Objective

To analyze the physiological response to an intermittent exercise at a high intensity.

Interval exercise data and questions to be asked.

(Figure 1) Shows the ⩒O2 and ⩒CO2 in the 8 repetitions.

Initial speed 13.1 km/h;

Speed adjustment from the 4th to the 5th repetition = 12.3 km/h).

New speed adjustment in the last three sets = 11.6 km/h.

(Figure 2) shows the evolution of the respiratory quotient and running speed. Note how in the first 5 series the respiratory quotient, although decreasing (from 1.27 to 1.12), is greater than 1, From the 6th series onwards this ergo-spirometric parameter almost reaches unity.

For each rest interval, regression lines were calculated for the decrease in averaged ⩒O₂ in the last minute of each repetition and the minimum of the rest interval, before starting the next repetition. (Figure 3) shows an example of the calculation of the regression line for the second repetition.

(Table 2) shows the regression equations for each of the intervals between repetitions. Note how the slope decreases as the repetitions progress.

The average ⩒O2 value for all the changes from rest to each of the 7 runs was 2208 ml/min, i.e. 85.2 % of the peak ⩒O2.

Based on the data provided, please answer the following question: Can you justify by ergo-spirometric parameters why it has been necessary to decrease the running speed?

In short, the woman cannot maintain the programmed speed because indirectly (through the respiratory quotient) she is in a state of lactic acidosis that is incompatible with this type of intervallic training. Thus, it was necessary to decrease the speed twice in order to adjust the metabolic activity to be as aerobic as possible. In addition, the fact of not being able to maintain a constant slope may mean either that the recovery time is insufficient or that the nervous system cannot adjust.

Figures

Tables