Effort Tests

Effort Tests

Physical capacity, in a colloquial understanding, means the ability for heavy or prolonged physical effort performed with large muscle group involvement without rapidly increasing fatigue, as well as the ability to efficiently remove homeostasis disorders. The determinant of this kind of physical capacity is the oxygen uptake (VO2max) and anaerobic threshold (PPA). Both of these parameters are widely used both in assessing the overall physical efficiency, and in determining training loads used in training and rehabilitation, recreation and sports.

Oxygen uptake is the maximal  factor that can determine an athlete’s capacity to perform sustained exercise. VO2 max refers to the maximum amount of oxygen that an individual can utilize during intense or maximal exercise.

This parameter reflects the biological potential of the body. Uptake oxygen depends on several factors related to efficient respiratory, circulatory and muscular system functioning. For most people VO2max value ranges between 20 and 85 ml/kg/min. The higher the uptake of oxygen, the more energy during exercise is obtained from efficient oxygen sources.

Anaerobic threshold is a strictly defined load exercise at which anaerobic ATP processes begin to dominate the re-synthesis of ATP, needed to cover the energy requirements of the working body.

Exceeding the exercise intensity (threshold intensity) is associated with a sudden increase in blood lactate, leading to lactic acidosis, resulting in rapid fatigue of the body. The higher the threshold intensity of the exercise, the lower the physiological level of work and possibly longer duration (energy depends on ATP).

The load corresponding to the PPA is considered to be the most effective in endurance training. This is because PPA is an effort load which at highest efficiency activates oxygen in the working muscles (improves effort metabolism), and supports the cardio- respiratory system, whose function, apart from muscle metabolism, determines the level of physical capacity.

expandcollapseAssessment Methods

In Rehasport Clinic we have adopted the direct method for determining oxygen uptake. This method is based on the person performing a continuous 15-20 minute test, based on exercise of increasing intensity until the individual reaches maximum load.

During the continuous procedure, ergospirometer recordes cardiovascular (HR – heart rate) and respiratory parameters (including VO2 – the amount of oxygen absorbed, VCO 2 – the amount of carbon dioxide emitted, Ve – lung minute ventilation). Oxygen uptake is calculated by a computer system, based on the difference in oxygen content between the inhaled and exhaled air, multiplied by minute ventilation of the lungs.

For the determination of PPA use two measurement methods.

  • Invasive:  based on the observation of line changes in the concentration of blood lactate during exercise. This method, otherwise known as the bloody method, is based on the tested person performing increasing intensity exercises. Each effort load is followed by a capillary blood sample from the fingertip, and takes about four minutes. During the test, the person’s heart rate is continuously recorded. After the performed analysis, we obtain the PPA as the range of effort load and HR.
  • The second of method used by us is a noninvasive method, based on the observation of changes in gas exchange . PPA evaluated by this method is called a ventilation threshold (VT). And in this case, we use a continuous effort for increasing intensity, which by the use of a ergospirometer monitors changes in cardiovascular and respiratory systems. To determine the ventilatory threshold we use the method of “V – slope”. It is based on computer analysis of linear regression of the growth curve of CO2 production, to O2 consumption growth curve and determines the point at which a disproportionate increase in CO2 production exceeds the increase in consumption of O2.
  • Equipped with the results of the above tests we can participate in any type of physical activity.