Annals of Case Reports (ISSN: 2574-7754)

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Case Report 1: Interval Exercise at High Intensity

Authors: Francisco Javier Calderon Montero*

*Corresponding Author: Francisco Javier Calderon Montero, Professor of Human Physiology at the Faculty of Physical Activity and Sport Sciences, INEF (National Institute of Physical Education and Sport Sciences), Polytechnic University of Madrid, Spain.

Received Date: 08 January, 2022

Accepted Date: 11 January, 2022

Published Date: 14 January, 2022

Citation: Calderon Montero FJ (2022) Case Report 1: Interval Exercise at High Intensity. Ann Case Reports 7: 733. DOI:

Athlete's Data

24-year-old woman participating in a research project looking at iron metabolism in three groups; pill, regular menses and menopause. After a medical examination and a maximal test, she performed intermittent exercise on the treadmill. The maximal parameters as well as the characteristics of the intermittent exercise are shown in (Table 1).


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.


Figure 1: Evolution of oxygen uptake and carbon dioxide output during intermittent exercise.

Figure 2: Evolution of respiratory quotient and running speed during intermittent exercise.

Figure 3: Example of calculation of the regression line in the second repetition. On the left, the drawing of the shape line and on the right the values of ⩒O2 (in red) and ⩒CO2 (in black) at the end of the repetition and during recovery.


Table 1


163 cm


57 Kg

Body surface Area

1,609 m2


2591 ml/min; ml/Kg/min


101 L

Max HR; Max Pulse O2

179 lat/min; 15,1 ml/heartbeat



Velocidad máxima

14,1 Km/h

Interval exercise

8 x 3 min 85 % of O2 max

1,5 min rest between repetitions

Table 1:

Intervalos de paso de serie

Ecuación de regresión

1ª a 2ª serie

y = 1222,8x - 94,8

2ª a 3ª serie

y = 1170,2x - 51,2

3ª a 4ª serie

y = 1058,4x + 165,6

4ª a 5ª serie

y = 1029,8x + 117,2

5ª a 6ª serie

y = 1065,8x + 17,2

6ª a 7ª serie

y = 973,4x + 175,6

7ª a 8ª serie

y = 926,6x + 229,4

Table 2:

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