Elective reconstruction of the ascending aorta for aneurysmal disease restores normal life expectancy. An analysis of risk factors for early and late mortality.

Objective: We investigated the survival of patients who had undergone elective reconstruction of the ascending aorta for degenerative aneurysms. The long-term survival was compared to an age- and sex-matched case-control population. An analysis of risk factors, influencing survival was made.

Energy cost, mechanical work and muscular efficiency in swing-through gait with elbow crutches.

Crutches are widely used to assist ambulation in disabled people. Many authors have shown that the use of crutches increases the energy cost as compared to normal walking. In this study we have measured the energy consumed and the mechanical work performed during swing-through crutch gait in order to assess if the greater energy expenditure is accompanied by an equivalent increase of the work done to move the body.

An evaluation of the maximal anaerobic capacity in man.

Maximal anaerobic capacity, i.e., the maximal amount of energy released by anaerobic processes (Ean max, J.

[Relationship between oxygen deficit and VO2max in supramaximal running].

The maximal accumulated oxygen deficit (DO2max, ml O2/kg) has been measured in 43 healthy male subjects with different VO2max (45-70 ml O2/kg.min) during the course of supramaximal runs performed until volitional exhaustion on an inclined treadmill. It was found that DO2max and VO2max were linearly related: DG2max = 39.

[Relation between endurance time and maximal oxygen consumption during supramaximal running].

The relationship between speed and the maximal length of time supramaximal runs can be sustained (temps-limite, tlim) has been studied in seven male subjects (physical education students). Within the range of intensity studied, tlim strictly depends on maximal oxygen consumption (VO2max). The relationship between tlim and the relative energy cost of the exercises per unit of time (E), calculated by subtracting the maximal power of aerobic metabolism (Emaxox) from E, removes the interindividual differences of tlim.

[Electric activity of the rectus femoris in supramaximal running].

The electrical activity of the rectus femoris has been analysed in nine subjects during the course of a supramaximal run performed until exhaustion. The integrated electromyogram and the median frequency do not change significantly as a function of time.

[Relation between maximal oxygen consumption and the record time in the 1500-meter run. Analysis of Lloyd's model].

Lloyd's equation (Lloyd, 1967 b) has been applied to the calculation of record time in the 1 500 meters foot race from VO2 max. Twenty-eight healthy male subjects participated in this investigation. Record times decrease with increasing VO2 max.

[Calculation of record-time in the 800-meter run: predictive value of Margaria's equation].

Margaria's equation (1976)--describing the relationship between the minimum time necessary to cover a distance equal or longer than 1,000 m (record-time TR) and the maximal oxygen consumption (VO2 max)--has been modified in order to be applied to the calculation of TR in the 800 m foot race. Fifteen subjects participated in this study (VO2 max = 63 +/- 3.5 ml O2 X kg-1 X min-1, measured TR = 131 +/- 10 seconds).

[Kinetics of oxygen consumption during running of supramaximal intensity in differently trained subjects].

The rate of increase of the oxygen consumption (VO2) at the onset of supramaximal exercise has been compared in trained and untrained subjects. The velocity constant of the VO2 increase up to its maximum (VO2 max) is proportional to the energy requirements of the exercise (WO2). For a given (WO2-VO2 max) value, the kinetics of VO2 is roughly the same in both types of subjects.

[Changes in the global electromyogram during static exercise; effect of age].

In normal man, the EMG changes in forearm muscles holding a tension of 30% maximal voluntary strength for 5 minutes are: (1) an increase of integrated EMG, (2) a slight decrease of the median frequency of the EMG power spectrum. These changes are largely reduced with age.

[Cardiovascular changes induced by isometric exercise in aged subjects].

Blood pressure and heart rate during static contraction of forearm muscles holding a tension of 30% maximal voluntary strength for 5 mn have been measured. Eleven young men and 11 elderly male subjects were used. Maximal voluntary strength is reduced by 19% in elderly subjects.

[Effect of the modality of exercise on the VO2 max].

1. Maximum oxygen consumption has been measured by means of three different exercises: cycle ergometry, treadmill running and uphill walking with a 20 kg-load. 2.

The sources of external work in level walking and running.

The work done at each step during level walking and running to lift the centre of mass of the body, Wv, and to increase its forward speed, Wf, and the total mechanical energy involved (potential + kinetic) Wext, have been measured at various 'constant' speeds (2-32 km/hr) with the technique described by Cavagna (1975). 2. At intermediate speeds of walking (about 4 km/hr) Wv = Wf and Wext/km is at a minimum, as is the energy cost.

The role played by elasticity in an exercise involving movements of small amplitude.

In an exercise consisting of repetitive small jumps on both feet at a frequency of 116/min, the mechanical work performed and the O2 consumption at steady state were measured. Of the positive work performed in the jump only 40% appears to be due to the chemical transformations taking place in the contractile componenet of the muscle fibres; the remaining 60% appears to be due to the elastic energy accumulated in the elastic elements of the contracted stretched muscles of the lower limbs during the falling phase of the previous jump, when the body hits the ground.