The concentration levels of 11 perfluorinated carboxylic (PFCA) and eight sulfonic (PFSA) acids were determined in the serum of 13 professional ski waxers. The same components were also determined in workroom aerosols and in fluoro containing solid ski waxes and ski wax powders. The highest median concentration (50 ng/mL) was detected for perfluorooctanoic acid (PFOA), which is around 25 times higher than the background level. For the first time perfluorotetradecanoic acid (PFTeDA) has been found in human serum. Positive statistically significant associations between years exposed as ski waxer and seven different PFCAs were observed. The serum concentrations of the PFCAs with carbon chain lengths from C(8) to C(11) were reduced by around five to 20% on average during the eight month exposure free interval, whereas the reduction was substantially larger when the carbon chain lengths were smaller than C(8) or larger than C(11). This study links for the first time PFCAs in the ski waxers serum to exposure from the work room aerosols. Not only professional ski waxers but also the significant larger group of amateur skiers and waxers are potentially exposed to these compounds.

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