribution, capillarity, and mitochondrial volume were estimated before and after 6 weeks of heavy-resistance exercise. Isokinetic torque production of the knee extensor muscles increased by a total of 17.6%, mainly during the first half of the training period. The cross-sectional area of the vastus lateralis muscle increased by 8.4%, mainly during the second half of the training period. Morphometrically determined fiber size, fiber type distribution, and capillarity from biopsies of vastus lateralis did not change significantly with training. Likewise, the surface densities of inner and outer mitochondrial membranes as well as the volume density of myofibrils remained unchanged. In contrast, the volume density of mitochondria decreased by 9.6%. However, due to the increase in total muscle volume, the calculated absolute volume of mitochondria remained constant, whereas the absolute volume of myofibrils increased by 10%. It is concluded that strength training of short duration in previously untrained young male subjects does not change the ultrastructural composition of mitochondria and that the apparent dilution of mitochondria can quantitatively be accounted for by the increase in myofibrillar volume.

Adenosine Triphosphatases↗
PubMed1979

[Prevention of arteriosclerosis. Current basis].

Despite the advances in therapy, the high incidence, high mortality, and prematurity of coronary heart disease demonstrate the need for prevention. Measurement of a series of easily determined risk factors permits the early recognition of subjects at risk with remarkable reliability. However, reduction of risk factors affords protection against the illness only if they are causally connected with the disease mechanisms. The major evidence for linking atherosclerosis and its consequences with risk factors is reviewed. Particular attention is focused on serum lipids and the "lipid theory", smoking, elevated blood pressure, and physical inactivity, which are, on the basis of current knowledge, not only the most important factors but those most readily influenced by changes in daily living habits. Among the multiple risk factors mention is also made of obesity, diabetes, psychosocial stress, and hereditary predisposition. The probability of a causal relationship between risk factors and disease mechanisms justifies every effort to prevent the development of these precursors, or to treat them prophylactically if already present.

Arteriosclerosis↗
PubMed1979

Liver function in physically trained subjects: galactose elimination capacity, plasma disappearance of indocyanine green, and aminopyrine metabolism in long-distance runners.

Physical exercise and physical training are known to affect several aspects of hepatic metabolism. To assess whether adaptation to long-lasting exercise modifies microsomal drug metabolism, 8 long-distance runners were compared with a group of medical students having significantly lower maximal rates of oxygen consumption. At rest the hepatic galactose elimination capacity and the indocyanine green plasma disappearance rate used as reference methods were the same in both groups. The plasma clearance of ([14C]dimethylamine) aminopyrine and the kinetics of 14CO2 in breath did not differ either. It is concluded that adaptation to long-lasting exercise can occur without evidence for changes in hepatic galactokinase activity, liver blood flow, or microsomal metabolism of aminopyrine.

Adaptation, Physiological↗
PubMed1979

Mitochondrial volume density in human skeletal muscle following heavy resistance training.

Needle biopsies were taken from triceps brachii of 6 healthy males before and after a 6 month intensive weight training programme. The tissue was sectioned, photographed under a Philips EM200 and subjected to stereological analysis. Cross sectional fibre areas were also calculated from cryostat sections stained for ATPase activity. Morphometric analysis indicated that training resulted in a significant 26% reduction in mitochondrial volume density and a 25% reduction in the mitochondrial volume to myofibrillar volume ratio. These changes were accompanied by significant increases in fibre area for both FT (33%) and ST (27%) fibres as determined from the light microscope. There was a significant correlation between the reduction in mitochondrial volume density and the increase in FT fibre area following training (r=0.845). It was concluded that heavy resistance training leads to a dilution of the mitochondrial volume density through an increase in myofibrillar size with hypertrophy.

Adenosine Triphosphatases↗
PubMed1978

[Medical significance and requirements of sports].

Kind and intensity of physical activity with preventive value of degenerative diseases are well known by sports medicine. The core of the problem is the transfer of established knowledge into action and the creation of attractive programs making physical activity an enjoyment and which let us forget the final objective, i.e. prevention of ill health.

Chronic Disease↗
PubMed1976

Ultrastructure and biochemical function of skeletal muscle in twins.

Muscle biopsies were obtained from eleven pairs of monozygotic and six pairs of dizygotic twins, and maximum oxygen consumption (Vo2) was measured. There were no differences between the two groups of twins in their intra-pair variation, except for two enzyme systems, glyceraldehyde-3P-dehydrogenase (GAPDH) and 3-hydroxyacyl-CoA-dehydrogenase (HAD). The effects of training were assessed by comparing the differences between twins when one member of each pair undertook a 23 week training programme. There were significant differences in VO2 max, heart volume and maximum oxygen pulse after training, and some significant cytological differences. It was concluded that environmental factors were stronger than genetic influences, as far as physical performance was concerned.

Adolescent↗