PubMed Health⌕ Search

Biomedical subjects

A Rotstein

Publications and source records attributed to A Rotstein.

28 records · Page 2Linked to original sources
PubMed1989

Effect of training load on OBLA determination.

Fifteen male long-distance runners, 35.9 +/- 8.2 years of age, participated in the study. They had 5.7 +/- 2.3 years of running experience, marathon best time of 2,58:51 +/- 0,14:45 h, 10-km personal record of 37:18 +/- 2:50 min, and maximal aerobic power of 64.6 +/- 5.8 ml.kg-1.min-1. Their 4 mM.l-1 lactate threshold (OBLA) was tested twice in a randomized order: once following a week of light, pre-race-like training, and once after a week of heavy training load. The parameters measured during the OBLA tests were: rating of perceived exertion (RPE), running economy (E), heart rate (HR), respiratory exchange ratio (R), and running velocity at OBLA. Compared with the light load treatment, RPE following the heavy training week rose by 0.8 units, HR and E remained unchanged, and R decreased slightly (0.012). Running velocity at OBLA was raised 0.42 km.h-1 by the heavy training, but a negative correlation was found between this change and the baseline (light load) OBLA velocity (r = -0.57). It is suggested that in athletes the usefulness of OBLA testing, aimed at assessing current performance capacity, could be compromised by lack of control over the immediately preceding training schedules. However, it appears that the susceptibility to the lack of such standardization may be reduced or absent in higher level runners.

Adult↗
PubMed1986

Effect of training on anaerobic threshold, maximal aerobic power and anaerobic performance of preadolescent boys.

To evaluate the effect of a 9-week interval training program on aerobic capacity, anaerobic capacity, and indices of anaerobic threshold of preadolescent boys, 28 10.2- to 11.6-year-old boys were tested. The test included laboratory evaluation of anaerobic capacity (Wingate anaerobic test) and evaluation of VO2 max and anaerobic threshold indices from a graded exercise test and measurement of blood lactate. The tests also included a 1200-m run to investigate the relationship of laboratory fitness indices, VO2 max, anaerobic threshold indices, and indices of anaerobic capacity to the performance of the run. It was found that in 10- to 11-year-old boys, a 9-week interval training increased the indices of anaerobic capacity: mean power by 10% and peak power by 14%. No change was found in percent fatigue. The training also increased VO2 max by 7% in absolute terms and by 8%/kg body weight. A significant increase was also found in the running velocity at the anaerobic threshold (running velocity at inflection point of lactate accumulation curve), but in relative terms (percent of VO2 max), the anaerobic threshold decreased by approximately 4.4%. It is concluded that proper training may improve maximal aerobic power and anaerobic capacity of preadolescent boys. It is also concluded that anaerobic threshold measures are less sensitive to the training regimen than VO2 max and that the 1200-m running performance is strongly associated with both aerobic and anaerobic capacities and less with the anaerobic threshold, which in preadolescent boys seems to be higher than in adults.

Anthropometry↗
PubMed1986

Acute effect of cigarette smoking on physiologic response to graded exercise.

To assess the acute effect of cigarette smoking on physiologic response to graded exercise, eight physical education students were tested. The protocol included running on a treadmill for 5-min periods at the speed of 6, 8, 10, and 12 km/h. Each subject performed the exercise twice 1 week apart, once after abstaining from smoking for 24 h and once immediately after smoking two cigarettes. The following measurements were performed at each work load: HR, oxygen consumption, tidal volume, breathing frequency, pulmonary ventilation, and blood lactate. Running velocity corresponding to 4 mM lactate and to 170 HR were calculated. The average HR was higher after smoking at rest and at all work loads tested (P less than 0.05). The average VO2 was lower after smoking at all work loads above 6 km/h (P less than 0.05), and VE/VO2 was significantly higher (P less than 0.001) during smoking at all work loads above 6 km/h. No changes were found in the other parameters measured. No difference was found in the calculated work load corresponding to 4 mM blood lactate or 170 HR. It is concluded that although the acute effect of smoking two cigarettes by subjects accustomed to smoking does not dramatically affect their work capacity, it does significantly change their physiologic response, manifested by a higher HR, lower VO2, and lower breathing efficiency.

Adult↗
PubMed1986

Acute and chronic pharmacokinetic studies of slow release ketoprofen (Oruvail) in rheumatoid arthritis.

Slow release preparations of non-steroidal anti-inflammatory drugs are used to simplify dose regimes in the treatment of rheumatoid arthritis with the aim of improving patients compliance. This study examines the acute and chronic pharmacokinetics of slow release ketoprofen in 13 rheumatoid patients with a mean age of 59.8 years. Pharmacokinetic parameters following the first dose including Tmax which was 6.92 h (s.e.m. = 0.80), Cmax 3.87 micrograms/ml (s.e.m. = 0.54), apparent half-life 8.8 h (s.e.m. = 1.0) and AUC 41.92 micrograms.h/ml (s.e.m. = 4.02) were not significantly different from those following the last dose after 3 months of chronic treatment, when these were Tmax 6.38 h (s.e.m. = 0.84) Cmax 3.57 micrograms/ml (s.e.m. = 0.33) apparent half-life 8.8 h (s.e.m. = 1.1) and AUC 43.18 micrograms.h/ml (s.e.m. = 5.34) respectively. These results show that no accumulation of ketoprofen occurred with chronic treatment. Clinical assessments were performed in an open design and showed significant improvement in pain, articular index, grip strength and duration of morning stiffness when these parameters were compared to treatment with paracetamol during an initial washout. The drug was well tolerated although there was a trend for the haemoglobin to fall and this parameter should be monitored during therapy with ketoprofen.

Administration, Oral↗
PubMed1984

Exaggerated systolic blood pressure response to exercise in a water polo team.

Twenty-three top-level water polo players (WP) were examined for blood pressure (BP) response to graded and continuous cycle ergometry. Testing also included resting muscle biopsy for fiber typing, exercise ECG recording for heart rate (HR), exercise concentrations of blood lactate (LA), measured VO2max, and ratings of perceived exertion (RPE). A control group (C), whose subjects were physically active in endurance sports, but were older and less fit than the experimental subjects, was tested by an identical protocol. The BP response to exercise was significantly higher in the WP group at all comparison criteria including onset of blood lactate accumulation, absolute HR, percent of HRmax, and power loads (including loadless pedaling). To date, we are unaware of other reports on whole groups of sportsmen showing an exaggerated BP response to exercise. While it would appear from previous studies that normotensive individuals showing such a response are at a greater risk of developing hypertension, the significance of this BP response in highly-trained athletes in a specific sport remains unclear.

Adolescent↗
PubMed1982

Hemoglobin, hematocrit, and calculated plasma volume changes induced by a short, supramaximal task.

The influence of a short, supramaximal task of 30 s duration on plasma volume (PV) was tested in 14 female physical education students. Hemoglobin (Hb), hematocrit (Hct), and osmolality (Osm) were tested pre- and post-exercise. Performance of the exercise test, consisting of 30 s all-out pedaling against a load of 4.4 J/kg body weight per pedal revolution, brought about a significant elevation in the measured variables. The changes in Hct, Hb, and Osm were 3.14%, 0.92g X dl-1, and 9.58 mOs/kg-1, respectively. The changes in PV, calculated from the increase in Hct alone and from changes in Hct and Hb, was found to be -10.4% and -11.2%, respectively. It is suggested that very short periods of maximal exercise can bring about some 10% - 15% drop in PV. Mechanisms for this decrease are not clear. It could result from changes in tissue osmolality, filtration pressure, or opening up of collapsed capillaries.

Adult↗
PubMed1974

Isolation and antibacterial activity of acylphloroglucinols from Myrtus communis.

Isolation procedures of two new acylphloroglucinols, myrtucommulone-A and myrtucommulone-B, from Myrtus communis leaves are given. Myrtucommulone-A was highly antibacterial against gram-positive bacteria but was not active against gram negatives. The chemical relation to other acylphloroglucinols and the antibacterial activity of the compounds isolated are discussed.

Anti-Bacterial Agents↗