Galley Proof 20/06/2019; 15:45 File: ies–1-ies192115.tex; BOKCTP/xjm p. 1 Isokinetics and Exercise Science -1 (2019) 1–10 1 DOI 10.3233/IES-192115 IOS Press Seasonal changes in gross efficiency and aerobic capacity in well-trained road cyclists Kamila Ploszczyca a , Jakub Foltyn b , Jakub Goliniewski b , Janusz Kre ¸˙ zelok c , Stanislaw Poprze ¸cki d , Mariusz Ozimek e and Milosz Czuba a,∗ a Department of Kinesiology, Institute of Sport, Warsaw, Poland b Department of Sports Training, The Jerzy Kukuczka Academy of Physical Education in Katowice, Faculty of Physical Education, Katowice, Poland c Department of Individual Sports, The Jerzy Kukuczka Academy of Physical Education in Katowice, Faculty of Physical Education, Katowice, Poland d Department of Biochemistry, The Jerzy Kukuczka Academy of Physical Education in Katowice, Faculty of Physical Education, Katowice, Poland e Institute ofSport, Warsaw, Poland Received 4 February 2019 Accepted 21 May 2019 Abstract. BACKGROUND: The purpose of this study was to evaluate changes to key aerobic performance determinants, namely maximal oxygen uptake (VO2max), lactate threshold (LT) and gross efficiency (GE) over the cycling season. METHODS: Twelve well-trained road cyclists completed three incremental tests during a season in order to determine VO2max, LT and GE. The laboratory tests were performed using the following sequence: after the transition period (TRAN), during the preparatory period (PREP) and during the competition period (COMP). RESULTS: VO2max did not change significantly over the season. Workload at lactate threshold (WLLT) increased by 11% between the TRAN and COMP periods (p< 0.001), which was accompanied by an increase in oxygen uptake at lactate threshold (VO2LT; p< 0.01). The percentage of VO2max at the LT changed from 80.1% to 85.6% (p< 0.05). GE increased from 21.9 ± 1.1% in TRAN to 22.8 ± 0.8% in COMP (p< 0.01). No significant correlations were found between VO2max and GE and between changes in GE and those in VO2max in any training period. CONCLUSIONS: In well-trained athletes, the training process contributes mostly to improvements in submaximal indicators, while it does not change VO2max. GE is an indicator that is expected to improve over the season, but further research is needed to explain the mechanisms responsible for the individual fluctuations of the GE value in athletes. Keywords: Cycling, performance, gross efficiency, oxygen uptake, lactate threshold, longitudinal changes 1. Introduction 1 Due to differences in racing times and different ex- 2 ercise intensities, cycling is associated with a num- 3 ber of physiological demands that the athlete’s body 4 * Corresponding author: Milosz Czuba, Department of Kinesi- ology, Institute of Sport, 01-982 Warsaw, Trylogii 2/16, Poland. E-mail: milosz.czuba@insp.waw.pl. is exposed to during competition. Adaptations to race 5 demands and achieving a high level of sports per- 6 formance occur following long-term training, which 7 should be oriented towards improving the physiolog- 8 ical indicators which have a decisive impact on cy- 9 cling performance. Previous literature revealed max- 10 imal oxygen uptake (VO 2max ), lactate threshold (LT) 11 and efficiency (the oxygen cost at a given power out- 12 put) are the key factors which interact to determine the 13 aerobic exercise performance [1–3]. 14 ISSN 0959-3020/19/$35.00 c  2019 – IOS Press and the authors. All rights reserved uncorrected proof version