| dc.description.abstract | Background. Successful endurance athletes train a relatively large volume at low intensity endurance training, which is interspersed by relatively low volumes of high intensity training. There is, however, strong indications that an increase in high intensity training load would positively impact physiological determinants of endurance performance.
Purpose. The primary aim of this study was to examine the performance effects of progressing in training load by different training intensity distributions in incremental treadmill roller-ski skating test to voluntary exhaustion. Secondary aim was to investigate the adaptations in laboratory determinants of performance at submaximal and maximal intensity levels in pre- and post-training comparison.
Methods. Following a standardized 8-week baseline-training period, 59 well-trained junior cross-country skiers (male, n = 43; female, n = 16) completed an intervention training period of 8 weeks. The contemporary training model (CG) included athletes who maintained typical training pattern and was compared to load-matched increases in low intensity (LITG) and high intensity training (HITG) by using the training impulse model (TRIMP). Pre- to post changes in endurance performance and physiological performance-determining variables were compared while treadmill roller-ski skating at submaximal stages and during incremental roller-skiing to exhaustion.
Results. The training intensity distribution was 92-4-4%, 85-4-11% and 91-5-4% for LITG, HITG and CG in zone 1-2-3, which present low-, moderate- and high intensity, respectively. The main findings were: (1) the covariate-adjusted linear model failed to elicit significant group-differences in performance (i.e. time to exhaustion) and physiological adaptations (e.g. V̇O2peak, blood lactate concentration, gross efficiency); (2) within-group improvement in time to exhaustion was observed for HITG (9.7 ± 13.3%) and LITG (5.9 ± 10.4%) (p < 0.01, for both), whereas no change was found for CG; (3) HITG improved V̇O2peak (L∙min⁻¹) significantly by 3.2 ± 5.1%, with values increasing from 4.30 ± 0.74 to 4.43 ± 0.68 L∙min⁻¹ (p = 0.01), while no change was detected in LITG and CG; (4) gross efficiency increased for LITG (0.4 ± 0.6%) and HITG (0.4 ± 0.5%) at first submaximal intensity (p < 0.05), and no change was evident in CG (p = 0.19); at second submaximal intensity improvement was similar for LITG and HITG (increase of 0.3 ± 0.5%, 0.3 ± 0.6%; p < 0.01, < 0.05, respectively) and no change was apparent in CG (p = 0.23).
Conclusions. This study found that training groups did not differ in time to exhaustion and physiological performance variables after completing a training period of 8 weeks. The within-group improvements were largest in HITG, as pre- and post-training change in time to exhaustion and V̇O2peak was greater compared to the extent of improvement in two other training groups. In post-test, both HITG and LITG reduced oxygen cost and improved gross efficiency at submaximal intensities with a similar magnitude of change in relation to pre-test, oppositely absolute oxygen demand raised for CG in submaximal workload after the training period.
Key Words: endurance capacity, training intensity, peak oxygen uptake, time to exhaustion, gross efficiency, periodization model, cross-country skiing | |
