RESEARCH ON THE VALIDITY OF V02 TEST RESULTS

Research on the Validity of V02 test Results when Using the Mouthpiece and Nose Clamp for Expired Air Collection



Research on the Validity of V02 test Results when Using the Mouthpiece and Nose Clamp for Expired Air Collection

Introduction

The possession of a high maximum oxygen uptake (V02 max) is a prerequisite for successful endurance performance since the strong linear relationship between oxygen uptake and speed of running, swimming or cycling means that those individuals with a high V02 max should be able to maintain a higher absolute work rate than those with a low V02 max. Increases in V02 max as a result of endurance training, may thus be one reason for an increase in endurance with training, the change in V02 max being dependent on factors such as intensity, frequency and duration of training, and the subject's initial fitness level. Despite the fact that V02 max may be increased by training, its adoption as an indicator of endurance fitness has been questioned. Firstly, it has been found to be largely predetermined genetically (Klissouras et al, 1973; Lortie et al, 1982) and secondly, training-induced changes in endurance performance may be independent of changes in V02 max (Williams and Nute, 1986).

An alternative description of an individual's training status may be obtained by assessing the individual's ability to sustain an exercise intensity that demands a high percentage of his or her V02 max. This is because V02 max describes the whole body's capacity to take up oxygen, while the fractional utilisation of V02 max (%V02 max) over a given period of time reflects the metabolic characteristics of the working muscles and specifically their capacity for aerobic metabolism. This ability to sustain a high %VO2 max has previously been examined in two ways, either by measuring the exercise time to exhaustion at a given %VO2 max (Hardman, 1982) or by estimating the highest %VO2 max sustainable during a given period of time from measurements of the average work rate (Mayes, et al, 1985).

Direct measurement of the concentration of blood lactate also provides important information concerning the performance capacity of the individual. Researchers have found that the exercise intensity corresponding to a given blood lactate concentration, i.e. 4 mmol.l-1 or the onset of blood lactate accumulation (OBLA), not only appears to be a good predictor of endurance performance (Sjodin and Jacobs, 1981; Williams and Nute, 1983), but is also highly responsive to the influence of training (Sjodin et al, 1982). Whilst it has been demonstrated repeatedly that both maximum oxygen uptake and the work rate corresponding to OBLA are higher during treadmill running than during cycling (Hermansen and Saltin, 1969; Jacobs and Sjodin, 1985), performance testing and training on a cycle ergometer has its advantages. This exercise mode allows exact measurement of the subject's work rate during performance tests and permits careful control of the intensity of the training sessions.

Discussion

In recent times it was observed that cycle ergo meter was used and the mouth guards were ...