Biomedical subjects

D M Davidson

Publications and source records attributed to D M Davidson.

58 records · Page 4Linked to original sources

PubMedDate not supplied

Rupture of the medial collateral ligament of the first metatarsophalangeal joint in a professional soccer player.

Worldwide, more people play soccer than any other team sport. The Federation Internationale de Football Association (FIFA) registered more than 150 million players in 1984. Although foot injuries in soccer range from midfoot sprains to stress fractures to capsulitis of the first metatarsophalangeal joint, we could find no case reports of a rupture of the lateral collateral ligaments of the great toe in soccer players. This is a report of the diagnosis, treatment, and outcome of such an injury in a professional soccer player.

Adult↗

PubMedDate not supplied

Effects of short-term exposure to carbon monoxide in subjects with coronary artery disease.

Twenty-four male subjects with stable angina pectoris performed graded exercise tests after being exposed to either carbon monoxide (CO) or clean air in a randomized crossover double-blind experiment in which each subject acted as his own control. Subject's blood carboxyhemoglobin levels were increased from a baseline level of approximately 1.5% to 3% of saturation, post-CO exposure. Cardiographic and respiratory gas exchange data were obtained during the tests in which the subjects exercised to the point of onset of anginal pain. The goal of the study was to determine if low-level CO exposure compromised the ability of these individuals to perform work. Data were evaluated statistically using a two-factor analysis of variance with repeated measures; the factors were exposure ATMOSPHERE (clean air vs. CO) and ORDER of exposure (clean air first, CO second vs. CO first, clean air second). One-tailed tests were used, and differences were considered significant at the p less than .05 level. The time to onset of angina was reduced 6% (p = .046) after CO exposure relative to clean air. Oxygen uptake (VO2) at angina was reduced by approximately 3% (p = .04). A subgroup of individuals who exhibited depression in the ST segment of their electrocardiograph tracings showed a 12% reduction in time to onset of angina and a 20% reduction in the time to onset of 0.1 mV ST segment depression; both of these findings were also statistically significant.

Aged↗

PubMedDate not supplied

Skeletal muscle profiles among elite long, middle, and short distance swimmers.

Skeletal muscle profiles of fiber composition and leg power and strength were obtained in 30 national caliber swimmers (20 males, 10 females). Subjects were classified into three groups based upon the distance of their primary events [long distance (LDS), middle distance (MDS), and short distance (SDS) swimmers]. Intergroup analyses showed that the LDS group had the highest values of percent Type I muscle fiber composition (percent Type I and percent Type I area), and the lowest values of leg power and strength values (vertical jump and torque-velocity relationships). In addition, when grouped by Type I fiber composition, subjects having greater than or equal to 50% Type I fibers had significantly lower vertical jump and torque values than those having less than 50% Type I fibers. Overall, the compositional and functional measurements were consistent with the specific metabolic and contractile demands of the different swim groups.

Adolescent↗

PubMedDate not supplied

Skeletal muscle profiles in elite springboard and platform divers.

This investigation determined the vastus lateralis muscle fiber composition, as well as leg power and strength, in a group of 10 world class divers. Male divers had a low mean percentage of Type I fibers (36%), which was consistent with the functional demands of their sport, whereas females had a mean value of 61%. The ratio of Type I/Type II cross-sectional fiber area was 0.95 in females and 0.82 in males. Angle-specific torque-velocity relationships, derived from Cybex testing of the knee extensors, revealed high torque values in males but not in females. The observed male-female differences have no clear explanation, unless muscle fiber composition has greater importance in the more difficult dives executed by men.

Adolescent↗