Metabolic adaptations to short-term training are expressed early in submaximal exercise

Abstract

In previous studies we have been able to demonstrate tighter metabolic control of muscle metabolism during prolonged steady-state exercise 5 to 6 days after the initiation of training and well before changes in oxidative potential. To examine whether the metabolic adaptations are manifested during the non-steady-state adjustment to submaximal exercise, 11 male subjects (Vo2 peak, 45 +/- 2.4 mL.kg(-1). min(-1), X +/- SE) performed 98 min of cycle exercise at 67% of Vo2 peak prior to and following 3 to 4 days of training for 2 h per day. Analysis of lactate concentration (mmol/kg dry weight) in samples rapidly extracted from vastus lateralis indicated reductions (p < 0.05) of 44% at 3 min ( 42.1 +/- 7.1 vs. 23.6 +/- 7.7), 29% at 15 min (35.4 +/- 6.4 vs. 25.0 +/- 6.0), and 32% at 98 min (22.9 +/- 6.9 vs. 15.6 +/- 3.2) with training. Training also resulted in higher phosphocreatine and lower creatine and P(i) values that were not specific to any exercise time point. In addition, Vo2 was not altered either during the non-steady state or during the steady-state phases of exercise. These results suggest that at least part of the tightening of the metabolic control and the apparent reduction in glycogenolysis and glycolysis in response to short-term training occurs during the adjustment phase to steady-state exercise.

Blood metabolite and catecholamine responses to prolonged exercise following either acute plasma volume expansion or short-term training

“…As we have found previously, a few days of training have not appeared sufficient for these adaptations to develop at least in the untrained (Green et al 1989). It has been reported that reductions in blood and muscle La -concentrations do occur, however, within the first few days of training (Green et al 1991b;Green et al 1995). Given the lower blood La -concentration observed in the present study, a similar adaptation appears to have occurred as has been noted previously (Green et al 1991b;Green et al 1995).…”

“…It has been reported that reductions in blood and muscle La -concentrations do occur, however, within the first few days of training (Green et al 1991b;Green et al 1995). Given the lower blood La -concentration observed in the present study, a similar adaptation appears to have occurred as has been noted previously (Green et al 1991b;Green et al 1995). When further statistical analysis was performed, a sequence effect (P < 0.05) was found, indicating an influence of the order of experimental conditions.…”

Learning an energy-demanding and biomechanically constrained motor skill, racewalking: Movement reorganization and contribution of metabolic efficiency and sensory information

“…The intensity (45-60% VO 2max ) and duration (7 Â 30 min) of practice trials were not sufficient to engender changes in aerobic fitness level to the studied population (Green, Cadefau, Cusso, Ball-Burnett, & Jamieson, 1995).…”

Oxygen uptake kinetics and maximal aerobic power are unaffected by inspiratory muscle training in healthy subjects where time to exhaustion is extended

“…_ V O 2 in muscle is known to rapidly adjust to short-term training in humans (Berry and Moritani 1985;Cadefau et al 1994;Green et al 1995;Phillips et al 1995) and _ V O 2 kinetics have previously been shown to improve after as little as 4 days of whole-body endurance training (2 h per day at 60% pre-training peak _ V O 2 ) (Phillips et al 1995). However, as a sole stratagem, IMT appears unlikely to be a sufficient stimulus to improve whole-body cardiopulmonary fitness in healthy subjects.…”