1. Foster, Carl PhD

Article Content


Maximal oxygen uptake (VO2max) has defined the concept of exercise capacity and endurance performance for more than half a century. The concept of a plateau of VO2 despite increasing muscle power output is a central tenant in the concept of VO2max. Recently, the concept of VO2max has been challenged, with suggestions that the plateau is more an artifact of testing procedures than of physiology.



This study was designed to compare VO2 responses during sequentially administered exercise tests, with an increased workload during the second test, to evaluate the presence of a plateau of VO2.



Competitive runners (6m,6f) performed incremental (3-min stages) treadmill exercise to fatigue, walked to recover for 3-min, then exercised for up to an additional 3-min at a faster pace (10.0 +/- 0.85 vs 11.0 +/- 0.85 mph).



During Run 1 the subjects did not consistently demonstrate criteria for a plateau of VO2. However, comparing Run 1 vs Run 2, there were no significant (P <.05) difference in VO2max (4.09 +/- 0.97 vs 4.03 +/- 1.16 L/min), VEmax (126 +/- 29 vs 126 +/- 35 L/min), or HRmax (184 +/- 6 vs 181 +/- 10 bpm). There were significant differences in VCO2max (4.40 +/- 1.08 vs 4.06 +/- 1.27 l/min) and RER (1.07 +/- 0.06 vs 1.00 +/- 0.06). There was some evidence of a differential effect for VO2max in Run 1 vs Run 2 in males (4.97 +/- 0.41 vs 5.07 +/- 0.40 L/min) vs females (3.21 +/- 0.21 vs 2.99 +/- 0.46 L/min).



The present data are supportive of the concept that VO2 plateaus during successive heavy exercise bouts with an increase in workload, and as such supports the traditional concept of VO2max.