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Biomedical subjects

M Grandmontagne

Publications and source records attributed to M Grandmontagne.

6 recordsLinked to original sources

Aerobic performance capacity in paraplegic subjects.

To determine adaptation to prolonged exercise in paraplegics, maximal O2 uptake (VO2max) and lactate threshold (LT) were evaluated during an arm cranking exercise in nine patients (P) and nine able-bodied (AB) subjects. Mean VO2max averaged 25.1 and 31.6 ml X min-1 X kg-1 in P and AB groups respectively. VO2max in P was found to be directly related to the level of spinal injury: the higher the lesion the lower the uptake. Lactate threshold expressed as a percentage of VO2max was higher in P (59%) than in AB (43%), and close to that observed in arm-trained athletes. Since training has less effect on VO2max in paraplegics than in able-bodied subjects, attributable to a deficiency in the circulatory adaptation of paraplegics to exercise, the observed differences between AB and P in lactate threshold and submaximal exercise indicate that the possible effect of training in paraplegics is located at the level of intracellular chemistry, with a diminution in glycogenolysis (higher LT) and a higher rate of lipid utilization (lower RQ).

Adult↗

Magnitude and duration of excess postexercise oxygen consumption in healthy young subjects.

Postexercise oxygen consumption was investigated in eight healthy subjects. The subjects exercised for about 80 minutes at 70% of their maximum VO2. Following the exercise the subjects rested in bed for 24 hours. Oxygen uptake was measured continuously during the first hour after exercise, then hourly for the next 11 hours, and finally at 24 hours after exercise. Heart rate and rectal temperature were recorded continuously during the first 12 hours and then at 24 hours after exercise. Blood was sampled hourly after exercise. The results were compared with those of an identical control experiment in which the subjects rested instead of exercising. Oxygen uptake of each time point in each subject was greater after exercise compared with the control experiment. Mean total oxygen consumption after exercise was 211 +/- 16 L/12 h as compared to 185 +/- 13 L/12 h in the control experiment (P less than 0.001). Also, the heart rate was higher during the first 12 hours following exercise than in the control study. No significant differences were observed in rectal temperature in the two experiments after the initial 30 minutes following exercise. The first meal taken after the cessation of exercise increased markedly the rate of oxygen consumption in comparison to the increase observed following the same meal in the control experiment. The respiratory exchange ratios were lower following exercise than in the control study. In conclusion, we have demonstrated that the excess postexercise oxygen consumption (EPOC), may persist for at least 12 hours, and possibly for 24 hours. Also, exercise caused enhancement of the stimulation in oxygen uptake seen after a meal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Ventilatory transients during exercise: peripheral or central control?

The fast component of the ventilatory changes that occur at the transition phases of exercise was studied in awake dogs trained to run on a treadmill. Two questions were examined: firstly, is the fast ventilatory component modified by changes in venous return to the lungs, such as those consecutive either to increased work loads or to beta adrenergic blockade?, and secondly, is this component altered by central ventilatory depressants? The results showed that at the onset of exercise, there is no correlation between the instantaneous increment in ventilation and the intensity of exercise, but at the end of the treadmill run, the fall in ventilation is closely linked to the power of the work performed. Ventilatory transients observed either at the start or at the end of exercise remain unaffected by administration of a beta-adrenergic blocking agent. But central depressant effects on ventilation caused by narcotic analgesics or hypnotic drugs altered the breathing pattern of the fast component of exercise-induced ventilatory changes. It is concluded that the instantaneous changes in ventilation occurring at the transition phases of exercise are controlled by mechanoreceptor mechanisms, but cerebral control is superimposed on the reflex control in regulating both tidal volume and breathing rate.

Animals↗

[Maximal oxygen uptake in French children in relation to age, sex and physical training].

1. Maximal oxygen uptake (VO2 max) was determined in 451 boys and girls ranging from 11 to 16 years and divided in two groups. Group I (n = 287) was considered as an untrained reference group. Group II (n = 174) was regularly trained. This group concerned school-children affiliated to a swimming club and trained 5 to 10 h per week. Body growth is nearly the same in the two groups until puberty but, at 15-16 years in the boys, 14-16 years in the girls, height and weight are higher in group II. 2. In group I, between 11 and 16 years, VO2 max increases by 50% in boys against only 25% in girls. For the same age, VO2 max remained smaller in girls, even before puberty although there is no difference in body growth. At 11 years, specific VO2 max averaged 47 ml . min-1 . kg-1 in boys and 40 ml . min-1 . kg-1 in girls and decreases with age only in sedentary girls down to 37 ml . min-1 . kg-1. From the results presented here it appears that maximal oxygen uptake in the average french schoolchild is similar to those of subjects from different countries with same cultural and socio-economical level. 3. In group II, VO2 max is similar in both sexes at 11-12 years old, and then up to 16 years of age increases more rapidly in boys (+100%) than in girls (+50%). Specific VO2 max ranges between 57 and 62 m. min-1 . kg-1 in boy swimmers and averages 53 ml . min-1 . kg-1 in girl swimmers. The influence of physical training on aptitude development is discussed and compared with previously published data.

Adolescent↗