Thursday, September 15, 2011

Max or Submax- That is the Question

When performing a VO2 max test it can be difficult to determine whether or not true, maximal oxygen consumption was attained. Historically VO2 max tests require the subject to run on a treadmill as long as they can and the amount of oxygen consumed in the last minute of the test is considered the VO2 max. This method often yields sub maximal scores. Physiologically there are four ways to determine whether maximal oxygen consumption has been reached.

1.       No increase in oxygen consumption with an increase in workload (plateau)
2.       Obtaining max HR
3.       RER > 1.1
4.       Blood lactate concentration above 8 mM

At least one of these must occur for a VO2 max test to be considered valid. One must be careful in measuring these criteria, particularly maximal heart rate. Simple formulas like (220-age yrs) are inaccurate and should be taken with a grain of salt.

Tuesday, September 13, 2011

VO2 Max: Falling Short of The Hype-rventilation

The VO2 max test is considered by many (myself excluded) to be the gold standard human performance test. It has been largely popularized by the Gatorade add campaign that ran in the early 2000’s featuring beautiful female athletes and well branded male athletes performing maximal treadmill tests. Additionally, during Lance Armstrong’s long reign over the peloton it was well documented that Lance had performed a VO2 max test with a score of 86 ml/kg/min. Naturally an extremely high VO2 max became directly associated with elite aerobic performance. This week I will be posting the 4 reasons the VO2 Max Test isn’t all its hyped up to be. Topics I will address include:

1.       It’s difficult to know if you are actually measuring a subjects maximal oxygen consumption
2.       The VO2 max test downplays the importance of bio-mechanical efficiency
3.       The VO2 max test downplays the importance of having a high lactate threshold
4.       The formulas used to determine caloric expenditure are poorly validated