A 'New' Method to Normalise Exercise Intensity

Exercise intensity has traditionally been described, prescribed and normalised as a fraction (%) of the maximal oxygen uptake ((V) over dotO(2max)). We hypothesised that the extent of inter-subject variability in the physiological responses to exercise would be greater when work rates were prescribed using % (V) over dotO(2max) as compared to % 'delta' (Delta), a method of normalising exercise intensity in which both the gas exchange threshold (GET) and the (V) over dotO(2max) are considered. 9 men completed a ramp incremental test on a cycle ergometer to establish the GET and (V) over dotO(2max). Subsequently, subjects completed 6 constant-work-rate exercise bouts at intensities corresponding to: 50%, 70% and 90%(V) over dotO(2max); and 60% GET, 40% Delta (that is, 40% of the difference between the GET and (V) over dotO(2max)) and 80% Delta. For all bouts, exercise was continued for 20 min or until task failure if this occurred sooner. When exercise was prescribed using the % Delta concept, there were significant reductions in the inter-subject variability in pulmonary gas exchange, blood lactate accumulation, heart rate, and ratings of perceived exertion (all P<0.05). In conclusion, the % Delta concept resulted in more consistent inter-subject physiological responses to constant-work-rate exercise and should be used in preference to % (V) over dotO(2max) to more effectively normalise exercise intensity.