Whichever the Initial Training Status, any Increase in Velocity at Lactate Threshold Appears as a Major Factor in Improved Time to Exhaustion at the Same Severe Velocity After Training

Abstract

The first purpose of this study was to assess the eventual training adaptations in the time to exhaustion at the same severe velocity occurring after severe interval-training programs in few- and well-trained subjects. In the event of such training adaptations, the second purpose was to identify the discriminant factors of performance improvement according to the initial training status. Seven few- and six well-trained subjects performed: firstly, an incremental test to determine the maximal oxygen consumption (VO2max), the energy cost of running (ECR), the velocity associated with the achievement of VO2max (vVO2max) and the lactate threshold (LT expressed in VO2, km x h(-1), % vVO2max); secondly, an all-out test at the velocity corresponding to the midway between vLT and vVO2max (vdelta50) to determine the time to exhaustion (tmax); such tests were carried out before and after 4- and 8-week severe interval-training programs. In the few-trained subjects, all factors of performance (i.e., VO2max, ECR, vVO2max, LT expressed in VO2, km x h(-1), % vVO2max) and tmax at the pre-training vdelta50 were improved after training (+8, -8, +7, +9, +14, +6% and +79%, respectively); only the increase in vLT was related to the one in tmax (r = 0.714, p < or = 0.05, n = 7). In the well-trained subjects, only vVO2max was improved (+3%) due to the decrease in ECR (-3%), tmax at the pre-training vdelta50 did not vary after training; only the three subjects (over six) who improved their vLT (+0.5, +0.5, +0.8 km x h(-1), respectively) improved their tmax (+10, +24, +101%, respectively) (r = 0.895, p < or = 0.01, n = 6). So, whichever the initial training status, any training-induced adaptation in vLT appeared as a major factor of performance improvement especially at supra-LT velocities.

Effects of training in normoxia and normobaric hypoxia on time to exhaustion at the maximum rate of oxygen uptake

“…However, if Demarle et al (2001) showed that T lim is improved by training when an event is performed at the same absolute work rate before and after training, the results obtained when T lim is performed at the same relative work rate are contradictory. While Billat et al (1999) and Heubert et al (2003) did not observe any improvement in T lim after training at a velocity eliciting _ V O 2max , Smith et al (1999) and Demarle et al (2003) did observe an improvement. In addition to this discrepancy, the training schedules performed in these previous experiments (Billat et al 1999;Smith et al 1999;Demarle et al 2001Demarle et al , 2003Heubert et al 2003) included interval training sessions.…”

Diagnostics of endurance performance on the level of gene expression

“…This distinction is also important because the improvement in endurance performance with training is more pronounced for factors reflecting the time-to-exhaustion or velocity at a high metabolic strain, than for VO2max, which typically only improves moderately [7,8].…”

“…The adequacy of these measures is amply demonstrated for elite athletes [7][8][9] but they are rarely performed in routine diagnosis. At best maximal oxygen uptake (VO2max) is 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 assessed in an incremental test, which allows, when accompanied with measures of mechanical work, to estimate the economy of a given exercise.…”

“…VO2max, however, is a steady state measure of maximal exercise performed at relatively short duration. This parameter, while reporting maximal aerobic performance, does not necessarily document fatigue resistance, which is probably more relevant to characterize performance of long distance events, which rely on the capacity to maintain substrate metabolism and metabolic stores.This distinction is also important because the improvement in endurance performance with training is more pronounced for factors reflecting the time-to-exhaustion or velocity at a high metabolic strain, than for VO2max, which typically only improves moderately [7,8].Towards a representative diagnostics of endurance performance it therefore appears sensitive to target the tests as close as possible to the muscle groups being trained and quantify both the maximal capacity for aerobic work and the time-to-exhaustion.Myocellular underpinning of exercise performance -As pointed out in a number of research papers, measures comparing structure-function relationships in the effector organ of mechanical work, skeletal muscle, can reveal unprecedented detail on the features that set the endurance training state. For instance, muscles of endurance-trained subjects have been shown to differ to un-trained subjects in terms of muscle size and fat content, slow fiber type composition and myocellular constituents of lipid metabolism [10,11].…”

An Evaluation of a Combat Conditioning Trial Program

“…The average gains seen in military training units are primarily the result of large gains by the least-fit individuals; individuals who are relatively highly fit initially essentially maintain their fitness. This trend has been evident in at least six studies (Demarle, Heugas, Slawinski, Tricot, Koralsztein, & Billat, 2003;Dyrstad, 2006;Knapik, Bullock, Canada, Toney, Wells, Hoedebecke, et al, 2003;Legaz Arrese, Serrano Ostariz, Casajus Mallen, & Munguia Izquierdo, 2005; Rosendal, Langberg, Skov-Jensen, & Kjaer, 2003; Trank, Ryman, Minagawa, Trone, & Shaffer, 2001). Figure 2 compares the present findings and the results in those studies.…”