Physiological responses to one- and two-leg exercise breathing air and 45 percent oxygen. C T M Davies, Anthony J Sargeant Journal of Applied Physiology 1974

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http://jap.physiology.org/content/36/2/142

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Improving human exercise performance with training

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This research study was designed and carried out by Professor Anthony J Sargeant as part of his PhD which was awarded by The Board of Studies in Physiology of London University in 1975. Using healthy normal subjects Tony Sargeant was able to show that large increases in the maximum oxygen uptake that could be achieved in one-leg exercise after one leg-training (consequent upon a direct training effect at the peripheral muscle level)  were not reflected in two leg exercise maximum oxygen uptake where maximum cardiac output (which had not been subjected to training stimulus by the one-leg exercise) was the determining factor.

The effects of training resulting from one-leg exercise on a stationary bicycle ergometer have been studied. Seven subjects were habituated to one- and two-leg progressive exercise tests on 11 successive days and were then trained for 60 min-day-1 (30 min each leg) 3 times per wk for 5-6 wk at approximately 80% of their one-leg VO2 max. VE max increased (P less than 0.05) by approximately 14 1-min-1 and VO2 max by approximately 0.34 1-min-1 (+14%; P less than 0.05) in one-leg exercise. This latter increase was not, however, reflected in the two-leg VO2 max which only increased 145 ml-min-1 (4.7%). It was concluded that training is specific and in one-leg work the phenomenon is mainly peripheral in origin, but in two-leg work the limitation to maximal exercise is still provided by the capacity of the central cardiovascular system to transport oxygen to a given effective muscle mass.

What limits Maximum Oxygen Uptake in Human Exercise?

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Anthony J Sargeant proposed this approach to using a reduced muscle mass to examine the limitation to maximum oxygen uptake (100% 0xygen cannot be used – hence 45%) enhanced oxygen increases Maximum Oxygen Uptake in 2-leg exercise where cardiac output is limiting – but does not increase the maximum oxygen uptake in 1-leg exercise where the limitation is not the delivery of oxygen but the muscle enzyme systems capability to take up and utilize the oxygen. This PhD research work was carried out in the laboratory of CTM Davies who in the tradition of the day put his name first on nearly all research leaving his laboratory.