No Change – No Gain; The Effect of Age, Sex, Selected Genes and Training on Physiological and Performance Adaptations in Cross-Country Skiing

Abstract

The aim was to investigate the effect of training, sex, age and selected genes on physiological and performance variables and adaptations before, and during 6 months of training in well-trained crosscountry skiers. National-level crosscountry skiers were recruited for a 6 months observational study (pre-post 1-post 2 test). All participants were tested in an outside double poling time trial (TT DP), maximal oxygen uptake in running (RUN-VO 2max), peak oxygen uptake in double poling (DP-VO 2peak), lactate threshold (LT) and oxygen cost of double poling (C DP), jump height and maximal strength (1RM) in half squat and pull-down. Blood samples were drawn to genetically screen the participants for the ACTN3 R577X, ACE I/D, PPARGC1A rs8192678, PPARG rs1801282, PPARA rs4253778, ACSL1 rs6552828, and IL6 rs1474347 polymorphisms. The skiers were instructed to train according to their own training programs and report all training in training diaries based on heart rate measures from May to October. 29 skiers completed all testing and registered their training sufficiently throughout the study period. At pre-test, significant sex and age differences were observed in TT DP (p < 0.01), DP-VO 2peak (p < 0.01), C DP (p < 0.05), MAS (p < 0.01), LT v (p < 0.01), 1RM half squat (p < 0.01), and 1RM pull-down (p < 0.01). For sex, there was also a significant difference in RUN-VO 2max (p < 0.01). No major differences were detected in physiological or performance variables based on genotypes. Total training volume ranged from 357.5 to 1056.8 min per week between participants, with a training intensity distribution of 90-5-5% in low-, moderate-and high-intensity training, respectively. Total training volume and ski-specific training increased significantly (p < 0.05) throughout the study period for the whole group, while the training intensity distribution was maintained. No physiological or performance variables improved during the 6 months of training for the whole group. No differences were observed in training progression or training adaptation between sexes

Responses to Maximal Strength Training in Different Age and Gender Groups

“…This may indicate that the Ser-encoding T allele might be favorable for muscle strength not only in power/strength athletes but also in the general population. Interestingly, when comparing the genotype frequencies for the rs8192678 between the present cohort and a highly trained Scandinavian cross-country athlete cohort ( Johansen et al, 2020 ), significant differences were found. Although in both cohorts the minor T allele frequency was comparable (∼39%), the TT genotype was underrepresented among the endurance athletes compared to the cohort investigated in the present study representing the general public (3% vs. 20%, respectively).…”

Effects of Individual Changes in Training Distribution on Maximal Aerobic Capacity in Well-Trained Cross-Country Skiers: A Follow-Up Study

“…Few studies have observed a significant improvement of aerobic capacity without considerable changes in training characteristics (i.e., training intensity distribution). A recent study by Johansen et al (2020) revealed no improvements in aerobic capacity in well-trained national-level crosscountry skiers within 6 months of season preparation (May to October). No to minor changes in training intensity distribution and time in different intensity zones were observed in that study.…”

“…Six national level cross-country skiers (three males and three females) participated in the present follow-up study, after previous participation in Johansen et al (2020). In the Johansen et al (2020) study, all included skiers were defined as well-trained cross-country skiers with VO 2max values ± 62 and ± 70 ml•kg −1…”

“…Maximal oxygen uptake (VO 2max ) is regarded as the most important single physiological factor for aerobic endurance performance in endurance sports, such as cross-country skiing ( Ingjer, 1991 ; di Prampero, 2003 ; Sandbakk and Holmberg, 2017 ). Accordingly, strong relationships have been established between improved VO 2max and improved performance level in cross-country skiers ( Ingjer, 1991 ; Mahood et al, 2001 ; Sandbakk et al, 2013 ; Johansen et al, 2020 , 2021 ). In addition, more successful skiers have displayed higher VO 2max values compared with less successful skiers ( Losnegard et al, 2013 ; Tønnessen et al, 2015 ; Sandbakk et al, 2016 ).…”

“…Cross-country skiers traditionally dedicate 80–90% of their endurance training at lower intensities (LIT), <82% of maximal heart rate (HR max ) ( Sandbakk and Holmberg, 2017 ). Therefore, less time have been spent in moderate- (MIT), 82–87% HR max , and high-intensity training (HIT), >87% HR max , throughout the preparation period ( Losnegard et al, 2013 ; Sandbakk et al, 2016 ; Johansen et al, 2020 ). HIT has been shown to be an efficient way to improve VO 2max in both healthy moderately trained individuals ( Helgerud et al, 2007 ; Støren et al, 2017 ) and highly trained endurance athletes ( Støren et al, 2012 ; Sandbakk et al, 2013 ; Rønnestad et al, 2014 , 2016 ).…”