THRESHOLDS ARE NOT STABLE
Hughes, E. F., Turner, S. C., & Brooks, G. A. (1982). Effects of glycogen depletion and pedaling speed on anaerobic threshold. Journal of Applied Physiology, 52, 1598-1607.
Males (N = 9) were evaluated for ventilatory threshold (VT) and anaerobic threshold (AT) under several varying conditions of cycle ergometer pedaling. VT and AT are proposed as being the points after which expired minute volume and blood lactate begin to increase nonlinearly as a function of work rate. The two varying conditions that were evaluated were: (a) work tempo (50 and 90 rpm), and (b) glycogen state (normal and depleted).
Under the glycogen depleted condition, VT shifted to a lesser and AT to a greater work rate relative to the normal glycogen state.
When the pedaling rate was increased to 90 rpm, relative to the values obtained at 50 rpm, AT was shifted to a lesser work rate.
A correlation of only r = .71 was obtained between Ss' VT and AT. In Ss of equivalent O2 uptake, lighter Ss (<70 kg) demonstrated AT at a work rate lower than heavier Ss (>80 kg).
Implication. Both the ventilatory and anaerobic thresholds can be affected by work tempo and glycogen state.
When Ss are matched for O2 uptake, lighter Ss will record lower ATs than will heavier Ss. Thus, in experiments using matched Ss, body weight will also have to be considered.
The relationship between ventilatory and anaerobic thresholds is low and the two should not be considered equivalent.
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