[Perceived effort: correlation with the anaerobic threshold and usefulness in a training program]. / L'effort perçu: corrélation avec le seuil anaérobie et utilité dans un programme d'entraînement.

Following the extensive technical progress in monitoring of sports performance, putting certain physiological principles out of reach for the everyday sportsman, we wondered if perceived effort (PE) as described by Borg is a parameter that is of use, or complementary, to the determination of the anaerobic threshold (AT) during an incremental test on a treadmill on one hand and to prescribing exercise adapted to the type of metabolic load on the other. 46 sportsmen (various soccer players, regional runners) were asked to complete a Conconi Test on a treadmill and at the same time were asked to evaluate their PE (as defined by Borg) at each performance level. We then plotted PE as a function of running speed, thus finding a point of inflexion (ascending) for PE. The speed corresponding to this point shows an excellent correlation with the AT as determined from cardiac frequency. The absolute value of PE at the AT varied little within our group, but seemed to vary according to the type of sport and the subjects' sports practice. Taking the limitations of this method in consideration, PE may be used as an additional indicator in the determination of the AT in an incremental AT-test and can be useful in the prescription of an exercise program.

Effects of priming exercise on VO2 kinetics and O2 deficit at the onset of stepping and cycling.

Breath-by-breath O2 uptake (VO2) kinetics and increase of blood lactate concentration (delta Lab) were determined at the onset of square-wave stepping (S) or cycling (C) exercise on six male subjects during 1) transition from rest (R) to constant work load, 2) transition from lower to heavier work loads, wherein the baseline VO2 (VO2 s) was randomly chosen between 20 and 65% of the subjects' maximal O2 uptake (VO2 max), and 3) inverse transition from higher to lower work loads and/or to rest. VO2 differences between starting and arriving levels were 20-60% VO2 max. In C, the VO2 on-response became monotonically slower with increasing VO2 s, the half time (t1/2) increasing from approximately 22 s for VO2 s = R to approximately 63 s when VO2 s approximately equal to 50% VO2 max. In S, the fastest VO2 kinetics (t1/2 = 16 s) was attained from VO2 s = 15-30% VO2 max, the t1/2 being approximately 25 s when starting from R or from 50% VO2 max. The slower VO2 kinetics in C were associated with a much larger delta Lab. The VO2 kinetics in recovery were essentially the same in all cases and could be approximated by a double exponential with t1/2 of 21.3 +/- 6 and 93 +/- 45 s for the fast and slow components, respectively. It is concluded that the O2 deficit incurred is the sum of three terms: 1) O2 stores depletion, 2) O2 equivalent of early lactate production, and 3) O2 equivalent of phosphocreatine breakdown.(ABSTRACT TRUNCATED AT 250 WORDS)