DiMenna, F., Otto, R. M., Rakowski, J. M., & Wygand, J. W. (2006). Prior exercise-induced alteration of VO2 kinetics and its implication for improved time to exhaustion. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 1533.

"The prior exercise effect on VO2 kinetics is well documented. Priming exercise that engenders a residual blood lactic acidosis increases phase II amplitude and decreases slow component amplitude during subsequent heavy-intensity exercise. Combined with a decreased change in blood lactate, these alterations would appear to facilitate increased exercise tolerance, although few studies have tested this hypothesis and results have been mixed".

This investigation evaluated whether prior heavy-intensity exercise improves performance during subsequent severe-intensity constant-load lower-body cycling. Triathletes (N = 5) performed lower body cycling performance trials to exhaustion without prior exercise (NPE) and after six minutes of heavy-intensity priming bouts of lower- (LBC) or upper-body (UBC) cycling. VO2 was measured breath by breath during the performance trial and time to exhaustion was recorded. A lower-body cycling graded exercise test was used to determine VO2peak, lactate threshold, and the sub-lactate threshold VO2/work rate relationship. The latter was used to establish work rates for the (LBC) priming bout (30%?) and performance trial (60%?). Work rate for the (UBC) priming bout was assigned according to body mass (1.3 W/kg). The best trial under each condition was used to determine time to exhaustion, end-exercise VO2, and blood lactate. VO2 slow component was quantified specific to a reference end point (30-second period before the duration of the shortest, best trial across conditions) and as the delayed-onset VO2 increase at end exercise per unit time. Baseline and early exercise parameters were calculated by averaging data from both trials. Breath-by-breath data from both trials were edited, interpolated, time aligned and averaged so that iterative non-linear regression could be used to model the response.

Lower-body cycling decreased the VO2 slow component during performance trial and reduced final blood lactate. End-exercise VO2 during the performance trial was unaffected by lower body cycling, however, because the early response (VO2 at minute 2) was increased. Upper body cycling had no effect on subsequent VO2 kinetics. Neither priming strategy affected time to exhaustion.

Implication. Despite favorable changes in the metabolic and gas exchange response, spot-specific priming exercise that results in a modest elevation of blood lactate at the onset of severe-intensity lower-body cycling does not improve time to exhaustion. Spot-specific priming does not improve performance.

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